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Research Progress and Development Direction of Hydrofracturing Design Models ZHANG Shicheng, CHEN Ming, MA Xinfang, ZOU Yushi, GUO Tiankui Xinjiang Oil & Gas    2021, 17 (3): 67-73.   Abstract （429）      PDF （2607KB）（299）       Knowledge map    Save Hydrofracturing model is the basis of hydrofracturing design,and also the crux where current bottlenecking problems lie. In order to promote the development of fracturing design models and softwares in China,fracture propagation models,numerical methods and popular commercial softwares for hydrofracturing are systematically analyzed,and their future development orientations are predicted. Research findings show that (1) Planar and complex fracture models are different in application conditions and accuracy. Most commercial softwares are planar fracture models-based,and most complex fracture models are pseudo-three-dimensional ones. (2) It is the focus of fracturing design softwares to develop models with satisfactory accuracy and efficiency. (3) Artificial intelligence data-driven fracture analysis,and fracture parameter inversion based on micro-seismic and fiber optic logging are the development orientation of fracturing design models. Reference | Related Articles | Metrics

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The Application Status and Prospect of DTS/DAS in Fracturing Monitoring of Horizontal Wells#br# LI Haitao, LUO Hongwen, XIANG Yuxing, AN Shujie, LI Ying, JIANG Beibei, XIE Bin, XIN Ye Xinjiang Oil & Gas    2021, 17 (4): 62-73.   Abstract （402）      PDF （5344KB）（231）       Knowledge map    Save The fractured horizontal well technology has been widely used in unconventional reservoir development in China，but there are still many technical problems in monitoring the fracturing performance of horizontal wells. The distributed optical fiber monitoring technology has been found with rapid progress over recent years，and developed the distributed temperature/acoustic sensing（DTS/DAS）technology，which has been widely applied to the fracturing performance monitoring of unconventional oil and gas reservoirs in the United States，Canada et al.，with good application results. In this paper，the basic principles of distributed optical fiber temperature/acoustic sensing are described，and the latest applications and research progress of DTS/DAS in fracturing monitoring of horizontal wells are summarized，including fracturing fluid distribution monitoring and leakage diagnosis，artificial fracture initiation and extension monitoring，effectiveness analysis of fracturing-based well completion，and quantitative fracture parameter interpretation. Also，the current technical limitations of the DTS/DAS technology in fracturing monitoring of horizontal wells are pointed out，and the development orientation of the distributed optical fiber monitoring technology for horizontal wells is reviewed. This paper is of great significance for accelerating the application process of the distributed optical fiber monitoring technology and improving the technical level for fracturing monitoring and evaluation of horizontal wells in unconventional oil and gas reservoirs in China. Reference | Related Articles | Metrics

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Optimization of Well Shut-in Time after Fracturing in Jimusar Shale Oil Reservoirs ZHANG Yanjun , XU Shucan , LIU Yafei , WANG Xiaoping , GE Hongkui , ZHOU Desheng Xinjiang Oil & Gas    2023, 19 (1): 1-7.   DOI: 10.12388/j.issn.1673-2677.2023.01.001 Abstract （373）      PDF （3496KB）（104）       Knowledge map    Save Well shut-in after fracturing is of great importance for increasing the oil recovery and production of shale oil reservoirs. The key is to determine the shut-in time. At present，there is no systematic and effective method for determining the time of shut-in either in China or across the world. The pressure transmission of the fracture system，the ion diffusion of the produced fluid and the capillary force imbibition are the key problems to be solved for addressing the above challenges. With laboratory experiments and field analysis，a comprehensive determination method for the shut-in time for Jimsar shale oil reservoirs was developed by clarifying the microscopic pore characteristics，wettability，laminae，and imbibition flooding potential of Jimsar shale oil reservoirs and analyzing the existing methods used and characteristics of shut-in time determination. It is concluded that the Jimusar shale oil reservoir provides strong imbibition and diffusion ability，and well shut-in after fracturing contributes to the displacement of oil. The shut-in time can be determined comprehensively in accordance with the required equilibrium time of the wellhead pressure，imbibition，and production fluid salinity. To determine the post-fracturing shut-in time for Jimsar shale oil reservoirs，the synergy of micro-fracture fluid charging and matrix imbibition should be taken into consideration. Specifically，with the second turning point of wellhead pressure decline taken as the lower limit and the turning point for the stable rising of salinity as the upper limit，the optimal shut-in time is determined，considering the imbibition equilibrium. The shut-in time after fracturing for Well Q was optimized based on laboratory experiments and field data. The suggested shut-in time for Well Q is about 55 days. This study provides an important reference for optimizing the shut-in time after fracturing. Reference | Related Articles | Metrics

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Progress and Application of the Key Technologies of Deep and Ultra-Deep Well Cementing YU Yongjin, XIA Xiujian, WANG Zhiguo, LIAO Fuguo, LIU Binhui, DING Zhiwei, Xinjiang Oil & Gas    2023, 19 (2): 24-33.   DOI: 10.12388/j.issn.1673-2677.2023.02.003 Abstract （335）      PDF （1607KB）（107）       Knowledge map    Save Deep and ultra-deep reservoirs are strategic alternatives for increasing reserves and production of hydrocarbons. Recently，significant progress has been made in deep well cementing，especially for special cementing working fluid systems(such as high temperature-resistant cementing additives，cement slurry tolerant of high temperature and large temperature deferences and ultra-high temperature cement slurry)，high temperature-resistant spacer，cementing tools，and cementing technology such as precise managed-pressure cementing，gradual wellhead pressure-holding and prestressed cementing. The cement slurry and cementing technology developed independently in China have been applied to deep well cementing operations in Sichuan，Tarim and Bohai Bay and other basins，and present remarkable performance in the successful cementing operations of Well Pengshen 6，the deepest vertical well in Asia，and Well Hongxing 1，the first well in China featuring 8-section-and-8-completion，and Well Qiantan1，the well with the highest temperature in Dagang Oilfield. Nowadays，the increasing complexity of targets of hydrocarbon exploration and development leads to a series of new challenges for cementing deep and ultra-deep wells. Consequently，it is necessary to strengthen the research on the basic theory，key materials，working fluid system，functional tools and technologies for cementing deep and ultra-deep wells，so as to provide more powerful technical support for deep and ultra-deep oil and gas exploration and development. Reference | Related Articles | Metrics

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A Global Review of Technical Status and Development Trend of Drilling Fluids for Deep and Ultra-Deep Wells LIU Fengbao, SUN Jinsheng, WANG Jianhua Xinjiang Oil & Gas    2023, 19 (2): 34-39.   DOI: 10.12388/j.issn.1673-2677.2023.02.004 Abstract （331）      PDF （573KB）（123）       Knowledge map    Save Drilling fluid is the core technology of deep and ultra-deep drilling and completion，and is one of the key technologies determining the success of a drilling operation. In this paper，the difficulties facing drilling fluids of deep and ultra-deep wells were analyzed，including wellbore instability，failure of drilling fluids at high-temperature and high-salinity conditions，high friction and environmental protection. Moreover，the latest technical progress of water- and oil-based drilling fluids in both China and other countries was reviewed. It was concluded that there are still large technical gaps in temperature and salinity resistance of drilling fluids between domestic drilling fluid systems and foreign advanced technologies，and therefore，it is urgent to strengthen research and development  efforts in terms of failure mechanisms of drilling fluid agents，anti-ultra-high-temperature drilling fluid agents and supporting technologies for special formations. Reference | Related Articles | Metrics

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Research Progress on Capture of CO2 by Alcohol Amine Absorption Method YANG Tianmeng, YANG Fan, REZEY Rehemtuli, GOU Guolei, LI Xiuhui, HOU Junwei Xinjiang Oil & Gas    2024, 20 (1): 52-60.   DOI: 10.12388/j.issn.1673-2677.2024.01.007 Abstract （279）      PDF （3625KB）（314）       Knowledge map    Save CO2 capture，utilization，and storage are the main technologies to cope with the greenhouse climate，achieve the strategic goal of carbon peak and neutralization，lead the transformation and upgrading of the global energy system，and promote the green and sustainable development of energy. The chemical absorption methods have the characteristics of high absorption efficiency and large processing capacity，most suitable for large-scale carbon capture in various industries. Among them，the alcoho lamine method is the most widely used and the most effective. After absorbing CO2，the alcoholamine solution becomes an alcoholamine-rich solution，which can be recovered by desorption treatment for cyclic utilization. However，in the process of CO2 capture by the existing alkanolamine absorbent，there are some disadvantages such as high energy consumption and great loss of absorbent，and it is necessary to improve the alcoholamine absorber to realize high absorption efficiency and a feasible process with low regeneration energy consumption. To solve the problems of large loss of absorbent and low regeneration rate，a new mixed alcoholamine absorber was developed for improvement. For the problem of high energy consumption for regeneration，the traditional thermal desorption process is improved and microwave desorption technology is selected. This paper introduces the mechanism and characteristics of CO2 absorption by alcoho lamine method，summarizes the basis for improving the mixed alcoholamine absorber，and expounds on the principle and characteristics of CO2 capture through microwave-assisted alcoholamine，providing a reference for industrial carbon capture and environmental protection. Reference | Related Articles | Metrics

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Research and Practice of Horizontal Wellbore Cleaning Technology LI Zhenchuan , YAO Changshun , HU Kaili , LAN Zuquan Xinjiang Oil & Gas    2022, 18 (1): 48-53.   DOI: 10.12388/j.issn.1673-2677.2022.01.008 Abstract （252）      PDF （4876KB）（57）       Knowledge map    Save In recent years， the large-scale development of unconventional oil and gas resources in China has led to a sharp increase in the number of horizontal wells. Due to the lack of scientific and systematic understanding on horizontal well bore cleaning， drilling process in horizontal section often appears stuck， completion ahead of schedule， disability of running casing to the predetermined well depth. In addition， poor wellbore cleaning can also cause very high implicit costs， including ROP controlling， increasing time consumption of reaming， circulation， and tripping. In this paper， by clarifying the mechanism of cutting migration in different sections of horizontal wells， analyzing the key elements of wellbore cleaning and proposing a method to evaluate wellbore cleaning by monitoring actual drilling friction， a set of efficient horizontal wellbore cleaning technology has been formed. Field practice in Mahu and Jimsar shale oil has verified the technical theory based on field data， which can guarantee the cleanness of horizontal section under the conditions of existing domestic equipments and instruments， and greatly ruduce inefficient production time consumption such as mud circulation and wiper tripping to increase speed and efficiency. Reference | Related Articles | Metrics

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Experimental on Distributed Photovoltaic Power Plant of Oil Production Platform ZHOU Kai, WANG Yang, CHEN Xiangyu, DUAN Shengnan, JIAN Ling, DAI Liya Xinjiang Oil & Gas    2022, 18 (2): 1-9.   DOI: 10.12388/j.issn.1673-2677.2022.02.001 Abstract （229）      PDF （2779KB）（101）       Knowledge map    Save At present，there are 3 types of oil production well sites in Xinjiang Oilfield，which are platform well，single well and cluster well sites. Pumping units and rodless pumps are main energy-consuming equipment，and electric heaters also consume some power. It has become the current trend to replace traditional energy sources with solar energy，because it is clean，harmless，and basically con- sumes no energy. Nevertheless，solar energy also has the disadvantages of poor continuity and stability，low energy density，high cost， large footprint and the necessity for outdoor installation. A distributed solar photovoltaic power generation test and modification was conducted on the oil production platform XY6 in Jimsar of Xinjiang Oilfield. The designed installed capacity is 8 kW. The in-situ gen- erated power is supplied to the power-consuming equipment located at the well site for self use，with the surplus power connected to the grid. In case of power shortage，power will be supplied from the grid. The layout of photovoltaic modules was decided after the optimum dip angle was calculated by designing the modules in series and parallel. In addition，an analysis was conducted by comparing with the data simulated by Pvsyst 7.2 to provide a detailed reference for the overall photovoltaic layout of the platform. By the end of the first quarter of 2022，about 3，000 kW·h power had been generated，and about 20，000 tons of carbon dioxide emissions had been reduced. Reference | Related Articles | Metrics

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Application of Air-Foam Drilling in Well Chaitan1 SUN Lanjiang , ZHANG Shuxia , LI Baoqing , XING Chao , LIU Wan , ZHONG Ninglong Xinjiang Oil & Gas    2022, 18 (4): 1-6.   DOI: 10.12388/j.issn.1673-2677.2022.04.001 Abstract （219）      PDF （699KB）（63）       Knowledge map    Save In many areas of Qaidam Basin，such as Yingxiongling，Ganchaigou and Xiandong，the shallow strata have poor lithology， loose cementation，fracture development，and frequently-occurred loss-return leakage in the process of drilling，which have seriously restricted the speed of drilling and affected the safety of drilling. This is a regional problem that needs to be solved urgently. Well Chaitan1 is a risk exploratory well located in Xiandong area. Conventional drilling fluid was used for the drilling of the surface section hole with a diameter of 660.4 mm. Leakage during the drilling was huge，and the plugging effect was not satisfactory. Therefore，it no longer possessed conditions to continue with the drilling. By using air-foam drilling technique and selecting the most suitable foaming agent and inhibitor for this well，the problem of frequently-occurred loss-return leakage in shallow strata has been solved，and the drilling cycle has been greatly shortened. By using the technique of sand cleaning-casing running，safe casing running has been realized in the well section with instable borehole and irregular hole diameters. The successful application of air-foam drilling technique in the Φ660.4 mm hole of Well Chaitan1 provides an approach and technical reserve for solving the problems of low pressure and likelihood for leakage and collapse in shallow strata during drilling in Qaidam Basin. Reference | Related Articles | Metrics

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New Energy Power System of PetroChina ZHANG Yanju, SHI Bingbo, ZHAO Jiaoyan, ZHANG Jiankang Xinjiang Oil & Gas    2022, 18 (2): 21-25.   DOI: 10.12388/j.issn.1673-2677.2022.02.004 Abstract （210）      PDF （483KB）（74）       Knowledge map    Save PetroChina Exploration and Development Research Institute has designed and implemented a new energy power system for PetroChina by reviewing and investigating in details the current business on new energy power based on the development status and trend of new energy projects in oil and gas fields in recent years. This system adopts a framework based on data middle platform，inte- grates big data，artificial intelligence technology and diversified data analysis algorithms，and establishes different data analysis models according to business scenarios for data analysis and governance，so as to realize intelligent data analysis. A data model based on the bottom layer of cloud platform has been constructed. Business intelligence（BI）report display tool has been used to realize the visual- ized analysis of new energy power data. On the basis of data lake architecture and BI report display，the new energy power system of PetroChina has been designed，developed and implemented. Through the construction of this system，PetroChina's demand for applying IT technology to its new energy power is met，the ideas and methods for new energy power development and data analysis are enriched， and the efficiency of data acquisition and use is improved，which provides a basis for the production management and decision-making analysis of new energy power in a better way. Reference | Related Articles | Metrics

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Research Progress and Application of Chemical Plugging Materials and Method for Carbon Dioxide Flooding ZHU Daoyi, SHI Chenyang, ZHAO Yanlong, CHEN Shengen, ZENG Meiting Xinjiang Oil & Gas    2023, 19 (1): 65-72.   DOI: 10.12388/j.issn.1673-2677.2023.01.010 Abstract （206）      PDF （1379KB）（88）       Knowledge map    Save Carbon Capture，Utilization and Storage （CCUS） technology is an important tool for the energy sector to enable efficient oil and gas production under the dual-carbon goal. Injecting CO2 into oil reservoirs can significantly enhance oil recovery. However，its mobility differs greatly from that of the crude oil，and there’s clear differentiation with oil and water，which results in a limited sweep efficiency of CO2. Therefore，it is urgent to develop efficient CO2 plugging materials and corresponding plugging control technologies to improve reservoir recovery and CO2 storage efficiency. This article explains the characteristics of plugging in the CO2 flooding process and gives an overview of the commonly used CO2 plugging materials and methods. It also describes their applications in oil fields across the world，and their potential for improving CO2 recovery and storage in Xinjiang Oilfield. This study is inspiring for the global research and development of plugging materials in the process of CO2 flooding in oilfields worldwide，and highlights the future direction of CO2 plugging technology in Xinjiang oilfields. Reference | Related Articles | Metrics

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Design of One-Trip PDM for the Ultra-Shallow Horizontal Well in Block Chepaizi and Its Application DONG Zhihui, YANG Zening Xinjiang Oil & Gas    2022, 18 (4): 33-37.   DOI: 10.12388/j.issn.1673-2677.2022.04.006 Abstract （203）      PDF （665KB）（26）       Knowledge map    Save Because the ultra-shallow horizontal well in Block Chepaizi of Xinjiang has shallowly-buried target layer, poor diagenesis, large difference in drillability, and very low and unstable angle-building rate, large-degree progressive displacement motor (PDM) is needed to control the trajectory of the angle-building section. A large-degree PDM has large torque during compound drilling, and is very likely to have screw failure, which is not conducive to safe drilling. For the drilling of horizontal section, it is necessary to trip out and replace the large-degree PDM with a small-degree one. A large-degree PDM can neither achieve trajectory control for the secondspud vertical section, the deviated section and the horizontal section in one trip nor satisfy the demand for safe drilling. The analysis shows the one-trip drilling technique for the ultra-shallow horizontal well in Block Chepaizi requires that the PDM should not only have a high angle-building rate, but also be able to reduce the torsional force produced by compound drilling, so as to prevent the screw from twisting off or breaking off. Based on this, short-bend point PDM that meets the requirements is optimized and designed, which has the distance from the bend point of a conventional one to the bottom of bit adjusted to 1.3 m from 1.8 m. After such adjustment, anglebuilding ability of the screw is basically unchanged, but the screw offset value is reduced from 0.056 m to 0.038 m, which further reduces the torsional force acting on the PDM enclosure under compound drilling conditions from 3.7 kN·m to 1.5 kN·m. The newly-designed PDM can effectively control the trajectory by way of slide drilling combined with compound drilling, and complete the directional drilling operation of the ultra-shallow horizontal well in Block Chepaizi in one trip. Reference | Related Articles | Metrics

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Design Optimization of Downhole Throttling for Gas Wells in Xinjiang Oilfield and Its Application  DU Junjun , CHI Ming , Xieraili·MAIMAITI , WANG Gang , WANG Wenwen , LIANG Haibo Xinjiang Oil & Gas    2022, 18 (4): 84-88.   DOI: 10.12388/j.issn.1673-2677.2022.04.015 Abstract （201）      PDF （751KB）（72）       Knowledge map    Save In order to meet the requirements of gathering and transportation pressure，and prevent wellhead hydrate freeze bloking，design optimization has been made for the downhole throttling process of high-pressure and medium/low-pressure gathering and transportation regarding well selection conditions，gas nozzle diameter，setting depth，and other key technical parameters based on the technological principle of downhole throttling，and wellbore temperature and pressure profiles have been simulated. The results show that the downhole throttling process can meet the pressure requirements of high-pressure and medium/low-pressure gathering and transportation，and effectively solve the problem of wellhead hydrate freeze bloking.  Reference | Related Articles | Metrics

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CO2Separate Injection and Matching Testing and Adjustment Technologies in Low-Permeability Reservoirs#br# LI Haicheng, , LIU Yun, , ZHAO Lichuan, , ZHU Zhenkun, , MA Junzhe, , HAN Yu, Xinjiang Oil & Gas    2022, 18 (2): 26-32.   DOI: 10.12388/j.issn.1673-2677.2022.02.005 Abstract （200）      PDF （4358KB）（52）       Knowledge map    Save Regarding the problems encountered during general CO2  injection for low-permeability reservoirs，such as water excessive advancement along a single layer，uneven gas absorption and failure to produce some reserves，CO2  separate injection and matching testing and adjustment technologies are developed. With a corrosion-resistant rubber selected，the packer has a temperature resistance  of 120 ℃ ，and a pressure resistance of 35 MPa. A single-pipe multi-layer technology is developed for CO2 injection. Multi-stage streaming nozzles are also developed. With a throttling differential pressure greater than 5 MPa，the nozzles can meet the demand for multi-layer separate injection in the field. By studying the characteristics of multi-stage streaming nozzles under working conditions， charts are plotted to guide field testing. In addition，matching CO2  sealing detection and separate-layer flow testing technologies are de- veloped to achieve separate-layer adjustment. With this technology and its matching technologies，inter-layer problems can be mitigat- ed，gas channeling can be postponed，and the production degree of thin and poor reservoirs can be improved. Reference | Related Articles | Metrics

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Study on Plugging Technology of Shizigou - Yingzhong Structural Belt in Qinghai Oilfield LIU Fenghe , Liu Dezhi, Qiao Shijun , Xing Xing, Lei Biao, Bai Yang Xinjiang Oil & Gas    2021, 17 (4): 1-7.   Abstract （199）      PDF （2795KB）（84）       Knowledge map    Save Targeting the technical difficulties of well leakage in drilling Shizigou - Yingzhong structural belt of Qinghai Oilfield，geological analysis，operation difficulty summarization and study on plugging measurements are carried out. Taking well SX58 in Shizigou- Yingzhong structural belt as an example，it is found that the low pressure fracture leakage in deep E 3 2 formation is the main factor of well leakage. Based on E 3 2 formation logging data and drilling feedback，combined with 3D printing technology，a simulated fracture model has been designed and developed，and its plugging experiment evaluation method is established. Through laboratory experiments，the plugging material and plugging slurry formula are optimized，which can provide reference and guidance for the follow-up optimal and fast drilling in Qinghai Oilfield. Reference | Related Articles | Metrics

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Strategy for Building a Digital Management System of Carbon Assets in Group Enterprises LU Jun Xinjiang Oil & Gas    2022, 18 (2): 10-15.   DOI: 10.12388/j.issn.1673-2677.2022.02.002 Abstract （198）      PDF （3472KB）（34）       Knowledge map    Save Targeting the pains currently troubling traditional management mode of carbon assets towards carbon peaking and carbonneutrality goals，a strategy for building a digital management system of carbon assets is put forwards，so as to realize the life-cycle management and whole-process management by using digital technology. A strategy for building a digital management system of carbon assets in group enterprises characterized by "three modules，four levels and eight functions" is proposed by analyzing the current situation of domestic carbon assets management mode，using such digital technologies as IoT，AI，big data and 5G，integrating with information physical system，and following the ways of strategic positioning，organization and personnel，process design，rules and regulations，digital means and operation supervision. Compared with traditional carbon assets management mode，this system remarkably features information sharing，which is conducive to breaking through the internal and external information barriers of enterprises，forming a connected effect of business flow，carbon flow and assets flow，improving the efficiency of carbon assets management，driving the low-carbon transformation and development of enterprises' relevant businesses，improving enterprises' low-carbon competitiveness，and promoting the development of carbon assets management business and the activation of carbon trading market in China. Reference | Related Articles | Metrics

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The Integrated Development Practices of Oil，Gas and New Energy in Tarim Oilfield Com⁃pany toward Carbon Peaking and Carbon Neutrality Goals#br# ZHANG Chenyang, WANG Fuhuan, WEI Hua, ZHANG Dapeng, MIAO Changsheng, PI Qiumei, LUO Risheng, GU Qiaoyuan Xinjiang Oil & Gas    2022, 18 (2): 16-20.   DOI: 10.12388/j.issn.1673-2677.2022.02.003 Abstract （196）      PDF （544KB）（52）       Knowledge map    Save The setting out of carbon peaking and carbon neutrality goals has defined a direction for China's green and low-carbon de- velopment，and will accelerate the development of new energy business into a fast track. As a traditional oil and gas enterprise，how to realize the holistic and balanced development of oil，gas and new energy business based on its own resource advantages，its practice path will provide an important reference for the development and transition of other oil and gas enterprises. PetroChina Tarim Oilfield Company has put forward a series of measures for the integrated development of oil，gas and new energy，and completed the preparation of the New Energy Development Plan of PetroChina Tarim Oilfield in the 14th Five-Year Plan period. By launching the accelerated de- velopment project of natural gas and the comprehensive utilization project of natural gas in Southwest Tarim，constructing a low-carbon demonstration zone of the highway crossing Tazhong Desert and a zero-carbon demonstration zone of Lunnan Oilfield，and executing a carbon capture，utilization and storage enhanced oil recovery（CCUS-EOR）project of clastic brown oilfield，an integrated develop- ment pattern of traditional energy industry and new energy has taken shape. These practices show that only when the traditional oil and gas industry has been clearly oriented，and the industry's advantages and resource characteristics have been identified，can a new way for the industry's transition and integrated development be found out，and the measures to fulfill the carbon peaking and carbon neutral- ity goals be worked out. Reference | Related Articles | Metrics

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Geothermal-Insulating Production Technology for Ultra-Deep and Ultra-Heavy Oil in Tahe Oilfield#br# LIU Lei, , FAN Weidong, , CHEN Hongju, , LIU Yuguo, , LI Jinghui, Xinjiang Oil & Gas    2022, 18 (2): 92-97.   DOI: 10.12388/j.issn.1673-2677.2022.02.014 Abstract （193）      PDF （1048KB）（39）       Knowledge map    Save Featuring a burial depth greater than 6，000 m and a viscosity greater than 100×104 mPa·s，the ultral-heavy oil in Tahe oilfield is very difficult to produce，and remains as a world-class problem since it cannot be produced normally by conventional production technology. Taking advantage of the extremely strong temperature sensitivity of Tahe ultral-heavy oil，and with the conditions of the ultra-deep and ultra-heavy oil wells in Tahe oilfield fully taken into account，a high-efficiency thermal-insulating nanomaterial is selected as coating material. A material with heat-proof physical properties is produced by synthesizing a polymer compound with special functional groups by technical means，which is then subjected to foam stabilizing and inerting treatment. A new and efficient thermal barrier system is constructed microscopically to effectively block the different performances of heat in an all-round way，and achieve the effect of producing ultra-deep and ultra-heavy oil by using geothermal resources. A pilot test on 2 wells has been completed. Under the conditions of using the formation heat only without any supplement of external heat，the maximum increase in wellhead temperature of a single well is 20 °C. Due to its environmental friendliness，high efficiency and energy conservation，this technology has a promising application prospect in the super-heavy oil blocks of Tahe Oilfield. Reference | Related Articles | Metrics

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A Method for Determining Effective Injection-Production Well Spacing for Low-Permeability Reservoirs and the Application LING Haochuan, WU Zheng, WANG Jijun, SUN Qiang, GENG Hongliu Xinjiang Oil & Gas    2023, 19 (1): 23-26.   DOI: 10.12388/j.issn.1673-2677.2023.01.004 Abstract （193）      PDF （514KB）（35）       Knowledge map    Save To make full use of the actual oilfield production test data to determine the effective injection-production well spacing for low-permeability reservoirs，the parametric equation of mobility function with the oil productivity index and the starting pressure was obtained by considering the low-permeability starting pressure gradient. The equation and the production test data can be used to get the mobility and drainage radius of the tested reservoir intervals. The regression analysis found that there is a semi-logarithmic relationship between the effective injection-production well spacing of low-permeability reservoirs and the physical property. Based on the relationship curve，the effective well spacing for directional well pattern development for low-permeability reservoirs can be determined. The application shows that the worse the reservoir properties，the smaller the effective well spacing；the effective well spacing of low-permeability reservoirs is 2 times the drainage radius，which means the valid producing coefficient has to reach 78.5% to ensure high efficiency between the producers and injectors. Using this method，the effective well spacing map of Bohai B Oilfield at different mobility was obtained. It’s suggested that the well spacing should be set between 300 m and 450 m at physical property range of 5 mD  to 20 mD. Reference | Related Articles | Metrics

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Study and Test of Individualized Bit for the Horizontal Sections of Glutenite in Xinjiang Oilfield WANG Xindong, WU Zhi, YAO Changshun, LI Yingxin, ZHANG Wutao, XIE Zhengsen Xinjiang Oil & Gas    2022, 18 (1): 54-58.   DOI: 10.12388/j.issn.1673-2677.2022.01.009 Abstract （192）      PDF （4642KB）（27）       Knowledge map    Save Mahu tight conglomerate oil field in Junggar Basin is a key area for Xinjiang oilfield to increase production. In the horizontal sections of glutenite in Aihu well area of Xinjiang Oilfield with strong heterogeneity and poor drillability， a drill bit has only a short footage and a high decommissioning rate， giving rise to long-time drilling. In view of the long drilling period there， formation lithology， drill bit usage and drilling parameters of the drilled wells were analyzed and studied， and a new type of individualized PDC bit was designed and developed. Packaged with optimized drilling parameters and drill string assembly， a technical scheme based on the new bit to improve the drilling speed was formulated. After the application of this new bit to the drilling in glutenite horizontal sections， mechanical penetration rate increased by 137.46% and footage increased by 32.7~153.3%， compared with the average parameters per bit in this block. Field application shows that the new individualized PDC bit specially designed is highly targeted， and the packaged technical scheme to increase drilling speed is reasonable. With this scheme， mechanical penetration rate and footage for one run of bit were significantly improved， and drilling period and cost were reduced， laying a sound foundation for the development and application of individualized bits similar to this application. Reference | Related Articles | Metrics

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Formation Mechanism of Hydrogen Sulfide in Thermal Recovery Wells of Bohai Offshore Heavy Oilfield XIAO Sa, LIU Yaqiong, CAI Jun, SUN Yubao, WANG Shaohua, CAI Yina Xinjiang Oil & Gas    2022, 18 (4): 38-43.   DOI: 10.12388/j.issn.1673-2677.2022.04.007 Abstract （191）      PDF （701KB）（29）       Knowledge map    Save Formation of H2S will bring great potential hazard to the safety of personnel and equipment in offshore oil fields. In order to determine the source of H2S in offshore heavy oil thermal recovery wells，the formation mechanism of H2S during thermal recovery development was investigated by conducting experiments. Simulated experimental study on the formation of H2S at different temperatures was carried out for the three reactions systems of heavy oil，heavy oil + distilled water，and heavy oil + water + core + methane. Besides， experiment was also conducted on the formation of H2S at high temperatures for sulfonate surfactant. The results show that for the heavy oil of Bohai S Oilfield，the concentration of H2S produced by the cracking and aquathermolysis of heavy oil increases with the increase in reaction temperature，and the organic gas produced is mostly the gas of light hydrocarbons below C5，with a small amount of C6+ gas. The aquathermolysis of heavy oil has caused the change in heavy oil composition. The contents of resin and asphaltene in heavy oil decrease，while the contents of saturated and aromatic components increase. This phenomenon becomes more obvious with the increase in reaction temperature. For the mixed system under study，at 200 ~ 300 ℃，aquathermolysis and TSR are dominant，which are the main sources of H2S；when the temperature reaches 350 ℃，cracking and TSR become dominant. At the same time，it is also found that it is very easy for sulfonate surfactant to produce H2S at high temperatures due to its instability at high temperatures. It is recommended that the use of sulfonate surfactant in the presence of steam be minimized in thermal recovery.  Reference | Related Articles | Metrics

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Current Status and Suggestions for Drilling Technology of CNPC Continental Shale Oil Reservoirs Xinjiang Oil & Gas    2024, 20 (3): 1-14.   DOI: 10.12388/j.issn.1673-2677.2024.03.001 Abstract （191）      PDF （2045KB）（79）       Knowledge map    Save Shale oil with medium to high maturity is the key field for China's shale oil strategic breakthrough，and strengthening the exploration and development of continental shale oil is an important way to ensure the security of national energy supply. The technical progress of shale oil drilling in Ordos，Junggar and Songliao Basins by China National Petroleum Corporation （CNPC） was introduced in detail，including large platform factory-like well placement，horizontal well casing program optimization，"one-run drilling" in separate well sections，high-performance drilling fluids for horizontal wells，integrated geological steering and other key technologies. By benchmarking against advanced shale oil drilling technologies in North America，the gap and development trend of shale oil drilling in China were analyzed in terms of well placement and wellbore configuration，geological-engineering integration and steering technology，supporting technology for accelerating rates of penetration （ROP），drilling fluid and cementing supporting technology. Development suggestions，such as continuously promoting large platform factory-like operations，optimizing wellbore configurations，integrating ROP acceleration technologies，strengthening research on geological-engineering integration，and accelerating the research and development of new-generation steering tools，were proposed in order to achieve the goals of ROP acceleration，cost reduction，and efficiency improvement in continental shale oil drilling，and moreover，the engineering goals of the shale oil revolution. Reference | Related Articles | Metrics

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Perforation Adjustment Modes of Oil & Water Wells for Water Flooding in Thick Reservoirs  TIAN Hongzhao Xinjiang Oil & Gas    2022, 18 (4): 52-55.   DOI: 10.12388/j.issn.1673-2677.2022.04.009 Abstract （188）      PDF （736KB）（13）       Knowledge map    Save Targeted at the problems of uneven vertical water flooding and gradual deterioration of development effect in the reservoirs of block B in G Oilfield with thick oil layers during water flooding，and combined with the actual geological parameters，a waterflood mechanism model for thick reservoirs is established. The influence of different perforation adjustment modes and adjustment timing of oil and water wells on the effect of water flooding is simulated and analyzed，and the optimal mode for next step of adjustment is given. Study results show that all oil and water wells should be perforated for production in the waterflood process of reservoirs，and high water-cut layers should be sealed off in time so that production can return to upward layers one by one after oil wells have water breakthrough. The effect of oil-water gravity differentiation should be fully utilized，which not only prevents the rapid formation of preferential channels after oil wells are waterflooded，but also reduces water cut. In addition，large production thickness of oil wells is beneficial to maintain higher oil production rate and better economic benefits，which is worth being applied and popularized.  Reference | Related Articles | Metrics

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Summary for Machine Learning Algorithms and Their Applications in Drilling Engineering LI Hongbo, LUO Pingya, BAI Yang, LI Daoxiong, CHANG Shuang, LIU Xinguo Xinjiang Oil & Gas    2022, 18 (1): 1-13.   DOI: 10.12388/j.issn.1673-2677.2022.01.001 Abstract （188）      PDF （1853KB）（63）       Knowledge map    Save In this era of Internet and Big Data，the application of machine learning，which is the core of artificial intelligence，in drilling engineering represents a general future development orientation. Drilling engineering is an essential part of hydrocarbon exploration and development technology. Machine learning-based drilling parameter optimization and accident prediction and warning are vital for economy，safety，efficiency，and environmental-friendliness. Given that it is hard to effectively guide the drilling operation for deep and ultra-deep wells using the previous experience and data，this research summarizes the present algorithms used in machine learning first，and gives a preliminary analysis for the benefits of machine learning in drilling engineering consequently. A review of global studies on applications of machine learning in drilling engineering is presented and the challenges are identified. Some suggestions are proposed，in an attempt to promote contributions of machine learning in the development of drilling engineering of China. Reference | Related Articles | Metrics

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Xinjiang Oil & Gas    2020, 16 (3): 94-97.   Abstract （188）      PDF （2356KB）（6）       Knowledge map    Save Related Articles | Metrics

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Status and Prospect of Technologies to Reduce Cost and Increase Efficiency for Drilling in Bohai Oilfield WANG Zan, WANG Xiaoqi, CHEN Liqiang, WU Zhanmin, SUN Lei Xinjiang Oil & Gas    2022, 18 (1): 66-72.   DOI: 10.12388/j.issn.1673-2677.2022.01.011 Abstract （187）      PDF （1719KB）（32）       Knowledge map    Save Bohai Oilfield is an important support for increasing offshore oil and gas reserves and production in China. In view of the complex geological conditions， the coexistence of multiple pressure systems， poor wellbore stability， highly risky drilling operation， and the great difficulty in comprehensively improving inefficient wells in Bohai Oilfield， an analysis and study of the system of innovative technologies to improve drilling speed and efficiency are conducted with safe drilling operation as the criterion. These technologies have been applied successfully in field， which include the wellbore stability study-based extreme extending techology for ERW， the technology of twin holes in monobore to use the slot more efficiently， the well structure optimization technology to minimize casing stages and sizes， the dynamic comprehensive analysis and optimization technology for coated tubulars， and the decision-tree model-based refined sidetracking technology. The future development trend of reducing cost and increasing efficiency for drilling in Bohai Oilfield is also looked into in order to provide technical reference for the efficient development of Bohai Oilfield.  Reference | Related Articles | Metrics

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Advances in Study on Temperature-Resistant and Salt-Tolerant Fluid Loss Reducers for Water-Based Drilling Fluids YUAN Yuehui, QU Yuanzhi, GAO Shifeng, RONG Kesheng, YE Cheng, LIU Kecheng Xinjiang Oil & Gas    2023, 19 (2): 62-68.   DOI: 10.12388/j.issn.1673-2677.2023.02.008 Abstract （179）      PDF （597KB）（47）       Knowledge map    Save The high-temperature and high-salinity environment in deep well drilling can lead to failure of drilling fluid performance，causing well collapse，lost circulation and other accidents，resulting in reduction of drilling safety and efficiency. As one of the most important additives in the drilling fluid system，the fluid loss reducer can reduce filtration through gel protection，viscosity increase and plugging，minimize damage to the formation and maintain the stability of the wellbore. With the continuous increase of deep and ultra deep well operations in China，more and more high-temperature and high-pressure formations，salt gypsum formations and other harsh formations have been encountered during drilling. The research and development of temperature-resistant and salt-tolerant fluid loss reducers has become the key to addressing the challenges in enhancing the drilling fluid technology for high-temperature and complex wells. Three types of water-based drilling fluid loss reducer were described in this paper，including the fluid loss reducers made of natural polymers and modified materials，synthetic polymers and inorganic/organic composites. It summarizes the recent research results of temperature-resistant and salt-tolerant fluid loss reducers for water-based drilling fluids in terms of raw material composition，synthesis（modification） method and product performance，discusses the future development direction of temperature-resistant and salt-tolerant fluid loss reducers for water-based drilling fluids in China，and provides theoretical guidance for the development and application of temperature-resistant and salt-tolerant fluid loss reducers.  Reference | Related Articles | Metrics

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Development of Viscosity Reducer for High Density Water-Based Drilling Fluid and Its Application#br# DENG Zhengqiang , OU Meng , BAI Hailong , JING Yujuan , HUANG Ping , SHAO Ping Xinjiang Oil & Gas    2023, 19 (3): 33-37.   DOI: 10.12388/j.issn.1673-2677.2023.03.005 Abstract （177）      PDF （548KB）（55）       Knowledge map    Save One of the main reasons for rheology out-of-control of high density water-based drilling fluid is the increase of inferior solid phase content. Inferior solid phase is dispersed in high density water-based drilling fluid，which enhances the system architecture，resulting in increased drilling fluid viscosity and higher shearing force. Based on the principle of viscosity reduction by competitive adsorption，WNTHIN，a low molecular weight polymer viscosity reducer was synthesized with 2-acrylamide-2-methylpropanesulfonic acid，styrene，maleic anhydride，N and N-dimethylacrylamide in a molar ratio of 1∶2∶1∶1.Test results of the viscosity reducer show that WNTHIN can significantly reduce the viscosity and shearing force of high density potassium polysulfonate water-based drilling fluid with a density of 2.40 g/cm3，with plastic viscosity reduced by 42.85%，static shearing force reduced by 51.35%，and the recommended WNTHIN dosage addition is 1.5%. The field application of WNTHIN in a well in Penglai Gas Field showed improved rheology of high density potassium polysulfonate water-based drilling fluid. The plastic viscosity dropped from 58 mPa·s to 30 mPa·s，the yield point dropped from 29 Pa to 14 Pa，and the 10 min static shearing force dropped from 28 Pa to 16 Pa. The performance of the high density water-based drilling fluid has been improved to meet the technical requirements for safe drilling in deep wells.  Reference | Related Articles | Metrics

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Exploration and Practice of Digital Transformation of Energy Conservation Management in Oil and Gas Field Enterprises#br# DONG Xingtao , LI Ping , ZHU Yusong , WEI Xumeng Xinjiang Oil & Gas    2022, 18 (2): 40-45.   DOI: 10.12388/j.issn.1673-2677.2022.02.007 Abstract （174）      PDF （581KB）（30）       Knowledge map    Save To ensure the realization of carbon peaking and carbon neutrality goals，energy conservation is the most cost-effective means. Oilfield enterprises are characterized by scattered production facilities，long process flow and extensive coverage of oil areas. The challenges they face in energy conservation management are reflected in the following aspects：the energy consumption measure- ment boundary is unclear，leading to the difficulty in identifying the subject to assume responsibilities；the monthly energy statistics is reported manually level by level，resulting in relatively lagged control of energy consumption；energy efficiency is evaluated by the sam- pling tests of testing agencies，which fails to achieve a whole coverage；energy-conservative measures are judged by individual experi- ence，lacking timeliness and effect tracking. With the development of the internet of things in oilfield enterprises，the automatic percep- tion ability of the production site and the information processing ability of the data background are enhanced continually. It has become a new proposition to improve energy efficiency，reduce energy consumption and realize fine and efficient energy conservation in the whole process of production. This paper summarizes the innovative practice of applying information technology to carry out energy- conservative business in domestic petroleum industry，and puts forward the practical path for implementing the digital transformation of energy conservation management in oilfield enterprises. Reference | Related Articles | Metrics

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Intelligent Prediction for Rate of Penetration Based on Support Vector Machine Regression SONG Xianzhi, PEI Zhijun, WANG Pantao, ZHANG Gonglingyan, YE Shanlin Xinjiang Oil & Gas    2022, 18 (1): 14-20.   DOI: 10.12388/j.issn.1673-2677.2022.01.002 Abstract （174）      PDF （1192KB）（62）       Knowledge map    Save Tarim Basin is rich in deep oil and gas resources. With the increase in well depth，however，formation drillability decreases and abrasiveness increases，resulting in low rate of penetration (ROP) and high drilling cost. Therefore，there is an urgent need for drilling optimization technology. ROP prediction is a key technology to optimize drilling. Accurate ROP prediction provides important basis for drilling parameter optimization and drilling tool selection. This study establishes several intelligent prediction models based on decision tree regression algorithm，random forest regression algorithm，support vector machine (SVM) regression algorithm and deep neural network respectively，by using the mud logging data acquired in real time from the drilling field，which are then compared and analyzed in aspect of root-mean-square error，R square，maximum error and relative error，so as to select the optimum prediction model for ROP prediction. The results show that SVM prediction model is superior to other models regarding prediction accuracy and stability. Key words:rate of penetration；machine learning；support vector machine；neural network Reference | Related Articles | Metrics

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Research and Application Progress of Nanofluid for Enhanced Oil Recovery LIANG Tuo, YANG Changhua, ZHANG Yanjun, LI Pan, QU Ming, HOU Jirui Xinjiang Oil & Gas    2023, 19 (4): 29-41.   DOI: 10.12388/j.issn.1673-2677.2023.04.004 Abstract （172）      PDF （5519KB）（168）       Knowledge map    Save In view of the limitations of traditional polymer and surfactant solutions in enhancing oil recovery，such as low viscosity retention and large adsorption loss，this paper examines the potential use of nanofluids for enhanced oil recovery and discusses recent research in this field. First，the synthesis of nanomaterials is described，and the methods used for evaluation of the stability of nanofluids in enhanced oil recovery in the field are summarized. Second，six mechanisms by which nanofluids enhance oil recovery are reviewed. These are：reducing interfacial tension，changing wettability，reducing crude viscosity，improving foam stability，structural disjoining pressure，and reducing pressure and increasing injection. Third，the use of nanofluids for enhanced oil recovery in the field is investigated. The “bottleneck” issues that limit the large-scale application of nanofluids in oilfields are also described. For example，there are currently no nanofluid flooding systems available for efficient development of unconventional reservoirs. Furthermore，there has been insufficient theoretical and technical discussion and research. More integrated research is required on inter-related matters such as the development of nanofluids containing two-dimensional nanosheets，determination of the mechanisms for enhanced oil recovery，and field pilot testing of the process. Finally，a direction for the practical introduction and application of nanofluids is proposed. Reference | Related Articles | Metrics

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Research Status and Development Proposal of ROP Improvement Technology with Percussion Rock-Breaking Method LI Gensheng, MU Zongjie, TIAN Shouceng, HUANG Zhongwei, SUN Zhaowei Xinjiang Oil & Gas    2024, 20 (1): 1-12.   DOI: 10.12388/j.issn.1673-2677.2024.01.001 Abstract （170）      PDF （7836KB）（182）       Knowledge map    Save Enhancing the rate of penetration （ROP） is crucial for optimizing the efficiency of oil and gas development and deep exploration in China and ensuring national energy security. The percussion rock-breaking drilling technology has been applied in oil fields at home and abroad，resulting in significant improvements in ROP. Further research efforts are expected to address the technical challenges of low drilling footage and limited ROP enhancements encountered during deep exploration of hard rock formations with high temperature and pressure. This paper presents and analyzes the practice and development trends of the drill bit percussion rock-breaking drilling technology assisted by axial percussion，torsional percussion，and axial-torsional coupled percussion. It illustrates that the percussion-assisted drill bit rock-breaking mechanism is the core of percussion rock-breaking ROP improvement technology. This paper also reviews the scientific advancements made by domestic and overseas research scholars in physical experiments，theoretical modeling，and numerical simulation of percussion-assisted drill bit rock-breaking. In addition，it offers relevant proposals for the development of percussion rock-breaking ROP improvement technology，i.e. advancing research on material structure optimization design，intelligent control，integration of multiple technologies，and optimization of well applications. This is expected to provide valuable insights for enhancing the drilling efficiency in energy development of our country. Reference | Related Articles | Metrics

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Analysis of Turbidity Testing Methods and Property Evaluation for Hydraulic Fracturing Proppants LIANG Tiancheng, YANG Nengyu, CAI Bo, MENG Chuanyou, YI Xinbin, YAN Yuzhong, HUANG Xin, TANG Jianhua Xinjiang Oil & Gas    2022, 18 (1): 32-37.   DOI: 10.12388/j.issn.1673-2677.2022.01.005 Abstract （170）      PDF （1572KB）（41）       Knowledge map    Save Hydraulic fracturing is one of the most effective technology for increasing production of uncoventional reservoirs. Turbidity is a key technical property for proppant evaluation. However， the current standard test method in China is different from the international test method， which impacts proppant optimization in hydraulic fracturing treatments in China. In order to improve proppant testing proficiency in China， this paper systematically investigates the influences of the procedures of sampling and sample preparation， liquid sampling position， and turbidity meter on the test value of turbidity. Moreover， considering the physical and chemical properties of suspended particles that affect proppant turbidity， the effects of turbidity on fracture conductivity and reservoir damage are studied. The influencing factors on conductivity and permeability during turbidity testing have been proposed.These studies have important implications for understanding proppant turbidity and proppant optimization and help to reduce costs for proppant manufacturers. Reference | Related Articles | Metrics

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Study Progress on Characteristics and Separation of Produced Fluid of CO2 Flooding XIONG Xiaoqin, , LIAO Tao , XING Xiaokai , ZHANG Zhunxi , DONG Zhengmiao , BI Yuanjun Xinjiang Oil & Gas    2022, 18 (2): 33-39.   DOI: 10.12388/j.issn.1673-2677.2022.02.006 Abstract （167）      PDF （1757KB）（88）       Knowledge map    Save Gas-liquid separation for the produced fluid of CO2 flooding is an important step in the process of carbon capture，utilization and storage（CCUS），and its efficiency directly affects subsequent crude oil dehydration，associated gas processing，produced water treatment，as well as the selection and operation life of related equipment. Based on the basic composition of the produced fluid，the impact of CO2 on the properties of associated gas，oil and produced water is stated，and the main impacting factors and mechanism of oil foaming and associated gas desorption are analyzed. And then，a solution for efficient separation of gas and liquid is put forward，main methods and application effect of gas-liquid separation are reviewed，and the direction and trend for future study on gas-liquid separation are pointed out. The results show that the relationship between the pressure reduction rate and the foaming characteristics of oil is the key scientific problem to determine the pressure and stage number for gas-liquid separation. Establishing a prediction model for the relationship between oil foam volume and defoaming time under the synergistic effect of multiple factors is helpful to determining the separation time. The organic combination of ultrasonic desorption technology and mechanical separation technology is expected to form a new cost-effective and efficient gas-liquid separation technology Reference | Related Articles | Metrics

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Study and Application of Microseismic Monitoring and Interpretation Technology in Unconventional Oil and Gas Reservoirs LIANG Xueli, LIU Hailong, CHENG Ning, ZHANG Rongli Xinjiang Oil & Gas    2021, 17 (3): 53-58.   Abstract （159）      PDF （9640KB）（33）       Knowledge map    Save This paper focuses on the study of the response characteristics of unconventional oil and gas reservoirs,such as tight sandstone,carbonate,rock with coal luster and shale. In addition,it also describes the microseismic monitoring results of reservoirs with different lithologies,and comprehensively interprets the microseismic monitoring results with the actual conditions of fracturing and seismic geology taken into account,achieving satisfactory results. Reference | Related Articles | Metrics

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Optimization and Application of Strength Criterion for Wellbore Mechanical Instability Evaluation in Drilling YANG Hu, CHEN Hao, LI Yilin, SUN Weiguo, ZHOU Penggao Xinjiang Oil & Gas    2022, 18 (3): 1-5.   DOI: 10.12388/j.issn.1673-2677.2022.03.001 Abstract （158）      PDF （855KB）（64）       Knowledge map    Save There is a lack of theoretical guidance and practical optimization method for the selection of strength criteria in wellbore stability evaluation in field， which may lead to the deviation of the drilling fluid density used. The collapse pressure calculated by six strength criteria widely used in rock engineering had been compared. The results show that the collapse pressure calculated by D-Pi criterion is the highest ， followed by M-C criterion ， H-B criterion and D-Pc criterion ； the collapse pressure calculated by LAm criterion and W-Cm criterion is in the middle. Through field practice ， a set of method for strength criteria optimization and application has been summarized. Applying the optimized strength criterion to the wellbore stability evaluation in later drilling to optimize the design and use of drilling fluid density can not only ensure the wellbore stability ， but also improve the drilling speed and oil and gas discovery. This method has been applied in some blocks and strata of Junggar Basin ， and achieved good results ， which is proved to be of popularization and application value. Reference | Related Articles | Metrics

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THE EXTRA INTENSITY OF PRESSURE BELOW THE CURVED LIQUID FACE AND ITS CALCULATION Xinjiang Oil & Gas    2010, 6 (2): 86-89.   Abstract （157）      PDF （231KB）（7）       Knowledge map    Save Related Articles | Metrics

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Practices of Zipper Fracturing for Tight Reservoir Development with Small Well Spacing WAN Tao , QIN Jianhua , ZHANG Jing Xinjiang Oil & Gas    2022, 18 (4): 26-32.   DOI: 10.12388/j.issn.1673-2677.2022.04.005 Abstract （155）      PDF （4308KB）（51）       Knowledge map    Save A fully coupled hydrodynamic model and field monitoring data are used to reveal the changes in in-situ stress during zipper fracturing in tight conglomerate reservoir under the volumetric development pattern of small well spacing，and the corresponding propagation pattern of fracture network. In the case that horizontal well adopts mono-interval and multi-cluster，staggered fracture arrangement and zipper fracturing，there exist stress interferences between wells and fractures at the same time. A large amount of fluid is injected into the wells fractured first to increase the pore pressure and induce the change in in-situ stress field. The mass and pressure transfer effect of fracturing improves the minimum horizontal principal stress，and reduces the two-way stress difference，which preactively creates geomechanical conditions more conducive to the formation of complex fracture network. The development effect of Mahu volumetric development demonstration zone in Junggar Basin with small well spacing shows that the stimulation effect of intervals subjected to centralized batch fracturing is much better，primary well pattern is more advantageous for the deployment of centralized fracturing and putting into production，and the wells to be fractured later have a more complex fracture network. By reducing the well spacing and conducting zipper fracturing，the horizontal stress difference is reduced continually，and the interferences between artificial fractures are mitigated，which is conducive to the formation of complex fracture network，and can effectively improve the production and recovery factor.  Reference | Related Articles | Metrics

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Problems Related to CO2 Recovery in Hydrogen Production Unit and Their Solutions ZHU Jun , YAN Jiangfeng Xinjiang Oil & Gas    2022, 18 (2): 98-102.   DOI: 10.12388/j.issn.1673-2677.2022.02.015 Abstract （153）      PDF （495KB）（18）       Knowledge map    Save 20，000 Nm 3/h hydrogen production unit owned by Tahe Refining and Chemical Co.，Ltd. employs a steam hydrocarbon conversion and pressure swing adsorption（PSA）purification technology. This unit produces 11，055 Nm 3 desorbed gas per hour，which is then fed into a reformer as fuel. The desorbed gas contains more than 50% CO 2，which does not participate in combustion，and is finally emitted into the atmosphere together with the flue gas（burnt product），resulting in carbon emissions. In 2020，a CO 2 recovery device was added to the hydrogen production unit，which recovers CO 2 using a new amino ethyl ethanol amine（AEEA）liquid. After being compressed and liquefied，the recovered CO 2 can be used for CO 2 flooding，with the remaining CO 2 returned to the reformer for combustion. This paper introduces the impacts of CO 2 recovery device and CO 2 recovery on process parameters，analyzes the problems arising after CO 2 recovery，and proposes corresponding solutions，providing a basis for the modification of this unit to realize complete recovery of CO 2 in the future Reference | Related Articles | Metrics

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Study and Application of Fracturing Technology for Tight Reservoir in the Southern Margin of Junggar Basin with High Temperature，High Pressure and High Closure Stress WEN Xianli, KONG Mingwei, LUO Yao, WANG Jian, ZHAO Chunyan, ZHAI Huaijian, WANG Rong Xinjiang Oil & Gas    2021, 17 (4): 15-20.   Abstract （153）      PDF （1354KB）（85）       Knowledge map    Save High-quality reservoir is developed in the deep layers of the lower assemblage of the southern margin of Junggar Basin, where embeds tremendous oil and gas resources. However，the reservoir there has a general burial depth greater than 5 700 m，a temperature greater than 130 ℃，a closure stress gradient greater than 0.02 MPa/m，an average porosity less than 10%，an average permeability less than 0.1×10 -3 μm 2 and strong heterogeneity. Due to the poor physical properties，high Young's modulus and high Poisson's ratio of the reservoir，fracturing faces great challenges in respect of fracture initiation，high pump pressure and efficient use，which present higher requirements for wellbore integrity，fracturing materials and technology. Through field study and practices，a fracturing technical system for tight reservoir with high closure stress has been developed，which is centered on the technology to reduce wellhead operating pressure and integrated with proppant combination and optimization technology and treatment parameter optimization technology. Thus，the bottleneck of the fracturing technology for deep reservoir with high temperature and pressure has been broken through. It has been successfully applied in 3 wells since 2020. After fracturing treatment，well-GQ6 has seen significant effect: the maximum daily oil production is 97.97 m 3 and the daily gas production is 2.03×10 4 m. This technical system provides new perspective for deep oil and gas exploration in the southern margin of Junggar Basin. Reference | Related Articles | Metrics