Abstract:

It is difficult for deep shale fracturing to create complex fractures and the fracture conductivity fails quickly，resulting in rapid decline in production. To clarify the impact of hydraulic fracture conductivity on deep shale gas production，a propped fracture conductivity computational model and a mathematical model for predicting the productivity of deep shale gas were established based on the test data on the conductivity of deep shale fractures，while also considering the effects of closure stress，proppant concentration and particle size on the conductivity. The production data of deep shale gas in the southern Sichuan were used to conduct historical matching and prediction on the model，which verified the accuracy of the model. The effects of proppant concentration，closure stress and proppant particle size on the production of deep shale gas were studied and analyzed. The results show that the stable production time and  Estimated Ultimate Recovery（EUR） of deep shale gas wells can be improved by increasing the proppant concentration and selecting proppants with smaller particle size，with the optimal proppant concentration falling between 1-2 kg/m²；when the closure stress was increased from 80 MPa to 110 MPa，the stable production time was reduced by 40%；the optimum proppant particle size is 40/70 mesh due to the combined effect of proppant particle size and the half-length of propped fracture. The results provide a theoretical basis for the fracture conductivity design and production forecast of deep shale gas reservoirs.

Key words:

"> deep shale gas, staged multi-cluster fracturing, stress sensitivity, fracture conductivity, production forecast

摘要：

深层页岩压裂难以形成复杂裂缝且裂缝导流能力失效快，导致产量迅速递减。为明确水力裂缝导流能力对深层页岩气产量的影响，基于深层页岩裂缝导流能力实验测试数据，考虑闭合应力、支撑剂铺砂浓度和粒径对导流能力的影响，建立了支撑裂缝导流能力计算模型和深层页岩气产能预测数学模型。采用川南深层页岩气生产数据对模型进行了历史拟合和预测，验证了模型的准确性。研究分析了铺砂浓度、闭合应力和支撑剂粒径对深层页岩气产能的影响。研究表明，提高铺砂浓度和选择小粒径支撑剂有利于提高深层页岩气井稳产时间和预测最终可采储量（EUR），最优铺砂浓度在1~2 kg/m²之间；当闭合应力从80 MPa增加到110 MPa时，稳产时间缩短了约40%；受支撑剂粒径和支撑裂缝半长综合影响，最佳支撑剂粒径为40/70目。研究成果为深层页岩气裂缝导流能力设计和产能预测提供理论依据。

关键词:

深层页岩气, 分段多簇压裂, 应力敏感, 裂缝导流能力, 产能预测