Abstract:

Tangdong Block of Dagang Oilfield has complex geology. The main target layers are the third member of Dongying Formation and Shahejie Formation. The target layers are deeply buried and rather thick, and the damage mechanisms between the reservoirs are very different. The applications of fine calcium carbonate and plugging agents for drilling fluids in reservoir damage prevention present insufficient performance for exploration and appraisal wells in this block, due to the low technical adaptiveness to the reservoirs and inferior practice management. The core permeability recovery rate for the reservoirs is only 67.5%. According to the core sensitivity evaluation and casting thin section analysis results of Well Tangdong 9X6, a reservoir protection technology system was developed for the drilling of the Tangdong exploration and appraisal wells, according to the potential damage factors. The protection system adopts the film-forming plugging reservoir protection technology and combines the applications of the single-well multi-layer/multi-point design method. The efficient implementation of the developed technology system is ensured with the help of refined technology implementation management and high-quality real-time evaluation. The film-forming plugging reservoir protection technology was applied to five wells in this block. The dynamic fluid loss of drilling fluids was reduced by 25.7%, and the permeability recovery rate was increased by 13.1%.  All the five wells met the geological expectations. Two wells have delivered high production, with initial daily production of 61.3 t and 101.1 t, respectively, which indicates good performance.

Key words:

film-forming plugging, drilling fluid, reservoir protection, permeability

摘要：

大港油田唐东区块地层复杂，主要目的层为东三段和沙河街组，目的层埋藏较深、储层段长，且各储层之间损害机理差异性大，应用细目碳酸钙和钻井液用封堵剂作为储层保护技术，由于储层针对性不足且技术实施管理不到位，导致该地区探评井储层保护效果欠佳，储层钻井液岩心渗透率恢复值仅为67.5%。根据唐东9X6井岩心敏感性评价和铸体薄片分析，针对潜在损害因素构建了唐东探评井钻井过程储层保护技术体系。该保护体系采用成膜封堵保护技术，配合应用单井多层/多点设计方法，通过精细技术实施管理、精益实时评价，确保了技术高效实施。该地区成膜封堵保护技术实施5口井，钻井液动态滤失量降低25.7%、渗透率恢复值提高13.1%，5口井均达到地质预期效果，其中2口井实现高产，初期日产分别达到61.3 t和101.1 t，取得了良好的效果。

关键词:

成膜封堵, 钻井液, 储层保护, 渗透率