顺北油田S井超深超高温碳酸盐岩断溶体油藏大型酸压关键技术

Key Technologies for Large-Scale Acid Fracturing of Ultra-Deep Fault-Karst Carbonate Reservoirs with Ultra-High Temperature for Well S in Shunbei Oilfield

李新勇 李骁 赵兵 王琨 苟波

LI Xinyong LI Xiao ZHAO Bing WANG Kun GOU Bo

中国石化缝洞型油藏提高采收率重点实验室，新疆乌鲁木齐 830011 西南石油大学石油与天然气工程学院，四川成都 610500

Sinopec Key Laboratory of Enhanced Oil Recovery for Fractured Vuggy Reservoirs, Urumqi, Xinjiang, 830011, China Petroleum Engineering School, Southwest Petroleum University, Chengdu, Sichuan, 610500, China

顺北油田S井目的层属于典型的超深超高温断溶体储层，工程地质条件和井筒条件复杂，酸压改造面临巨大挑战。针对上述酸压改造难点，提出了“回填井段集中改造+酸损伤降破+管柱浅下+加重压裂液组合提排量+前置液造缝+交替注入造高导流裂缝+自生酸疏通远端断溶体”的复合酸压技术，通过试验优选了超高温工作液体系，包括180 ℃聚合物压裂液、160 ℃加重瓜胶压裂液、160 ℃交联酸和自生酸；基于数值模拟结果优化了大型酸压方案，推荐压裂液规模为1 800～2 200 m3，酸液规模为800～1 000 m3。现场试验表明，相同注液排量下，注加重压裂液的井口压力比注聚合物压裂液降低了7%，应用效果明显。S井大型酸压后，测试天然气产量10.45×104 m3/d，取得了顺北4号断裂带开发的突破，也为类似油气藏大型酸压方案优化设计提供了技术借鉴。

The target formation of Well S in Shunbei Oilfield is a typical ultra-deep fault-karst carbonate reservoir. Due to the complex engineering and geological conditions and wellbore conditions, acid fracturing is confronted with great challenges. In light of above difficulties in reservoir stimulation, a set of compound acid fracturing technologies was proposed by "centralized treatment by backfilling + acid damage to reduce fracture pressure + shallow pipe string + flow rate increase by weighted fracturing fluid + pad fluid fracturing + alternative injection for high conductivity fracture + autogenous acid to connect the far fault-karst". A set of acid fracturing fluid systems was optimized for resistance to ultra-high temperature by tests, included polymer fracturing fluid at 180 ℃, weighted guar gum fracturing fluid at 160 ℃, crosslinking acid at 160 ℃, and autogenous acid. Then, an optimized large-scale acid fracturing treatment plan was made based on recommendations for working fluid scales by numerical simulation. The recommended scale of fracturing fluid was 1 000–1 200 m3 and the scale of acid fluid was 800–1 000 m3. The field test showed a significant decrease in the wellhead pressure with weighted fracturing fluid, which was 7% lower than that with polymer fracturing fluid under the same injection rate. After the large-scale acid fracturing of Well S, the test production of natural gas was 10.45 × 104 m3/d, which made a breakthrough in the exploration of the Shunbei No. 4 fault zone and provided valuable guidance for the large-scale acid fracturing design of similar reservoirs.

中国石化科技攻关项目“顺北超深断溶体油藏高效酸压技术研究”（编号：P20064-3）资助

https://doi.org/10.11911/syztjs.2021068