吉木萨尔页岩油CO_(2)吞吐方案优化及试验效果评价

Optimization of CO_(2) Huff and Puff Scheme for Jimsar Shale Oil and Evaluation of Test Effect

针对吉木萨尔页岩储层衰竭式开发采收率低,传统提高采收率措施难以有效增产的问题,提出了CO_(2)吞吐提高采收率的方法。运用数值模拟方法,建立了工区储层油藏数值模拟模型,依据水平段长度及油层厚度优选了适用于CO_(2)吞吐的试验井,明确了基质增能对于CO_(2)吞吐的决定性作用,并对CO_(2)吞吐的工作制度进行了优化。最终将优化方案应用于现场试验,结果表明:试验井间存在裂缝窜扰,导致CO_(2)吞吐注入阶段气窜严重,CO_(2)未充分进入基质置换原油,整体开发效果较差。研究内容对页岩油藏注CO_(2)吞吐提高采收率具有参考意义,可为调整CO_(2)吞吐开发方案提供借鉴。

A method of enhanced recovery efficiency by CO_(2) huff and puff was proposed in response to the low recovery efficiency in natural depletion of shale gas reservoirs in Jimsar and the difficulty of traditional recovery enhancement measures to effectively increase the production.A numerical simulation model of reservoir in the work area was established by the numerical simulation method.Test wells suitable for CO_(2) huff and puff were selected according to the horizontal interval length and reservoir thickness.The decisive role of matrix energy enhancement in CO_(2) huff and puff was clarified,and the working system of CO_(2) huff and puff was optimized.Finally,the optimized scheme was applied to the field test.The results showed that,there was fracture channeling between the test wells,resulting in serious gas channeling in the injection stage of CO_(2) huff and puff,and CO_(2) did not enter the matrix sufficiently to replace the crude oil,resulting in poor overall development efficiency.The study provides a reference for enhancing oil recovery by CO_(2) huff and puff in shale reservoir and for adjusting the scheme of development by CO_(2) huff and puff.