摘要
针对新疆克拉玛依油田七中区克拉玛依组下亚组砾岩油藏二元复合驱体系注入初期在深部地层发生堵塞,导致试验效果低于设计方案的问题,利用电子探针X射线显微分析仪研究其堵塞的微观分布和成因表明,相对分子质量和质量浓度均过高的二元复合驱体系与储集层配伍性差,注入后主要赋存于黏土矿物堆积的复杂孔隙和喉道中,导致砾岩储集层物性变差,驱油过程流动性变差;而砾岩储集层中所含的大量高岭石易于在较高的注入速度下发生脱落,并与注入的二元复合驱体系作用,从而导致储集层孔隙的堵塞。在此认识基础上,开展了物理解堵实验研究,选择不同物性的典型天然岩心,先后注入高、中、低不同相对分子质量和质量浓度的二元复合驱体系,压力平稳后计算阻力系数和残余阻力系数,判断其流动性。结果表明,砾岩储集层物理解堵存在渗透率界限,即通过逐步降低二元复合驱体系相对分子质量和质量浓度,可以有效缓解渗透率大于50 m D的中、高渗储集层的堵塞,但无法缓解渗透率小于50 m D的低渗储集层的堵塞。现场配方调整后,注入压力稳步下降,产液量稳中有升,堵塞得到有效的缓解。预计研究区砾岩油藏二元复合驱可以实现提高采收率15%的目标。
Regarding the problems of poorer experiment effect than the designed one due to plugging in deep layers at the initial binarycombination injection stage into the conglomerate reservoirs in the lower Karamay formation in District Qizhong of Karamay oilfield, Xinji-ang, the microscopic distribution and genesis of the plugging are studied using electron-probe X-ray microanalyzer. The result shows thatthe binary combination system with excessive molecular weight and mass concentration matches poorly with the reservoir and mainly oc-curs in complex pores and pore throat where clay minerals accumulate, which results in poor physical properties of the conglomerate reser-voir and poor mobility during the oil displacement process. Large amount of kaolinite in the conglomerate reservoir tends to drop off at rela-tively high injection rate and reacts with the injected binary combination system, resulting in the plugging of reservoir pores. Based on theabove understanding, experimental study on physical plugging removal is carried out. Typical natural cores with different physical proper-ties are selected, and binary combination systems with high, moderate and low molecular weights and mass concentrations are injected in tothe cores. Resistance coefficient and residual resistance coefficient are calculated under steady pressure and then the mobility could be de-termined. The result shows that physical plugging removal in the conglomerate reservoir has a permeability limit that the plugging in moder-ate and high permeability reservoirs(>50 m D) could be effectively relieved by gradually decreasing the molar weight and mass concentra-tion of the binary combination system, but it doesn't work for the plugging in low permeability reservoirs(<50 m D). After field formula ad-justment, injection pressure decreases steadily, liquid production increases and plugging is effectively relieved. It is predicted that the bina-ry combination flooding in the conglomerate reservoir could improve recovery factor by 15% in the study area.
出处
《新疆石油地质》
CAS
CSCD
北大核心
2016年第6期703-708,共6页
Xinjiang Petroleum Geology
基金
国家油气重大专项(2016ZX05010-004)
中国石油科技重大专项(2014E-34-07)
关键词
克拉玛依油田
七中区
克拉玛依组
砾岩油藏
二元复合驱
微观分布
堵塞成因
物理解堵
Karamay oilfield
District Qizhong
Karamay formation
conglomerate reservoir
binary combination flooding
microscopic distri bution
plugging genesis
physical plugging removal