摘要
针对裂缝型储层注气窜流问题,通过仪器检测和物理模拟方法,开展了缓膨颗粒微观形态、强度、粒径、溶胀性、抗剪切性、封窜效果和气驱采收率研究。结果表明:缓膨颗粒形状不规则、表面粗糙,骨架呈空间网状结构,存在一些分布均匀、致密的孔洞,使其具有较高的吸水、保水能力。随溶胀时间延长、矿化度降低,缓膨颗粒弹性模量降低;与中性环境相比,缓膨颗粒在酸性环境下弹性模量较大,膨胀7d的缓膨颗粒弹性模量可达到61kPa以上,具有较高的强度。随溶胀时间延长,缓膨颗粒粒径增大,溶胀速度逐渐变快,到第10d仍然没有达到完全吸水。浓度越大、矿化度越高,缓膨颗粒溶胀速度越慢,与中性环境相比,酸性环境下溶胀速度较慢。随溶胀时间延长,缓膨颗粒抗机械剪切性变差。随匹配系数减小,封堵CO_(2)气窜效果呈“先变好后变差”趋势,匹配系数1.08效果最好。与缓膨颗粒浓度和注入量相比,匹配系数对封堵CO_(2)气窜效果影响最大。与CO_(2)驱相比,“缓膨颗粒封堵+CO_(2)驱”方式采收率较高,说明缓膨颗粒对裂缝进行了有效封堵,改善CO_(2)驱气窜效果显著。
Aiming at the gas channeling during gas injection in the fractured reservoirs,the microscopic mor-phology,strength,particle size,swelling property,shear resistance,channeling plugging effect and gas flooding recovery of the retarding swelling particles were studied through instrument detection and physical simulation.The results show that the retarding swelling particles have the characteristics of being irregular in shape and rough in surface,a skeleton in a spatial network structure,and some uniformly distributed and dense pores,which make them have the capacity of high water absorption and water retention.With the prolonging of swelling time and the decrease of salinity,the elastic modulus of retarding swelling particles decreases;com-pared with neutral environment,the elastic modulus of retarding swelling particles is larger in acidic environ-ment,and the elastic modulus of them after 7days of swelling can reach above 61k Pa,indicating high strength.With the extension of the swelling time,the particle size of the retarding swelling particles increases,and the swelling speed gradually becomes faster,and it still does not reach the complete water absorption on the 10th day.The higher the concentration and the higher the salinity,the slower the swelling speed of the retarding swelling particles.Compared with the neutral environment,the swelling speed is slower in the acidic environment.With the extension of swelling time,the mechanical shear resistance of the retarding swelling particles deteriorated.With the decrease of the matching coefficient,the effect of plugging CO_(2) gas channeling shows a trend of"first become better and then worse",and the matching coefficient of 1.08 is the best.Compared with the concentration of the retarding swelling particles and the injection rate,the matching coefficient has the greatest influence on the plugging CO_(2)gas channeling.Compared with CO_(2) flooding,the"retard-ing swelling particle plugging+CO_(2)flooding"method has a higher recovery rate,indicating that the retarding swelling particles can effectively plug the fractures and improve the gas channeling of CO_(2) flooding.
作者
张跃
Zhang Yue(Exploration and Development Research Institute of Daqing Oilfield Co.,Ltd.,Daqing Heilongjiang 163712)
出处
《中外能源》
CAS
2022年第7期42-49,共8页
Sino-Global Energy
关键词
缓膨颗粒
CO_(2)驱
裂缝
气窜
匹配系数
retarding swelling particles
CO_(2)flooding
fractures
gas channeling
matching coefficient