长庆油田低渗储层微粒运移堵塞损害机理

The mechanism of particle migration and plugging in low-permeability reservoir of Changqing Oilfield

张栋梁 饶利平 蔡绪森 苏帅 沈传海 张维 姚征 王旭明

中国石油长庆油田分公司第九采油厂，宁夏 银川 750005 北京华油明信能源技术有限责任公司，北京 102200

No.9 Oil Production Plant, Changqing Oilfield Company, PetroChina, Yinchuan 750005, China Beijing Huayou Mingxin Energy Technology Co., Ltd., Beijing 102200, China

为明确长庆油田低渗储层微粒运移堵塞损害机理，以C4+5储层为研究对象，系统地构建了“以岩石矿物分析￣孔隙结构描述￣粒径大小表征为静态层面，以水驱宏观损害量化评价实验为动态层面，以孔喉微观变化￣采出液矿物分析为佐证层面”的低渗储层微粒运移堵塞损害机理的综合研究方法，全方位地开展了C4+5储层的损害机理研究。结果表明：长庆油田C4+5储层孔隙孔径范围为20.0~70.0 μm，喉道尺寸为4.0~14.0 μm；石英、长石等岩石骨架颗粒棱角分明，磨圆度差，不利于细小微粒在多孔介质中的长距离运移；黏土矿物主要为绿泥石和伊利石等速敏性矿物，直径范围为2~10 μm，易在孔隙喉道处产生微粒架桥式堵塞；岩心正反向水驱过程中,存在多孔介质内部的震荡式微粒堵塞；短岩心驱替采出液中的矿物组分以绿泥石和伊利石为主，水驱前后岩心孔隙中黏土颗粒的微观状态发生了明显变化，证实了储层损害的根源在于绿泥石和伊利石引起的微粒型堵塞。该研究成果明确了C4+5储层的损害机理，为现场油水井解堵作业的实施提供了方向。

In order to clarify the mechanism of particle migration and plugging in low permeability reservoirs in Changqing Oilfield, taking C4+5 reservoir section as the research object, a comprehensive research method of particle migration and plugging damage mechanism in low-permeability reservoir has been systematically constructed, which is "takes rock mineral analysis and pore structure description and particle size characterization as the static level, takes the quantitative evaluation experiment of water drive macro damage as the dynamic level, and takes the pore throat micro change and produced fluid mineral analysis as the supporting level". The damage mechanism for C4+5 reservoir has been studied comprehensively. The results show that the pore diameter range in C4+5 reservoir of Changqing Oilfield is 20.0￣70.0 μm, throat size is 4.0￣14.0 μm. Quartz, feldspar and other rock skeleton particles are angular and poorly rounded, which is not conducive to the long-distance migration of fine particles in porous media. Clay minerals are mainly velocity sensitive minerals such as chlorite and illite, with a diameter range of 2￣10 μm. It is easy to produce particle bridging plugging at the pore throat. In the process of core forward and reverse water flooding, there are oscillating particle plugging in porous media. The mineral components in the produced fluid of short core flooding are mainly chlorite and illite, and the microscopic state of clay particles in the core pores has changed significantly before and after water flooding, which confirms that the source of reservoir damage is particulate plugging caused by chlorite and illite. The research results define the damage mechanism of C4+5 reservoir, and provide direction for the implementation of follow-up plug removal on site.

10.6056/dkyqt202303011