储层损害的岩石力学—化学耦合作用研究进展  

Research Progresses in Formation Damage Related Rock Mechanics-Chemistry Coupling

作　　者：吴娟[1] 康毅力[1] 张浩[1] 游利军[1] 李前贵[1] 

机构地区：[1]西南石油大学"油气藏地质及开发工程"国家重点实验室

出　　处：《钻井液与完井液》2007年第1期76-81,共6页Drilling Fluid & Completion Fluid

基　　金：油气藏地质及开发工程国家重点实验室基金项目(PLN9720);四川省青年科技基金项目(02ZQ026-042)资助。

摘　　要：以往研究储层的应力敏感性损害多是从纯力学角度出发,针对油气藏和工程作业的实际情况,提出重视力学—化学耦合作用对储层渗透率的影响。总结了压溶作用机理,明确了压溶作用最终导致裂缝闭合、岩石渗透率下降并具有不可逆性。压溶作用机理的基本模式为水薄膜模式、岛状沟道构造模式、格莱茨模式。压溶作用的主要影响因素包括温度、压力、矿物溶解性、流体化学性质、流体饱和度。水化学作用对恒定围压下裂缝渗透率变化起着主导作用,必须重视水化学效应对力学效应的影响。在钻井完井过程中应尽量保持压差恒定,防止应力敏感损害储层,并尽量避免滤液侵入油气层,特别是在高温高压环境下压溶作用导致渗透率下降的幅度更大。力学-化学耦合作用还弱化岩石结构面的连接,扩大裂缝宽度,使岩体强度急剧下降,导致发生诱发性井漏。研究岩石力学-水化学耦合作用对于保护储层、优化裂缝性油气藏具有重要的现实意义。This paper discuss the influences of the rock mechanics-chemistry coupling, not just the rock mechanics, on the reservoir permeability, summarizes the pressure solution mechanism and shows that pressure solution will finally lead to the fracture closure and result in an irreversible decrease in permeability. The mechanisms of pressure solution can be classified as water membrane model, island channeling model and Gratz model. Factors affecting pressure solution includes temperature, pressure, solubility of the minerals, chemistry and saturation of the fluids. Water chemistry is the major factor affecting the permeability of fractures at constant confining pressure, thus attention should be paid to the effects of the water chemistry. The differences between the pressure of the mud column and the formation pressure should be maintained constant during drilling to prevent the formation permeability from being damaged. Mud filtrate invasion, especially in HTHP conditions, results in a significant decrease in permeability. Rock mechanics-chemistry coupling also decreases the connection among the structural planes of rocks and widens the fractures. The rock strengths are thus decrease quickly, leading to induced mud losses. The research of effect of the rock mechanics-chemistry coupling is of great importance to the reservoir protection.

关 键 词：防止地层损害 岩石力学 水化学作用 力学-化学耦合 应力敏感性 压溶 研究进展 

分 类 号：TE258[石油与天然气工程—油气井工程]