鄂尔多斯盆地北部致密砂岩气层粘土微结构与流体敏感性  

Clay microstructure and fluid sensitivity of fine gas sands in the north of Ordos basin

作　　者：张浩[1] 康毅力[1] 李前贵[1] 游利军[1] 尤欢增[2] 

机构地区：[1]油气藏地质及开发工程国家重点实验室(西南石油学院) [2]中石化华北分公司

出　　处：《钻井液与完井液》2005年第6期22-25,共4页Drilling Fluid & Completion Fluid

基　　金：四川省青年科技基金项目(编号:02ZQ026-042)资助

摘　　要：在钻井过程中,随着外来工作液进入储层,致密砂岩气层中粘土矿物微结构容易遭受破坏,发生膨胀、分散及运移堵塞孔喉,导致储层渗透能力降低。鄂尔多斯盆地北部上古生界塔巴庙地区储层岩石气测孔隙度平均值约为7.6%,渗透率平均值为0.38×10-3μm2左右,气藏压力系数在0.85~0.98之间,储层的粘土矿物类型丰富,属典型低压致密砂岩气藏。采用X-射线衍射、扫描电镜等方法分析了该盆地粘土矿物含量、类型、产状和微结构,结合流体敏感性实验分析了气层潜在敏感性损害。该盆地气层粘土矿物含量、微结构类型及稳定性与流体敏感性程度密切相关,外来工作液进入储层容易导致酸敏、碱敏、盐敏等损害。通过对气层粘土矿物微结构评价,并结合室内流体敏感性实验,从粘土微结构的角度对流体敏感性损害机理进行了研究,从减少敏感性损害的角度提出实施保护储层的屏蔽暂堵钻井液技术。该钻井液能够起到保护储层及减少泥页岩水化膨胀保护井壁稳定的作用。室内实验和现场应用表明,屏蔽暂堵钻井液体系对保护储层和提高产量具有良好的效果。When the external working fluids came into the fine gas sands, the clay microstructures were often destructed and the permeability decreased as a result of pore and throat plugging induced by swelling, dispersion and migration of clay particles. The typical low pressure fine gas sands reservoir located in the Neopaleozoic Tabamiao area in the north of Ordos basin had an average porosity of about 7.6%, an average perm of about 0.38×10~ -3 μm^2 and a pressure coefficient range of 0.85～0.98 and contained rich clay minerals. The clay minerals contents, types, attitude and microstructures were analyzed by X-ray diffraction and SEM and the potential sensitivity damage of the gas reservoir was also analyzed by fluid sensitivity evaluation. Results showed that the fluid sensitivity was close to the clay contents, the microstructure type and its stability and the acid, alkali and salt sensitivity were prone to occur when the external working fluid came into the reservoir. The mechanism of fluid sensitivity damage was studied by the evaluation of the clay mineral microstructures coupled with laboratory fluid sensitivity and the corresponding shielding temporary plugging drilling fluid technology was proposed to reduce the sensitivity damage. Laboratory experiments and in-situ practices indicated that this drilling fluid had positive effects on formation protection and production increase.

关 键 词：致密砂岩 粘土矿物 微结构 防止油层损害 酸敏碱敏 盐敏 鄂尔多斯盆地 

分 类 号：TE348[石油与天然气工程—油气田开发工程] TE254.4