摘要
针对哥伦比亚M油田T砂岩储层物性变差现象,以地震、岩心和薄片资料为基础,通过分析储层微观结构特征,认为逆断层挤压导致的动力变质作用是研究区储层物性变差的主要因素。T砂岩形成于滨浅海沉积环境,储层分布稳定,物性较好。研究区5井钻遇逆断层,在逆断层的上、下盘分别钻遇2套T砂岩,但岩石胶结致密,裂缝发育,镜下观察发育大量缝合线,颗粒之间以凹凸接触和缝合接触为主,石英次生加大和角砾岩化明显,裂缝和粒间孔隙被胶结物充填,孔隙度低。分析认为,T砂岩遭受逆断层所产生的动力变质作用影响,形成局部异常高压带,导致断层附近石英颗粒的破碎和研磨,颗粒粒度变小,压溶作用使石英部分溶解形成缝合线,同时硅质胶结物再沉积充填孔隙,最终导致岩石胶结致密、物性变差。结合构造解释模型和周边钻井资料,预测动力变质作用范围在15 m以内。地应力集中是动力变质作用形成的地质背景,逆断层发育是动力变质作用形成的直接原因,由于动力变质作用范围有限,因此不会影响M油田的整体开发。
Based on the seismic,core and slice data,it was found that the main factor for T sandstone reservoir abnormal variation in Colombia M oilfield is dynamic metamorphism caused by thrust fault through analyzing the characteristic of reservoir microscopic structure. The sedimentary environment of T sandstone is littoral-neritic sea,so the reservoir deposited steadily with good properties. Well-5 was drilled through a small thrust fault,of which two sets of T sandstones at the hanging wall and footwall were drilled. Those sandstones drilled are characterized by dense rock cementation,developed fracture,a large number of stylolites found out by microscope,concave and convex contact and stitching between particles,obvious quartz overgrowth and breccias and fracture and inter-granular pore filled with cement. It was analyzed firstly that the dynamic metamorphism resulted from thrust fault caused a local abnormal high pressure zone,in which the quartz grain was crushed and grounded to smaller grain size. Secondly,part quartz was dissolved by pressure solution to become stylolite.Thirdly,the dissolved siliceous cement deposited again and filled residual pore,leading to dense cementation and poor physical property. Combined with tectonic interpretation model and the surrounding well data,the scope of dynamic metamorphism was speculated to be within 15 m. In short,stress concentration is the geological background of dynamic metamorphism,and thrust fault is the direct reason of dynamic metamorphism. Because the range is limited,M oilfield could continue normal development.
出处
《油气地质与采收率》
CAS
CSCD
北大核心
2016年第4期41-45,共5页
Petroleum Geology and Recovery Efficiency
作者简介
赵伯宇（1984-）,男,山东聊城人,工程师,硕士,从事开发地质工作.联系电话：（010）59568459,E-mail：zhaoboyu@sinochem.com.
