东濮凹陷三叠系砂岩裂缝形成机理及控制因素

Analysis of formation mechanismand control factors of Triassic sandstone fracture

杨广林

Yang Guanglin

中原油田分公司勘探开发科学研究院，河南  濮阳  457001

Research Institute of Exploration and Development, Zhongyuan Oilfield Company, SINOPEC, Puyang 457001, China

东濮凹陷卫北三叠系发现的砂岩裂缝油藏是一个独有的油藏类型，砂岩基质不含油，裂缝含油，裂缝既是储集空间，又是渗流通道。裂缝的发育程度控制着油藏的富集程度，影响着油井产能的高低。研究裂缝发育分布规律是提高该类油藏勘探开发效果的需要，而裂缝形成机理及控制因素分析是关键。通过野外露头剖面、岩心、薄片观察，岩石声发射实验、单轴和三轴岩石力学实验研究，认为构造裂缝为该地区主要的裂缝类型，构造运动是裂缝形成的主要外因，燕山运动和喜马拉雅运动形成了本区的两期裂缝；储层岩性及厚度是砂岩裂缝形成的内因，控制了裂缝的密度及发育程度。研究明确了大断层附近为裂缝发育区，指导了砂岩裂缝油藏勘探开发。

Fractured reservoir sandstone of Triassic in Weibei Area, Dongpu Depression, is a particular style of reservoir, because there is no oil in matrix, but in the fractures. Fracture is both reservior space and percolating channel. The development degree of fracture controls the enrichment degree of reservior and affects the productivity of oil wells. Study on the development and distribution rules of the fractures is the demand for reservoir exploration and development, in which the analysis of formation mechanism and control factors is the key factor. From the research of field outcrop profiles, core and slice, through the experiments of acoustic emission,
uniaxial and triaxial rock mechanics, it is believed that structural fracture is the main cracks type and structural movement is the main external cause of fracture formation. Yanshan Movement and Himalayan Movement caused the fracture in two periods. The reservoir lithology and thickness is the internal cause of sandstone fractures, which control the fracture density and development. It is made clear that there is fracture developed area close to the major fault, which can guide the exploration and development of sandstone fracture reservoir.