鄂尔多斯盆地延长组长7段致密油储层应力敏感性及影响因素  

Stress sensitivity and its influence factors of tight oil reservoir in Chang 7 Member, Ordos Basin

作　　者：杨孝[1] 冯胜斌[2,3] 王炯[2,3] 牛小兵[2,3] 尤源[2,3] 梁晓伟[2,3] 王维斌[2,3] Yang Xiao Feng Shengbin Wang Jiong Niu Xiaobing You Yuan Liang Xiaowei Wang Weibin(Department of Reservoir Evaluation, PetroChina Changqing Oilfield Company Exploration and Development Research Institute of PetroChina Changqing Oilfield Company National Engineering Laboratory of Low-permeability Oil ＆ Gas Exploration and Development)

机构地区：[1]中国石油长庆油田公司油藏评价部 [2]中国石油长庆油田公司勘探开发研究院 [3]低渗透油气田勘探开发国家工程实验室

出　　处：《中国石油勘探》2017年第5期64-71,共8页China Petroleum Exploration

基　　金：国家重点基础研究发展计划(973)项目"淡水湖盆细粒沉积与富有机质页岩形成机理研究"(2014CB239003);国家科技重大专项"鄂尔多斯盆地致密油资源潜力;甜点区预测与关键技术应用"(2016ZX05046005)

摘　　要：致密油采用准自然能量开发方式下,对储层的应力敏感性及其控制因素进行研究具有重要的意义。基于地层压力条件下的应力敏感性实验,明确了鄂尔多斯盆地延长组长7段致密油储层主要表现为渗透率的应力敏感性,应力敏感性属弱到中等强度。利用铸体薄片、恒压和恒速压汞、场发射扫描电镜、微米CT成像等测试手段,对长7段不同应力敏感性类型储层的岩石学特征、微观孔隙结构进行系统分析和对比研究,揭示塑性组分含量、填隙物类型及其含量、孔喉尺度是长7段致密油储层应力敏感性不同的主要控制因素。基于长7段致密油开发先导试验区生产实践和储层特征的综合分析,认为在长7段致密油水平井压裂裂缝改造区域,地层压力的快速下降致使应力敏感性对水平井的石油产量和递减率产生显著的影响;同时,在长7段致密油开发过程中,应针对不同物源体系、不同成因类型、不同物性的储层制定不同的开发技术方案,以降低应力敏感性对致密油产能的影响程度。It is important to identify the stress sensitivity of tight oil reservoir and its influence factors, when the tight oil reservoir is developed by quasi-natural energies. Stress sensitivity experiment was conducted on the tight oil reservoir in Chang 7 Member of Yanchang Formation in the Ordos Basin under the reservoir pressure. It is indicated that the permeability of the Chang 7 tight oil reservoir is of medium to weak stress- sensitive. The petrology and micro-pore structure of the Chang 7 tight oil reservoirs with different types of stress sensitivity were analyzed and compared by the techniques of cast thin section, constant pressure mercury intrusion, constant-rate mercury intrusion, field emission scanning electron microscopy and Micro-CT, etc. The results suggest several influence factors on stress sensitivity, including the content of plastic components, types and contents of interstitial materials, and pore throat size. Through comprehensive analysis of the practices in the pilot development zone and the reservoir characteristics of Chang 7 tight oil reservoirs, it is found that the stress sensitivity affects greatly the oil production rate and the decline rate of horizontal wells due to sharp decrease of formation pressure in the stimulated intervals of Chang 7 reservoirs. Moreover, different development plans are prepared for the Chang 7 tight oil reservoirs depending on provenances, origins and physical properties, so as to mitigate the influence of stress sensitivity on productivity.

关 键 词：鄂尔多斯盆地 长7段 致密油 应力敏感性 岩石学 孔隙结构 

分 类 号：TE122.2[石油与天然气工程—油气勘探]