致密储集层岩石应力敏感性测试与评价方法  

Measurement and evaluation of the stress sensitivity in tight reservoirs

作　　者：窦宏恩[1] 张虎俊[1] 姚尚林[1] 朱丹[2] 孙涛[1] 马世英[3] 王小林[1] 

机构地区：[1]中国石油勘探开发研究院 [2]中国石油大学(北京) [3]北京大学页岩气研究所

出　　处：《石油勘探与开发》2016年第6期1022-1028,共7页Petroleum Exploration and Development

基　　金：国家油气科技重大专项"国内油气开发发展战略研究"(2016ZX05016-006)

摘　　要：针对行业标准SY/T 5358—2010中储集层岩石应力敏感性测试方法、评价方法和判定标准存在的诸多问题,从5个方面提出了该标准需要修订的具体内容;根据班恩和马克西莫夫的岩石应力方程,推导出了Terzaghi有效应力公式,说明了Terzaghi公式不仅适合土壤力学而且也适合岩石力学。根据前人由渗透率模量公式导出的Terzaghi有效应力与岩石渗透率的指数关系式,拟合定外压变内压和定内压变外压两种不同的实验条件所测得的实验数据,都具有较高的拟合精度,由于定外压变内压测试与油藏开发实际相符,建议采用定外压变内压操作。研究认为:岩石应力敏感性强弱可用应力敏感系数(α)来评价,推荐标准:0.005 MPa^(-1)<α≤0.025 MPa^(-1)为弱敏感;0.025 MPa^(-1)<α≤0.035 MPa^(-1)为中等偏弱敏感;0.035 MPa^(-1)<α≤0.045 MPa^(-1)为中等偏强敏感;0.045 MPa^(-1)<α≤0.100 MPa^(-1)为强敏感;α>0.100 MPa^(-1)为极强敏感。同时,根据多个文献的实验数据证实了砂岩储集层渗透率越低应力敏感性越强。The revised details of SY/T5358—2010 of National Energy Administration Standard from five aspects are put forward, it is aimed at existing flaws of the standard, including measurement procedures, evaluation method and discrimination criteria of the rock stress sensitivity. Terzaghi＇s effective stress was derived according to stress equation of Bane and Maximov, which indicates Terzaghi formula, is not only suitable for soil mechanics, but also for rock mechanics. An exponential model of Terzaghi effective stress and rock permeability was built from former researcher＇s formula of permeability modulus. The exponential model was used to fit experimental data, with a good accuracy under two different experiment conditions, constant confining pressure（constant-external pressure） and changing-pore-fluid pressure（changing-internal pressure）, and constant-pore-fluid pressure（constant-internal pressure） and changingconfining pressure（changing-external pressure）. Since constant-external pressure and changing-internal pressure accords with the actual oilfield development, it is recommended to be used in the laboratory operation. It is concluded through the study that the stress sensitivity of reservoir rock can be evaluated with stress sensitivity coefficient α of the exponential model, the stress sensitivity coefficient, 0.005 MPa^-1a≤0.025 MPa^-1, denotes weak stress sensitivity; 0.025 MPa^-1a≤0.035 MPa^-1 middle-weak stress sensitivity, 0.035 MPa^-1a≤0.045 MPa^-1 middle-strong stress sensitivity, 0.045 MPa^-1a≤0.100 MPa^-1 strong stress sensitivity, and a≥0.100 MPa^-1 strongest stress sensitivity. Meanwhile, measurement data of stress sensitivity in several literatures proves that the lower the sandstone reservoir permeability, the stronger the stress sensitivity will be.

关 键 词：致密储集层 岩石上覆压力 孔隙压力 Terzaghi有效应力 应力敏感性 应力敏感系数 

分 类 号：TE311.2[石油与天然气工程—油气田开发工程]