疏松砂岩应力敏感性及对井眼坍塌的影响  

Stress sensitivity of unconsolidated sandstone reservoir and its effect on borehole collapse

作　　者：赵博 惠江涛[2] 许洋[3] 王举[3] 苏亚中[3] 王俊[3] ZHAO Bo;HUI Jiangtao;XU Yang;WANG Ju;SU Yazhong;WANG Jun(Oil Industry Training Centre, China University of Petroleum (East China), Qingdao, Shandong 266580, China;NO.5 Oil Production Plant of Qinghai Oilfield, Haixi, Qinghai 817000, China;NO.1 Oil Production Plant of Qinghai Oilfield, Haixi, Qinghai 817000, China)

机构地区：[1]中国石油大学(华东)石油工业训练中心,山东青岛266580 [2]青海油田采油五厂,青海海西817000 [3]青海油田采油一厂,青海海西817000

出　　处：《中国科技论文》2020年第9期980-986,共7页China Sciencepaper

基　　金：国家重点研发计划项目(2016YFC0304005);国家重点基础研究发展计划(973计划)项目(2015CB251201)。

摘　　要：针对开展井壁坍塌失稳等工程地质灾害分析时,因忽略其物性参数的应力敏感性而导致模拟结果出现误差的问题,首先通过疏松砂岩储层岩样的应力敏感性实验得到了其物性参数与有效应力之间的关系模型,然后基于该模型探讨了钻井过程井周地层物性参数响应特征,最后对比分析了当考虑和不考虑物性参数应力敏感性时的井壁失稳状况。结果表明:平衡钻井过程中弹性模量、泊松比、内聚力除了会在井周应力集中区增大外,在井周其他区域均表现出不同程度的减小趋势;井周应力集中区由于应力升高导致渗透率和孔隙度有所降低,而其他区域孔隙度和渗透率则由于有效应力的降低而升高;任意钻井液密度下忽略物性参数应力敏感性时的井眼扩大率均小于考虑应力敏感性时的井眼扩大率。可见,考虑疏松砂岩油气藏物性参数的应力敏感性对于井壁稳定等工程地质灾害的分析和模拟至关重要。Analysis of engineering geological hazards such as wellbore instability during oil and gas development in unconsolidated sandstone reservoirs usually ignore the stress sensitivity of physical parameters,leading to errors in simulation results.For this reason,the relationship model between the physical parameter and the effective stress was developed by experiments.Based on the model,the responses of physical parameters such as the elastic modulus within the near-wellbore region during the drilling operation were also discussed.Finally,the wellbore instability with and without considering stress sensitivity of physical parameters were respectively analyzed.The results show that the mechanical parameters such as the elastic modulus in overbalanced drilling operation all decreased in other areas except the stress concentration area around the borehole.Likewise,the permeability and porosity of the stress concentration area around the borehole will decrease due to the increase of effective stress,while the permeability and porosity of other areas around the borehole will increase due to the decrease of effective stress.Finally,it is also found that for all different drilling fluid densities,the borehole enlargement rates when the stress sensitivity of physical parameters is not considered are all lower than that when the stress sensitivity is considered.Therefore,it is very important to consider the stress sensitivity of physical parameters of unconsolidated sandstone reservoirs for simulation of borehole stability and other engineering geological disasters during development.

关 键 词：疏松砂岩 井眼坍塌 物性参数 应力敏感性 钻井工程 

分 类 号：TE357.1[石油与天然气工程—油气田开发工程]