玛湖油田致密砂砾岩储层岩心差应变实验

Core differential strain test of tight glutinite reservoir in Mahu oilfield

为了获得新疆玛湖油田百口泉组致密砂砾岩储层地应力大小数据并指导压裂设计和施工,利用该储层段钻井中获取的砂砾岩和泥岩岩心进行了室内差应变实验,并依据实验数据对储层三向主应力大小进行了分析。实验结果表明,百口泉组储层段水平最大主应力与垂向主应力大小相近,砂砾岩储层水平最大主应力平均为71.8 MPa,水平最小主应力平均为51.1 MPa;泥岩隔层水平最大主应力平均为72.9 MPa,水平最小主应力平均为56.1 MPa。同时,利用压裂、成像测井等工程数据对水平最大、最小主应力进行评价,验证了差应变实验数据解释地应力大小的可靠性,表明通过差应变实验得出的主应力数值能够反映玛湖油田百口泉组致密砂砾岩储层现今地应力状态,可用于钻井、压裂等工程设计。

In order to obtain the in-situ stress data of the tight glutinite reservoir of Baikouquan Formation in Mahu oilfield,Xinjiang,so as to guide the fracturing design and operation,indoor differential strain tests have been carried out on the glutinite and mudstone cores obtained in the reservoir section drilling,and three directional principal stresses of the reservoir have been analyzed based on the test data.The results show that the size of the maximum principal stress in the Baikouquan reservoir is similar to that of the vertical principal stress.The average maximum and minimum horizontal principal stresses in the glutinite reservoir are 71.8 MPa and 51.1 MPa,respectively,and those in the mudstone interval are 72.9 MPa and 56.1 MPa,respectively.At the same time,the maximum and minimum principal stresses have been appraised based on engineering data,including fracturing and imaging logging data,which verifies the reliability of in-situ stress interpretation with differential strain test data.Therefore,principal stress values obtained by differential strain tests can reflect the current geostress state of the tight glutinite reservoir of Baikouquan Formation in Mahu oilfield and can be used in engineering design such as drilling and fracturing.