【作者】 陈青；

【导师】 王允诚；

【作者基本信息】 成都理工大学 ， 油气田开发工程， 2007， 博士

【摘要】 川西须家河组气藏储层致密、埋深深、地层压力高及圈闭形成历史复杂、勘探难度高，同时对压裂工艺技术的要求也高。在已有的5口压裂施工井中，3口井施工时未成功，施工时最高井底压力达到128MPa、159.6MPa、135.1MPa。因此，研究区须家河组可能存在“高破裂压力”，开展须家河组致密砂岩储层“高破裂压力”研究成为实现该区储层压裂改造突破的关键因素。通过对川西深层须家河组特征的认识，在破裂模拟实验的基础上，系统分析了影响破裂压力的地质、工程因素，取得了如下主要成果：(1)岩石力学参数测试情况表明，岩石抗张强度随孔隙度的增加呈指数式下降。通过与侏罗系的对比，深层须家河组的抗张强度一般高于侏罗系一倍以上，从而导致深层须家河组破裂压力高。(2)运用美国大型设备—岩石物性参数自动测试系统(MTS系统)，在该地区进行了破裂模拟实验。多数岩石经钻井液浸泡后泊松比增大，局部水平应力将会升高，从而使水力压裂时岩石的破裂压力增大。(3)采用测井方法、压裂方法，结合差应变测量结果，开展了深层11口井地应力剖面图解释。最小主应力偏高是导致破裂压力高的一个原因。(4)首次系统地总结了深层须家河组的破裂压力高的主要地质原因和储层原因。储层的致密程度加大，造成岩石抗张强度比侏罗系高一倍多；埋深增大地应力增加和地层压力增加是影响储层破裂压力升高的主要因素；(5)首次系统地总结了深层须家河组的破裂压力高的工程因素。影响程度较大的因素是井眼应力畸变、裂缝的弯曲摩阻。(6)在对岩层弯曲派生应力、井眼应力畸变等各种影响因素进行定量分析的基础上，提出了川西地区深层破裂压力评价的公式。(7)利用生产压裂资料，对川西须家河组进行了部分单井破裂压力验证和评价，通过初步分析认为是可用的，有待今后实际应用检验。更多还原

【Abstract】 It have characteristics of tight stratum、deep bury、high pressure、complex trap、difficult exploration in Xujiahe Reservoir of west Sichuan. All of these bring much more requests for fracture technology. Among operating 5 wells, 3 wells fracture operation have failed because of high wells pressure. Their pressure are 128MPa、159.6MPa、135.1MPa. So it is possible that there is a high fracture pressure area in Xujiahe Reservoir. It is the key factor to study of high fracture pressure for fracturing success in the deep Xujiahe Reservoir.On the basis of fractured modeling test, it is studied in detail on geology factors and engineering factors by means of knowledge about geology characteristics in Xujiahe Reservoir. It have been get some results here:(1)It is affected in the rock mechanics test that rock tensile strength exponential declines with porosity increasing. Rock tensile strength of Xujiahe reserveoir is higher 1 twice than Jurassic reservoir. This will make fracture pressure too high.(2)The big fracture modeling test has been done in Xujiahe Reservoir. Horizontal stress will increase after rocks are soaked in mud. This will make fracture pressure too high.(3)11 wells stress section have been interpretation by well log method and fracture method with differential stress test. Min horizontal stress is so high to make fracture pressure too high.(4)Geology factors and reservoir factors have been studied in detail here. Tight stratum、high pressure、high stress are important factors to increase fracture pressure.(5) Engineering factors have been studied in detail here. Stress of well bore distortion、fissure frictional resistance made by bending are the key factors for high fracture pressure.(6)The formula of fracture pressure has been brought out here based on rock bending distortion and stress of well bore distortion, etc.(7)Well fracture pressure has been demonstrated and evaluated with fracture operating well.更多还原