鄂尔多斯盆地中生界异常低压成因定量分析  

Quantitative analysis of the Mesozoic abnormal low pressure in Ordos Basin

作　　者：李士祥[1,2,3] 施泽进[1] 刘显阳[1,3,4] 杨时雨[3,4] 邓秀芹[2,3] 刘广林[2,3] 李继宏[2,3] 

机构地区：[1]成都理工大学能源学院 [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 [4]中国石油长庆油田公司勘探部

出　　处：《石油勘探与开发》2013年第5期528-533,共6页Petroleum Exploration and Development

基　　金：国家科技重大专项(2011ZX05044;2011ZX05001-004)

摘　　要：鄂尔多斯盆地中生界具有明显的异常低压特征，根据其低压分布特征，从构造抬升、温度降低、溶蚀增孔作用等方面定量剖析了异常低压的成因机制。中生界地层压力演化主要经历了晚三叠世到早白垩世期间的压力增大并达到最大阶段，以及早白垩世末以来的压力降低直至现今的异常低压阶段。早白垩世末以来，构造抬升引起的孔隙反弹、地层温度降低和溶蚀增孔作用共同造成的压力降低幅度达20-25MPa，降低比例达54％-77％，这3者的共同作用是鄂尔多斯盆地中生界地层压力降低的主要原因，其中温度降低是影响压力降低的最主要因素。上述3因素与其他多种因素共同作用，使得地层压力逐渐降低，最终形成了现今地层压力为10～18MPa的异常低压分布格局。Abnormally low pressure is characteristic of the Mesozoic reservoirs in the Ordos Basin. Based on the study of low pressure distribution, the formation mechanisms of abnormally low pressure were quantitatively analyzed from several aspects, such as tectonic uplift, stratum temperature decrease and dissolution-increased porosity. The Mesozoic reservoir pressure experienced two major evolutionary stages： the pressure rising to maximum pressure stage from the Late Triassic to the Early Cretaceous, the pressure decreasing to abnormally low pressure stage from the end of Early Cretaceous to now. Since the late Early Cretaceous, porosity rebound caused by tectonic uplift, stratum temperature decrease and dissolution caused pressure decrease of up to 20-25 MPa, the decrease ratio is about 54%-77%. The three factors are the main reason for the pressure decrease of the Mesozoic in the Ordos Basin, and among them stratum temperature decrease is the most important factor. Combined with other factors, they made the formation pressure reduced graduallv and eventually formed the abnormally low pressure distribution 19attern of 10-18 MPa.

关 键 词：异常低压 构造抬升 地层温度降低 溶蚀增孔作用 延长组 中生界 鄂尔多斯盆地 

分 类 号：TE122.1[石油与天然气工程—油气勘探]