鄂尔多斯盆地上古生界异常低压分布特征及形成过程  

Distribution characteristics and formation process of Upper Paleozoic abnormally low pressure zones in Ordos basin

作　　者：袁际华[1] 柳广弟[1] 

机构地区：[1]中国石油大学油气成藏机理教育部重点实验室,北京102249

出　　处：《石油与天然气地质》2005年第6期792-799,共8页Oil & Gas Geology

基　　金：国家重点基础研究发展规划(973)项目(2001CB209103)

摘　　要：鄂尔多斯盆地上古生界多见异常低压、低压,高压少见。平面上,苏里格庙地区地层呈异常低压、低压,米脂区地层呈高压和常压,其他地区地层以常压和低压为主;垂向上,水层压力基本沿静水压力趋势线分布,而气水层和气层压力均偏离静水压力趋势线,气层压力偏离程度大于气水层,且压力系数随深度的增加而减少。包裹体测试数据和盆地埋藏-剥蚀资料都表明,鄂尔多斯盆地上古生界异常低压气藏的形成大体分两个阶段:晚侏罗世—早白垩世末的充气增压阶段;早白垩世末至今散失降温降压阶段。气藏压力的降低主要与盆地抬升降温、天然气散失和气水密度差等因素有关。In Ordos basin, abnormally low and low pressures are common, while high pressure is rare in Upper Paleozoic. Laterally, the Upper Paleozoic in Suligemiao area displays abnormally low and low pressures, while that in Mizhi area dispalys normal and high pressures, and the other areas mainly display normal pressure and low pressure. Vertically, pressure of acquifers basically distribute along the trend line of hydrostatic pressure; while that of gas-bearing acquifers and gas-bearing formations deviate from the trend line of hydrostatic pressure, the latter has larger extent of deviation than the former, and the pressure coefficient decreases with increasing depth. Both the test data of inclusions and the burial-denudation data of the basin indicate that the Upper Paeozoic gas pools with abnormally low pressure in Ordos basin would have been formed in two stages： gas charging and pressurizing from Late Jurassic to Early Cretaceous, and gas-dispersion, temperature lowering and depressurizing stage from the end of Early Cretaceous up to present time. The depressurization of gas pool would have mainly resulted from basin uplift, temperature lowering, gas dispersion and density contrast of gas and water.

关 键 词：异常低压 上古生界 鄂尔多斯盆地 

分 类 号：TE112.1[石油与天然气工程—油气勘探]