巴楚—麦盖提斜坡区油、气、水成因分析及其勘探意义

摘要

针对巴楚—麦盖提斜坡区油气田的油、气、水特征存在较大差异性的现象,在对比油、气、地层水地球化学特征的基础之上,探讨分析了它们的成因.研究认为,和田河气田原油裂解气和干酪根裂解气的混合气在中—下寒武统膏岩封闭作用下发生硫酸盐热还原反应以后,以水溶气的方式运移至上覆奥陶系—石炭系圈闭中,形成了现今高干燥系数、重碳同位素特征的气藏,以及奥陶系风化壳顶面附近低矿化度、高变质系数的Na2SO4型地层水.中—下寒武统膏岩层对巴楚—麦盖提斜坡区油气形成、演化和分布有重要影响,膏岩层之下可以作为一个潜在的勘探领域.%By comparing with geochemistry characters of oil, gas and formation water, the genesis of fluids has been analyzed in the Bachu-Maigaiti Slope of Tarim Basin. It is considered that the gypsum layer of the Lower-Middle Cambrian is the important geological factor which controlled the genesis of oil, gas and water, and controlled the different distribution of oil-gas field. The oil-cracked gas and kerogen-cracked gas, sealed up by gypsum rock from the Lower-Middle Cambrian in Hetianhe gas field, occurred TSR reaction. After that, they migrated to the Ordovician-Carboniferous traps in the way of water-soluble gas, then the gas pool was formed with high dryness coefficient and heavy carbon isotope presently. At the same time, the type of Na2SO4 formation water with low salinity and high metamorphic coefficient also generated nearest to the top of the Ordovician weathered crust. It is suggested that the layer under the gypsum rock would be a potential area for oil and gas exploration.