摘要
作为西气东输工程的重要气源地，库车坳陷古近系、新近系膏盐岩下油气储量异常丰富。其中，库姆格列木群（E1-2km）膏盐岩主要由海侵盐水混杂部分陆源物质形成，吉迪克组（N1j）膏盐岩的成盐物质则以陆相为主。巨厚、分布广泛的膏盐岩分布具有明显的规律性：垂向上岩性组合可分为MG，GS，GD，GM等4个类型，平面上则以克拉苏构造带中部地区和秋里塔格构造带东段为中心呈环带状分布。垂向上，致密、热导率高、塑性强的膏盐岩与侏罗系、三叠系烃源岩和白垩系储层形成优质的生储盖组合，不仅使地层温度降低、压力升高，延缓了有机质热演化、成岩作用演化进程，有利于油气藏的形成与储层物性的改善，也阻隔、吸收了构造应力，从而在强烈构造挤压应力下有效保存了油气藏。
Abstract
As the vital gas source of West-East Gas Transmission Project, plenty of natural gas gathers under the gypsum-salt rock of Paleogene and Neogene in Kuqa Depression. Salt in E1-2km mostly originated from transgression brine mixed with part of terrigenous materials, while salt in N1j was mainly terrigenous. The thick and wide-spread salt distributes regularly. There are four kinds of lithology combinations vertically, including MG, GS, GD and GM. On the plane, it is distributed annularly with central Kelasu structural belt and eastern Qiulitage structural belt as the center. Vertically, the gypsum-salt rock with compactness, high thermal conductivity and strong ductility, the Triassic and Jurassic source rock and the Cretaceous reservoir form excellent source-reservoir-cap assemblage, which not only reduces formation temperature, enhances pressure, delays thermal evolution of organic matter and diagenesis evolution process, and is conducive to forming reservoirs and enhancing reservoir properties, but also absorbs the tectonic stress, thus effectively preserves reservoirs under the strong tectonic compression stress.
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