柯东地区白垩系克孜勒苏群储层特征及控制因素

以野外露头、岩心观察为基础,综合采用普通薄片、铸体薄片、阴极发光薄片、扫描电镜、物性分析、黏土矿物X射线衍射等多种测试手段,对塔西南柯东地区白垩系克孜勒苏群碎屑岩储层基本特征进行了分析,并结合盆地构造活动、沉积特征、成岩特征研究了该套碎屑岩储层发育控制因素。结果表明:塔西南柯东地区白垩系克孜勒苏群砂岩以长石岩屑砂岩为主,次为岩屑长石砂岩;储层发育原生粒间孔、少量溶孔和微孔隙,孔隙结构为微细喉—细喉,储层孔隙度一般在10%左右,渗透率在(0.1~10.0)×10-3μm2,为低孔低渗储层;影响该区储层发育的控制因素有岩相、埋藏方式和成岩作用,其中岩相和碳酸盐胶结作用是主控因素。因此,寻找非致密胶结粗粒岩相发育带是该区下一步油气勘探的方向和突破点。

Characteristics and controlling factors of Cretaceous Kezilesu Group reservoir in Kedong Area

Based on outcrop and core observations, this paper investigated the basic geological characteristics of Cretaceous Kezilesu Group cJastic reservoirs in Kedong Area of southwest Tarim Basin by applying various measurements, such as the analyses of normal thin section, cast thin section and cathodoluminescence thin section, scanning electron microscope and X-ray diffraction of clay minerals. Combined with the tectonic activities, depositional and diagenetic characteristics of the basin, the controlling taetors of clastic reservoir development were studied. The result shows that Cretaceous Kezilesu Group sandstone is mainly feldspar lithic sandstone, followed by lithic feldspar sandstone. The reservoir spaces include primary intergranular pores, few intergranular dissolution pores and mieropores. The pnre structure is from micro-fine throat to fine throat and it is low porosity and low permeability reservoir with porosity of about 10% and permeability of 0.1-10 rod. The controlling factors influencing the reservoir development in this area are lithofacies, diagenesis and buried way, in which, the cementation of carbonate is the master control factor. Therefore, the coarse grain lithofacies reservoir is new target and breakthrough point fnr further exploration in Kedong Area.