盐湖沉积硬石膏特征及其在油气勘探中的应用

CHARACTERISTICS OF ANHYDRITE IN SALINE LAKE DEPOSITS-AN APPLICATION IN HYDROCARBON EXPLORATION

研究了塔里木盆地塔北隆起轮台断隆第三系盐湖沉积中硬石膏的结构、构造，并进行了硬石膏的微量元素分析和电子探针分析，共划分出11种构造类型和8种结构类型。将硬石膏的组构及元素特于沉积环境的分析、构造应力分析、成岩作用及储集层物性研究，认为研究区第三纪主要为间歇性盐湖沉积环境，水动力条件总体较弱；第三系储集层所处的成岩阶段可划分为早成岩A期和B期（吉迪克组）和晚成岩A期（苏维依组）；粘土矿物演化主要受控于气候因素；硬石膏是储集层中主要的胶结物，储集层物性变差的主要因素之一是硬石膏连晶状胶结的非均质性。

This paper studies the structures and textures of anhydrite of Tertiary saline lake in Luntai fracture-uplift zone, Tabei uplift,Tarim basin, and also makes the analysis of trace elements and electronic probe of anhydrite. Eleven types of structure andeight types of texture of anhydrite have been recognized. These patterns are applied in the interpretation of sedimentaryenvironments, the analysis of tectonic stress and the study of diagenesis and physical property' It is considered that theTertiary in this region is mainly of saline lake deposits formed under a weak hydrodynamic condition. The diagenetic stage ofTertiary can be divided into Early diagenetic periods A and B (Jidik FM) and Late diagenetic period A (Suweiyi FM). Claymineral evolution is mainly controlled by climate. Anhydrite is the major cement of the reservoir of this region. One of themain factors making the reservoir becoming poor is the heterogeneity of the crystal intergrowth cementation of anhydrite.