吐哈盆地三叠系砂岩的孔隙类型及次生孔隙形成机理探讨

DISCUSSION ON THE PORE TYPES OF THE TRIASSIC SANDSTONE IN THE TULUFAN-HAMI BASIN AND THE FORMATION MECHANISM OF SECONDARY PORES

依据X -衍射、岩石薄片、扫描电镜、岩石物性等分析测试资料 ,详细研究并阐述了吐哈盆地三叠系砂岩的储层物性特征、次生孔隙类型及其形成机理。综合分析认为 ,吐哈盆地三叠系储层主要为中上三叠统长石质岩屑砂岩 ,孔隙类型以次生孔隙为主 ,储层物性相对较差 ,总体属于中孔 -低渗或低孔 -低渗性储层 ;吐哈盆地三叠系砂岩在成岩作用过程中发育形成了较为有利的裂隙 -溶蚀型次生孔隙 。

According to the X ray diffraction, rock thin section, scanning electron microscope, rock physical property and other testing data, the physical property features of reservoirs and the types and formation mechanism of secondary pores for the Triassic sandstone of the Tulufan Hami Basin were discussed and expounded in detail. The comprehensive analyses showed that the Triassic reservoirs of the Tu Ha basin are mainly the Middle Upper Triassic feldspathic litharenite,and the pore types are dominated by secondary pores. As the reservoirs have relatively poor physical properties, they belong to medium porosity and low permeability or low porosity and low permeability resrvoirs on the whole. During the diagenesis of the Triassic sandstone in the Tu Ha Basin, the more favorable fissure solution typed secondary pores were developed, which constitute the major hydrocarbon bearing space types of the Triassic sandstone in the Basin.