CHARACTERISTICS OF RESERVOIR AND THE FORMING CONDITION OF GAS RESERVOIR IN MIDDLE-EAST AREA OF CHAIDAMU BASIN
DENG Jin hui 1,SHI Ji'an 1,WANG Qi 1,HU Yong 2,ZHOU Rui nian 2,ZHANG Dao wei 2 (1.Lanzhou Institute of Geology, Chinese Academy of Sciences, Lanzhou 730000,China;2.Institute of Exploration and Development Research, Qinghai Petroleum Administra
The Qigequan formation is one of the important reservoirs and the important layers that produce gas. Based on the study of depositional characteristics and forming condition of gas pool we can concluded that: (1) Rock granularity of the reservoir is generally. very fine and mudbearing siltstone, which belong to a shore shallow lake sedimentation system. (2) Diagenetic degree of the reservoir rocks is very low so primary porosity of rock is well developed and have excellent permeability. (3) In the Quaternary system, Pleistocene series, lake basin underwent a changeable process of expanding, stabilizing and shrinking. So the sedimentary facies of shore lake, shallow lake, and deeper lake are joint each other vertically. (4) The gas reservoirs in the study area have the characteristic of generating itself, storaging itself and enveloping itself, and primary reservoirs exist in K 2 -K 10 .