EFFECTS OF PORE EVOLUTION ON OIL AND GAS DISTRIBUTION IN THE TRIASSIC SYSTEM OF LUNNAN AREA IN THE TARIM BASIN

According to tbe data of drilling,core analysis and geochcmistry of wells deeper than 4000m in the Triassic system of Lunnan area,the author analyses and studies the geneses and evolutionary patterns of deep reservoirs and concludes that the type of the effective storing and gathering space of deep clastic rocks in the Triassic system of Lunnan area is secondary solution pore space.Based on the source of polar solution.the solution pore space in the deep Triassic system is divided into pore space of two-stage evolution,The solution pore space of Ⅰ stage is the main site for oil and gas accumulation,and the solution pore space of Ⅱ stage is the site for the redistribution and late-stage accumulation of oil and gas.On the basis of the study of pore evolution combined with sandbody distribution and its relation to oil-generating depressions,it is considered that the Triassic system of South Lunnan area is a favorable place for prospecting the oil and gas pools of solution pore space-typed reservoirs.