Study On Shale Gas Accumulation Conditions Of The Carboniferous-Permian In Juyanhai Depression,Yin'e Basin

The petroleum exploration of Juyanhai depression in Yin'e basin is low,lacking analysis of core samples of Carboniferous-Permian mudstone and the study of unconventional oil and gas.This thesis is focused on the Carboniferous-Permian mudstone in Juyanhai depression of Yin'e basin,and through field geological investigation,sample collection and indoor test and analysis,the characteristics of mudstone development,the geochemical characteristics and reservoir characteristics of mudstone are studied.Based on the comparison with the geological characteristics of gas-generating mudstone from China and overseas,a preliminary evaluation of shale gas accumulation conditions is carried out.The main conclusions are as follows:Carboniferous-Permian mudstone in study area developed in Wuzhuer sag,Tiancao sag and Jigeda sag.The mudstone average thickness is 400m and the buried depth is960?3200m.The organic geochemical characteristics of Carboniferous-Permian mudstone in study area indicate that the TOC value is between 0.42%?6.68%,the organic matter is mainly of type?Kerogen,the Ro value is between 0.54%?0.80%and most beyond0.70%,reaching the mature stage.And the mudstone in Wuzhuer sag belongs to good-excellent source rock,whose organic matter is mainly of type?Kerogen,at low mature-mature stage;the mudstone in Tiancao sag belongs to medium-good source rock,whose organic matter is mainly of type?Kerogen,at mature stage;the mudstone in Jigeda sag belongs to medium source rock,whose organic matter is mainly of type?Kerogen,at high mature stage.The mineral composition of mudstone is dominated by quartz and clay minerals.The reservoir space is diverse and the dissolution pores and micro-fractures are well developed,which provides a good space for the accumulation and migration of shale gas.The porosity and the permeability of the mudstone are similar to gas-generating shale from China and overseas.According to the analysis results of gas-bearing characteristics,the average total gas-bearing content of Carboniferous-Permian mudstone in Well MED1is 1.332m~3/t,which indicates that enough shale gas can be accumulated in the study area.According to analysis of mudstone thickness,burial depth,organic geochemical characteristics,reservoir characteristics and gas-bearing characteristics,Carboniferous-Permian mudstone in Juyanhai depression,Yin'e basin has shale gas accumulation conditions.The northwest area of Wuzhuer sag and the middle area of Jigeda sag are favorable areas for shale gas accumulation.