Characteristics Of Organic Matter Shale Deposit And Reservoir In The Niutitang Formation,southeast Chongqing

Based on the theory of sedimentology and reservoir geology,this paper takes the field outcrop profile data,drilling core data and sample analysis data,and analyzes the data of the Niutitang Formation in the southeastern part of Chongqing,Organic matter shale deposition and reservoir development characteristics were studied,and the reservoir favorable area was evaluated.The paper has made the following achievements and understanding.According to the rock type,sedimentary structure,lithofacies change and other sedimentary facies signs,the sedimentary facies and sequence division of the organic shale in Niutitang Formation were carried out.According to the difference of lithology,it is divided into carbonaceous,siliceous and calcareous-sandy shelf microfacies.According to the lithological changes,the sediments can be divided into shallow water shelf and deep water shelf.The microphase stacking relationship is divided into two third order sequences.On the basis of the above,the evolution and spatial distribution of sedimentary facies of Niutitang Formation are discussed in detail.The reservoir space of the organic shale in Niutitang Formation was studied in detail.The reservoir space of Niutitang Formation was interbedded,intergranular pores,intergranular pores and organic matter pores and fractures.The porosity distribution was 0.1 % To 2%,with an average of 0.98%;the permeability is?0.0001 0.015?× 10^-3?m²,with an average of 0.072 × 10^-3?m².The organic geochemical characteristics of organic matter shale are analyzed in depth.The geochemical analysis data show that the abundance of organic matter in the Niutitang Formation is high and the TOC value is generally greater than 2%.The high value area on the plane is concentrated in the Xiushan-Youyang area,and the TOC content in the northwest direction is reduced.The overall thermal evolution is high and the Ro average To 3.13%,in the mature stage.Based on the comparison of the evaluation parameters of the domestic shale gas and the rich organic shale in Chongqing,the favorable area of shale gas in Niutitang Formation is defined as the depth of 500 4500 m,the effective thickness About 30 90 m,TOC content of 1.5 4.5%,the surface conditions are relatively good zone,and divide the shale gas into a class ? favorable area and a class II prospective area.