Study On Shale Gas Enrichment Conditions In Yichang Area

Content:This paper systematically studies the?1?sedimentary characteristics of the shale in the Upper Ordovician Wufeng formation-Lower Silurian Yichang,?2?the organic geochemistry characteristics?3?reservoir characteristics?pore structure??4?tectonic preservation conditions,draw the conclusions:?1?Yichang slope Belt in the Upper Ordovician Wufeng formation-Lower Silurian,the development of deep shelf facies,The sedimentary environment of the shale in the Wufeng formation in the Jiaoshiba area is similar to that of the dominant sedimentary facies zone.The organic matter types of?2?shales in Yichang are mainly I,?₁ type,organic carbon content is high,organic matter maturity is in mature-high mature stage,and has similar geochemistry characteristics with the area of Jiaoshiba.The?3?shales in Yichang reservoir space is mainly nanometer-grade pore,by means of NMR,nitrogen low temperature adsorption and pressure mercury-nitrogen low-temperature adsorption method to determine the pore size distribution of YD-1 well shale samples,it shows that the main pore size of the YD-1 shale sample is about 4nm,and the shale sample is polished by argon ion.,the pore types of shale development are mainly pore of organic matter,intergranular pore,dissolution hole,also can see micro-fracture development,argon ion polishing shows the pore size of shale development is mainly mesoporous,which is consistent with the results of NMR,nitrogen low-temperature adsorption and high pressure mercury and nitrogen low-temperature adsorption method.the experimental results is added each other.?4?Yichang is a stable slope belt,according to the drilling core of YD-1 well,the development thickness of the whole Longmaxi Formation is 1200 m,and the mudstone of 57 meters is developed in the lower part of the Longmaxi formation.Upward from the siltstone gradually transition to sandstone,and according to data,the Yichang distribution area is extensive,has the good cover condition,and the Wufeng formation-the lower part of the Longmaxi formation develops the hundred meter thick Linxiang formation and the Baota formation dense limestone,indicated that the Yichang Wufeng formation-The Lngmaxi formation shale gas roof bottom slab condition is superior,Like the area of the Jiaoshiba,it has good preservation conditions.The above conditions indicate that Yichang has good prospects for shale gas resources.