Assessment Of Resource Potential And Economy Concerning Shale Gas Of Longmaxi Formation In Pengshui-Nanchuan Area

The facies of Longmaxi formation is shallow marine shelf in Pengshui-Nanchuan area where organic rich shale is widely developed with a thickness of 10-120m.Shale reservoir has high TOC content,mainly distributed in 1.0%-5.0%,which has high thermal evolution degree and Ro is more than 2.0%and kerogen type is mainly ?type.Shale reservoir also has high brittleness mineral content and porosity concentrated in 2%-3%,with low permeability.The forming characteristics of Longmaxi Formation shale micron-size pore.nanoscale pore and micro-fracture were quantitatively characterized.Combined with test data of Ro,X-ray diffraction mineral composition,controlling factors of pores forming characteristics were analyzed on the three above surfaces.The positive factors of micron-size pore are quartz and illite,and the negative are depth and carbonate.The positive factors of organic matter pore are Ro and illite-smectite,and the negative is calcite.The positive factors of micro-fracture are quartz,Ro and Toc,and the negative is calcite.As shale gas reservoir belongs to Self-generated,hydrocarbon is the key consideration in reservoir evaluation.From the total air content,discussed factors affecting hydrocarbon reservoir,the study found that the total air content 0.5 m3/t can be used as demarcation line to distinguish reservoir and non reservoir.The index and the total content showed different degrees of relationship.Using the grey correlation theory and referencing to the previous achievements and experience data,the reservoir is classified evaluation.At the same time,the classified evaluation scheme and the image features of reservoir space are established and the reservoir of PY1 is classified evaluation.Shale gas geology resource is 6886.38×108m3 and recoverable resource is 826.37×108m3 of Longmaxi formation in Pengshui-Nanchuan area.Preliminarily delineated the shale gas exploration area is Longmaxi formation and then a vision zone,four advantageous area and four target zone are optimized in Pengshui-Nanchuan area.On the basis of single well production and the expected economic benefits,Using the real option method,the wells of PY1,PY3 and PY4 on shale gas development is evaluated from the aspects of economy.Reasonable development of the three wells is forecasted:rational development period of PY1,PY3 and PY4 is respectively for 13 years,15 years and 10 years.From the aspects of exploration and development,comprehensive utilization.government subsidies and environmental protection,development proposals of shale gas industry was achieved.