Overpressure is developed in shale gas reservoirs of the Wufeng-Longmaxi Formation in the Sichuan Basin,but the characteristics of the change of shale gas content during the evolution of overpressure are not clear.In order to explore the dynamic evolution process of Longmaxi Formation shale reservoir pressure and gas content,take L3H1 in Luzhou block of Sichuan Basin as an example,and reconstruct the anomalous pressure evolution process in Luzhou block with the help of basin simulation,fluid inclusion thermometry,laser Raman spectroscopy and other tests based on the previous research,and finally,combine with the paleo-temperature-pressure conditions,reveal the dynamic evolution process of shale reservoir pressure and gas content in Longmaxi Formation shale reservoirs of Luzhou block.The results show that:well L3Hl is a well of the Wufeng-Longmaxi Formation shale reservoir,which has been developed overpressure,but the change characteristics of shale gas content during the overpressure evolution process are still unclear.The results show that the mean temperature of fluid inclusions in well L3H1 is 98.6 ℃ to 214.4 ℃,with a mean value of 155.41 ℃,the freezing temperature is-9.3 ℃ to-2.2 ℃,with a mean value of-4.97 ℃,the displacement of methane laser Raman peak is 2 910.13 cm-1 to 2 910.57 cm-1 with a mean value of 2 910.32 cm-1,and the methane density is 0.262 g/cm3,which is the same as that in well L3H1,with a mean value of-3.97 ℃.0.262 g/cm3～0.284 g/cm3,the average value is 0.275 g/cm3;the pressure evolution process of L3H1 well is closely related to the hydrocarbon generation and drainage of organic matter,the reservoir pressure and pressure coefficient increase with the increase of organic matter maturity,at the maximum paleo-buried depth,the maximum pressure is 189.39 MPa,the pressure coefficient is 2.48,and the pressure relief occurs in the stage of stratigraphic uplift;the evolution of gas content of L3H1 well can be divided into the following categories well gas content evolution can be divided into three stages,the wet gas stage increases with the maturity of organic matter,adsorbed gas and free gas content increases,water-soluble gas content has the characteristics of first increasing and then decreasing,the dry gas stage,with the increase of maturity,free gas content gradually increases,adsorbed gas content increases with the first and then decreases sharply,water-soluble gas content continues to decline,the lifting stage,the adsorbed gas content increases gradually,water-soluble gas and free gas content gradually The content of adsorbed gas gradually increased and the content of water-soluble gas and free gas gradually decreased.
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维普
