A gas-bearing property evaluation method for tight sandstone anhydrous gas reservoirs

Abstract

The invention discloses a tight sandstone anhydrous gas reservoir gas-bearing capacity evaluation method, and solves the technical problem of low tight sandstone anhydrous gas reservoir gas-bearing capacity evaluation precision in the prior art. The method mainly comprises the following steps: sequentially calculating a shale content curve Vsh, an effective porosity curve phi e, a pure rock neutron curve CNL1, an apparent sandstone skeleton hydrogen content index curve CNL2 and a gas content evaluation index parameter GASFG curve, and finally carrying out gas content evaluation according to the gas content evaluation index parameter GASFG curve. According to the method, the excavation effect of the natural gas on the neutron logging curve is fully utilized to quantitatively characterize the gas-bearing index parameters, and the technical problem in the prior art that the tight sandstone anhydrous gas reservoir is difficult to accurately evaluate the gas-bearing property of the reservoir under the condition that stratum water and other data are lacked is effectively solved through classification evaluation. Practice proves that the technology not only can accurately evaluate the gasbearing capacity of the tight sandstone anhydrous gas reservoir, but also can effectively identify the high gamma reservoir, so that an accurate exploration method is provided for oil and gas exploration.

Description

technical field [0001] The invention belongs to the technical field of exploration and development of gas reservoirs, and in particular relates to a method for evaluating gas-bearing properties of tight sandstone anhydrous gas reservoirs. Background technique [0002] In recent years, the exploration results of narrow channel tight sandstones in the Jurassic Shaximiao Formation in the Qiulin block in central Sichuan show that the source-reservoir configuration in this area is good, which is favorable for the development of reservoir facies. At present, the test results of new wells and old wells in this block have confirmed that sand formations No. 5, No. 8 and No. 11 of the Shaximiao Formation have all obtained high-yield gas wells without producing formation water, showing good exploration potential. With the deepening of the research, it was found that some wells in the study area showed good reservoir characteristics on the well logging curves, but the test results were ...

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Problems solved by technology

[0007] The technical problem to be solved by the present invention is to provide a method for evaluating the gas-bearing property of tight sandstone anhydrous gas reservoirs, and to solve the technical problem of low accuracy in evaluating the gas-bearing properties of tight sandstone anhydrous gas reservoirs in the prior art

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