Method for predicting total organic carbon (TOC) content of shale

Abstract

A method for predicting the total organic carbon (TOC) content of shale comprises the following steps: subjecting a shale sample to a physical test and analysis to obtain the rock parameters of the shale sample; based on the rock parameters, obtaining first mathematic relationship between TOC of the shale sample and each well logging parameter of multiple well logging parameters; carrying out well logging analysis, based on the results of the well logging analysis, obtaining second mathematic relationship between TOC and each well logging parameter; aiming at each well logging parameter, judging the consistency between the first mathematic relationship and the second mathematic relationship; aiming at each well logging parameter, when the first mathematic relationship and the second mathematic relationship are consistent, based on the first mathematic relationship or the second mathematic relationship, calculating the similarity between TOC and the well logging parameter; choosing the well logging parameter having the maximal similarity as the prediction parameter; and based on the value of the prediction parameter, and the first mathematic relationship and the second mathematic relationship between TOC and the prediction parameter, predicting the TOC of the shale sample.

Description

technical field [0001] The present disclosure relates to the field of unconventional shale gas exploration and development, in particular to a TOC prediction method for shale organic carbon content based on rock physics and well logging analysis. Background technique [0002] Shale gas refers to natural gas with methane as the main component and stored in high-carbon mudstone or dark (black) mudstone in the form of free and adsorbed states. Free and adsorbed properties are the main characteristics of shale gas. The TOC of shale is the key factor for the enrichment of shale gas, and it is one of the symbolic parameters that distinguish unconventional gas reservoirs from conventional gas reservoirs. The prediction of TOC is a new subject for geophysical technology. [0003] There are many factors affecting shale gas enrichment, including shale thickness (scale), TOC, thermal evolution degree, and formation pressure. Among them, TOC is one of the important factors. The higher ...

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Problems solved by technology

[0005] However, shale has regional differences and differences in characteristics. For example, although shale in China and the United States are well developed, their geological characteristics are quite different, mainly in the geological structure conditions and shale deposition types in the shale distribution area. , shale depositional age, thermal evolution conditions, shale maturity period and maturity, burial depth, preservation conditions, etc. Therefore, the method proposed above is not universal, and it is debatable whether it is applicable to the shale in the target selection area

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