Method for computing relative content of CO2 in formation by using well-log information

Abstract

The invention relates to a method for computing relative content of CO2 in a formation by using well-log information. The method comprises the following steps: (1) converting a gas volume ratio under the conditions of ground and gas reservoirs: converting relative CO2 content obtained through ground test into relative CO2 content under formation condition; (2) determining an average hydrogen index of gas: computing the average hydrogen index of the gas in pores; (3) correcting water-containing influence on well-logging counting rate: eliminating the influence on the well-logging counting rate caused by formation water, and highlighting the difference of response to CO2 and methane caused by the well-logging counting rate; (4) establishing a quantitative computation model for the relative CO2 content: computing the relative content of the CO2 under the formation condition. According to the method, through establishing a well-logging counting rate value, the average hydrogen index of the gas and the computation model for the CO2 content and predicting the relative content of the CO2 in the formation, the accuracy of the model is relatively high, the practicability is relatively high, and the popularization and application value is relatively good.

Description

technical field [0001] The invention relates to a method for calculating CO in formations by using well logging data 2 The method of relative content, using CO in the formation 2 Response characteristics on the logging curve, establishing logging count rate, gas average hydrogen index and CO 2 The quantitative relationship between relative contents belongs to the field of geophysical exploration. Background technique [0002] to CO 2 The study of gas reservoirs is not only a basic scientific research, but also an applied scientific research, which has great economic benefits. In recent years, with the CO 2 The promotion of use in the fields of industry, agriculture and national defense, CO 2 It has become a gas resource with a wide range of uses and high economic value, and there has been a promising market demand and development prospects in our country. my country has successively discovered a batch of high CO 2 Most of the gas reservoirs are distributed in the cont...

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Problems solved by technology

[0006] The purpose of the present invention is to effectively overcome factors such as formation physical properties, water saturation, etc. 2 Influence of Quantitative Calculation Accuracy: Based on Current Logging Technology in Evaluating CO 2 CO cannot be accurately predicted in gas reservoirs 2 Based on the current situation of CO content in the formation, a method is proposed to calculate the CO content in formation by using logging data 2 method of relative content

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