A method for rapid identification of unconventional gas reservoirs

Abstract

The invention discloses a method for quickly identifying unconventional gas reservoirs, comprising the following steps: a. collecting and arranging the mud logging engineering parameters and geological parameters of the target layer; b. calculating the mud logging clay index by using the mud logging engineering parameters and the geological parameters MLCF; c. Using the mud logging engineering parameters and geological parameters to calculate the free gas content index MLGA of the formation encountered; d. Using the calculated mud logging clay index MLCF and the free gas content index MLGA of the drilling formation to make a MLCF-MLGA intersection diagram; e. Rapidly identify the development of unconventional gas reservoirs by using the MLCF-MLGA crossplot. The invention utilizes the advantages of timely, efficient, real and rapid mud logging interpretation while drilling, and comprehensively uses mud logging engineering and geological parameters to quickly identify the development of tight lithologic gas reservoirs.

Description

technical field [0001] The invention relates to a method for quickly identifying unconventional gas reservoirs, and belongs to the application field of drilling-while-drilling data processing technology in the field of oil and gas industry exploration and development in the electromechanical field. Background technique [0002] Unconventional natural gas refers to hydrocarbon (or non-hydrocarbon) resources that are different from conventional natural gas in terms of accumulation mechanism, occurrence state, distribution law, or exploration and development methods. Unconventional natural gas mainly includes tight sandstone gas, coalbed methane, shale gas, etc. my country's unconventional oil and gas resources are very rich, and the development of unconventional energy has important strategic significance for ensuring national energy security, improving the environment, safe coal production, and solving "three rural" (agriculture, rural areas, and farmers) issues. [0003] The ...

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Problems solved by technology

[0003] The initial achievements in shale gas exploration in Fuling Jiaoshiba and Yibin Changning indicate that the exploration and development of tight lithologic gas reservoirs represented by shale gas and tight sandstone gas have entered a new stage. The ideal demands and practical needs of China's oil industry. At present, major domestic oil companies are making great strides in the field of unconventional oil and gas. However, it is difficult to succeed in the strategic succession of China's domestic conventional oil resources. Most oil fields in the eastern part of the land have entered the middle and late stages of development. More water is produced than oil is produced. Although the oil reserves in the central and western regions are large, the investment is large, the technology is complicated, and the degree of exploration is not high, and the understanding of unconventional gas reservoirs needs to be deepened. Mud logging interpretation technology is starting from scratch. Currently, for Currently, there are mainly the following problems in the exploration and development of unconventional oil and gas reservoirs:

[0004] 1. Formation reservoir performance is usually poor. Some people believe that shale gas occurs in ultra-low porosity and ultra-low permeability reservoirs, and the pore size can be as low as nanometers. This poses a strong challenge to traditional accumulation theory and interpretation and evaluation techniques

[0005] 2. Unconventional accumulation theory has not yet reached a consensus, and there are certain differences: At present, a series of intense discussions on the occurrence of unconventional oil and gas reservoirs and supporting geological theories for exploration and development have been carried out around the focus of shale gas reservoir accumulation theory in the industry , How to successfully transplant foreign advanced experience to domestic exploration and development theoretical research and exploration practice, how to quickly and effectively determine effective unconventional oil and gas reservoirs, and how to achieve the unification of engineering geological goals are still inconclusive, and urgently need deeper and wider research. Theoretical Innovation and Practical Practice

[0006] 3. Mud logging interpretation technology has not yet started: At present, most of the mud logging interpretation methods use statistical methods, and the differences in horizons, well data, and even equipment will have a significant impact on statistical data and conclusions. Changing the statistical model cannot be applied in early exploration wells, while some other methods have serious human influence, and may even cause serious inaccuracies in the interpretation results, which cannot ensure the objectivity of the conclusions

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