Fast prediction method of tight gas production based on segmented decline

Zhiqiang Fan,Kaifeng Wen,Tingting Jiang,Min Jing,Tao Zhang,Xiaoke Gong,L Li,S Zhu

doi:10.1051/e3sconf/202233801012

Zhiqiang Fan, Kaifeng Wen + Show 6 more

Open Access

https://doi.org/10.1051/e3sconf/202233801012

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Abstract

The physical properties of tight gas reservoirs are poor. During the stable production period of gas wells, most of the recoverable reserves are produced in the declining stage. It is of great significance to accurately study the declining law of tight gas. However, tight gas production declines rapidly in the early stage and slower in the middle and late stages, and the single model fitting and prediction results have large errors. In view of the above problems, according to the production change characteristics of tight gas wells, the decline stage is divided into three stages, and a segmented production decline law analysis method is established. The research results show that the early production decline of tight gas wells is exponential decline, the relatively slow middle-term production decline belongs to depletion decline, and the late production decline belongs to linear decline. Based on the study of the law of production decline, a gas reservoir production prediction software was compiled, and the production variation characteristics of single wells and gas reservoirs under certain stable production requirements were studied.

Highlights

This stage is in the early stage of instability, mainly based on the linear flow of fracturing fractures, and the pressure drop rate is large; the second stage is the natural continuous production stage, the pressure drop rate remains stable, the production decline is slow, and the gas well production begins to reach the level of reserves production
* Corresponding author: 2020050162@stu.cdut.edu.cn fit well the production history of Well A, and the predicted annual gas production in the later stage of production is consistent with the actual value
It is imperative to carry out research on the law of stepwise decline in tight gas wells to reasonably predict the production of gas wells

Summary

Variation characteristics of tight gas single well production

The production changes of gas wells during the production process show obvious two-stage characteristics. This stage is in the early stage of instability, mainly based on the linear flow of fracturing fractures, and the pressure drop rate is large; the second stage is the natural continuous production stage, the pressure drop rate remains stable, the production decline is slow, and the gas well production begins to reach the level of reserves production. From the fitting results of actual production data of Well A (Figure 1), the three traditional decline models cannot. Fit well the production history of Well A, and the predicted annual gas production in the later stage of production is consistent with the actual value. Inconsistent, the annual gas production predicted by different declining methods is higher or lower. It is imperative to carry out research on the law of stepwise decline in tight gas wells to reasonably predict the production of gas wells

Stepwise decline model for tight gas wells

Compilation of tight gas reservoir production prediction software

Findings

Conclusion