Fast prediction method of tight gas production based on segmented decline

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.