Research on Contribution Rate of Commingled Multi-layer Tight Gas Reservoir in Sulige Gas Field

Abstract

Sulige gas field is a typical tight sandstone gas reservoir in China, the main production interval was identified in the Shihezi formation and Shanxi formation, and the development wells are produced by commingled method. Therefore, it is necessary to obtain the reliable contribution rate of different formation by carrying out the gas production test before studying the contribution rate of different formation and dynamic performance. However, most gas wells in tight gas reservoir rarely perform production logging test from the term of cost control. This brings a great challenge to effectively understand the contribution rate of different formation, and the contribution rate with time also causes great uncertainties in estimating the utilization extent of different formation. In order to solve this problem, it is necessary to study the factors which influence the contribution rate and its change of different formation under commingling conditions and lay the foundation for further understanding dynamics performance for different formation. Before studying the contribution rate of different formation against formation coefficient, storage coefficient, fracture length, and fracture conductivity, a conceptual model of single well is established based on the reservoir characteristics and test data of the Sulige gas field. The main factors which influence the contribution rate were determined by gray correlation method, also established a forecasting model of the contribution rate of different formation by multiple regression method. The results show that formation coefficient, storage coefficient affect the contribution rate greatly, and the half-length of the fracture and fracture conductivity only have impact on the contribution rate at the initial stage. Compared with real contribution rate of different formation, 80% of the forecasting results are in good agreement with the test results, which basically satisfy the engineering requirements. The main contributions of this paper include: (1) for commingled multi-layer tight gas reservoir, theoretically analyzing the main factors which influence the contribution rate of different formation and the dynamic law of the contribution rate of different formation; (2) establishing the forecasting model of the contribution rate of different formation. Conclusions obtained from this paper are of great significance to understand the dynamic performance of commingled multi-layer tight gas reservoir.

Copyright 2017, Shaanxi Petroleum Society.

This paper was prepared for presentation at the 2017 International Field Exploration and Development Conference in Chengdu, China, September 21–22, 2017.

This paper was selected for presentation by the IFEDC&IPPTC Committee following review of information contained in an abstract submitted by the author(s). Contents of the paper, as presented, have not been reviewed by the IFEDC&IPPTC Committee and are subject to correction by the author(s). The material does not necessarily reflect any position of the IFEDC&IPPTC Committee, its members. Papers presented at the Conference are subject to publication review by Professional Committee of Petroleum Engineering of Shaanxi Petroleum Society. Electronic reproduction, distribution, or storage of any part of this paper for commercial purposes without the written consent of Shaanxi Petroleum Society are prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of IFEDC&IPPTC. Contact email: paper@ifedc.org or paper@ipptc.org.