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• 专家论坛 •

### 弹性二相法新式的推导及应用

1. 中国石油勘探开发研究院，北京 100083
• 收稿日期:2022-06-14 出版日期:2023-04-26 发布日期:2023-04-26
• 作者简介:陈元千（1933—），男，教授级高级工程师，1952年考入清华大学石油工程系，1956年毕业于原北京石油学院钻采系，长期从事油气藏工程、油气田开发和油气储量评价工作。地址：北京市海淀区志新北里16号楼东楼706号，邮政编码：100083。E-mail：shixiaomin1@petrochina.com.cn

### Derivation and application of a new formula of the elastic two-phase method

CHEN Yuanqian(),SHI Xiaomin

1. CNPC Research Institute of Petroleum Exploration & Development, Beijing 100083, China
• Received:2022-06-14 Online:2023-04-26 Published:2023-04-26

Abstract:

For volumetric closed gas reservoirs, when the gas well produces with stable production rate, it can be divided into unsteady state stage, transient stage and pseudo steady state stage according to the variation behaviours of flowing bottom hole pressure and producing time. The unsteady state stage is called the elastic one-phase stage, and the pseudo steady state stage is called the elastic two-phase stage. The latter is a dynamic method to evaluate the Original Gas in Place（OGIP） controlled by gas wells. The elastic two-phase method proposed by CHEN Yuanqian in 1991 in the pseudo steady state stage has been repeatedly listed in the National Oil and Gas Industry Standards, and has been widely valued and applied in China. Based on the diffusion equation considering the elastic expansions of natural gas, rock and irreducible water in a gas well with stable production in the finite closed gas reservoir boundary, a new elastic two-phase method for the pseudo steady state stage represented by flowing bottom hole pressure and cumulative production rate is derived, which can be used to evaluate the original gas in place（OGIP）controlled by a gas well. The new formula of elastic two-phase method is superior to the old formula which based on the relationship between flowing bottom hole pressure and production time, and the new can overcome the influence of production fluctuation on the evaluation results. The application shows that the new formula of elastic two-phase method is practical and effective.

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