摘要
在四川盆地东部,多数石炭系气藏渗透性差,在气井产能测试中产量、压力难以在较短时间内达到稳定状态,从而限制了传统稳定试井方法的应用。为缩短测试时间、节约成本,同时提高低渗气井产能评价的准确性,对传统的稳定试井流程进行了改进:首先气井以适当产量稳定生产至流压达到稳定,然后关井,压力恢复至地层压力,再以3~4个递增的工作制度生产相同的时间,而不必要求流压达到稳定。根据改进的流程所获得的测试资料,建立了利用稳定点的产能测试数据来校正不稳定点产能测试数据的产能评价方法,并对川东石炭系气藏4口气井的产能测试进行了实例分析。结果表明,直接利用未达到稳定状态的产能测试数据计算的气井无阻流量往往偏高,而利用稳定点校正方法所计算的气井产能更加符合气井的生产实际。改进的测试方法可极大地缩短低渗气井产能测试时间,并且通过稳定点校正方法可提高此类低渗气藏气井产能评价的准确性,从而更好地指导气井合理配产,实现低渗气藏的高效开发。
In eastern Sichuan Basin, most Carboniferous gas reservoirs are poorly permeable, so the production rate and pressure can- not reach the steady state in a short time when the gas well productivity testing is carried out. As a result, the application of traditional steady well test method is restricted. In this paper, the flow chart of traditional steady well test was modified so as to shorten the test time, cut down the cost and increase the productivity evaluation accuracy of low-permeability gas wells. Firstly, the gas well is pro- duced stably at an appropriate rate until the flowing pressure is stable. Secondly, the well is shut down. And thirdly, when the pressure is resumed to the reservoir pressure, the production is carried out for the same period in 3-4 progressive working systems, and the flowing pressure doesn＇t have to reach the steady state. Then, a new productivity evaluation method was developed according to the testing data obtained from the modified flow chart. In this new productivity evaluation method, the productivity testing data of stable points is used to correct the productivity testing data of unstable points. Finally, this method was practically applied to the productivity testing of 4 gas wells in Carboniferous gas reservoir in the eastern Sichuan Basin. It is indicated that the absolute open flow （AOF） of gas wells is higher if it is calculated directly using the productivity testing data of unsteady state, and the gas well productivity cal- culated by means of the stable-point correction method is more accordant with the actual production. The modified test method can shorten the productivity testing time of low-permeability gas wells significantly and the stable-point correction method can increase the productivity evaluation accuracy of this type of low-permeability gas wells, so as to provide the good guide for rational proration of gas wells and realize the efficient development of low-permeability gas reservoirs.
出处
《天然气勘探与开发》
2017年第4期73-78,共6页
Natural Gas Exploration and Development
基金
国家科技重大专项"四川盆地大型碳酸盐岩气田示范工程"(编号:2016ZX05052)
关键词
四川盆地
东
石炭纪
低渗透气藏
稳定试井
无阻流量
产能评价
稳定点
二项式
合理配产
Carboniferous in eastern Sichuan Basin
Low-permeability gas reservoir
Steady well test
Absolute open flow （AOF）
Productivity evaluation
Stable point
Binomial
Rational proration
