低渗气藏连通性分析新方法的应用及认识

A New Method to Analyze Connectivity of Low-permeability Gas Reservoirs

在气藏生产过程中是否存在井间连通、井间干扰大小等问题备受关注。针对这些问题,传统的方法就是气藏关井测压或开展干扰试井测试。苏里格气田为典型的低孔—低渗气藏,所需关井时间较长,由于生产任务重,这些传统方法均难以付诸实施。对苏里格气田XX区块石盒子—山西组气藏生产时间超过1年的气井,在不关井、不影响生产的前提下,利用产量和压力的动态变化、井网密度、气井投产前最大关井套压等资料,运用一种新的生产数据分析技术求取单井物性参数、井控半径、储量等,从而简单、快捷、可靠地分析判断是否存在井间连通及井间干扰现象,为苏里格气田低渗气藏连通性分析提供了一种新方法。

For gas reservoirs, whether connectivity and interference existing among wells or not during production are a matter of great concern. The traditional methods are shut-in pressure test or interference well testing. For typical low-permeability and low-porosity gas reservoirs, Sulige gasfield, the shut- in operation often needs a longer period. So, the traditional methods are not highly impracticable. In this study, some wells from Shihezhi-Shanxi Formation gas reservoir in the field are taken as examples. And their production time all exceeds one year. On the assumption of no shut-in and keeping the regular production, a technology of production-data analysis is presented to calculate the physical-property parameters of single well, well- control radius, and reserves by means of the dynamic change of both production and pressure, the well spacing density, and the maximum shut-in casing pressure before a gas well went into production. This technology may very simply and reasonably decide whether connectivity and interference exist or not, which has proved itself to be a new method to analyze the connectivity of low-permeability reservoirs in Sulige gasfield.