致密气藏水平井动态分析方法及生产规律

摘要

Dynamic analysis of horizontal drilling well is difficult in the tight gas reservoir development.A new method for dynamic analysis of horizontal wells of tight gas reservoirs is established based on production and pressure coupling,along with introduction of quasi-pressure standardized production and material balance time.This method is used to analyze the dynamic characteristics of horizontal well production and evaluate the horizontal well development effect.Based on the actual production data of horizontal wells in Sulige gas field,it is realized that the new method can reflect the dynamic characteristics of different flow phases of horizontal wells.An exponent function exists between normalization decline rate and material balance pseudo-time.The coefficient A and index B of power function presents the good regularity inⅠ,Ⅱ,Ⅲ horizontal well standardized decline rate curve.Analysis both for standardized decline index and for material balance time shows parabolic relation in the early stage and linear relation in the late stage.Compared with Ⅱ and Ⅲhorizontal wells,the decline index of Ⅰ horizontal well greatly reduced with the change of materil balance time.The time to achieve the pseudo-radial flow and boundary dominated flow is shorter thanⅠhorizontal well.This study puts forward a new method of dynamic analysis of tight gas reservoir, reveals the objective laws of horizontal well production,and improves the theoretical level and analysis technique of the horizontal well development of tight gas reservoir.%致密气藏水平井动态分析是气田开发难点之一.本文引入拟压力标准化产量和物质平衡时间,提出了一种基于产量和压力相耦合的新动态分析方法,分析水平井生产动态特征,评价水平井开发效果.针对苏里格气田水平井实际生产数据,①本文的方法能够反映水平井不同渗流阶段动态特征;②标准化递减率与物质平衡时间呈明显的幂函数关系;且Ⅰ、Ⅱ、Ⅲ类水平井标准化递减率幂函数的系数、指数都逐渐增大;③标准化递减指数与物质平衡时间的关系,前期呈现抛物线关系,后期呈现线性关系.相比较Ⅱ、Ⅲ类水平井,Ⅰ类水平井的标准化递减指数与物质平衡时间下降幅度较大,达到地层拟径向流、边界控制流阶段所需要时间较短.