强非均质致密砂岩气藏已开发区井网完善方法

为提高致密气田开发区采收率、实现规模效益开发,需要充分有效动用地质储量。针对如何完善井网的实际问题,主要基于储量复算、动储量评价和变井距加密方法 3个方面考虑:①针对致密砂岩的强非均质性,利用Voronoi网格的非均匀切片法开展储量评价,相比容积法计算储量,有效减少了因各参数平均带来的误差;②对700余口生产超过10年的井分阶段预测动储量,形成Ⅰ类、Ⅱ类、Ⅲ类井分阶段动储量评价经验公式,有效解决了致密气井生产初期动储量计算不准确的问题;③在井网评价与完善方面,根据强非均质储层的特征,充分结合地质、地震和生产动态认识表征未动用储量分布,采用变井网加密方式,以保证加密井部署的合理性。此井网完善方法为致密砂岩气藏老区效益稳产提供强有力支撑。

Improvement of well pattern in development area of tight sandstone gas reservoir

In order to improve gas recovery and ensure the development of gas fields,well pattern infilling should be carried out in the old areas of tight sandstone gas reservoirs. And the work should be carried out from four aspects:reserve recalculation,dynamic reserves evaluation,well control area prediction and variable well spacing infilling. Using Voronoi grid to reduce the error caused by the average parameters in the calculation of reserves,which reflects the strong heterogeneity of tight sandstone. The empirical formulas of compensating for dynamic reserves by stages are formed for class Ⅰ,Ⅱ and Ⅲ wells,which effectively solves the problem of inaccurate calculation of dynamic reserves due to weak energy replenishment at the initial stage of gas well production. According to the characteristics of strong heterogeneous reservoirs,variable well pattern encryption method is adopted. Under the background of dynamic and static inconsistencies,reference to seismic interpretation results can ensure the rationality of infill well deployment and reduce investment risk. The above well pattern infilling method can provide strong support for stable production in the old area of tight sandstone gas reservoir.