Well production interference ratio in tight sandstone gas reservoir and its inspiration to well pattern optimization: a case study of Sulige gas field, NW China

Abstract

In view of the characteristics of low permeability, strong heterogeneity, small effective sand scale and poor connectivity of tight gas reservoir, well pattern infilling optimization is the main method to improve gas recovery. Taking Sulige gas field as an example, based on the study of sedimentary facies, effective sand-body distribution, combined with production performance and engineering parameters, the well control drainage was obtained. Meanwhile, the interwell connectivity and interference probability was qualitatively analyzed by interference well test, and the critical well spacing density was determined. In order to quantitatively reveal the gas grabbing degree at different well spacing density and determine whether the final cumulative gas production of gas wells with interference is economical and feasible, the evaluation index of "gas well production interference ratio (GWPIR)" was defined specifically, and the intersection plot of GWPIR relating to gas reserve abundance and well spacing density was draw. Different from the traditional method of well number interference probability, through the combination of GWPIR plot and economic evaluation, well pattern optimization from both two perspectives of pursuing higher economic benefits and recovery degree can be realized, providing technical support for improving gas recovery and long-term stable production of gas field.