Investigation of the well performance in shared gas fields

Abstract

The evaluation of well deliverability and gas migration is one of the most prominent challenges of shared fields. These fields are under production by two or more countries, in which normally only data of internal (domestic) part is available and there is a lack of data availability for production of external (foreign) part. Moreover, the basic assumption under most of the well performance models is constant drainage area, which, in fact, is not the actual case. Therefore, this study was aimed at presenting an analytical well performance method, accounting for the non-volumetric effects in the internal region of a shared reservoir. Consequently, the proposed method was used to estimate gas migration, production profile of external region and material balance calculation in shared reservoirs. In so doing, a new dynamic material balance equation was introduced to calculate the average field pressure through evaluating internal wells deliverability. It was noted that data of the external region is not needed in this study. The results of this analytical approach were compared against numerical modeling, and it was found that both models are in close agreement and as a result, proved the accuracy of the method within the typical ranges of rock and fluid parameters of gas reservoirs. • Variable common boundary is observed in shared fields. • The amount of gas migration is calculated through wells deliverability of internal region. • New pseudo-time and dynamic material balance models are performed. • Having a relationship between both regions is required for performance analysis.