New Method for Evaluating the Used Geological Reserves of Low Permeability Sandstone Gas Reservoir

Sulige gas field has entered a stable production stage, which is a typical representative of low permeability sandstone gas reservoir of strong heterogeneous in China. Due to more and more development wells are being developed, it is necessary to re-evaluate the reservoir resource. With the development degree increase, the reserves producing degree increase, which challenge the long-term stable production and later production capacity construction. Evaluating the used geological reserve is necessary to make clear the remaining unproducing reserve in order to achieving long-term stable production. In this paper, the He-8 and Shan-1 member of Su X Block in Sulige Gas field which has the most abundant data is taken as the researching objective to re-calculate geological reserve by volumetric method. According to the current various well patterns and their respective control degrees, the “method of area controlled by single well” is adopted to calculate the used geological reserve of various well patterns so as to determine the used geological reserve scale and distribution. Results show that the total used geological reserves account for 62.86% of the recalculated reserves of this block. It is feasible to achieve long-term stable production. The research results play an important role in the further well deployment and lay the foundation for the study of stable production technical policy. It also could provide certain reference for efficient development of other blocks of the Sulige gas field and other similar gas reservoirs of other gas fields.