The Study and Application of the Connectivity of the Carbonate Reservoirs in Tarim Basin

Wang, Jinxi; Zhang, Huquan; Chen, Fangfang; Zhou, Junfeng

The heterogeneity of the carbonate fracture-cave reservoir is very strong which presents multiple fracture-cave systems, multiple pressure systems and multiple development characteristics of seepage unit. It's why the accuracy rate of carbonate reservoir drilling is high but the proportion of high efficient wells is low and the increase of the production is difficult. So the main difficulty which restricts the highly efficient development of the carbonate fracture-cave reservoir is the identification of the connectivity of the fracture-cave reservoir.

Many scholars have used some methods in the analysis of the connectivity of the carbonate reservoir between wells and obtained certain results. They mainly used the dynamic data in the production including the method of analysis of the change of formation pressure and the method of interference testing analysis between wells. These methods are mainly applied to the areas with a high degree of development and rich drilling wells, but have poor applicability to the areas in early-medium period of the development of the carbonate reservoir.

In this paper, taking YM2 area of Tabei Uplift as an example, we make an integrated analysis of geology, geophysics and reservoir, and form a set of reservoir connectivity analysis technology series including seicmic describe static, dynamic verification, iterative adjustment. First step is choosing seismic attribute data of fracture and cave prediction based on the geophysical response characteristic of fracture and cave reservoir, gridding the sesimic data as sesimic cells and judging the connection of seismic datas based on the contact relation of the cells. Then we analyze reservoir connectivity with static and synamic data, maintaining the same law for the seimic predcion and production dynamic data. The resolution of seismic data is used to build reservoir geologic model and choose welltest interpretation model. The oil and gas production dynamic data such as daily oil production and pressure buildup test data are used to adjust seismic parameters and choose optimal seicmic atrribute threshold, through repeated iteration, make sure reservoir connectivity resboundary accurately, realize prediction of fracture-cave reservoir reservoir connectivity. The prediction result can clearly reflect the distribution pattern of reservoir and is used to improve producible extent of proved reserves and success ratio of well deployment.

AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013