Low Porosity Fractured Reservoir Characterization For Exploration and Horizontal Drilling

Abstract

TX 75083-3836 U.S.A., fax 01-972-952-9435. AbstractYurubcheno-Takhomskaya oil and gas accumulation zone (YTZ) located in the western part of the Siberian platform is known as a really challenging exploration object. The main reservoirs are located in Riphean carbonates made up of single p.u. porosity dolomites. Prospective drilling of the territory demonstrated high heterogeneity of this formation. Prospective wells drilled to this formation tests results vary from 0 to more than 600 m3 oil per day.The article describes efforts made on a new exploration approach elaboration based on an integral analysis of the structural, seismic and borehole data. First of all, this is seismic profiling on the regular orthogonal grid with the employment of modern seismic techniques and technologies, and also the study of the distribution of fractures in-situ (directly in the location of the deposition) with the integrated use of equipment and technology of formation micro-scanners and dipole sonic tools.This new approach consists on high-potential zone localization controlled by the disintegrated levee-like stromatolithic constructions, which are more exposed to fractured formation due to high silification in the southern and northern slopes of the Madrinskiy and Irkineevo-Katangskiy rifts respectively. Besides, highly productive may turn out to be the highly fractured streaks and sections, controlled by the regional and zonal fault zones. Such localization of the highly productive sections within the huge oil-and-gas-bearing territory allows hoping for the realization of the opportunity of the recovery of reserves of the entire region by limited number of high flowrate wells with the natural recovery drive.