Effect of Chemical Composition of Sandstone on Deformation of Reservoir Rocks

Abstract

Deformation bands appreciably alter the parochial petro-physical characteristics of reservoirs rocks. Notwithstanding, the effect of the ingrained unstable mineralogy, grain size and sorting of sandstones on the nature and distribution of deformation bands is yet to be understood. To identify the effect of chemical composition of the sandstone on band, cataclastic deformation bands in the matrix of oil bearing rock, sandstone at Abakaliki anticlinorium, were studied using the mineralogy of the outcrop. The scanning electron images were analyzed. In the coarse sample the deformation bound was more than the fine-grained section. The microscopic image and SEM were analyzed for grain size effect. Current observations show that close to the fault, more of the dipping conjugates of cataclysmic bands occurred. The grain sizes generated indicated that the primary grain size determines the intensity of deformation band which significantly reduces porosity of the sandstone. The lost in porosity affects permeability which constitute barriers to fluid flow in the reservoir. The XRD analysis revealed the preference of cataclastics of feldspar grains inside the host sandstone and deformation band. The bands develop before carboniferous source rock mature or petroleum migrates.