Effect Of Production Induced Stresses On Reservoir Productivity

Abstract

The importance of permeability sensitivity to the changes in pore pressure drop or effective overburden stress increase has been examined at laboratory using two types of rocks, sandstone and limestone. Whereas the experimental data were used as an input in the modified Darcy equation for single-phase steady-state flow through porous medium. The selected rocks were tested for triaxial compressive strength, permeability, x-ray diffraction, grain size distribution, stress-strain relationship and thin sections structure. The experimental work conducted in this study showed that the permeability of the tested rock samples was significantly influenced by the increase of effective overburden stress (i.e. pore fluid pressure drop). This result is supported by thin sections examination and stress-strain relationship, which have shown that pore structure was highly affected by the increase in the overburden stress. Therefore it is very important to include the effect of effective overburden stress increase (or pore fluid pressure drop) in any reservoir productivity prediction technique