Experimental study of the effect of stress and fluid sensitivity on propped and un-propped fracture conductivity in preserved reservoir shale

A good amount of work has been done on analyzing the effect of stress and fluid sensitivity on fracture conductivity in sandstones. This thesis tries to answer similar questions with regard to shale formations. Shales are very sensitive to aqueous fluids and their mechanical properties change when exposed to it. This mechanical property change in shale is mainly caused due to clay swelling. Some of the previous researchers working on shale fluid sensitivity failed to use preserved reservoir cores for their experiments and allowed them to dry out. This study has been conducted on preserved Utica and Eagle Ford core samples. Experiments were conducted to study the effect of effective stress on propped and un-propped fracture conductivity. These experiments were conducted at reservoir temperature and pressure conditions to mimic field conditions. Different fluids were flowed through the fracture to compare the effect of different fluids on fracture conductivity. To prevent clay swelling various clay stabilizers are used in the field during drilling and fracturing operations. Experiments were conducted to test the effectiveness of different clay stabilizers in preventing fracture conductivity reduction. Some of the clay stabilizers were more effective than others but all of them were unable to prevent fracture conductivity reduction when fracture was flowed with a high pH fluid.