ast resources of natural gas occur in very low permeability and fine-grained rocks, referred to as gas shales and tight sands. Successful exploitation of gas from gas shales and tight sands requires drilling horizontal boreholes and completions that include inducing fractures into the surrounding rock mass thereby creating enhanced permeability through larger surface areas for gas production. The stability of the boreholes during horizontal drilling is dependent on the trade-off between pressure maintained in the borehole and the stress regime. The inducement of fractures into the reservoir rock is normally accomplished by pumping fluids with or without proppant under high pressures into the formation.
