The development of stabilized foam has created the potential for a widely suitable fluid in water-sensitive and/or under-pressured reservoirs. Foams, to date, have proved to be effective fracturing fluids in shale, coal and tight sands, but proppant placement has been a problem. With the use of a stable foam pad, proppant can be transported with a crosslinked fluid at optimum concentrations for maximum fracture conductivity. The stable foam pad has excellent fluid-loss characteristics and will retain energy to flow back the gelled water stage. With the use of a stable foam pad and crosslinked proppant-carrying fluid, the advantages of both fluids can be utilized in creating a highly conductive fracture with minimal formation damage.

In coal seams where proppant may not be needed due to low closure stresses, stable foam alone can be an efficient fracturing fluid. With higher viscosities and better fluid-loss control properties than previous foams, a wider and longer fracture can be generated with similar volumes of fluid.

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