Horizontal Well Acidizing of a Carbonate Formation: A Case History of Lisburne Treatments, Prudhoe Bay, Alaska

Summary Stimulating horizontal wells in carbonate formations can lead to significant increases in productivity if effective fluid diversion can be achieved. Many horizontal wells are completed with slotted or pre-drilled uncemented liners throughout long producing intervals. These completions prevent effective use of conventional cased-hole diverting techniques, such as ball sealers and some particulates. Stimulation fluids can be mechanically placed or diverted with such materials as particulates, foam, and/or high-viscosity fluids. A combination of nitrogen foam and viscous emulsified acid pumped through coiled tubing (CT) has been successfully used to treat horizontal wells in the Lisburne field at Prudhoe Bay, Alaska. This paper documents treating techniques and production results of acid stimulation treatments pumped in horizontal wells that are completed with slotted or predrilled uncemented liners throughout long producing intervals. Case histories of four wells are used to illustrate treatment designs and production response.