Production from depleted shale wells could be improved through the use of a stimulation technique being developed by Maurer Engineering Inc. that consists of drilling drain holes across hydraulic fractures, the Austin-based company said.
Oil and gas production from fracked shale wells depletes by as much as 70% in the first two years, requiring refracking every two to three years at a cost of $2 million or more, Maurer said.
The rapid depletion occurs primarily due to a 10- to 15-foot constriction zone produced at the frac/horizontal well interface during the fracking process. As wells are produced, small solid particles produced from crushed proppants and crushed formations propagate down the frack and into the constriction zone, further plugging the fracks.
Maurer's new stimulation system consists of drilling 3- to 4.75-inch diameter drain holes from the horizontal well to bypass constriction zones and provide large passageways from the fracks to the horizontal wells.
"The drain holes are relatively inexpensive, since they are drilled with small rigs and they are completed openhole or with slotted liners," Maurer said. "We estimate that their cost will be 70% less than refracking." If necessary, the drainholes can be fracked using conventional straddle packers, and the drain holes can be sidetracked to cross the fracks in different places.
Maurer is seeking investors, service companies, licensees and operators interested in utilizing the patent-pending technology in shale wells.