Maurer Engineering Inc. has developed a shale stimulation technique that consists of drilling drain holes across hydraulic fractures to improve production in depleted shale wells.
The oil and gas production from fracked shale wells deplete by up to 70 percent in the first two years, requiring refracking every two or three years at a cost of $2 million or more. This high cost significantly decreases the economics of shale wells and causes some of these wells to be abandoned after only 20 to 30 percent of the oil in place has been produced.
A lower cost stimulation system is needed that eliminates the need to refrac the wells so often.
The rapid depletion occurs primarily due to a 10- to 15-ft. constriction zone produced at the frac/horizontal well interface during the fracking process. As the wells are produced, small solid particles produced from crushed proppants and crushed formations propagate down the frac and into the constriction zone further plugging the fracs.
This new stimulation system consists of drilling 3 to 4-3/4 in. diameter drain holes from the horizontal well to bypass the constriction zones and provide large passageways from the fracs to the horizontal wells.
The drain holes are relatively inexpensive since they are drilled with small rigs and they are completed open-hole or with slotted liners. The company estimates that their cost will be 70 percent less than refracking.