Operators have reported 28 horizontal completions in southern Ellis County, Okla., in the past 18 months in a low permeability play for oil and gas in the lower member of the Pennsylvanian Cleveland formation.
The 28 completions, some reported as Marmaton in regulatory filings, have averaged an initial 514 b/d of oil and 1.3 MMcfd of gas.
Exploration and production companies have drilled more than 1,070 horizontal wells in the Cleveland reservoir in the Texas Panhandle and western Oklahoma since 1995, but most of the wells have been drilled and completed in the Upper Cleveland reservoir. Participants in the Lower Cleveland play include EOG Resources Inc., Chesapeake Energy Corp., Mewbourne Oil Co., Primary Natural Resources III LLC, and Plano Petroleum LLC.
The Lower Cleveland sand at an average depth of 9,400 ft is 50-120 ft thick. It produces at higher average oil rates than the Upper Cleveland, and there is no depletion risk from prior production, said Plano Petroleum, a private Plano, Tex., independent.
Geologic limits of the Lower Cleveland sand have yet to be defined by drilling, but mapping from deeper subsurface control indicates the best quality Lower Cleveland sand appears to be centered in southern Ellis and northern Roger Mills counties, Okla. Strong results have been reported with open-hole, packer-type completions and cemented completions.
Plano Petroleum started a five-well horizontal program in mid-2011 and has completed two Lower Cleveland horizontal wells and one horizontal well in the shallower Tonkawa reservoir. The company has spudded two more Cleveland wells.
The company’s first Lower Cleveland well, Nelwyn 1H-7 in 7-17n-24w, Ellis County, had an initial flow rate of 570 b/d and 1.7 MMcfd and recovered 31,315 bbl of oil, 10,727 bbl of natural gas liquids, and 69 MMCF of dry gas in its first 90 days on production.
The Sharon 1H-18, in 18-17n-24w, Ellis County, is flowing back following a 14-stage hydraulic fracturing procedure to stimulate production in the Lower Cleveland. Its initial flow rate was 578 b/d and 1.1 MMcfd. Adeline 1H-4, a horizontal Tonkawa producer in 4-17n-22w, Ellis County, flowed at an initial rate of 199 b/d and 312 Mcfd.
Plano Petroleum sees large, low-risk development potential on its acreage in the Cleveland, Tonkawa, Cottage Grove, and Cherokee oil reservoirs.
Plano has more than 13,250 gross acres, 8,000 net acres, in the stacked pay area and owns production from horizontal wells in the Tonkawa, Cottage Grove, Upper and Lower Cleveland, and Cherokee reservoirs. Plano is the operator of 19 sq miles with each section having one to four separate oil reservoirs prospective for horizontal drilling. The company’s acreage block is 87% held by production.