Wells competed by Continental Resources Inc. last year reaffirmed the repeatability and growth potential of the Springer play in South Central Oklahoma Oil Province (SCOOP), said Harold G. Hamm, Continental chairman and chief executive officer.
"These individual delineation wells in the play are generating excellent returns, with shallow decline rates compared to other unconventional resource plays," Hamm said. He foresees the Springer becoming "the most productive play in Oklahoma, and it's right in our backyard."
Continental operated nine drilling rigs in the Springer play in late 2014, with a focus on rapidly expanding its understanding of the play's productive extent. The Springer shale sits 1,000 ft above the Woodford, which has been Continental's primary target in the SCOOP.
"We expect to realize even stronger well economics as development drilling gets under way utilizing extended laterals, pad drilling, and other drilling and completion efficiencies," Hamm said.
The American Association of Petroleum Geologists said the SCOOP targets the Woodford shale across a seven-county area south of Oklahoma City. The Woodford is more than 10,000 ft deep in this area with areas prospective for oil, wet gas, and dry gas.
Separately, Marathon Oil Corp. is using extended-reach laterals to improve initial production rates in the SCOOP resource play (UOGR, September/October 2014, p. 29).
Continental's delineation wells
Continental said its four Springer delineation wells had an average lateral length of 4,475 ft. The company expected estimated ultimate recovery (EUR) of 940,000 gross boe per well in the oil fairway for a well with about that lateral length although that had yet to be confirmed with production data as of late 2014.
Hamm anticipated drilling Continental's first extended lateral well in the Springer play in late 2014, with a planned lateral length of 7,500 ft. Continental expected an average EUR of 1.6 million gross boe for extended lateral wells of this length.
The average Springer well cost proved to be consistent with Continental's forecast of about $9.7 million. The four delineation wells were drilled to an average vertical depth of 12,625 ft and average total measured depth of 17,650 ft.
"The Springer adds another significant oil resource driver to Continental's strategic growth outlook," Hamm said. Early results indicated the emerging play was 84% liquids, 67% oil, and 17% natural gas liquids.
The four new wells, all in Grady County, were:
• The Nancy J 1-28H well with an initial 24-hr production test rate of 1,815 boe/d, of which 79% was crude oil. Continental has a 57% working interest.
• The AC Walters 1-27H with an initial 24-hr test rate of 1,630 boe/d, of which 78% was crude oil. Continental has 83% working interest.
• The Schoof 1-17H with an initial 24-hr production of 1,465 boe/d, of which 74% was crude oil. Continental holds 99% working interest.
• The Ince 1-21H with an initial 24-hr production test rate of 1,037 boe/d, of which 86% was crude oil. Continental has a 77% working interest in the Ince 1-21H, which is 25 miles south of the Nancy J, AC Walters, and Schoof wells.
Continental's Springer production as of November was 6,000 net boe/d (9,200 gross boe/d), of which 70% was oil.
During an analyst presentation in September 2014, Continental unveiled results of its first 11 test wells drilled in the oil window.
The discovery Springer oil well, the Wilkerson 1-20H, started production in January 2013 with an initial peak 24-hr production rate of 2,038 boe/d from a 4,200-ft perforated lateral. That well is in Township 7N, Range 6W, Section 20.
WoodMac comments
Consultant Wood Mackenzie Ltd. said the Springer shale, also known as the Goddard shale, likely will grow inventory and reserves for operators already targeting the Woodford shale.
"We view the Springer shale as an opportunity for operators to capture upside from stacked laterals in part of the basin where the Woodford is relatively thin, whilst evidencing that operators continue to gain traction from new unconventional technologies in their bid to rekindle the region's once prolific fields," WoodMac said.
Continental has said the Springer shale formation is up to 150-ft thick, highly siliceous, over-pressured, and low in clay and has excellent stimulation containment.
Analysts and consultants await more information from operators about the Springer shale. Continental has released initial production rates for 11 wells in Grady, Stephens, and Garvin counties, Okla.
Initial type curves for Continental's Springer shale wells suggest the play has a shallow decline rate relative to other tight oil plays, WoodMac said.
The key to mastering the Springer shale's variable geology will be contingent on an operator's "ability to keep laterals within the target zone and take advantage of natural fracture pattern," WoodMac said.
Offset well performance is another factor to watch. Early Springer well tests were completed in sections alongside producing Woodford horizontal wells.
"Any prolonged periods of abnormal production declines in those wells would reduce the ability to increase well inventory vertically through the stratigraphic column, removing a key value driver of leasehold in the area as well as the wider Mid-Continent," WoodMac said.
Gas-processing capacity was expected to be sufficient for the area based on capacity expansions announced by Enable Midstream Partners and Oneok Partners LP.