The best place to find oil and gas is where oil and gas has been found. That adage characterizes Oklahoma’s eastern Anadarko Basin, where operators have added the Mississippian-age Sycamore Formation to the 1,700-foot stacked-pay hydrocarbon menu.

The eastern Anadarko is geologically complex, with Mississippian facies trending from shelf basinward south and west, while tectonics grade from the deeper, gassier overpressured west to the shallower, oilier, normally pressured eastern Anadarko.

That complex downhole profile is similar to the Utica and Eagle Ford shales. Regionally, the Sycamore overlies the Woodford Shale and underlies the Caney Shale, a Barnett Shale equivalent.

Current Sycamore/Woodford efforts are concentrated in the Scoop play’s northeast quadrant near the geographic center of eastern Anadarko hydrocarbon play, which grades north into the Merge play and concentrates heavily farther north in the Stack play west of Oklahoma City.

Encouraged by horizontal results from Meramec/Osage Stack exploration efforts, operators, including Tulsa, Okla.-based, privately held Casillas Operating LLC, began evaluating the entire Mississippian column during the past half-decade.

In March 2016, Casillas, the most active Sycamore operator, formed a capital partnership with Kayne Anderson Energy Funds and went acquisition shopping, picking up 12,500 acres from Chesapeake Energy Corp. and 30,000 acres from Continental Resources Inc. in McClain, Grady and Garvin counties. The acreage, formerly part of the Golden Trend, was underexplored with modern tight-formation horizontal-drilling techniques.

Casillas completed its first Woodford horizontal wells in 2016 and followed with its first Sycamore horizontal in April 2017. That program expanded into six wells in the Upper Sycamore and eight wells in the Lower Sycamore in 2018. Similarly, Casillas found the underlying Woodford also presented two productive benches after drilling 15 wells in the Upper Woodford and 11 in the Middle Woodford in 2018.

Based on that program, Casillas established 62 operated drilling units with 60% suitable for extended laterals across its 53,000 contiguous acres. The acreage features 900 operated locations and a 15-year inventory of 2,800 wells.

To date, Casillas has drilled 40 wells and completed 38, increasing production from 175 barrels (bbl) and 8 million cubic feet per day (MMcf/d) of gas when efforts began in 2016, to 7,900 bbl and 103 MMcf/d in November 2018. Casillas is targeting an exit rate of 33,000 barrels of oil equivalent per day (Mboe/d) in 2019 after developmental efforts turn to stacked-and-staggered spacing tests involving the Sycamore and Woodford.

The Sycamore provides 250 feet of pay on average in two benches separated 120 feet vertically across Casillas’ acreage at total vertical depth, grading from 13,000 feet on the west to 8,500 feet in the east. To date, Casillas’ 14 Sycamore wells exhibit average 30-day IP rates of 1,224 boe/d (58% oil) with EURs in the 2.9 million boe range. The underlying Woodford is roughly 500 feet deeper with a similar, but = gassier, production profile.

Casillas has evolved its completion design during the past two years, reducing proppant volume while maintaining fluid volumes, reducing well costs by $1 million on a 10,000-foot normalized lateral. A 10,000-foot lateral generates an average 59% rate of return on a $10-million well, with rate of return increasing to 72% on normalized $9 million well cost.

Casillas operates in a toney zip code. Neighbors include Gulfport Energy Corp., directly west. Gulfport acquired 46,400 acres for $1.5 billion from Vitruvian II Woodford LLC in February 2017. Additionally, Continental holds acreage both northwest and southwest of Casillas, while Newfield Exploration Co., which is planning to merge into EnCana Corp. during this quarter, holds smaller parcels south and north of Casillas’ holdings.

In the northwest, Continental is targeting Sycamore objectives as part of its massive Project SpringBoard full-field Scoop development program. The company will employ up to six rigs to drill 250 Sycamore/Woodford wells in Grady County with an additional eight rigs targeting the Springer Formation uphole.

Continental’s Sycamore effort represents Phase II of the SpringBoard project, with the Sycamore Formation projected to add 300,000 net reservoir acres to Continental’s extensive Scoop holdings. Phase II drilling is slated to begin in early 2019.

West, Gulfport completed one Sycamore well in 2018. The company is focusing on cycle time-reduction and lateral extension while looking at a cube development program incorporating the Sycamore and the underlying Woodford in 2019.

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