Horizontal exploration of Mississippian age formations in Oklahoma has been ongoing since 2009. This paper reviews hydraulic fracturing completions during the 2009-2012 time period.
The wellbore architecture, stage isolation, and completion types in these treatments generally can be categorized into two methods—cemented plug-and-perf (CPP) and mechanical sleeve and packers (MSP). Fracturing fluid types used include friction-reduced fresh/brine water, combinations of friction-reduced water, and linear and crosslinked gel. The proppant pumped during this time period was various-sized sand (100- to 16/30-mesh), with some operators using resin coated proppant (RCP) for tail-in at the end of the treatment. The number of stages, fluid, and proppant volume required varied considerably across the north Oklahoma and southern Kansas regions of the play.
Heterogeneity in the Mississippian producing interval is captured from log analysis of recently drilled vertical well disposal sites. These disposal wells are adjacent to the horizontal pad development, and they provide a rough characterization of the Mississippian producing unit in that area.
A large variability in production outcome was observed in the early production period of this play. For selected groups of similar completions, production was normalized to lateral length, gross pay thickness, and calculated producing bottomhole delta pressure. This modified productivity index helped identify potential best completion practices in this highly diversified play.
The Mississippian play in Oklahoma and Kansas (Fig. 1) has been productive since 1948. According to public domain data, there are ±18,000 Mississippian production wells in Oklahoma and Kansas. There are presently ±5,500 active producing Mississippian wells. Most of these are vertical completions.