Mapping Hydraulic Fracturing in the Permian Basin - Geometry and Placement

The radical expansion of North American hydraulic fracturing activities has created strong demand from oil and gas operators for services relating to the determination of actual fracture dimensions and positioning. The ability to graphically envision how and where a hydraulic fracture propagates allows exploration specialists to make strategic decisions regarding a number of fiscally important parameters.

West Texas is an example of a portion of the domestic industry that reflects a recent shift from unconventional gas to unconventional liquid hydrocarbons. Currently, two Permian Basin plays are dominating drilling and completion activity in West Texas.

The Wolfberry in the Midland Basin is a thick column of siltstones, sands, shales and limestones with low permeability. This play (a combination of Wolfcamp, Dean and Spraberry zones) has been targeted by operators for more than 60 years, but only relatively recent improvements in hydraulic fracturing processes can ensure consistent profitability.

Most completions are in vertical wells, with the various reservoirs perforated and stimulated in 9 to 12 separate fracturing treatments. What has changed that has so positively impacted profitability? In addition to relatively firm liquid hydrocarbon commodity pricing, increases in fracturing stage count, lowering of average polymer concentrations, the use of premium proppants for deeper zones and the application of up-front diagnostic science have all been recognized as major contributors to success.

The second focused area of activity is the upper portion of the Bone Spring (sometimes called the Avalon or Leonard Shale), a segment of the Southeastern New Mexico Delaware Basin, where hydrocarbon-rich shales overlie alternating sequences of limestones and sandstones. Multiple, parallel horizontal wells are used to most effectively produce these properties. Seven to 15 treatment stages per lateral are typical, and fluids are generally a hybrid mixture of slickwater and linear or crosslinked guars.

For operators who are in the early stages of development in these two plays, up-front science has proved invaluable in their efforts to optimize spacing, well positioning, lateral placement and prevent inter-well communication or bypassed reserves. One of the primary tools employed in up-front science is microseismic mapping of individual fracturing treatments.