Abstract

The "core" region of the Barnett Shale play in eastern Tarrant and western Dallas Counties, Texas, has prime development potential. This stems from a combination of maximum target thickness of 450' to 500' and a thick Viola Limestone, affording a significant barrier to Ellenberger water production. Structural complexity increases approaching the Ouachita Thrust belt to the east, as reflected in increased variability in Barnett natural fractures and rock stress properties.

Borehole image logs from 3 horizontal wells in the Barnett reveal significant variability in natural fracturing, faults and drilling induced fracture distribution along their laterals. The presence or absence of drilling induced transverse and longitudinal fractures can be directly linked to the changes in frac gradient and proppant placement during the fracture treatments and flowback response. A geomechanical study of all 3 wells identified the geometry of critically-stressed fractures and faults. Variation in differential stress along the lateral and changes in the geometry of critically-stressed fractures and faults can significantly alter the induced hydraulic fracture response (complex vs. planar fractures) in these stages, ultimately governing production response.

We developed criteria to use drilling induced fracture patterns from horizontal borehole image data to optimize the fracture stage design, custom fitting the stimulation to lateral changes in stress anisotropy.

From production histories, we show that stage-by-stage modification of the pump-ins, accommodating borehole image log-derived information, was able to improve frac efficiency and EUR, even in highly fractured laterals.

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