Paper: Oriented Fracturing A Practical Technique For Production Optimization

Understanding of the near wellbore stress distribution is critical to implement effective fracturing strategies. Reservoir quality variations, mixed lithologies with plastic behavior will alter the near wellbore stress distribution reducing the compressive stress of the rock. Thus, constant stress gradients (0.1 psi/ft.) are misleading and rock mechanical properties measurements may prove to be of extreme importance. This work discusses the development of criteria for orienting perforating/fracturing strategies. We present, an improved completions methodology that couples a systematic and enhanced geomechanical reservoir characterization with effective fracture placement and increased production results. Case-specific examples demonstrate the advantages of using detailed stress profiles and accurate reservoir description as key components of a GeoMechanical Model. Orientated Perforation strategies are suggested to address different and complex issues; multiple fractures, near-wellbore tortuosity, maximum proppant concentration, vertical coverage, natural fractures, tortuosity and erosional effects, with subsequent impact on improved reservoir performance and well deliverability. Net pressure matches and geomechanical data indicate that effective oriented fracturing stimulation treatments can be implemented where others have failed or unacceptable production changes occurred. The technique can be selcctively applied to: I ) A "smart completion" approach can be implemented; zone determination. design and placement of perforations are based on detailed geomechanical description. 2) Perforations are placed were they are needed the most based on input from the geomechanical model, fully accounting for the formation mechanical properties, 3) Methods to obtain principle stresses to determine optimum phasing with the preferred fracture plane, 4) More efficient placement of fracture stimulation treatments optimizing fracture geometry and treatment volumes. Based on a detailed geomechanical model an effective perforation strategy can be implemented to ensure vertical coverage and proper placement of hydraulic fractures. The advantage of such approach reflects in the improved efficiency of the perforating/fracturing strategies, minimization of treatment failures, treatment design/redesign and the significant impact on production optimization. Recommendations for strategic placement of perforations (density and phasing) and the mechanics for fracture initiation from vertical, deviated and horizontal wellbores are also discussed.