Optimization of Hydraulic Fracturing and Production Enhancement: Case Studies for US Shale Plays and Tight Sand Reservoirs

Abstract Plug and Perf (PnP) has been predominant for years as the preferred completion method for unconventional reservoirs. However this technique can be costly and time consuming. The Coiled Tubing Activated Frac Sleeves (CTAFS) technique utilizes fracture sleeves that can be hydraulically opened using coiled tubing and fractured through the annuls, minimizing time between stages and reducing total fluid consumption. This paper evaluates the fracturing and production performance of the Plug and Perf technique compared to Coiled Tubing Activated Fracture Sleeves (CTAFS) in a US shale oil play (Eagle Ford) and in tight sand reservoirs (Cotton Valley, Bone Spring and Granite Wash). It focuses on a strategy of improving ultimate recovery by using fracturing modeling, proper completion selection and field data to determine the optimal stage spacing of the multistage completion systems (PnP and CTAFS). The fracture models were created using existing logs and geomechanical modeling results in the surrounding area to create an optimal geometric spacing for the stages. The basics of the primary multistage completion systems are discussed and briefly compared from an operations point of view. Effective fracture dimensions can be achieved by selecting better locations for the stage clusters in Plug ad Perf and single fracture injection points using Coiled Tubing Activated Frac Sleeves (CTAFS). Fracture treatment schedules for each completion technique are recommended in terms of proppant type, concentration, fracture fluid type and volume. Two different fracture treatments were used to analyze the effect of fracturing fluid and completion type on fracture geometry. Coiled Tubing Activated Frac Sleeves with an optimized fracture treatment schedule outperformed the PnP as it fully controls fracture placement, leading to bigger drainage areas. For PnP, cumulative production decreased with an increasing number of clusters and the less efficiency of the stages on productivity. Adding more sleeves accelerated the EUR because of a larger drainage area. The CTAFS technique allowed tighter spacing of frac stages and ensured that the fracture was created at the sleeve in contrast to PnP technique in which some zones could remain untreated.