Previously, a process for production optimization in horizontal well multi-fracs has been outlined in SPE168812 (Barree et Al, 2014), which described a methodology to optimize completions based on production analyses and economics. However, with the increasing availability of near and far-field data, particularly diagnostics such as fiber optics, there is clearly a need to quickly evaluate and optimize what is actually happening in and around the pad to the rock fabric itself. This paper looks to determine an optimized methodology to assess sequential operations in a typical 4-well pad development. The exercise is based on recent improvements in simulation theory and computing, which have been done using calibrations from pre- and post-job diagnostic data. This exercise is shown to allow the engineer a realistic means to investigate sequential fracturing operations by optimizing the time to initially evaluate multiple smaller sequential operations. The best results from this can then be used to evaluate the much larger actual job design which that can minimize "stress shadow effects", both inter-well and far field, which can be used to maximize both stimulated (SRV), or more importantly the connected reservoir volume (CRV) linked to the created fracture surface area.
Originally, hydraulic fracturing treatments were designed for vertical wells using complex charts, nomographs and simple "calculations" to determine designs. Typically, these designs were actually based on just fluids and material volumes, using multiples of 800 gallons and sand concentrations of 0.5-0.75 lbm/gallon fluids. Then, in the 1960's, simple computer programs based on a single fluid efficiency and the fracture shape in 2-D were used, based on simple mathematical models (Gidley et Al,1989; Khristianovic and Zheltov, 1955; Perkins and Kern - PKN, 1961; Geertsma and de Klerk - GdK or KGD, 1969). These simplified models were in no way meant to actually represent the frac or how they grow, but they did allow practitioners to start to evaluate design parameters and appreciate the importance of various factors in optimizing frac design. As simulation and diagnostic capabilities advanced (Barree and Woodruff, 2002; Barree et Al, 2007) it became possible to better represent what was actually being observed by ever more detailed frac diagnostics and ultimately it became possible to target more difficult to treat reservoirs, which culminated in the 1990's with the economic development of Tight Gas Sand (TGS) reservoirs and ultimately the present day unconventional, or more generally termed ‘shale’ reservoirs.