Evaluating the Long Term Benefits of Improved Fracture Treatments

摘要

It is understood that improved hydraulic fracture treatments increase production rates from most reservoirs. However, are these gains short lived, or do they yield incremental recovery? Is the improved productivity related to recovery of additional reserves or merely an acceleration of existing reserves? Frequently, the impacts of design improvements are demonstrated by improved initial production (IP) rates or perhaps evaluated base on 6- to 12-month cumulative production increases. Field development decisions are often made based on these initial results, never again to be reviewed for long term corroboration. Rarely are the rate, reserves, and economic impact of these design changes evaluated and documented over longer production periods. As such, while a particular design change may pay out in two or three months, the question remains as to whether the enhancement represents merely a short term acceleration of production or in fact an increase in hydrocarbon recovery. This paper will review the production results from several tight gas and unconventional reservoirs in which hydraulic fracture designs were upgraded to premium proppant, for which the results were documented in previous SPE papers. Areas evaluated include wells in the Cotton Valley-Taylor and Haynesville Lime of East Texas, the Haynesville Shale of North Louisiana and the West Texas Canyon Sand; all were evaluated and documented shortly after implementation. Raw production differences will be reviewed along with decline curve analyses, using updated production to evaluate both near and long term recovery impacts. In addition to (re)evaluating for technical success, economic evaluations are provided to determine whether the design improvements truly resulted in favorable economic outcomes, as suggested in the original evaluations. When possible, these new evaluations will be compared to original recovery forecasts to ascertain whether the original conclusions still hold. This paper should be of interest to anyone who evaluates the benefits of fracture design changes in their completions, and will provide insight on the accuracy of initial evaluations compared to actual long term production. It will also further investigate the benefits of improved fracture designs.