Abstract
AbstractEvaluating EUR and production forecasting in multi-frac horizontal wells completed in unconventional shale reservoirs during early, exploration and appraisal stages is very challenging. With the absence of suitable production facilities to handle produced fluids, production data are limited to short flow backs and extended production for some key wells to early production facility (EPF).This method uses the flow capacity as an intrinsic parameter that captures and reflects the major drainage mechanism and recovery characteristics of the well within the unconventional reservoir. Thus, the flow capacity may serve as a reference parameter that can be estimated from early-time data. This parameter may have the ability to reflect the future production behavior of the well in terms of cumulative production through proportional comparison of flow capacity to EUR.To show applicability of the workflow, it was applied to an existing unconventional project and showed consistent results. The workflow incorporates RTA analysis for several wells to create a single correlation that describes the relationship between Ac√k and EUR. Plotting gas flow capacity (Ac√k), estimated during the early 3-4 weeks of flowback, versus the estimated EUR from modeling techniques showed a strong correlation.The proposed workflow is designed to estimate EUR for wells completed in unconventional reservoirs during the early phases of development, where there is no production facility to handle produced hydrocarbons and flow back period is limited to cleanup only. The advantages of the proposed workflow over the currently available methods are: (1) Incorporating several wells analyses to create a single correlation that describes the relationship between Ac√k and EUR (2) The ability to evaluate EUR from as-early-as 3-4 weeks of flowback data. The early evaluation of these wells will expedite critical completion and development decisions which will impact project economics.