Accurate prediction of long-term performance of multi-frac horizontal wells (MFHW) targeting unconventional reservoirs is still a challenge due to variability in reservoir properties, well spacing, stimulation design, and production optimization strategies. The use of type curves to normalize the aforementioned variables has been adopted by operating companies mainly for reserves booking and as a benchmark for well performance. This paper presents a simple yet powerful methodology to create a Permian Basin universal oil type curve that is easily scaled based solely on 1-year cumulative production. The proposed method employs a correlation between 1-year cumulative production and estimated ultimate recovery (EUR) to explain the dynamic behavior of MFHW. The case studies include history-matched simulation cases and actual data from horizontal wells in multiple basins with at least two years of production history. The population of wells include nano- to micro-Darcy rocks in the Permian Basin. These formations have wide ranges in initial reservoir pressures, rock and fluid properties, well spacing, stimulated reservoir volume (SRV), flowback, and artificial lift strategies. EUR values per well were generated via numerical modeling using a production history match. Our results show that the ratio of early to late production is independent of rock and fluid properties, stimulation design, well spacing, and production optimization strategies. The results show that 1-year cumulative volume is a good proxy for well performance driven by subsurface dynamic and static properties. The correlations developed should be a valuable supplementary tool when analyzing well performance by arriving at a reasonable range of oil EUR for a specific 1-year cumulative oil volume. The main application of this paper is to simplify the type curve process by creating a universal type curve that removes any bias when conducting decline curve analysis and narrows uncertainty in the EUR. While this methodology does not eliminate the need to do a more thorough analysis of unconventional wells, the results show that a simplistic parameter like 1-year cumulative oil volume can be extremely useful in predicting long-term well performance with an acceptable level of uncertainty (± 15%). This paper also has numerous applications in evaluating best practices related to well spacing, landing point sensitivities, and field development planning, to name a few. The results from this paper might serve to remove bias in MFHW production forecasting and provide reproducible forecast.
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