The combination of horizontal drilling, multistage completion and hydraulic fracturing has been the key factor for the successful development of the Bakken play. This dominant status reflects in two aspects: the enhancement of well production, making stripper well even dry well valuable for industrial development, and the effect of long-term flow conductivity on the ‘sustained yield’ of well. This paper quantitatively analyzed the stimulation design factors and their interactions contributing to incremental and long-term productivity of horizontal wells in Bakken respectively for different geologic environment.

Data from more than 1000 wells located in the Bakken Central Basin area containing production and stimulation design have been collected from the Premium Services of North Dakota Industrial Commission (NDIC) website and the FracFocus.org. Wells were grouped and analyzed by similar water cut based on cumulative production for the normalization of variation in geologic heterogeneity. Response surface methodology (RSM) was applied as the methods of quantitative analysis to determine the contributing factors and their interactions. In this study, 2-month and 12-month cumulative oil production per perforated length were used as the indicators of incremental productivity and long-term productivity respectively.

The data are divided into three reservoir-homogeneous groups according to different water cut range and a separate slickwater fracturing group. The effects of stimulation design factors and their interactions on the incremental productivity and long-term productivity were investigated. Results indicates that among all the factors, perforated length, proppant/perf length, water/ perf length, percentage of ceramic are the most contributing factors of stimulation design to incremental and long-term productivity. Different group are influenced by different combination of contributing factors. Most groups share the same significant interaction between perforated length and water/ perf length, as perforated length increases and water/ perf length decreases meawhile, the cumulative oil production per perforated pength climbs rapidly, with the amount of other design factors fixed.

Previous similar analysis focused on 30, 60 and 90-day cumulative production with smaller data volume to generate well performance metrics for the lack of enough wells. This paper utilized the larger data set with longer production time span and analyzed the stimulation design factors contributing to incremental and long-term productivity of horizontal wells in Bakken respectively. These results are more valuable for optimization of stimulation design in the Bakken play and similar reservoirs faced with dynamic and changing oil market.

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