The Optimum Cluster Interference Percentage in Multi-Stage Fractured Wells

In a number of shale formations, including the Bakken and Barnet shales, cluster spacing was fixed to 700 feet. In Eagle Ford and DJ Basin, tight cluster spacing was used for cluster spacing of up to 15 feet. This study presents an combined workflow to calculate the percent of interference and its effect on the well performance in addition estimate the acceptable interference percentage that provides the highest well profitability. Analytical rate transient analysis (RTA) and reservoir numerical simulation were coupled to calculate the ratio of the effective fracture surface area (A_Ce) for hydrocarbon production to the actual stimulated fracture area (A_Ca) from the numerical simulation. The percentage of interference was calculated by (1-A_Ce/A_Ca). The discounted cash flow analysis was combined to the integrated workflow to estimate the acceptable percentage of interference and the optimum spacing depending on the well's profitability. This study presents an integrated workflow for quantifying the percentage of cluster interference as a function of spacing. The workflow was integrated with an economic model to estimate the acceptable interference percent in order to maximize the NPV. The higher the stage number and tighter cluster spacing, the higher the cluster interference will be. The acceptable interference percent is a function of formation properties and economic parameters. The acceptable interference percent was found to be 16% in the case of 0.0001md, 2.5$/Mscf. Increasing the formation permeability increases the acceptable interference percent to accelerate production and increase the recovery. As the higher gas price or lower interest rate, tighter spacing is recommended, where, at 8$/Mscf, the NPV was continuously increasing up to the lowest spacing in this study of 20 ft.