DFIT-Driven Formation Properties Impact on the Performance of Unconventional Wells with Consistent Drilling and Completion Practices

Abstract The scope of this paper is to investigate the impact formation properties, driven from diagnostic fracture injection test (DFIT), have on the performance of unconventional wells with identical drilling and completion practices. The objective is to study the relationship of closure time and transmissibility with well performance, to improve the decision-making process and performance prediction of future wells within an area of application. The performance of unconventional wells is mainly driven by either formation related parameters such as rock quality, reservoir pressure, and fluid properties, or stimulation related parameters such as fracture geometry and complexity. Four scattered wells within the same application area with identical drilling and completion practices targeting the same unconventional formation were used for this study. The stimulation design was fixed for all four wells, leaving formation properties as the only variable. DFIT was implemented on all four wells to acquire key formation related properties, mainly closure time and transmissibility. These two parameters were then correlated with well performance to quantify its impact, and identify potential prediction techniques for future wells. Closure time refers to the time required for a fracture to close after injection, while transmissibility refers to the ability of fluids to pass through rock with a certain height and fluid viscosity. The use of both parameters yielded key insights when plotted against wells productivity index (PI), especially that all four wells had approximate closure and pore pressure gradients. When closure time was plotted against PI, an inverse exponential correlation was matched with an accuracy of more than 99%, indicating that a longer closure time consistently yielded lower well performance. On the other hand, a transmissibility versus PI plot showed a direct exponential correlation with an accuracy of 98%, emphasizing on the positive impact transmissibility has on well performance. The combined use of closure time and transmissibility yielded definitive and consistent results across all four wells which can be used to drive conclusions on well evaluation, and navigate the decision-making process at the subject application areas. The novelty of this work lies in the utilization of DFIT-driven parameters, mainly closure time and transmissibility, in evaluating the performance of unconventional wells within an area of application. Correlations with well PIs were matched with a high degree of accuracy, indicative of the methodology’s validity, and potential broader application.