Optimal Application of Rejuvenation Technologies in Unconventional Plays Based on Sensitivity Analysis of Reservoir Modeling Variables

Abstract

Abstract

Although the rejuvenation of shale reservoirs has been successful in many cases, the complexity of the intervention process brings along with it many variables that still need to be better understood. The objective of this study is to optimize the application of rejuvenation technologies on an existing well by understanding its impact on the reservoir, to be able to accelerate or even increase hydrocarbon recovery. In particular, this article focuses on reservoir simulation modeling of horizontal unconventional wells that have employed rejuvenation technologies such as fluid diversion and a method of selective zone treatment. We show that renewed focus on understanding reservoir response to various rejuvenation technologies will enable us to provide informed solutions.

The production-history matched reservoir model of the wells simulates the injection, flow-back, shut-in and production periods during the initial and restimulation treatments. Pressure-dependent permeability variation and the effect of capillary pressure are incorporated to simulate the varied dynamics of the reservoir. Fracture geometry predicted through fracture modeling is incorporated into the reservoir model for both the initial and restimulation treatments. While employing the use of fluid diversion, significant uncertainty lies in understanding how the fluid pumped during restimulation affects initial completions and untouched zones. This study presents a sensitivity analysis on various cluster efficiencies that may be possible while using fluid diversion, in order to understand its impact on recoverable reserves. Varying treatment volumes and shut-in times are also studied in order to see its impact on fluid migration and recovery. While selective zone treatment is modeled, a key challenge is to identify untapped reservoir potential.

The impact of rejuvenation techniques on reservoir response is quantified in terms of cumulative hydrocarbon fluid produced and fluid migration in time. It is seen that the amount of treatment fluid that restimulates initial completions plays an important role in the optimal application of rejuvenation technologies. Production forecasts from these reservoir models provide key insights on parameters that are influential in effective depletion of the reservoir and its correlation with cluster efficiency, treatment schedule and effective drainage of the reservoir. These parameters ultimately affect the economics of the decision-making process.

AAPG Datapages/Search and Discovery Article #90260 © 2016 AAPG/SEG International Conference & Exhibition, Cancun, Mexico, September 6-9, 2016