A Simulation-Based Screening of Production Parameters in Unconventional Reservoirs

Abstract

Multi-stage hydraulic fracturing is the most commonly used completion technique to produce oil and gas from unconventional reservoirs. The fracture surfaces create a highly conductive area for the drainage of the hydrocarbons from a tight matrix. It is therefore believed that the production performance for unconventional reservoirs is mainly controlled by the fracture and completion design. However, the in-situ properties of the reservoir matrix and the fluid compositional variability in the matrix could also influence the production performance. Therefore, it is necessary to clearly identify the most important parameters related to both matrix and fractures, in order to fully optimize the production from the unconventional reservoirs. In this paper the fractional factorial experimental design is used to perform sensitivity analyses on the unconventional reservoir parameters. This approach allows us to screen the most important matrix and fracture parameters that will affect the production and rank them based on their individual weighting factors. The approach is simulation-based and uses an in-house compositional flow simulator for deformable organic-rich source formations. The problem includes a selected list of 15 parameters related to the formation, fracture and fluid properties, and wellbore conditions. The screening considers the evolution of the weighting factors, during 1, 5 and 10 years of production. The results show that 9 out of 15 major parameters dominate the production performance of the well, which are matrix porosity, bottomhole pressure, stress-dependence of the matrix permeability, fracture width, fracture permeability and large pore threshold. The rank of each parameter is dependent on the production time.