Interporosity Flow Between Matrix and Fractures in Carbonates: A Study of its Impact on Oil Production

Abstract

Newly developed oil fields are increasingly hosted in carbonate deposits, with these carbonate reservoirs being the subject of numerous studies. However, the efficiency of oil production in carbonate reservoirs is generally lower than that of sandstones. A key feature of carbonate deposits is the presence of fractures. Many characteristics of these fractures, including their size and spatial orientation, have been widely studied; however, some of the most important aspects that control the interactions between the rock matrix and fractures in these deposits are still not yet fully understood. This study investigates the interactions between the matrix and fractures in carbonate deposits using field data (well tests) that are supplemented by core studies and aims to investigate specific features that influence oil production from wells located in the porous and fracture–pore zones of carbonate reservoirs. The results show that fractures influence both initial and cumulative oil production. Differences in the behavior of open and partially filled fractures were also investigated, and the characteristics of interporosity flow between the matrix and fractures in the rock were determined through the application of processing well tests using the Warren–Root model and further analyzed using flow coefficients. A direct relationship between cumulative oil production and the interporosity flow between the matrix and fractures was identified, which confirms the influence of interporosity flow on bottomhole pressure. Consequently, bottomhole pressure should be considered to be a key parameter in determining the efficiency of oil production in fracture-pore carbonate reservoirs.