Characterization and modeling of transition zones in tight carbonate reservoirs

  • Jorge Costa Gomes

    Student thesis: Master's Thesis

    Abstract

    There is no sharp interface between oil and water in any given reservoir due to the general heterogeneity of a given system, instead a zone exists in which there is two-phase flow of both water and oil and is known as the transition zone (TZ). Naturally, tight carbonate reservoirs exhibit thick TZ's that could contain large amounts of original oil in place (OOIP) and hence significant addition of reserves could be left behind if the rock-fluid interactions and recovery mechanisms are not well understood. This thesis presents the results of both static and dynamic properties, including fluid flow analysis, of carbonate samples collected along a thick TZ of a heterogeneous cyclic carbonate reservoir of Abu Dhabi. The samples were collected from the same well and rock and fluid typing was conducted taking into consideration the pore size distribution, the irreducible water saturation, the residual oil saturation, the oil and formation water characteristics, and the wettability all with respect to depth. The importance of this analysis is to better understand the capillary pressure behavior (drainage and imbibition cycles) as a function of depth. This provides essential information pertaining to fluid distributions in TZ's, wettability variations and the flow path connectivity within a porous medium. Moreover, a mechanistic flow model using a unique approach to model wettability variations with respect to depth and space was developed, taking into account the presence of a thick TZ, and its impact on oil recovery. This is extremely important for all professionals involved in field development activities to better understand the fluid flow behavior of porous carbonates at different heights above the free water level (HAFWL), as a function of oil trapping and rock wettability.
    Date of Award2014
    Original languageAmerican English
    SupervisorAli AlSumaiti (Supervisor)

    Keywords

    • Applied sciences
    • Earth sciences
    • Geology
    • Petroleum engineering
    • 0372:Geology
    • 0765:Petroleum engineering

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