A new solution to the pressure-transient behaviour in a multilayered reservoir with formation crossflow

  • Mohamed Tariq Alhamami

    Student thesis: Master's Thesis

    Abstract

    Multilayered reservoirs have been studied in the literature for two types of systems: (1) layers that are separated by impermeable barriers (no formation crossflow) and (2) layers that communicate in the reservoir. In this work, the general problem of distinct n homogenous layers, in which any two adjacent layers are crossflowing in the formation, is solved analytically. A new solution of the corresponding pressure transient behavior is proposed for a uniform-flux vertical well in a multilayered reservoir with formation crossflow. Layer parameters, including permeability, porosity, and layer thickness between crossflowing layers, are distinct for each layer. The solutions are presented for an infinite-acting system with no wellbore storage or skin factor effects. In an n-layer reservoir system, any mid-layer that is bounded between an upper and a lower producing intervals involves a special mathematical treatment since its pressure is dependent on the amount of fluid flux gained or lost at its common interfaces. Moreover, a new parameter is introduced to quantitatively describe the crossflow between layers that defines the degree of communication with time. After a careful examination of the early time performance, it is shown that the pressure behavior is remarkably different from that of an equivalent single layer system and is influenced by the degree of communication between the layers. It is also highlighted that a crossflow will cease to exist when a pressure equilibrium is reached between the layers; hence at late times, multilayered reservoirs behave like a single homogenous system. When all the corresponding layer parameters are identical, the proposed solution for an n layer reservoir reduces to the exponential integral (Ei) solution of a single layer. study herein provides an analytical tool to estimate individual layer properties and to model the response of any number of reservoir layers with formation crossflow.
    Date of AwardDec 2016
    Original languageAmerican English
    SupervisorJing Lu (Supervisor)

    Keywords

    • Applied sciences
    • Formation crossflow
    • Pressure transient equation
    • Transient equation
    • Petroleum engineering
    • 0765:Petroleum engineering

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