Ilk, Dilhan (2010-08). Well Performance Analysis for Low to Ultra-low Permeability Reservoir Systems. Doctoral Dissertation. Thesis uri icon


  • Unconventional reservoir systems can best be described as petroleum (oil and/or gas) accumulations
    which are difficult to be characterized and produced by conventional technologies. In this work we
    present the development of a systematic procedure to evaluate well performance in unconventional (i.e.,
    low to ultra-low permeability) reservoir systems.
    The specific tasks achieved in this work include the following:
    ? Integrated Diagnostics and Analysis of Production Data in Unconventional Reservoirs: We identify
    the challenges and common pitfalls of production analysis and provide guidelines for the analysis of
    production data. We provide a comprehensive workflow which consists of model-based production
    analysis (i.e., rate-transient or model matching approaches) complemented by traditional decline
    curve analysis to estimate reserves in unconventional reservoirs. In particular, we use analytical
    solutions (e.g., elliptical flow, horizontal well with multiple fractures solution, etc.) which are
    applicable to wells produced in unconventional reservoirs.
    ? Deconvolution: We propose to use deconvolution to identify the correlation between pressure and
    rate data. For our purposes we modify the B-spline deconvolution algorithm to obtain the constantpressure
    rate solution using cumulative production and bottomhole pressure data in real time
    domain. It is shown that constant-pressure rate and constant-rate pressure solutions obtained by
    deconvolution could identify the correlation between measured rate and pressure data when used in
    ? Series of Rate-Time Relations: We develop three new main rate-time relations and five
    supplementary rate-time relations which utilize power-law, hyperbolic, stretched exponential, and
    exponential components to properly model the behavior of a given set of rate-time data. These
    relations are well-suited for the estimation of ultimate recovery as well as for extrapolating
    production into the future. While our proposed models can be used for any system, we provide application almost exclusively for wells completed in unconventional reservoirs as a means of
    providing estimates of time-dependent reserves. We attempt to correlate the rate-time relation
    model parameters versus model-based production analysis results. As example applications, we
    present a variety of field examples using production data acquired from tight gas, shale gas
    reservoir systems.

publication date

  • August 2010