A Quadratic Cumulative Production Model for the Material Balance of an Abnormally Pressured Gas Reservoir Conference Paper uri icon


  • Abstract The premise of this work is the concept, development, and application of an approximate relation for the material balance of abnormally pressured gas reservoirs. In particular, the proposed approximation is formulated directly from the rigorous material balance for the case of an abnormally pressured gas reservoir. Our "quadratic cumulative production" result is given by: (1)pzpizi[1[1G]GpGGp2] where is defined as a function ofGp The -function is defined by the "cumulative effective compressibility" [ ce (p)] and represents the influence of abnormal pressure. If we assume =constant (but this does not mean that ce (p) is constant), then we obtain the "quadratic" formml: (2)pzpiziGpGp2where=1Gand=G Eq. 2 is the base definition of the "quadratic cumulative production" relation ( is constant; therefore, and are constant). We have shown this relation to be an extraordinarily accurate approximation of the rigorous material balance for the case of a dry gas reservoir with abnormal pressure effects. Eq. 2 is suited not only for use as a characteristic model, but also for use as a data analysis mechanism (i.e., in this work we use Eq. 2 to develop a suite of analysis plots, plotting functions, a type curve, etc.). We also address the case of being a linear function of Gp (as opposed to being constant) which results in a formulation where p/z is cubic in terms of Gp. In this work, we provide the following new results: The "quadratic cumulative production" model for the material balance behavior of abnormally pressured gas reservoir.A suite of 6 (six) plotting functions based on the p/z-G2 material balance model.A suite of 4 (four) -Gp performance plots which are used to calibrate the analysis process.A new type curve pD[=(pi/zi-p/z)/pi/zi] versus GpD[=Gp/G], based on the new p/z-G2 material balance model. Objectives The primary objectives of this work are:

name of conference

  • All Days

published proceedings

  • All Days

author list (cited authors)

  • Gonzalez, F. E., Ilk, D., & Blasingame, T. A.

citation count

  • 19

complete list of authors

  • Gonzalez, FE||Ilk, D||Blasingame, TA

publication date

  • January 2008