Analysis of unsteady responses of natural gas reservoirs via a universal natural gas type-curve formulation

H. Ayala, F. Luis, Peng Ye

Research output: Chapter in Book/Report/Conference proceedingConference contribution

8 Scopus citations

Abstract

Gas decline curve analysis has traditionally relied on the use of liquid (oil) type curves along with the concepts of pseudo-pressure and pseudo-time and/or empirical curve fitting of rate-time production data using Fetkovich type curves for gas well performance and reserve estimations. In this work, we show that a single-line, universal type curve can instead be derived for the analysis of unsteady state of natural gas wells under boundary dominated flow (BDF). The proposed decline equation - presented in its analytical, closed functional form - models production from any gas well producing at constant bottomhole pressure under BDF. On the basis of this decline model, a universal type-curve is formulated for type curve matching of natural gas well producing under BDF, for any drawdown condition, and regardless of intrinsic reservoir and fluid properties. New-generation analytical procedures for gas well performance analysis are presented, which does not necessitate the calculation of pseudo-pressure or pseudo-time. Explicit OGIP predictions are thus enabled from the proposed universal type curve matching. The importance of conducting unambiguous reserve estimations based on rate-time data and reliably predicting future well performance cannot be overstated. The proposed single-line type curve is demonstrated to do so by successfully matching rate-time production BDF data, predicting future performance, and reliably estimating fluid in place for a large number of numerical simulations and field cases. It is finally shown that the proposed formulation can be alternatively implemented in terms of straight-line analysis of l/qscb versus time plots that enable future well performance and explicit reserves estimations.

Original languageEnglish (US)
Title of host publicationSociety of Petroleum Engineers - SPE Annual Technical Conference and Exhibition 2012, ATCE 2012
Subtitle of host publicationUnconventional Wisdom
Pages3913-3931
Number of pages19
StatePublished - Dec 1 2012
EventSPE Annual Technical Conference and Exhibition 2012: Unconventional Wisdom, ATCE 2012 - San Antonio, TX, United States
Duration: Oct 8 2012Oct 10 2012

Publication series

NameProceedings - SPE Annual Technical Conference and Exhibition
Volume5

Other

OtherSPE Annual Technical Conference and Exhibition 2012: Unconventional Wisdom, ATCE 2012
CountryUnited States
CitySan Antonio, TX
Period10/8/1210/10/12

All Science Journal Classification (ASJC) codes

  • Fuel Technology
  • Energy Engineering and Power Technology

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    Ayala, H., Luis, F., & Ye, P. (2012). Analysis of unsteady responses of natural gas reservoirs via a universal natural gas type-curve formulation. In Society of Petroleum Engineers - SPE Annual Technical Conference and Exhibition 2012, ATCE 2012: Unconventional Wisdom (pp. 3913-3931). (Proceedings - SPE Annual Technical Conference and Exhibition; Vol. 5).