SPE Reservoir Evaluation & Engineering
Volume 15, Number 3, June 2012, pp. 351-360

SPE-145798-PA

The Use of Combined Static- and Dynamic-Material-Balance Methods With Real-Time Surveillance Data in Volumetric Gas Reservoirs

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DOI  More information 10.2118/145798-PA http://dx.doi.org/10.2118/145798-PA

Citation

  • Ismadi, D., Kabir, C.S., and Hasan, A.R. 2012. The Use of Combined Static- and Dynamic-Material-Balance Methods With Real-Time Surveillance Data in Volumetric Gas Reservoirs. SPE Res Eval & Eng  15 (3): 351-360. SPE-145798-PA. http://dx.doi.org/10.2118/145798-PA.

Discipline Categories

  • 6.6 Reservoir Monitoring/Formation Evaluation
  • 6.7.1 Estimates of Resource in Place
  • 6.6.5 Well Performance Monitoring, Inflow Performance

Keywords

  • Combined static and dynamic material balance, Estimating gas-in-place, Rate estimation in spite of WHT reversal

Summary

Estimating in-place volume associated with each well, leading to estimation of total reservoir in-place volume, is the cornerstone to any reservoir-management practice. Yet, conventional methods do not always lend themselves to routine applications, particularly when used in singular fashion. However, combining these methods on the same plot has considerable merit in that they converge to the same solution when material-balance (MB) -derived average-reservoir pressure is used in a volumetric system.

This study presents a systematic procedure for estimating the gas-initially-in-place (GIIP) volume when real-time surveillance data of pressure, rate, and temperature are available at the wellhead. Specifically, we show that log-log diagnosis, followed by combined static- and dynamic-MB analysis and transient-productivity-index (PI) analysis, leads to consistent solutions. Thermodynamic behavior of fluids is also explored to ensure that converted pressures at the bottomhole and measured rates have consistency and accuracy for reservoir-engineering calculations.

Layered systems were selected for this study because they represent most situations. Two synthetic cases probed issues pertaining to average-reservoir-pressure computation with the pseudosteady-state (PSS) approach, and two field examples validated the approach presented here.

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History

  • Original manuscript received: 10 June 2011
  • Meeting paper published: 21 September 2011
  • Revised manuscript received: 8 February 2012
  • Manuscript approved: 1 March 2012
  • Published online: 10 May 2012
  • Version of record: 12 June 2012