Estimating in-place volume and reservoir connectivity with real-time and periodic surveillance data

Abstract This paper demonstrates the value of collecting and interpreting real-time data. With an intensive data gathering strategy, starting at wells' inception to the mature production phase, we show how transient pressure and rate data can be used to manage a complex carbonate gas reservoir. In particular, reservoir connectivity is discerned with pulse testing and with the leading-edge p/q graph, and continuous updates of in-place volume are made with both static and dynamic material-balance methods and corroborating the same with rate-transient analysis. Interwell connectivity information was deduced during underbalanced drilling by way of interference test between two pairs of wells. Thereafter, transient-pressure tests on individual wells characterized the layered, dual-porosity system, with production logs corroborating the notion of layering. Production maturity over three years has paved the way for estimating connected in-place gas volume associated with each well using the transient-PI, and also with a new method introduced here. This new approach entails plotting both static and dynamic material-balance data on the same graph, yielding the same solution. Errors associated with real-time rate measurements presented interpretation challenges for rate-transient analysis; however, application of a physics-based filtering algorithm resolved this issue. Flow-after-flow tests that were embedded in monthly variable-rate production allocations, in turn, allowed us to obtain average-reservoir pressure explicitly to do the static material-balance analysis.

[1]  Louis Mattar,et al.  The "Flowing" Gas Material Balance , 1998 .

[2]  D. O. Ogbe,et al.  A Correlation for Interference Testing With Wellbore-Storage and Skin Effects , 1989 .

[3]  Owen J. Hehmeyer,et al.  Examples of Right-Time Decisions from High Frequency Data , 2008 .

[4]  I. Ershaghi,et al.  Triple-Porosity Systems for Representing Naturally Fractured Reservoirs , 1986 .

[5]  Henry J. Ramey,et al.  Decline Curve Analysis Using Type Curves for Two-Porosity Systems , 1981 .

[6]  Roland N. Horne,et al.  Processing and Interpretation of Long-Term Data Acquired From Permanent Pressure Gauges , 2002 .

[7]  C. Shah Kabir,et al.  An Integrated Geologic and Engineering Assessment of Fracture-Flow Potential in the Ratawi Reservoir of the Wafra Field, Partitioned Neutral Zone , 2008 .

[8]  Sammy Haddad,et al.  A Method to Diagnose Depletion, Skin, , and Drive Mechanism Effects Using Reservoir Monitoring Data , 2004 .

[9]  Ram G. Agarwal,et al.  Analyzing Well Production Data Using Combined-Type-Curve and Decline-Curve Analysis Concepts , 1999 .

[10]  A. Rashid Hasan,et al.  Ensuring Sustained Production by Managing Annular-Pressure Buildup , 2009 .

[11]  H. Kazemi,et al.  Analysis of Production Data From Hydraulically Fractured Horizontal Wells in Shale Reservoirs , 2010 .

[12]  C. S. Kabir,et al.  Diagnosis of reservoir compartmentalization from measured pressure/rate data during primary depletion , 2009 .

[13]  J. E. Warren,et al.  The Behavior of Naturally Fractured Reservoirs , 1963 .

[14]  Bulent Izgec,et al.  Sustaining Production by Managing Annular-Pressure Buildup , 2010 .

[15]  W. R. Roberts,et al.  The Boris Field Well Management Philosophy- The Application of Permanent Downhole Flowmeters to Pressure Transient Analysis: An Integrated Approach , 2004 .

[16]  Tor K. Kragas,et al.  Permanent Fiber-Optic Monitoring at Northstar: Pressure/Temperature System and Data Overview , 2004 .

[17]  C. S. Kabir,et al.  Understanding well performance with surveillance data , 2010 .

[18]  Jasmeet Singh Saluja,et al.  Improved Management of a Fractured Carbonate Reservoir using a Smart Fields Approach , 2008 .

[19]  C. S. Kabir,et al.  Analytic Wellbore Temperature Model for Transient Gas-Well Testing , 2005 .

[20]  Mehdi Azari,et al.  Case History Review of the Application of Pressure Transient Testing and Production Logging in Monitoring the Performance of the Mars Deepwater Gulf Of Mexico Field , 2008 .

[21]  J. L. Pletcher.  Improvements to Reservoir Material-Balance Methods , 2002 .

[22]  R. Horne.  Listening to the Reservoir—Interpreting Data From Permanent Downhole Gauges , 2007 .

[23]  D. O. Ogbe,et al.  A Method for Analyzing Pulse Tests Considering Wellbore Storage and Skin Effects , 1988 .

[24]  M. M. Kamal.  The Use of Pressure Transients To Describe Reservoir Heterogeneity , 1979 .

[25]  Christopher J. Jablonowski,et al.  A Procedure for Assessing the Value of Oilfield Sensors , 2009 .