1. Analysis of Production Data
Module for:
Analysis of Reservoir Performance
Analysis of Production Data
T.A. Blasingame, Texas A&M U.
Department of Petroleum Engineering
Texas A&M University
College Station, TX
(979) —
PETE 324 (03A) — Analysis of Production Data

2. Analysis of Production Data
Production data — "low frequency" (taken at large (or even random) intervals) and "low resolution" (data quality (i.e., accuracy) is minimal).
Simple Analysis:
Rate-time decline curve analysis.
EUR analysis (usually rate-cumulative or variation).
New stuff — advanced analysis based on a simple, yet robust model (e.g., Knowles qg-Gp analysis)
Decline type curve analysis:
Systematic, model-based analysis approach.
Model identification — transient data analysis.
Volume estimates — pseudosteady-state behavior is dictated by material balance (very consistent).
PETE 324 (03A) — Analysis of Production Data

3. Production Analysis — Example Case
Rate and pressure profile for a mid-continent (U.S.) gas well, note the daily and seasonal fluctuations in the data.
PETE 324 (03A) — Analysis of Production Data

4. Production Analysis — EUR Analysis
Estimated ultimate recovery (EUR) profile for a mid-continent (U.S.) gas well — there is considerable variation in the data.
PETE 324 (03A) — Analysis of Production Data

5. Production Analysis — WPA (Data Edit Plot)
Note the transient "spikes" are edited out of the data used for type curve matching. This dataset is more or less typical.
PETE 324 (03A) — Analysis of Production Data

6. Production Analysis — WPA Approach
Note that the WPA approach provides a unique analysis/ interpretation of the well performance history.
PETE 324 (03A) — Analysis of Production Data

7. Production Analysis — the hard way...
"Van Everdingen-Meyer Method:
"Analysis by simulation" (use analytical solution to define x-axis plotting function).
Considers all of the data, needs a complete model to generate an appropriate analysis/interpretation.
Theoretically simple, practical.
Pro: Theoretically simple and practical (can use field data).
Con: Limited by solution model as well as data quality.
From: SPE — Whitson and Sognesand (1988).
PETE 324 (03A) — Analysis of Production Data

8. Production Analysis — Original Type Curve Approach
"Analytical" rate decline curves:
Data from van Everdingen and Hurst (1949), replotted as a rate decline plot (Fetkovich, 1973).
This looks promising — but this is going to be one really big "type curve."
What can we do? Try to col-lapse all of the trends to a single trend during boun-dary-domination flow (Fet-kovich, 1973).
From: SPE — Fetkovich (1973).
From: SPE — Fetkovich (1973).
PETE 324 (03A) — Analysis of Production Data

9. Production Analysis — Fetkovich Type Curves
Composite Transient Type Curve:
Collapses the transient flow trends into "stems" related to reservoir size and skin factor (Fetkovich, 1973).
Composite Total Type Curve:
Addition of the "Arps" empirical trends for "boundary-dominated flow behavior (Fetkovich, 1973)."
Assumptions:
Constant bottomhole pressure.
"Liquid" flow (not gas).
From: SPE — Fetkovich (1973).
From: SPE — Fetkovich (1973).
PETE 324 (03A) — Analysis of Production Data

10. Production Analysis — Fetkovich Type Curves (1)
Fetkovich "Analytical" Type Curve.
PETE 324 (03A) — Analysis of Production Data

11. Production Analysis — Fetkovich Type Curves (2)
Fetkovich "Composite" Type Curve (analytical/empirical).
PETE 324 (03A) — Analysis of Production Data

12. Production Analysis — Decline Type Curves
Fetkovich Derivative Type Curve:
Good concept, but just try to take the derivative of produc-tion data...
Fetkovich-McCray Type Curve:
Concept is to generate "inte-gral" functions for data analy-sis, much better performance than simply using rate.
Still Need:
Variable pressure/rate methods.
Other models — fractured wells, horizontal wells, etc...
From: SPE — Doublet, et al (1994).
From: SPE — Palacio, et al (1993).
PETE 324 (03A) — Analysis of Production Data

13. Production Analysis — Decline Type Curves
UNFRACTURED Well Case:
Variable Rate/Pressure Approach:
Use "material balance time" (x-axis) and "pressure drop nor-malized rate" (y-axis) functions.
Good news:
New concept provides unique behavior during boundary- dominated flow regime.
Not-So-Good-News:
Wellbore pressure data are critical.
From: SPE — Palacio, et al (1993).
From: SPE — Doublet, et al (1994).
PETE 324 (03A) — Analysis of Production Data

14. Production Analysis — Decline Type Curves (1)
"Fetkovich-McCray" Type Curve for an Unfractured Well — Production Time Format.
PETE 324 (03A) — Analysis of Production Data

15. Production Analysis — Decline Type Curves (2)
"Fetkovich-McCray" Type Curve for an Unfractured Well — Material Balance Time Format.
PETE 324 (03A) — Analysis of Production Data

16. Production Analysis — Decline Type Curves
FRACTURED Well Cases
Infinite-conductivity vertical fracture case
Finite-conductivity vertical fracture case(s).
From: SPE — Doublet, et al (1996).
From: Current Work — Pratikno (2002).
From: Current Work — Pratikno (2002).
PETE 324 (03A) — Analysis of Production Data

17. Production Analysis — Decline Type Curves (3)
"Fetkovich-McCray" Type Curve for a Fractured Well (Infinite Conductivity) — Material Balance Time Format.
PETE 324 (03A) — Analysis of Production Data

18. Production Analysis — Decline Type Curves (4)
"Fetkovich-McCray" Type Curve for a Fractured Well (FcD=0.5) — Material Balance Time Format.
PETE 324 (03A) — Analysis of Production Data

19. Production Analysis — Decline Type Curves (5)
"Fetkovich-McCray" Type Curve for a Fractured Well (FcD=10) — Material Balance Time Format.
PETE 324 (03A) — Analysis of Production Data

20. Production Analysis — Decline Type Curves
Horizontal Well Cases — "Infinite-conductivity" horizontal well case(s).
From: SPE — Shih, et al (1995).
From: SPE — Shih, et al (1995).
From: SPE — Shih, et al (1995).
PETE 324 (03A) — Analysis of Production Data

21. Production Analysis — Decline Type Curves
Decline Type Curve Analysis: "Break-glass-in-case-of-fire" cases
From: SPE — Doublet, et al (1995).
From: Unpublished — Marhaendrajana (2002) (multiwell analysis — do not use).
From: SPE — Doublet, et al (1995).
PETE 324 (03A) — Analysis of Production Data

22. Production Analysis — Decline Type Curves (6)
"Fetkovich" Type Curve for an Unfractured Well — Water Influx model ("ramp rate" case).
PETE 324 (03A) — Analysis of Production Data

23. Production Analysis — Decline Type Curves
Agarwal, et al Methodology:
Basically the same as Blasingame, et al work.
More like pressure transient test analy-sis/interpretation.
From: SPE — Agarwal, et al (1998).
From: SPE — Agarwal, et al (1998).
From: SPE — Agarwal, et al (1998).
PETE 324 (03A) — Analysis of Production Data

24. Production Analysis — Multiwell Analysis
Multiwell case can be "recast" into single well case using cumulative production for entire field.
Homogeneous reservoir example shows that all cases (9 wells) align — same behavior observed for heterogeneous reservoir cases.
From: SPE — Marhaendrajana (2001).
From: SPE — Marhaendrajana (2001).
From: SPE — Marhaendrajana (2001).
PETE 324 (03A) — Analysis of Production Data

25. Production Analysis — Reality Check
Production data analyses and pressure transient analyses "see" the reservoir as a volume-averaged set of properties.
New solutions/models will also have this view of the reservoir, but quantifying heterogeneity may be possible by the analysis of data at the "local" level.
Scaling will remain a major issue — regardless of the mechanism used to analyze reservoir performance.
From: Simulator Parameter Assignment and the Problem of Scaling in Reservoir Engineering — Halderson (1986).
PETE 324 (03A) — Analysis of Production Data

26. Production Analysis — Future
Future of Production Data Analysis:
Evolutionary changes:
Better data acquisition (major issue).
Multiwell analysis (major issue).
Better software (major issue).
More reservoir/well solutions (minor issue).
Revolutionary changes:
Direct dataflow into integrated packages for analysis/simulation (5-10 years).
Real-time rate-pressure optimization, simul-taneous monitoring and control (5-10 years).
PETE 324 (03A) — Analysis of Production Data

27. Analysis of Production Data End of Presentation
Module for:
Analysis of Reservoir Performance
Analysis of Production Data
End of Presentation
T.A. Blasingame, Texas A&M U.
Department of Petroleum Engineering
Texas A&M University
College Station, TX
(979) —
PETE 324 (03A) — Analysis of Production Data