Petroleum Engineering. WELL TEST: ANALYSIS AND DESIGN

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EG551Q_continuous_assessment_20172.pdf

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WELL TEST: ANALYSIS AND DESIGN

CONTINUOUS ASSESSMENT

INSTRUCTION SHEET

Well test was carried out on a well completed in an oil reservoir with the properties listed in table 1. The

schedule consisted of a short clean-up period followed by a build-up period (first build up), constant rate

production for approximately 24 hours and a 48 hour build up period (second build up).20

Table 1: Well testdata

Parameter Value Parameter Value

φ 0.15 B 1.35 bbl/STB h Dw

315 ft

7.5 in

µ Ct

0.8 cp

1.35 e-5 psi-1

Files 1. Pressure data: Pressuredata.txt

2. Rate data: Ratedata.txt

Import pressure data in excel and identify first build up, production and second build up.

Tasks 1, 2 and 3, must be carried out manually.

Task 1: Reservoir properties from first build up 1. For the first pressure build up data, construct an equivalent time curve

2. Calculate permeability, skin and initial pressure

Task 2: Reservoir properties from production data 1. For the sustained 24 hour production data, construct a semilog graph of pressure vs time.

2. Calculate permeability, skin and wellbore storage.

Task 3: Reservoir properties from second build up 1. For the second build up test data, construct a log-log graph of pressure vs time and derivative of pressure

vs time.

• Use excel or Kappa to generate pressure derivative vs time curve on log-log scale.

2. Calculate permeability, skin and wellbore storage by Bourdet’s type curve match

3. Identify boundary

Task 4: Reservoir properties from Kappa Saphir 1. Calculate reservoir permeability, skin and wellbore storage for first build up, production and second build-

up

2. Identify boundary

3. Perform sensitivity analysis for variation of skin, wellbore storage and permeability

2

Report The objective of this exercise is to compare the quality of the data generated through various methods: semilog

analysis of pressure drawdown and buildup, type curve matching and through use of software. The report must not be longer than 8 pages. Calculations stated in tasks 1-3 must be included in appendices as Appendix A,B and C. Submit the semilog graphs for tasks 1 and 2 as a hard copy only. Suggested structure of report is:

1. Introduction and objectives: Discuss the types of well tests and their specific applicability, associated

instrumentation (gauges). Steps need in preparation of a well test.

2. Methodology: Stages in well test, type of data collected, type of analyses.

3. Results (summary): Discuss key results from first build up, production and drawdown from both manual

and software computations. Cross compare the results and comment on the observations.

4. Uncertainty analysis: Identify the sources of error in the estimation of reservoir properties and address

the uncertainities in manual computations. Comment on how improvement of model in Kappa, may affect

the estimates of reservoircharacteristics.

5. Conclusions

Submission instructions 1. Submission Deadline: 12:00 PM of 8 March 2019.

2. Mode of submission: One hard copy along with plagiarism cover sheet must be submitted to the PG office and an electronic copy must be submitted through Turnitin submission on MyAberdeen.

  • EG551Q WELL TEST: ANALYSIS AND DESIGN CONTINUOUS ASSESSMENT
  • Files
    • Tasks 1, 2 and 3, must be carried out manually.
  • Task 2: Reservoir properties from production data
  • Task 3: Reservoir properties from second build up
  • Task 4: Reservoir properties from Kappa Saphir
  • Report
  • Submission instructions