Produced Water Produced Water Reinjection PerformanceReinjection Performance

Joint Industry ProjectJoint Industry ProjectTerraTek, Inc.TerraTek, Inc.

Triangle EngineeringTriangle Engineering

Taurus Reservoir Solutions (DE&S)Taurus Reservoir Solutions (DE&S)

E-first TechnologiesE-first Technologies

AdvantekAdvantek

VIPSVIPS

Data AnalysisData Analysis

– Data sets analyzed:Data sets analyzed:

Elf 3 Well 1 + 2Elf 3 Well 1 + 2

Statoil Heidrun B3HStatoil Heidrun B3H

Marathon West BraeMarathon West Brae

– Each dataset has unique interpretation Each dataset has unique interpretation problemsproblems

– Analysis of impairment of injectivity (k, S)Analysis of impairment of injectivity (k, S)

– Simple damage model Simple damage model

Methodology for AnalysisMethodology for Analysis

1.1. Convert THP to BHP Convert THP to BHP

2.2. Find and mark all significant events Find and mark all significant events (stimulations, transition matrix-frac,…)(stimulations, transition matrix-frac,…)

3.3. Conventional p,Q vs t and p vs Q plotsConventional p,Q vs t and p vs Q plots

4.4. Modified Hall plot (consider variations in pModified Hall plot (consider variations in presres))

5.5. Check initial (or expected) injectivity by Check initial (or expected) injectivity by analytical or numerical calculationanalytical or numerical calculation

Methodology for Analysis – cont’dMethodology for Analysis – cont’d

6.6. If fracturing identified, check frac pressure If fracturing identified, check frac pressure from all available sourcesfrom all available sources

7.7. Calculate II in matrix modeCalculate II in matrix mode

8.8. Calculate II in fracture mode Calculate II in fracture mode

9.9. If good data is obtained for number of If good data is obtained for number of datasets, correlate II changes with basic datasets, correlate II changes with basic parametersparameters

10.10. Try to develop general correlation (similar to Try to develop general correlation (similar to PEA23)PEA23)

Elf 3 CharacteristicsElf 3 Characteristics

PW only, high solids content, extreme PW only, high solids content, extreme pluggingplugging

Frequent acid jobsFrequent acid jobs

Difficulty in deciding matrix vs fracture Difficulty in deciding matrix vs fracture regime due to imposed THP limitation of 90 regime due to imposed THP limitation of 90 barsbars

Analysis shows extreme reduction in perm Analysis shows extreme reduction in perm (or skins on the order of 1000)(or skins on the order of 1000)

Statoil Heidrun B3HStatoil Heidrun B3H

Fracture and matrix injection, SW Fracture and matrix injection, SW onlyonly

Difficulties with BHP conversion and Difficulties with BHP conversion and ppres res interpretationinterpretation

Significant damage (k/10, S=100)Significant damage (k/10, S=100)

Marathon West BraeMarathon West Brae

SW only, very detailed history SW only, very detailed history

Hall plot shows unexplained slope Hall plot shows unexplained slope change (after shutdown?)change (after shutdown?)

Large damage (k/100, S=800)Large damage (k/100, S=800)

Data set Injection Water type Water quality (ppm) Injection regime Inj. Index Inj Index ReservoirPerm in invaded

(sanitized name) period (days)AW,GW,SW,PWOIW TSS TSS DH

(analysis) expected from res. perm

perm (md)

zone (radial flow)

7.      Marathon 2 (W. Brae) 0 - 384 SW (coarsely filtered)

0 ? ? Matrix + possibly slight fracturing?

16 bbl/psia/d 1066 bbl/psia/d 2000 30

385-970 SW (coarsely filtered)

0 ? ? Matrix 13 bbl/psia/d 1066 bbl/psia/d 2000 25

11.  Statoil 1 (Heidrun) B3H 0-921 SW (clean) 0 ? ? fracture 1 m3/kPa/d 3.699 438 90

922-1592 SW (clean) 0 ? ? matrix .25 m3/kPa/d 3.699 438 27

12.  Elf 3 Well 1 0-2300 PW 100-300 252 100+? matrix+fracture 0.1-1 m3/kPa/d

23.52 m3/kPa/d

1700 5 to 50

Elf 3 Well 2 0-413 PW 100-300 252 100+? mixed? 02-0.7 m3/kPa/d

14.8 m3/kPa/d

4000 40-100

413-613 PW 100-300 252 100+? matrix 0.15 14.8 4000 35

613-1556 PW 100-300 252 100+? fracture after about 750 days

0.26 14.8 4000 60

SummarySummary

ConclusionsConclusions All data sets show significant reduction of All data sets show significant reduction of

injectivity compared to theoreticalinjectivity compared to theoretical

Perm reduction and skin plots help visualize Perm reduction and skin plots help visualize the problemthe problem

Each case must be processed very carefully, Each case must be processed very carefully, assembly line approach will give misleading assembly line approach will give misleading resultsresults

Simple damage model looks promising, can Simple damage model looks promising, can incorporate dynamic changes (p(t), incorporate dynamic changes (p(t), stimulations, …)stimulations, …)