Unocal Alaska Web-Based Gas-Lift Surveillance

Paul BurtisChris Ruff

Scott Herman February 2002

Unocal Alaska Operations Map

Typical Gas-Lift Completion

TOL @ 10,516’

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4

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TD = 15,114’ETD =15,070’91 / 12,805’; 99 /13,281’; 104 /15,049’

RKB = 44.3’ Rig Floor to DCB TBG SpoolCASING AND TUBING DETAIL

SIZE WT GRADE CONN ID MD TOP MD BTM.17-3/4” .312W Spiral Weld Surf. 600’13-3/8” 61 J-55 Buttress Surf. 5,802’9-5/8” 47 N-80 Buttress 8.681 Surf. 67’9-5/8” 40 N-80 Buttress 8.835 67’ 5,883’9-5/8” 43.5 N-80 Buttress 8.755 5,883’ 7,900’9-5/8” 47 N-80/P-110 Buttress 8.681 7,900’ 11,210’Window 10,845 10,857’7” 29 L-80 TKC-Butt 6.184 10,516 12,365’4-1/2” 11.6 N-80 Hydril 511 3.958 12,257’ 15,072’4-1/2” pre-drilled liner has ½” predrilled holes—8 hpfTubing:5-1/2” 17.0 L-80 LTC 4.892 42.9 10,516’

JEWELRYNO Depth ID Item1 42.9’ 4.930” CIW 5-1/2” DCB Tubing Hanger: 5-1/2” LTC top & btm2 304’ 4.562 Baker TE-5 TBG Retrievable SCSSSV3 2,875’ 4.892” #16 5-1/2” SF-02 McMurry GLM w/ 1-1/2” R-2 valve

5,064 4.892” #15 5-1/2” SF-02 McMurry GLM w/ 1-1/2” R-2 valve5,629 4.892” #14 5-1/2” SF-02 McMurry GLM w/ 1-1/2” R-2 valve6,150’ 4.892” #13 5-1/2” SF-02 McMurry GLM w/ 1-1/2” R-2 valve6,212’ 4.892” #12 5-1/2” SF-02 McMurry GLM w/ 1-1/2” R-2 valve6’690’ 4.892” #11 5-1/2” SF-02 McMurry GLM w/ 1-1/2” R-2 valve6,751’ 4.892” #10 5-1/2” SF-02 McMurry GLM w/ 1-1/2” R-2 valve7,231’ 4.892” #9 5-1/2” SF-02 McMurry GLM w/ 1-1/2” R-2 valve7,287’ 4.892” #8 5-1/2” SF-02 McMurry GLM w/ 1-1/2” R-2 valve7,723 4.892” #7 5-1/2” SF-02 McMurry GLM w/ 1-1/2” R-2 valve7,821 4.892” #6 5-1/2” SF-02 McMurry GLM w/ 1-1/2” R-2 valve8,257’ 4.892” #5 5-1/2” SF-02 McMurry GLM w/ 1-1/2” R-2 valve8,814’ 4.892” #4 5-1/2” SF-02 McMurry GLM w/ 1-1/2” R-2 valve9,336’ 4.892” #3 5-1/2” SF-02 McMurry GLM w/ 1-1/2” R-2 valve9,857’ 4.892” #2 5-1/2” SF-02 McMurry GLM w/ 1-1/2” R-2 valve10,339’ 4.892” #1 5-1/2” SF-02 McMurry GLM w/ orifice

4 10,504’ 4.455” Baker ‘XN’ Nipple5 10,440’ 6.00” Baker Model F Permanent Packer with 18 ft seal-bore

extension6 10,456’ 4.937” Baker tubing seal assembly (L= 20 ft)7 10,516 6.188” Baker tie-back seal assembly (L= 6.70 ft)

TOL @ 12,257’

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Typical Gas-Lift Surveillance Processes

Vendor-Driven Predominant at Unocal Unocal delegates design and surveillance Results in unknown optimization level

Operator Staff-Driven Engineer Part-Time

Work typically prioritized downward Technician Full-Time

Optimum results

Typical Gas-Lift Surveillance Processes

Vendor-Driven

Timetable driven surveillance

Engineering staff typically uninformed about key design and operation parameters

Operators not fully aware of these parameters

Unocal Alaska Gas Lift Program - 2000

Total Rate

Gain(boe/day)

FundsSpent($ US)

# ofJobs

SuccessRate(%)

Payout(months)

2,115 $225,000 15 87% 0.3

Unocal Alaska Gas Lift Surveillance Process

Dedicated staffing

Informed decisions based on data

Web-assisted surveillance

Surveillance Program - 2000

PBU’s FlowingPressureTraverses

NodalModels

Acoustic FluidLevels & 3-Pen

Charting7 14 25 15

• Optimization work performed on 19% of active

gas lift wells in 2000

• Gas lift diagnostics run on 34% of active gas lift

completions

Unocal Alaska Web-Based Surveillance

Unocal Alaska Web-Based Surveillance

Unocal Alaska Web-Based Surveillance

Surveillance Program - 2001 Results

• Previous program well turnaround = 60 days

• Current process = 2 days

• Average production deferment = 50 bopd

• Deferred yearly program revenue = $480,000

Conclusions

• Gas lift completions require continuous

surveillance to yield optimum returns

• Web-based technology is available to

systematically change current surveillance

• This technology requires key staff understand

their key performance / design parameters