Green Completions

Lessons Learned

from Natural Gas STAR

Producers Technology Transfer Workshop

ExxonMobil Production Company,

American Petroleum Institute and 

EPA’s Natural Gas STAR Program

September 21, 2004
Reducing Emissions, Increasing Efficiency, Maximizing Profits Page 2

Green Completions: Agenda

 Methane Losses

 Methane Recovery 

 Is Recovery Profitable?

 Industry Experience

 Discussion Questions
Reducing Emissions, Increasing Efficiency, Maximizing Profits Page 3

Methane Loss During Well Completions

 It is necessary to clean out the well bore and 

formation surrounding perforations

 After new well completion

 After well workovers

 Produce the well to an open pit or tankage to 

collect sand, cuttings and reservoir fluids for 

disposal

 Vent or flare the natural gas produced

 Venting may lead to dangerous gas buildup

 Flaring is preferred where no fire hazard or 

nuisance
Reducing Emissions, Increasing Efficiency, Maximizing Profits Page 4

Methane Losses: 

Well Completions and Workovers

 EIA reported annual losses due to flaring and 

venting from onshore gas well completion, 

workovers and blowdowns to be 76 Bcf

 Estimated 45 billion cubic feet (Bcf) of natural gas 

lost annually due to well completions and 

workovers1

Note:

-

1Percentage that is flared and vented is not known

- Value of natural gas at $3/Mcf

- Value of condensate at $22/bbl

Annual Natural Gas Venting and Flaring

Venting and 

Flaring from 

Well 

Completions 

and 

Workovers 

59%

Venting from 

Blowdowns, 

41%

 Estimated a total of 

480,000 barrels (Bbl) 

condensate lost annually 

due to venting and flaring 

 A total of $145 million 

lost due to well 

completions and 

workovers
Reducing Emissions, Increasing Efficiency, Maximizing Profits Page 5

Methane Recovery by Green Completions

 Recover natural gas and condensate produced 

during well completions or workovers

 Estimated 24 Bcf of natural gas can be 

recovered annually using Green Completions

 Use portable equipment to process gas and 

condensate suitable for sales

 Direct recovered gas through permanent 

dehydrator and meter to sales line, reducing 

venting and flaring
Reducing Emissions, Increasing Efficiency, Maximizing Profits Page 6

Green Completions: Equipment

 Truck- or trailer- mounted 

equipment to capture 

produced gas during 

cleanup

 Sand trap

 Three-phase separator

 Use portable desiccant 

dehydrator for workovers 

requiring glycol 

dehydrator maintenance Temporary, Mobile Surface 

Facilities, Source: BP
Reducing Emissions, Increasing Efficiency, Maximizing Profits Page 7

Green Completions: Preconditions

 Permanent equipment on site before 

cleanup

 Piping to well head

 Dehydrator

 Lease meter

 Stock tank

 Sales line gas can be used for energy and/ 

or gas lift in low pressure wells
Reducing Emissions, Increasing Efficiency, Maximizing Profits Page 8

Green Completions: 

Low Pressure Wells

Portable Compressors, Separator and 

Other Equipment on a trailer

Source: Herald

 Use portable compressors when pressure in 

well is low 

 Artificial gas lift to clear 

fluids

 Boost gas to sales line

 Higher cost to amortize 

investment
Reducing Emissions, Increasing Efficiency, Maximizing Profits Page 9

Green Completions: Benefits

 Reduced methane emissions during 

completions and workovers

 Sales revenue from recovered gas and 

condensate

 Improved relations with state agencies and 

public neighbors

 Improved safety

 Reduced disposal costs
Reducing Emissions, Increasing Efficiency, Maximizing Profits Page 10

Is Recovery Profitable?

 Partners report recovering 2% to 89% 

(average of 53%) of total gas produced 

during well completions and workovers

 Estimated 7 to 12,500 thousand cubic feet 

(Mcf) (average of 3,000 Mcf) of natural gas 

can be recovered from each cleanup 

 Estimate 1 to 580 Bbl of condensate can be 

recovered from each cleanup

Note: Values for high pressure wells
Reducing Emissions, Increasing Efficiency, Maximizing Profits Page 11

BP Experience

 Capital investment ~ $1.4 million on portable 

three phase separators, sand traps and 

tanks

 Used Green Completions on 106 wells 

 Total natural gas recovered ~ 350 million 

cubic feet per year (MMcf/yr)

 Total condensate recovered ~ 6,700 Bbl/yr
Reducing Emissions, Increasing Efficiency, Maximizing Profits Page 12

BP Experience

 Total value of natural 

gas and condensate 

recovered 

~ $840,000 per year

 Investment recovered 

in 2+ years

Portable Three Phase Separator, Source: BP

Note:

- Value of natural gas at $1.99/Mcf

- Value of condensate at $22/Bbl
Reducing Emissions, Increasing Efficiency, Maximizing Profits Page 13

Devon Energy Experience

 Implemented Reduced Emission Completion (REC) 

in the Fort Worth Basin

 REC performed on 30 wells at an average 

incremental cost of $8,700

 Average 11,900 Mcf of natural gas sold vs. vented 

per well

 Natural gas flow and sales occur 9 days out of 2 to 3 

weeks of well completion

 Low pressure gas sent to gas plant

 Conservative net value of gas saved is $50,000 per well

 Expects emission reduction of 1.5 to 2 Bcf in year 

2005
Reducing Emissions, Increasing Efficiency, Maximizing Profits Page 14

Weatherford Durango Experience

 Successfully completed pilot project in the 

Fruitland coal formations in Durango, 

Colorado

 Well depth: 2,700 to 3,200 feet

 Pore pressure: estimated at 80 pounds per 

square inch gauge (psig)

 Well type: coal bed methane

 Hole size: 5 1⁄2 inches

 No. of wells: 3 well pilots

 Captured 2 MMcf of gas and sold by client
Reducing Emissions, Increasing Efficiency, Maximizing Profits Page 15

Weatherford Portable Equipment
Reducing Emissions, Increasing Efficiency, Maximizing Profits Page 16

Weatherford Green Completions

 Use natural gas from pipeline along with proprietary 

foaming agent as compressible fluid to initiate 

cleanout

 Cleaning system consists of a wet screw 

compressor in addition to the booster, three phase 

separator and sand trap

 Wet screw compressor used when well pressure is 

less than 80 psig

 Estimate a clean up pressure of 300 to 400 psig at a 

well depth of 8000 feet

 Suggests use in all kinds of completion and 

workover cleanup operations
Reducing Emissions, Increasing Efficiency, Maximizing Profits Page 17

Discussion Questions

 To what extent are you implementing this 

opportunity?

 Can you suggest other approaches for 

reducing well venting?

 How could these opportunities be improved 

upon or altered for use in your operation?

 What are the barriers (technological, 

economic, lack of information, regulatory, 

focus, manpower, etc.) that are preventing 

you from implementing this practice?