natural gas recycle and recovery system dramatically ... · alek ozegovic weatherford . spe/iadc...

SPE/IADC Managed Pressure Drilling and Underbalanced Operations Conference & Exhibition

8-9 April 2014 NH Eurobuilding Hotel, Madrid

Natural Gas Recycle and

Recovery System

Dramatically Reduces

Drilling Cost and

Environmental Impact

1

Alek Ozegovic Weatherford



2

Outline

Recycle & Recovery Process

Equipment Involved

Advantages

Unique Requirements

Case Studies

Economical and Environmental Impact

Conclusions



3

Traditional UBD Layout (Gas Well)



4

Summary of Traditional UBD

On-site nitrogen membrane

40 m3/min N2 consumes 10,000 lpd of diesel

All drilling liquids recycled

All returned lift gas is flared

All produced gas is flared

* Cost of UBD becoming prohibitive in some cases *



5

Something Has to Change

Why do we require generated N2 on location?

We don’t

Why do we need inert gas to drill a well?

We don’t

Is an alternative lift gas available?

Methane!

Can we utilize a neighboring pipeline to “buy” CH4

as our lift gas and “sell” it back to the pipeline?

Yes, but there needs to be an existing pipeline



Natural Gas From Formation

Gas

Drilling Mud

Pipeline

SHUT OFF

SUPPLY GAS

AND OPEN

SALES LINE

Valve

NOT

NECESSARY

TO FLARE

WHILE

DRILLING BY

R&R

BUYING GAS

FROM

PIPELINE TO

START UBD

BOOSTERS

UBD

CHOKE

SEPARATOR

RIG MUD TANKSRIG

PUMPS

SHAKER

ST

AN

DP

IPE

ANNULAR

Flare Stack

H2S SCRUBBER

COMPRESSORS

PRODUCING

NATURAL

GAS WHILE

DRILLING



7

Compressors Scrubber

Booster & Mist

Pump

UBD Choke &

Separator

Flare Stack

MAC Skid



8

Why Recycle and Recover Gas?

Cost Savings Using natural gas as a nitrogen replacement, thereby not requiring the

nitrogen generating equipment

Reduced cost of diesel to run the equipment with bi-fuel modifications

Direct distribution of produced gas for selling to the pipeline rather than

flaring (generate revenue while drilling)

Reduce Environmental Impact

Reduced flaring of gas on location while drilling

Possible carbon tax credit by reducing emissions



9

1st CASE STUDY – UBD

GAS WELL (CANADA)



10

Depleted limestone reservoir

4 – 6 kPa/m [0.18 – 0.26 psi/ft]

Drilled with foam fluid system

water, methane, surfactant

Methane supplied from pipeline until well

produced and then methane was recycled

for drilling with excess sent to pipeline



11

Data reporting compiled on a daily basis

and captured in End of Well Report

Some wells were multi-leg horizontals

0

100

200

300

400

500

600

700

800

900

1000

00:00

02/02

12:00

02/02

00:00

03/02

12:00

03/02

00:00

04/02

12:00

04/02

00:00

05/02

12:00

05/02

00:00

06/02

12:00

06/02

00:00

07/02

12:00

07/02

00:00

08/02

12:00

08/02

00:00

09/02

12:00

09/02

00:00

10/02

Prod

uced

Gas

Vol

ume

(103

m3 )

1400

1500

1600

1700

1800

1900

2000

2100

2200

2300

2400

2500

2600

2700

Hole

Dep

th (

m)

Cumulative Produced Gas

Cumultive Sales Gas

Cumulative Flare Stack Gas

Cumulative Buy Gas

Hole Depth

911 e3m

3 (36 mmscf) of gas produced

throughout the job.

Produced = Sales + Flare - Buy



12

0

500

1000

1500

2000

2500

3000

2 6 10

14

18

22

26

30

34

38

42

46

50

54

58

62

66

70

74

78

82

86

90

94

98

10

2

10

6

11

0G

as

Pro

du

ctio

n (

e3m

3)

Wellhead Number

Gas Production for R&R UBD Wells

Recovered Gas (e3m3) Flared Gas (e3m3) Produced Gas (e3m3)

Recovered Gas=Sold Gas-Buy Gas

Flared Gas=Produced Gas+Buy Gas-Sold Gas

YEAR 1 YEAR 2 YEAR 3 YEAR 4



13

Flush

Production

Matrix

Production



14

AVERAGE FLARED GAS WAS

~25% OF PRODUCED GAS



15

0

500

1000

1500

2000

2500

3000

2 6 10

14

18

22

26

30

34

38

42

46

50

54

58

62

66

70

74

78

82

86

90

94

98

10

2

10

6

11

0G

as P

ro

du

ctio

n (

e3m

3)

Wellhead Number

Gas Production for R&R UBD Wells

Recovered Gas (e3m3) Flared Gas (e3m3) Produced Gas (e3m3)

Recovered Gas=Sold Gas-Buy Gas

Flared Gas=Produced Gas+Buy Gas-Sold Gas

YEAR 1 YEAR 2 YEAR 3 YEAR 4

Total Recovered Gas = 61,600 e3m3



16

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

55000

60000

65000

$0

$2,000,000

$4,000,000

$6,000,000

$8,000,000

$10,000,000

Cu

mu

latv

e R

eco

ve

red

Ga

s (e

3m

3)

Cu

mu

latv

e R

eco

ve

red

Ga

s M

ark

et

Va

lue

($

)

Market Value for Recovered Gas

Recovered Gas in Dollars

Recovered Gas

CDN $ 9,855,058

61,600 e3m3

PROJECT TIMELINE • The gross heat of combustion of 1 m3 of commercial quality natural gas is around 0.039 GJ • Gas price is based on monthly average gas price in Alberta from http://www.ngx.com/natgas.html

http://www.ngx.com/natgas.html



17

0

6000

12000

18000

24000

30000

36000

$0

$1,000,000

$2,000,000

$3,000,000

$4,000,000

$5,000,000

$6,000,000

Cu

mu

latv

e R

eco

ve

re

d G

as (e

3m

3)

Cu

mu

latv

e R

eco

ve

re

d G

as M

ark

et

Va

lue

($

)

Market Value for Flared Gas

Flared Gas Value

Flared Gas VolumeCDN $ 5,261,960

29,983 e3m3

PROJECT TIMELINE



18

2nd CASE STUDY –

SOUR GAS WELL



19

Sour Gas Well Recovery Application

Used to drill a deep horizontal (~3725mTVD, 700m lateral).

Potential for sour gas, estimated to be 13.7% H2S (12% on real test)

The regulatory board issued a flare permit for a maximum of 240 e3m3

cumulative gas flared throughout the entire operation (National Park).

How can we do this?



20

Mitigating H2S Hazards Provided equipment compatible with sour gas, and

resistant to deterioration of all of the flexible elements in

the fluid handling system, i.e. ensured rubber compatibility.

Provided connections to pipeline and directly transported

produced sour gas into pipeline system.

Sour gas level measurements taken with a Gas Tec

monitor while drilling, ensuring safety to all personnel on

location.

Supplied real-time engineering control and data acquisition

system. All drilling parameters monitored throughout the

operation.



21

Pipe line

WFT

4 Phase

Separator

Flare

Stack

Tank Farm

Settling Time

WFT

Control

Manifold

Rigs Choke

Manifold

Standpipe

Manifold

Standpipe Bleed Off

to Separator

Produced

Water

RBOP

Annular

Bleed Off

To Shakers

Bleed Off

Separator

Oil Dump to

Tank Farm

Gas

Oil

Water

Solids

Multiphase Flow

Foam

Defoamer

OPEN FLUID

CLOSED FLUID

OPEN SOLIDS

CLOSED SOLIDS

SCRUBBERS ON TANK VENTS

H2S

Scrubber

H2S

Scrubber

Sample Catchers

Solids Control Tank

Low Volume

Pump

Compressor

Processing

UnitCompressor

Supply gas

Supply gas

from pipeline

Produced gas

to pipeline

Process Flow Diagram – Closed Loop



22

Sour Gas Well Recovery Application - Results

Recovered over 98% of the total natural gas with

12% H2S over a drilling period of 21 days

Total gas flared was 8.5 e3m3 (0.3 MMscf), well

below permit

Reduced environmental impact & increased safety

Sweet gas pipeline for supply; produced sour gas

and returned to a sour gas processing facility

Drilling fluid contamination was mitigated using H2S

scavenger and dump & dilute methodologies



23

Planning for R&R application?



24

QHSE Integrated for R&R Process

Pre-job planning including development of a UB drilling

program with specific SOP’s

HAZOP & HAZID

Site visits to optimize equipment layout and spacing

Auto alarms & shutdowns; intrinsically safe and certified

equipment along with LEL & H2S monitoring

Relief and vent lines tied into a closed loop and not open to

atmosphere

Data monitoring and post well review



25

Unique Requirements for R&R Pipeline Gas Supply

Need to be in a developing field for this to be feasible

Constant pipeline feed pressure & minimal fluid content

Buy & Sell gas specifications

Additional metering equipment with advanced

metering calculations for accurate real-time

measurement data

Equipment modifications to compress natural gas

Adequate lease for equipment and associated piping



26

Reduce/Eliminate Flaring

Safety

Environmental

Economic

Closed-Loop Circulation System

Mitigate H2S & CO2 exposure

Drilling Fluid Compatibility

Oil Wells – Flow Drilling applications



27

Thank you!

natural gas recycle and recovery system dramatically ... · alek ozegovic weatherford . spe/iadc...

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