I N NOVATI N G WH I LE DR I LLI N G
Preventing lost circulation,
instability offshore Malaysia
BY STEPHEN WHITFIELD, ASSOCIATE EDITOR
From an operator’s perspective, minimiz-
ing downhole losses while maintaining
wellbore stability is one of the biggest
challenges to successfully drilling an
extended-reach well. Michael Yao, Senior
Rock Mechanics Advisor at Hess, noted
that extended laterals tend to have more
breakouts than vertical or less deviated
wells. This means a higher mud weight is
often required to keep the wellbore stable.

Equivalent circulating density (ECD) is
also typically higher. Moreover, there is a
greater uncertainty in how the cuttings
transport will behave, which can make
hole cleaning more difficult.

If ECD, mud weight and hole cleaning
are not managed properly, the operator
runs the greater risk of wellbore instabil-
ity, borehole collapse and lost circulation,
all of which can increase the potential for
the well to miss its target depth and to add
significant costs to the drilling program.

“If you’re drilling a less deviated well,
the drilling margin is typically wide. We
have much more freedom to navigate mud
weight and ECD between the pore pres-
sure and the fracture gradient. It’s like
driving in light traffic,” Dr Yao said, noting
that drilling an extended-reach well is
more akin to driving in a traffic jam. “Hole
cleaning becomes more challenging, and
the difference between the ECD and mud
weight is much larger due to the hydrau-
lics of these wells. There are much more
challenging conditions to maneuvering
the mud weight and ECD.”
Further, addressing the dual challenges
of lost circulation and wellbore instability
in extended-reach wells requires a holistic
approach to strengthening the wellbore
if the formation is depleted, he said. This
has to be a collaborative effort among the
operator’s drilling engineers, subject mat-
ter experts and rig site teams, as well as
the service companies.

Dr Yao highlighted one such effort on
a shallow gas field offshore Malaysia at
an IADC Drilling Engineers Committee
Technology Forum in November. In its
most recent extended-reach well in the
formation, the company had experienced
lost circulation in the reservoir section,
which showed unexpected depletion from
production, and well startup was delayed.

Hess drilled the 8 1/2-in. section of an extended-reach well offshore Malaysia with
an ECD ranging from 12.0-12.6 lb/gal and a 10.8-gal mud weight. By maintaining
these parameters, the operator was able to drill the section without any losses.

18 With this well, which had a measured
depth (MD) of 12,642 ft and true vertical
depth (TVD) of 3,925 ft, Hess aimed to pre-
vent losses and maintain wellbore stabil-
ity in the 8 ½-in. lateral section. Modeling
showed the level of breakout at different
mud weights ranging from 10.6 lb/gal to
11.2 lb/gal. Understanding limited level of
breakouts need to be tolerated, Hess chose
a 10.8-lb/gal mud weight for the section as
a reconciliation between wellbore stability
and lost circulation concerns.

Hydraulics modeling showed that ECD
for the section would range between 12.3-
12.9 lb/gal at the 10.8-lb/gal mud weight.

However, even at that mud weight and
ECD, the section could still see losses if the
pore pressure fracture gradient was on the
low side due to depletion. Hess formulated
a “stress cage” to prevent losses in case
of low pore pressure fracture gradient. A
stress cage is a wellbore strengthening
model of the mechanism that boosts up
the fracture gradient to be above expected
ECD through the addition of mud additives.

The 8 ½-in. section was drilled at an
average ROP of 50 ft/hr, with a pump rate
of 450 gal/min and a rotation of 140-150
rev/min. The ECD stayed primarily within
the range indicated by hydraulics mod-
eling (12.0-12.6 lb/gal). Stress cage was
implemented prior to drilling into depleted
reservoir as precaution.

Reservoir pressure was then measured
by the Formation Pressure While Drilling
(FPWD) tool once the sensor was in con-
tact with permeable formation. Based on
that, the fracture gradient was expected
to be higher than the ECD. The stress cage
materials were deemed unnecessary and
then screened out. The well was subse-
quently drilled to total depth (TD).

Dr Yao noted the importance of collabo-
ration between different stakeholders in
drilling the well without any losses. “We
put tremendous scrutiny into our plans for
the wellbore strengthening material ahead
of time, and during the operations we had
a lot of eyes looking at screens while the
drilling was happening to see how every-
thing was performing. Communication
and collaboration were key during the
whole process.”
The well also provides a valuable blue-
print for handling similar wells in the
future, he added. DC
M A R C H/A P R I L 2023 • D R I L L I N G C O N T R AC T O R



IADC DDR Plus™
THE NEW IADC STANDARD FOR
DRILLING DATA RECORDING
The IADC DDR Plus™ is a print and electronic data collection
system aimed at securing accurate and relevant drilling
data that industry can use to assess performance against
drilling Key Performance Indicators, and is available in print
format and as an electronic schema.

This revised edition expands the legacy main codes and
incorporates a series of cascading sub-codes to improve
granularity in reporting.

3174556 No.

DAILY DRILLING REPORT
LEASE WELL NO.

REPORT NO.

API WELL NUMBER
WATER DEPTH
OPERATOR CONTRACTOR
SIGNATURE OF OPERATOR’S REPRESENTATIVE
SIGNATURE OF CONTRACTOR’S RIG MANAGER
D.P. SIZE
WEIGHT GRADE
TOOL JT O.D.

TYPE THREAD
REPORT DATE
RIG NO.

FIELD OR DISTRICT
MUD PUMP STROKE LENGTH
STRING NO.

NO. OF DAYS
FROM SPUD
FUEL USED
CUMULATIVE ROTATING
HOURS FUEL
ON HAND
MP1 DATE
TIME DRILLING ASSEMBLY / BHA
(At end of tour)
SPUD RIG RELEASE
NO. PAUSE
ITEM O.D.

LENGTH BIT
RESUME TD
MP3 BIT RECORD
TIME DISTRIBUTION – HOURS
1 2
SIZE WEIGHT
IADC CODE
PRESSURE GRADIENT
FUNNEL VISCOSITY
TYPE PV/YP
SERIAL NO.

GEL STRENGTH
FLUID LOSS
JETS TFA
DEPTH OUT
3. REAMING
4. CORING
5. CIRCULATE &
CONDITION MUD
6. TRIPS
LENGTH WIRE LINE RECORD
RKB. TO
CSG. HD.

SET AT
TYPE SIZE
REEL NO.

NO. LINES
DRILLING CREW PAYROLL DATA
LENGTH SLIPPED
LENGTH CUT OFF
START DATE OF TOUR 1 _____________________________
PRESENT LENGTH
WELL NAME & NO. __________________________________
WEAR OR TRIPS
SINCE LAST CUT
DEPTH INTERVAL
FROM TIME
2. DRILLING
NO. JOINTS
COMPANY _________________________________________
CUMULATIVE WEAR OR TRIPS
MUD RECORD
BIT NO.

1. RIG UP / TEAR DOWN
/ MOVE
STATE / COUNTRY
WEIGHT & GRADE
MAKE MP4
MANUFACTURER CODE – OPERATION
NO. COUNTY
SIZE LAST
CASING TUBING
OR LINER
MP2 TO
DEPTH DRILL..D
REAM..R CORE..C
DEV. CORE
NO. DIR.

FORMATION (SHOW CORE RECOVERY)
HORIZ DISP.

TVD DEVIATION
RECORD TIME LOG
pH FROM
TO ELAPSED
TIME RPM
DEPTH & EQUIPMENT
CODE NO. ACTIVITY
SUB CODE & SUB CODE
WT. ON
PUMP BIT
PRESSURE DEV.

DIR. RIG MANAGER _____________________________________ RIG NO. ____________________
MP 1
LINER SIZE
MP 2
S.P.M. LINER
SIZE HORIZ
DISP. TVD
S.P.M. DEPTH
MP 3
LINER SIZE
MP 4
S.P.M. DEV.

LINER SIZE
DIR. S.P.M.

TVD TOTAL
PUMP OUTPUT
TOUR 1
CREW FROM ______________________ TO _______________
EMPL. ID NO.

NAME INJURED ON
THIS TOUR?
YES OR
NO? INITIALS
HRS. HORIZ
DISP. DETAILS OF OPERATIONS IN SEQUENCE AND REMARKS
SOLIDS DEPTH IN
T O
U R
TOTAL DRILLED
STANDS __ D.P.

TYPE TOTAL HOURS
SINGLES __ D.P.

1 INNER
CUTTING STRUCTURE
OUTER DULL CHAR.

MUD & CHEMICALS ADDED
AMOUNT TYPE
AMOUNT BEARINGS/
SEALS TOTAL
8. REPAIR RIG
GAUGE OTHER DULL
CHAR. T
O U
R 1
LOCATION KELLY DOWN
7. SERVICE/MAINTAIN
RIG REASON
PULLED WT. OF STRING
9. REPLACING DRILL
LINE 10. DEVIATION SURVEY
REMARKS 11. WIRELINE LOGS
12. RUN CASING
& CEMENT
13. WAIT ON CEMENT
14. RIG UP / DOWN
BOP 15. TEST BOP
16. DRILL STEM TEST
NO. OF DAYS SINCE LAST LOST TIME ACCIDENT ____________________
DRILLER 17. PLUG BACK
DRILLING ASSEMBLY / BHA
(At end of tour)
18. SQUEEZE CEMENT
19. FISHING
NO. 20. SPECIALIZED
DIRECTIONAL WORK
ITEM O.D.

LENGTH BIT
BIT RECORD
FROM TIME
SIZE WEIGHT
PRESSURE GRADIENT
FUNNEL VISCOSITY
21. OTHER
IADC CODE
22. OTHER
MANUFACTURER 23. OTHER
TYPE PV/YP
31. RUN/RETRIEVE
RISER EQUIP.

SERIAL NO.

32. SURFACE TESTING
JETS GEL
STRENGTH FLUID
LOSS TFA
33. OPERATING STATUS
35. WELL CONTROL
36. COILED TUBING
37. COMPLETION
ACTIVITIES 38. SUBSEA
INSTALLATIONS TYPE
TOTAL HOURS
SINGLES __ D.P.

INNER DRILL..D
REAM..R CORE..C
DEV. CORE
NO. DIR.

FORMATION (SHOW CORE RECOVERY)
TO ELAPSED
TIME HORIZ
DISP. TVD
CODE NO.

RPM DEPTH
ACTIVITY & EQUIPMENT
SUB CODE & SUB CODE
WT. ON
PUMP BIT
PRESSURE DEV.

DIR. MP 1
LINER SIZE
TVD MP 2
S.P.M. LINER
SIZE HORIZ
DISP. S.P.M.

DEPTH MP 3
LINER SIZE
MP 4
S.P.M. DEV.

DIR. LINER
SIZE S.P.M.

TVD TOTAL
PUMP OUTPUT
TOUR 2
CREW OBM (YES/NO) _______
FROM ______________________ TO _______________
EMPL. ID NO.

NAME HRS.

INJURED ON
THIS TOUR?
YES OR
NO? INITIALS
HORIZ DISP.

DETAILS OF OPERATIONS IN SEQUENCE AND REMARKS
SOLIDS TOTAL DRILLED
STANDS __ D.P.

2 CUTTING STRUCTURE
OUTER DULL CHAR.

LOCATION MUD & CHEMICALS ADDED
AMOUNT TYPE
AMOUNT T
O U
R 2
KELLY DOWN
BEARINGS/ SEALS
TOTAL TOTALS
DEPTH TIME LOG
FROM DEPTH IN
T O
U R
TO DEVIATION
RECORD pH
DEPTH OUT
34. SAFETY
DEPTH INTERVAL
MUD RECORD
BIT NO.

GAUGE OTHER DULL
CHAR. REASON
PULLED WT. OF STRING
DAYWORK TIME SUMMARY
(OFFICE USE ONLY)
HOURS W/CONTR. D.P.

REMARKS HOURS W/OPR. D.P.

HOURS WITHOUT D.P.

HOURS STANDBY
BOILER HRS
TOTAL DAYWORK
NO. OF DAYS SINCE LAST LOST TIME ACCIDENT ____________________
DRILLER DAILY MUD COST
© 2020 International Association of Drilling Contractors
TOTAL MUD COST
APPROVED © 2020 International Association of Drilling Contractors
APPROVED No.

3174556 OBM (YES/NO) _______
© 2020 International Association of Drilling Contractors
APPROVED No.

3174556 PRINTED IN U.S.A.

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