UNCOVER THE OVERLOOKED GUMAI PLAY POTENTIAL AT … PetroChina... · LOWEST POINT OF PROSPECTIVE GWD ♦In NEB, Marmo and NBE Fields, a value of 200 and 300 units was applied as a

UNCOVER THE OVERLOOKED GUMAI PLAY POTENTIAL

AT JABUNG BETARA COMPLEX, INDONESIA: A BEST CASE STUDY OF

GAS WHILE DRILLING (GWD) CLASSIFICATION IN FINDING THE NEW PAYS

Authors:

I Gusti Agung Aditya Surya Wibawa*, Beiruny Syam,

Hendra Niko Saputra, Mawar Indah Nursina, Abghia Dini Fanzuri

PetroChina International Companies in Indonesia

SEAPEX Exploration Conference

Fairmont Hotel, Singapore

2nd – 5th April 2019

PRESENTATION OUTLINE

1. EXPLORATION HISTORY & HIGHLIGHT

2. JABUNG BETARA COMPLEX GEOLOGICAL SETTINGS

3. JABUNG BETARA COMPLEX GWD OVERVIEW

4. GWD DATABASE AND CLASSIFICATION

5. GWD INTERPRETED DISTRIBUTION

6. SUMMARY & STUDY BREAKTHROUGH

EXPLORATION HISTORY

1992 1996-1998 2006 2013 2015 2023

EXPLORATION HIGHLIGHT

♦ High Gas While Drilling in Gumai Formation has founded in many development

wells during drilling activities.

♦ 77 potential wells were drilled on Betara Complex Structure (exploration +

development), but only 12 wells have wireline logs in intra GUF section (were

trying to acquire wireline in development wells but need more justification)

♦ The first testing program of Gumai Formation was conducted in NEB Basement-1

(exploration well) on 2013 by the result of 4.45 MMSCFD, 15 BCPD (CO2

content: 0%).

♦ Another good testing results in Gumai Formation has been proven on NEB-96,

NBE-1, Marmo-3 and Sabar-2 that act as our key wells.

♦ Based on Gas while drilling and testing data, further analysis is conducted to

predict reservoir distribution by generating structure maps and attributes anaylsis.

JABUNG BLOCK OVERVIEW : GEOLOGICAL SETTING

There are 77 potential wells that have been drilled in the Betara Complex area

but only 12 wells that have complete mudlog, wireline log and DST result data in Gumai Formation.

Basement configuration of South Sumatra Basin

(Ginger & Fielding, 2005)

MARMO-3

NBE-1

NEB-1

NEB-6

NEB BASE-1

NEB-96

NEB-5

SABAR UTARA-1

NEB-55

SABAR-2

The Betara Complex is a

combination of 5 major

fields in Jabung Block:

1. Northeast Betara

(NEB),

2. Sabar,

3. Marmo,

4. Northeast Betara

Extension (NBE),

5. North Betara (NB)

Field.

JABUNG BLOCK

Situation of South Sumatra

Basins and other basins to

the north and south. These

basins were formed and

developed in very similar

way in both timing and

tectono-stratigraphy

BETARA COMPLEX AREA

±500 sq km

GEOLOGICAL SETTINGS –

JABUNG BLOCK STRATIGRAPIC COLUMN

Syn-Orogenic

/Inversion

Post-Rift

Syn-Rift

Pre-Rift

Jabung Block Stratigraphy (Suta, 2003)

R

R

R

R SR

SR

SR SR

S

S

S

S

R

SR

S

: Reservoir

: Source Rock

: Seal

Legend

Fm. Target

GAS WHILE DRILLING OVERVIEW

1. More than 1000 feet of gross gas column existed in

the Gumai Formation interval in Betara Complex area.

2. Gas and Condensate is the predominate fluid type in

this area

A B

Average thickness: 700 ft – 1600 ft

Net to gross: 170 ft – 500 ft

Sand character: Lenses

GAS WHILE DRILLING DATABASE

: Good test result Ranking parameter:

Testing result, TG value, RT value, Cross over, & C5 availability)

GAS WHILE DRILLING DATABASE

: Poor test result

TESTING SUMMARY (GUF INTERVAL)

*) KEY WELLS: NEB-96, NEB BASE-1, SABAR-2, NBE-1 & MARMO-3

LOG FEATURE NEB BASE-1 (EXAMPLE KEY WELL)

Reservoir properties ‐ Lithology : Sandstone ‐ Rt : 27.3 ohm.m ‐ Xover : Narrow ‐ TG : 250 U (C1-C5)

‐ Porosity : 11.4 % ‐ Sw : 50.6 % ‐ Rate : 4.45 MMCFPD + 158 BCPD

#DST - 4

LOWEST POINT OF PROSPECTIVE GWD

♦ In NEB, Marmo and NBE Fields, a value of

200 and 300 units was applied as a cut-off

when determining potential reservoir zones.

♦ For the Sabar Field, 150 units were used for

the cut-off for overlooked potential.

♦ The cut-off values obtained from lowest

depth of gas while drilling were compared

to DST results using 5 key wells in the study

area

NEB FIELD

SABAR FIELD

TOTA

L G

AS

(UN

IT)

WELLS

HC Potential Cut off line

40/64": 161 psi WHP, 990F WHT, 1.011 MMSCFD (SG: 0.82). CO2: 0.8%, H2S: 0 ppm.

36/64" : 1325 psi WHP, 1290F WHT, 247 BCPD (SG: 0.720, 650 API), 5.804 MMSCFD (SG gas: 0.820), no water, GOR: 23506 scf/stb.

TESTED WELLTESTED WELL

MARMO &

NBE FIELD

HC Potential Cut off line

TOTA

L G

AS

(UN

IT)

Gas converter:40 unit = 0.8% = 8,000 ppm190 unit = 3.8% = 38,000 ppm

WELLS

TESTED WELL

36/64": 1377 psi WHP, 1370F WHT, 549 BCPD (SG: 0.71, 680API). No water. 4.929 MMSCFD (SG gas: 0.830), GOR: 8986 scf/stb, CO2: 1.8%, H2S: 0 ppm.

SABAR-1 SABARUTARA -1

SABAR-3 SABAR-2

MUD WEIGHT INTERVAL FOR EACH FIELD

g

♦ Based on cross-plot above showed that our

current efficient mud weight range (Gumai

Formation - 12 1/4” drilling section) for each field

as followed:

1. NEB Field in range of 9 – 9.9 ppg.

2. Marmo, NB and NBE Field in range of 9.2

– 10 ppg

3. Sabar Field in range of 9.6 – 9.7 ppg

♦ The mud weight range is limited by proven zone

from 5 wells with flowed DST results.

GW

D (

un

its)

MUD WEIGHT (PPG)

GW

D (

un

its)

MUD WEIGHT (PPG)

0

500

1000

1500

2000

2500

3000

3500

4000

4500

8.8 9 9.2 9.4 9.6 9.8 10 10.2

Potential Zone

Proven Zone (by DST)0

500

1000

1500

2000

2500

3000

3500

4000

4500

8.8 9 9.2 9.4 9.6 9.8 10 10.2

Potential Zone

Proven Zone (by DST)

MW = 9 – 9.9 ppg

NEB FIELD

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

9 9.2 9.4 9.6 9.8 10 10.2

Potential Zone


MARMO & NB,

NBE FIELD

0

500

1000

1500

2000

2500

3000

3500

4000

4500

8.8 9 9.2 9.4 9.6 9.8 10 10.2

Potential Zone


MW = 9.2 – 10 ppg

0

100

200

300

400

500

600

700

800

9.58 9.6 9.62 9.64 9.66 9.68 9.7 9.72

Potential Zone

Proven Zone (by DST)GW

D (

un

its)

MUD WEIGHT (PPG)

SABAR FIELD

0

500

1000

1500

2000

2500

3000

3500

4000

4500

8.8 9 9.2 9.4 9.6 9.8 10 10.2

Potential Zone


MW = 9.6 – 9.7 ppg

NEB-96 5.164 MMSCFD,

135 BCPD

SABAR-2 4.929 MMSCFD,

549 BCPD

NBE-1 5.9 MMSCFD,

254 BCPD

MARMO-3 1.01 MMSCFD

SEQUENCE CLASSIFICATION

NEB-6

Wavelet

IGUF A

IGUF B

IGUF C

IGUF D

GUF

IGUF A

IGUF B

IGUF C

IGUF D

BRF

UTAF

GUF is divided into 4 sequences based on flooding surface marker to observed its reservoir distribution

RESERVOIR DISTRIBUTION IN IGUF-A

A

B

Sabar-2

NEB-4

NEB BASE-1

NEB-6 Int GUF

Int GUF-A

Int GUF-B

Int GUF-C

Int GUF-D

BRF GUF

UTAF

NEB-4 A B SABAR-2 NEB BASE-1 NEB-6

+-

DST #4 4.45 MMCFPD +

158 BCPD (CO2: 0%)

RESERVOIR DISTRIBUTION IN IGUF-A

A

B

Sabar-2

NEB-4

NEB BASE-1

NEB-6


COSINE PHASE in purpose of looking at its

continuity

DST #4 4.45 MMCFPD +

158 BCPD (CO2: 0%)

Int GUF

Int GUF-A

Int GUF-B

Int GUF-C

Int GUF-D

BRF GUF

UTAF

RESERVOIR DISTRIBUTION IN IGUF-C

Int GUF

Int GUF-A

Int GUF-B

Int GUF-C

Int GUF-D

BRF GUF

UTAF


+-

A

B

Sabar-2

NEB-4

NEB BASE-1 NEB-6

DST #7 4.9 MMCFPD +

549 BCPD (CO2: 1.8%)

RESERVOIR DISTRIBUTION IN IGUF-C



continuity

DST #7 4.9 MMCFPD +

549 BCPD (CO2: 1.8%)

A

B

Sabar-2

NEB-4

NEB BASE-1 NEB-6

Int GUF

Int GUF-A

Int GUF-B

Int GUF-C

Int GUF-D

BRF GUF

UTAF

RESERVOIR DISTRIBUTION IN IGUF-D

NBE-1 A B MARMO-3 NEB-96

+-

DST#2 1.01 MMSCFD

(CO2: 0.8%)

DST#3 5.804 MMSCFD +

247 BCPD

DST#5 5.164 MMSCFD + 135

BCPD (CO2: 47%)

A

B

MARMO-3

NBE-1

NEB-96

Int GUF

Int GUF-A

Int GUF-B

Int GUF-C

Int GUF-D

BRF GUF

UTAF

RESERVOIR DISTRIBUTION IN IGUF-D

NBE-1 A B MARMO-3 NEB-96

Int GUF

Int GUF-A

Int GUF-B

Int GUF-C

Int GUF-D

BRF GUF

UTAF


continuity

DST#2 1.01 MMSCFD

(CO2: 0.8%)

DST#3 5.804 MMSCFD +

247 BCPD

DST#5 5.164 MMSCFD + 135

BCPD (CO2: 47%)

A

B

MARMO-3

NBE-1

NEB-96

ATTRIBUTE ANALYSIS IN IGUF-A

NEB Base-14.45 MMCFPD + 158 BCPD

TG : 250 U ; CO2 : 0%

NB-5TG : 209 U

NEB-96TG : 279 U

NB-40TG : 237 U

NEB-7TG : 440 U

NEB-13TG : 994 U

NEB-6TG : 1164 U

NEB-11TG : 1247 U

DEPTH STRUCTURE MAPCI : 25 ft

NEB-96TG : 279 U

NB-40TG : 237 U

NEB-13TG : 994 U

AVERAGE POSITIVE AMPLITUDE MAPCI : 25 ft

GT : 229.5’

GT : 293’

NEB-6TG : 1164 U

GT : 152’

*GT : Gross Thickness

NB-5TG : 209 U

NEB-11

TG : 1247 U

NEB-7

TG : 440 U

NEB Base-14.45 MMCFPD + 158 BCPD

TG : 250 U ; CO2 : 0%

The graph shows that thick reservoir correlate with high value of attribute in IGUF A

R2= 0.6688

ATTRIBUTE ANALYSIS IN IGUF-B

NEB-12TG : 260 U

NEB-35TG : 346 U

NEB-42

TG : 101 U

NEB BASE-1TG : 32 U

NEB-96TG : 354 U

NB-5

TG : 740 U

NEB-43

TG : 852 U

NEB-94TG : 1805 U

NB-4

TG : 4500 U


NEB-6

TG : 375 U

NEB-35

TG : 346 U

NEB-42TG : 101 U

NEB BASE-1

TG : 32 U

NEB-96

TG : 354 U

NB-5TG : 740 U

NEB-43TG : 852 U

NEB-94

TG : 1805 U

ENVELOPE MAPCI : 25 ft

GT : 168.5’

GT : 63.2’

GT : 105.5’


NB-4

TG : 4500 U

NEB-12

TG : 260 U

NEB-6TG : 375 U

The graph shows that thick reservoir correlate with high value of attribute in IGUF B

R2= 0.7206

ATTRIBUTE ANALYSIS IN IGUF-C

NEB-12TG : 260 U

NEB-35TG : 346 U

NEB-42TG : 101 U

NEB BASE-1TG : 32 U

NEB-96TG : 354 U

NB-5TG : 740 U

NEB-43TG : 852 U

NEB-94TG : 1805 U

NB-4TG : 4500 U


NEB-6TG : 375 U

NEB BASE-1TG : 32 U

NEB-6TG : 425 U

NEB-40TG : 233 U

NEB-1

TG : 533U

NEB-87TG : 131 U


GT : 55’

GT : 105.3’

NEB-5TG : 188 U


GT : 84.1’

NB-7TG : 1619 U

SABAR-2

4.93 MMCFPD + 549 BCPDTG : 300 U ; CO2 : 1.8%

NEB-15TG : 1197 U

NEB-7TG : 1805 U

NEB-31

TG : 227 U

SABAR UTARA-1

No recovery

The graph shows that thick reservoir correlate with high value of attribute in IGUF C

R2= 0.667

ATTRIBUTE ANALYSIS IN IGUF-D


NEB-6TG : 425 U

NEB-14

TG : 498

NEB-5TG : 2806 U

NORTH BETARA-6TG : 1386 U

NEB-31TG : 2571 U

NEB-66TG : 3108 U

NBE-15.804 ; 247TG : 898 U

MARMO-31.01 ;

TG : 1977 U ; CO2: 0.8%

NEB-11TG : 1119 U

MARMO-2

0.01TG : 1386 U

NEB BASE-20.01 BOPD ;

TG : 20 UNEB-55

0.27 MMCFPD ; TG : 286 U

NEB-965.16 ; 135

TG : 3477 U


NEB BASE-2TG : 20 U

NEB-55

TG : 286 U

NEB-31TG : 2571 U

NEB-965.16 ; 135

TG : 3477 U

NEB-11TG : 1119 U

NEB-66TG : 3108 U

GT : 148’

GT : 161’

MARMO-31.01 ;

TG : 1977 U ; CO2: 0.8%

NORTH BETARA-6TG : 1386 U

NEB-5TG : 2806 U

NEB-14

TG : 498

NEB-6TG : 425 U


1B

1A

The graph shows that thick reservoir correlate with small value of attribute in IGUF D.

R2= 0.614

SUMMARY & STUDY BREAKTHROUGH

Summary:

♦ The pattern of gas while drilling values in the Betara Complex area generally follow the

distribution of the sediments. The thicker the sediment the larger the gas while drilling values.

♦ In interpreting potential reservoir zones, GWD analysis has shown to be a useful tool, but

needs to be integrated with seismic attributes and reservoir characterization.

♦ Data quality control on the cut-off value must be periodically checked to observe the

developing pattern of GWD value for future developments.

Study Breakthrough:

♦ GWD classification has implemented as one of our quick look interpretation tools to control

drilling targets and propose field data acquisition such as SWC, pressure test, fluid analysis

and fluid sample interval.

♦ Study of GWD analysis acted as one of our preliminary justification in reviving our old wells

that have good potential indication in Gumai Formation (example: 2016 - conduct re-entry

well program by cased hole logging).

Thank you

SEAPEX Exploration Conference

Fairmont Hotel, Singapore

2nd – 5th April 2019

Documents

UNCOVER THE OVERLOOKED GUMAI PLAY POTENTIAL AT … PetroChina... · LOWEST POINT OF PROSPECTIVE GWD ♦In NEB, Marmo and NBE Fields, a value of 200 and 300 units was applied as a