*Mark of SchlumbergerOther company, product, and service names are the properties of their respective owners.Copyright © 2013 Schlumberger. All rights reserved. 13-XX-XXXX

SonicScope ProcessingDF13−2−9

1:1000 MD

COMPANY:CNOOC LTD.− ZhanJiang

WELL:DF13−2−9

FIELD:DF13−2

StateHaiNan

COUNTRY:P.R.China

Date Processed:13−Aug−2013

Job Number:

Well Location:Ying Ge Hai

Latitude:18* 32ʼ 6.844" N

Elevations:KB:

SonicScope ProcessingDF13−2−9

1:1000 MD

CNOOC LTD.− ZhanJiangDate Logged:08/13/2013

Processed at:SCPI

Longitude:107* 39ʼ 33.385" E

DF:GL:

DTRP_ProcessedQPINV_COH_PR_RDCAV

GR0 200( gAPI )

SPJ_MH_RA SPJ_ DTRP_Processed40 240

MH_Processed

( us/ft )

SonicScope Processing107* 39ʼ 33.385" E

FOLD HERE The well name, location and borehole reference data were furnished by the customer.

Any interpretation, research, analysis, data, results, estimates, or recommendation furnished with the services or otherwise communicated by Schlumbergerto the customer at any time in connection with the services are opinions based on inferences from measurements, empirical relationships, and/or assumptions;which, inferences, empirical relationships and/or assumptions are not infallible and with respect to which professionals in the industry may differ. Accordingly,Schlumberger cannot and does not warrant the accuracy, correctness, or completeness of any such interpretation, research, analysis, data, results, estimates, orrecommendation. The customer acknowledges that it is accepting the services "as is," that Schlumberger makes no representation or warranty, express or implied,of any kind or description in respect thereto, and that such services are delivered with the explicit understanding and agreement that any action taken basedon the services received shall be at its own risk and responsibility, and no claim shall be made against Schlumberger as a consequence thereof.

@ 2010 Schlumberger. All rights reserved.

775

800

DTCO_RT40 240( us/ft )

DTRP_Processed40 240( us/ft )

DT_QPINV_R140 640( us/ft )

140 640

QPINV_COH_PR_R

( us/ft )BS

10 20( in )

DCAV10 20( in )

MD1 : 1000

m

DTCO_RT40 240( us/ft )

40 240

SPJ_MH_RA SPJ_

( us/ft )DTRS_Processed

40 240( us/ft )

DTRP_Processed40 240( us/ft )

825

850

875

900

925

950

975

1000

1025

1050

1075

1100

1125

1150

1175

1200

1225

1250

CHALLENGEAcquire high-quality sonic measurements while drilling an HPHT well with high shock and vibration; evaluate geomechanics in real time to manage drilling risks.

SOLUTIONUse SonicScope* 825 multipole sonic-while-drilling service to deliver robust real-time and memory sonic data, including downhole slowness-time-coherence data, for real-time data quality control.

RESULTSAcquired excellent match between real-time and memory compressional and shear slowness in high stick and slip environment; accurately evaluated high-porosity gas formation despite mud invasion; successfully reached total well depth with geomechanics analysis.

“Schlumberger’s latest LWD sonic service provides high-quality real-time and memory data that can meet our timely decision requirements for exploration wells.”

Chief logging engineer Operator, South China Sea

Facing challenges in South China Sea high-pressure, high-temperature wellsAn operator drilling offshore South China Sea encountered many challenges during the exploration and evaluation stages. The two main issues involved the narrow mud weight window and the presence of a high-pressure formation. The need for high-quality logging-while-drilling (LWD) sonic measurements was critical to managing the overall risks of the drilling operations.

Acquiring high-quality sonic data for accurate real-time geomechanic analysisGeomechanic research is performed before drilling the well to reduce the associated drilling risks and save rig time. Reliable, real-time sonic data is an integral part of the evaluation. Information from offset wells is compared with surface seismic data, and a good match between the two reduces uncertainty and boosts the confidence of operators.

Reached total depth with reduced riskUsing SonicScope 825 service, the operator obtained reliable LWD sonic data for both real time and memory. The real-time slowness acquired matched the memory data, and the time-lapsed logging measurement helped quantify the impact of mud invasion in the high-porosity formations, as a reduced slowness was acquired in the gas zone. This data helped the operator successfully reach total depth with reduced risk and uncertainty. Having proven success after first-time use of the service, the operator has decided to run the latest LWD sonic service in both 14¾-in and 12½-in hole sections in future HPHT deepwater wells.

CASE STUDY

Drilling

Real-time data aqcuired is an excellent match with memory sonic data in shallow unconsolidated section.

Operator Optimizes Drilling Performance, Successfully Reaching Total Depth with SonicScope 825 ServiceLWD service supports critical geomechanic analysis in South China Sea, reducing drilling risks in the HPHT environment

slb.com/SonicScope *Mark of SchlumbergerOther company, product, and service names are the properties of their respective owners.Copyright © 2013 Schlumberger. All rights reserved. 13-DR-0216

Real-Time Slowness Projection Quadrupole Coherence Memory Compressional

Comparison

Quadrupole Shear Real-Time Compressional

Density Caliper

in us/ft us/ft

us/ftus/ft

gAPI

in

Memory Compressional

Gamma Ray

0 200

10 20 40 240 140 640

140 64040 24010 20

Memory Slowness Projection

Bit Size MD 1:1000

m

775

800

825

850

875

900

925

950

975

1,000

1,025

1,050

1,075

Real-Time Compressional Memory Shear

us/ft

us/ft

us/ft

us/ft

us/ft

40 240

40 240

40 240

40 240

40 240