Severe Risk. High Risk. Medium Risk. Low Risk. Drilling Dynamics Sensors and Optimization. Accurate, real-time measurements for productive drilling

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1 Severe Risk High Risk Medium Risk Low Risk Drilling Dynamics Sensors and Optimization Accurate, real-time measurements for productive drilling

2 Drilling Dynamics Sensors and Optimization Reduce shocks Optimize ROP Maximize bit performance Avoid lost-in-hole and NPT costs Prevent fluid kicks and fractures Schlumberger drilling dynamics sensors deliver accurate, real-time, downhole measurements for productive drilling reaching TD in less time. Schlumberger drilling dynamics sensors measure shock and vibration, weight on the bit and torque at the bit, annular pressure and temperature, and hole size. These measurements enable drillers to optimize drilling parameters and minimize the risk of drillstring fatigue, premature trips for failure, stuck pipe, kicks, and lost circulation. Real-Time Shock Outputs Schlumberger MWD and LWD tools and PowerDrive* rotary steerable systems all provide real-time and memory logs of the level and duration of downhole shocks they are being subjected to ( = no shocks, 1 = medium shock levels, 2 = high shock levels, and 3 = severe shock levels). Shocks can be characterized in terms of counts per second (cps), peak shocks, and cumulative shocks. The PowerPulse* MWD telemetry system and the TeleScope* high-speed telemetry-whiledrilling service record the number of shocks greater than 5 g s per second as a moving average over a period of 1 s, transmit the answer uphole as shock cps, and aid definition of shock risk level, 1, 2, or 3. Our tools also measure stick/slip, indicated by variations in collar rpm downhole over a specified time period. The variation measurement sent uphole can be compared to surface rpm and reported as a stick/slip level and risk, 1, 2, or 3. These shock count and stick/slip measurements are basic outputs that Schlumberger provides to help our engineers and customers understand when potential BHA damaging shock levels are occurring, allowing remedial action to be taken and enabling more efficient drilling.

3 Use real-time measurements to improve drilling efficiency Depth, ft ROP Averaged Over Last 5 ft ft/h 5 Rotational Speed c/min 2 Stick/Slip Indicator c/min 2 Surface WOB Surface Torque Collar Rotational Speed 1, lbf 5 c/min 2 Severe Risk High Risk Medium Risk Low Risk Transverse RMS Vibration 1, ft lbf 2 gn 1 Shock Peak gn 5 6, ft Vibration levels correspond with BHA being in whirl 6,5 ft 7, ft Vibration levels successfully mitigated via a modification in surface rpm, allowing successful completion of hole section Track 5 of this depth log provides vibration risk level information.

4 Shocks greater than 5 gn Shock cps Shock cps 1 18 Time, s The shock cps provided by our MWD tools is a moving average. Advanced Stick/Slip Measurement An advanced measurement to be used in conjunction with the standard downhole stick/slip measurement is available from all Schlumberger MWD tools to help evaluate the severity of stick/slip. This advanced measurement is the percentage of time during a stick/slip cycle that downhole string rotation is below 5 rpm. The measurement is split into four levels ( = %, 1 = 1% to 24%, 2 = 25% to 49%, and 3 = 5% or more). Time, s Stick/slip value Downhole rpm Variations in downhole collar rpm indicate stick/slip. Four-Axis-Shock Measurements Adding an optional modular vibration chassis (MVC) to the PowerPulse MWD telemetry system or TeleScope high-speed telemetry-while-drilling service provides a real-time four-axis shock measurement that can be used for more detailed analysis of drillstring dynamics. Because the MVC is an integral component, no extra collars or connections are needed. The MVC s real-time four-axis shock measurement alerts the driller to harmful downhole dynamic motions, such as bit bouncing, stick/slip, and whirling, which, if undetected, can lead to poor drilling efficiency, bit damage, and premature drillstring fatigue. Typically, the MVC is used in conjunction with an IWOB* integrated weight on bit sub that provides DWOB* downhole weight-on-bit and DTOR* downhole torque-at-thebit. This enables the driller to adjust weight on the bit, torque at the bit, drillstring rotation speed, and other drilling parameters to reduce the downhole shocks identified by the MVC, significantly improving ROP and extending BHA life.

5 Lateral Vibration Shock Width gn 4 ms 3, Depth, ft Surface Weight on Bit Surface Torque Axial Vibration lbf 4, ft.lbf 2, gn 1 ROP Downhole Weight on Bit DownholeTorqueDownhole Drillstring Rotation Speed ft/h 5 lbf 4, ft.lbf 1, 1 c/min 3 Shock Peak gn 2 Torsional Vibration radian/s 3, XX,32 XX,34 XX,36 Stick/slip threshold weight XX,38 These surface and downhole measurements were used to optimize drilling in a West Africa field.

6 4 Period with downhole rpm less than 5 Period with downhole rpm greater than 5 3 Downhole rpm 2 1 Surface rpm Time, s Advanced stick/slip measurement shows the duration of the stuck period during a stick/slip cycle. WOB, tons WOB, tons Average WOB = 6.7 tons Time, s Average WOB = 6.5 tons Time, s IWOB downhole measurements enable a driller to optimize ROP. One axis torque is measured by strain gauges. The other three axes are axial and radial shock measurements made by three mutually perpendicular accelerometers. These accelerometers are axially aligned with the direction and inclination (D&I) package in the center of the collar to ensure that the shock measurements accurately represent BHA vibration. Because the shock measurements are aligned with the BHA axis, the driller can identify and correct poor drilling conditions before the BHA experiences excessive fatigue. Weight-on-Bit and Torque-at-the-Bit Measurements The IWOB integrated weight on bit sub an optional component of the PowerPulse MWD telemetry system provides real-time DWOB downhole weight-on-bit (WOB) and DTOR downhole torque-at-the-bit measurements. These direct dynamic measurements of the amount of surface weight being transferred through the PowerPulse collar to the bit and of the torque generated below the collar enable a driller to optimize ROP by identifying downhole problems and correcting or avoiding them. IWOB measurements make it possible to distinguish drillstring effects BHA hanging on ledges, high friction coefficients, and BHA whirl from bit effects stick/slip and locked cones. These measurements allow bit usage to be maximized through continuous monitoring of bit condition, and eliminate unnecessary trips to change bits because the driller can tell whether a reduction in drilling efficiency is due to bit wear or to a change in lithology. By detecting potential sticking problems, IWOB measurements help avoid lost-in-hole and NPT costs, and help drillers reach TD sooner.

7 Downhole torque, instantaneous - average Time, s rms IWOB torsional vibration measurements show the rms magnitude of downhole torque fluctuation. Because the IWOB sub is an integrated component of the PowerPulse collar, it eliminates the need for intersub wiring and electrical connections. Actual downhole torque and WOB are measured and transmitted to surface via MWD telemetry in real time. Advanced downhole processing allows accurate interpretation of measurement vibrations to identify stick/slip and other phenomena. A measurement of the root mean square magnitude of downhole torque fluctuation at the MWD tool also is available in real time. This measurement is a valuable indication of drilling inefficiency and can be used to minimize the risk of twistoff events and identify BHA whirl and other mechanisms. IWOB downhole measurements are especially beneficial for optimizing directional drilling with steerable mud motors. The real-time measurements improve drilling efficiency by allowing swift correction of mud and hole cleaning problems such as cuttings buildup, mud gel strength, and friction so that TD can be reached faster with less BHA damage. IWOB measurements eliminate much of the guesswork in determining the forces acting on the drillstring. Combining these measurements with MVC four-axis shock and APWD* annular pressure while drilling measurements automatically removes interfering factors, such as pressure, temperature, and bending. Quick identification of the sources of ineffectiveness and potential problems enables the correct remedial action to be taken, reducing cost and NPT. A Shock & Vibration DVD box set, available free from Schlumberger, discusses how shock and vibration slows ROP and adversely affects BHA components and hole quality. To order a set, contact your local Schlumberger representative. Tool twist off (left) and impact damage to bit (right) resulted from shock and vibration.

8 Integrating downhole and surface measurements to optimize drilling These examples show how drilling performance and efficiency can be improved by integrating data from our downhole sensors with surface sensor measurements. Bit on Bottom Flag Block Position ft 15 ROP 1 ft/h Hook Load 1, lbf 5, Bit Depth Value ft Downhole WOB lbf 6, Surface WOB lbf 6, Vibration, X-Axis gn 4 4 Torsional Total Pump 55 Vibration Flow 4, 1,2 Surface Torque ft.lbf galus/min 1, ft.lbf 3, Surface Lateral Vibration Drillstring Turbine gn Rotation RPM, 4 Speed Real-Time Downhole Torque 12 2, 4, 1, ft.lbf 3, c/min c/min ECD psi/1, ft Annular Temperature 65 7 degc 15 Annular Pressure 5,2 psi 7,2 Standpipe Pressure 2,8 psi 4,4 High lateral shocks Increasing surface WOB reduces shocks Increased WOB reduces lateral shocks Increasing surface WOB reduced the lateral shocks detected by downhole sensors.

9 Block Velocity 2 ft/s ROP 5 ft/h 2 4 Surface WOB lbf 6, Hook Load lbf 5, Vibration, X-Axis gn Bit Depth Value ft Downhole WOB Bit Depth lbf 5, ft Surface Torque ft.lbf 2, Downhole torque lbf 2, Torsional Vibration 4, Lateral Vibration 4 Annular 12 Temperature 1 3 degf Total Pump Flow 1 1, galus/min 9 ECD lbm/galus Annular Pressure psi Bit on Bottom Standpipe Pressure psi 14 5,.5 5, Whirl started and was not stopped after shutting down for short period of time. Whirl finally stopped after longer period off bottom. Off bottom for short time shocks return Off bottom for short time shocks return Off bottom for longer time shocks reduced Two attempts to reduce BHA whirl by raising the bit off bottom to dissipate energy were unsuccessful because the bit was not kept off bottom long enough. On the third try, the bit was kept off bottom for a longer time, which reduced torsional and lateral shocks when drilling resumed.

10 The APWD sensor provides accurate measurements for keeping pressure inside a narrow operating margin early detection of shallow water flow optimizing tripping procedures underbalanced drilling Annular-Pressure-While-Drilling Measurements The APWD annular pressure while drilling sensor provides an accurate real-time measurement of equivalent circulating density (ECD), equivalent static density (ESD), and annular temperature. This enables the driller to optimize drilling performance and minimize risk by improving practices for hole cleaning, borehole stability, and well control, and to keep annular pressure between tight limits in wells that have small margins between fracture gradient and pore pressure. While the pumps are on and drilling fluid is flowing, MWD telemetry delivers APWD data in real time. During connections and leakoff tests when the fluid is static, minimum, maximum, and average pressure values are recorded downhole and transmitted to surface when the pumps are turned on. In deviated wells that require extensive drilling while sliding, and in extended-reach and deepwater wells constricted by friction and barite sag, APWD sensors near the bit can identify increased ECD due to cuttings buildup or barite sag, lack of rotation, or poor hydraulics. That allows corrective action to be taken before a stuck pipe occurs. Near-bit APWD sensors can also detect small downhole fluid losses or gains as they occur. This early detection can help a driller identify potential well control issues before any indication of a fluid influx or lost circulation is seen on surface, and allows the driller to maintain a tight overbalance to optimize ROP without sacrificing safety. By monitoring the effect of swab-surge on ECD, these near-bit sensors allow tripping speeds to be optimized to prevent fluid influxes and fractures. monitoring barite sag tracking motor performance leakoff tests discriminating influxes from sweeping detecting kicks and influxes. In addition, a driller can use APWD measurements to discriminate a formation fluid influx from the harmless flow of mud over the bell nipple a common occurrence when circulation is stopped. Mistaking the mud flow for an influx caused by increasing formation pressure can result in a needless mud weight increase that slows ROP and may cause lost circulation. APWD sensors have been integrated into many Schlumberger MWD and LWD tools and systems, some of which include an internal pressure sensor in addition to the annular sensor. Annular and internal pressure measurements, together with inferred motor torque and rpm, permit a directional driller to continuously monitor motor performance and motor wear, maximizing drilling performance while extending motor life by preventing stalls.

11 Caliper Measurements Ultrasonic and electrical caliper measurements while drilling are not only important to petrophysicists for LWD log quality control, but can also be crucial to drilling success. Analysis of real-time caliper information, especially in combination with APWD measurements, can identify washouts, hole cleaning problems and wellbore stability issues. Schlumberger ultrasonic sensors measure standoff accurately up to 3 in beyond the drill collar over a wide range of mud weights and formation properties. As the drillstring rotates, these measurements are binned azimuthally, and can be transmitted, by quadrant, in real time to make caliper images. Azimuthal standoff measurements are useful for understanding interpreted density responses and making estimates of average hole size that can be used to correct neutron porosity measurements. A differential caliper inferred from density measurements can be used as a quality control on the ultrasonic caliper. Our azimuthally averaged electrical caliper can be used to quantify washouts in larger boreholes. This caliper, available only in water-base muds (WBM) with a resistivity of less than.5 ohm.m, provides hole size estimates up to 36 in, and is accurate to less than.5 in over most ranges of formation resistivity. Because our azimuthally averaged electrical caliper can be used to estimate hole size while tripping, it allows a time-lapse picture of dynamic wellbore conditions. A caliper measurement while tripping is also valuable for cementing operations, because total hole volume can be crucial information for successful cementing.

12 Drilling optimization workflow These workflow charts suggest remedial actions that can be taken to mitigate axial, lateral, or torsional vibration. Vibrations Recognize the Symptoms Conventional Cures While Drilling Vibrations Recognize the Symptoms Conventional Cures While Drilling SURFACE MEASUREMENT OR SYMPTOM LATERAL VIBRATION (bit/bha whirl) SURFACE MEASUREMENT OR SYMPTOM TORSIONAL VIBRATION (stick/slip) Increased mean surface torque Loss of toolface Reduced ROP Decrease rpm by 1% Increase WOB by 1% Topdrive stalling Increased delta surface torque rpm/torque cycling Loss of toolface Reduced ROP Place top drive in high gear; ensure soft torque operational Decrease WOB by 5% Increase rpm by 1% DOWNHOLE MEASUREMENT Increased mean downhole torque High-frequency downhole shocks 1 to 5 Hz Repeat three times unless WOB limit is exceeded Yes No Does vibration continue? Yes DOWNHOLE MEASUREMENT Increased delta downhole torque Increased torsional acceleration Repeat three times unless WOB limit is exceeded Yes No Does vibration continue? Yes Increased lateral shocks Increased torsional acceleration Loss of real-time data/measurement Increased shock count Pick up off bottom and allow string torque to unwind Restart drilling with 7 rpm Increase WOB by 1% of original Increase rpm to original value Increased stick/slip indicator Downhole collar rpm greater than surface rpm Loss of real-time data/measurement Increased lateral shocks Increased shock count Pick up off bottom and allow string torque to unwind Restart drilling with 1% increased rpm Decrease WOB 15 to 2% No Vibration resumes? No Vibration resumes? POSTRUN EVIDENCE Cutters/inserts damaged, typically on shoulder or gauge Broken PDC blades Worn hybrids (equivalents) with minimal cutter wear Overgauge hole from calipers One-sided wear on stabilizers and BHA Yes Pick up off bottom and allow string torque to unwind Restart drilling with 7 rpm Increase WOB to original value Increase rpm to 25% below original value POSTRUN EVIDENCE Cutters/inserts damaged, typically on nose and taper Overtorqued connections Twist-offs and washouts BHA failure Yes Pick up off bottom and allow string torque to unwind Restart drilling with 7 rpm Increase WOB to 25% below original value Gradually return rpm to 15% above original BHA failure CONTINUE DRILLING CONTINUE DRILLING

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14 Specifications MWD Shocks & Stick-Slip Measurement Range Resolution Shock count to 255 cps 1 cps Shock peak to 1,2 gn 4 gn Stick/slip to 381 rpm 3 rpm Collar rotation speed to 255 rpm 1 rpm Shock and stick/slip risk to 3 1 MVC Measurement Range Resolution X-axis axial rms vibration to 3.2 gn.125 gn Y-axis lateral rms vibration to 6.8 gn.25 gn Z-axis lateral rms vibration to 6.8 gn.25 gn Lateral rms vibration to 6.8 gn.25 gn Torsional rms vibration to 5,1 ft.lbf 5 ft.lbf Shock peak level to 1,2 gn 4 gn Peak shock width to 2.5 ms 2 us IWOB Sensor WOB Torque Measurement range 65, to 19, lbf 8, to 15, ft.lbf Resolution 5 lbf 9 ft.lbf Absolute accuracy see table below see table below Scale factor 5 lbf/count 9 ft.lbf/count IWOB Estimated Absolute Accuracy Downhole Conditions Error on WOB Error on Torque 3, lbf WOB (total electronics error) ± 2.85% (cross talk) ± 2.85% 5, ft.lbf torque (cross talk) ± 1,41 lbf (total electronics error) ± 25 ft.lbf ± 5 psi differential pressure ± 885 lbf ± 7 ft.lbf ±15 dogleg (sliding, worst orientation possible) ± 3,33 lbf ± 438 ft.lbf Hydrostatic pressure 15 lbf/1, psi 5 ft.lbf/1, psi Temperature 41 lbf/degf 4 ft.lbf/degf Accuracy depends on deviations of downhole conditions such as applied WOB, running torque, sliding dogleg, hydrostatic pressure, and temperature away from the corresponding values at the last downhole rezero point. The effect of differential pressure (ΔP) will be eliminated by surface software based on standpipe pressure. The error due to dogleg exists when the MWD tool is in sliding mode. When the tool is in rotary mode, the error vanishes because of data filtering.

15 APWD Sensors (from EcoScope* multifunction LWD service, arcvision* array resistivity compensated tools, or TeleScope service) Resolution Accuracy Available ranges Annular temperature resolution Annular temperature accuracy Record rate Real-time rate 1 psi to.1% of full scale to 5, psi to 1, psi to 2, psi 1 degc 1 degc 4-s minimum average of 2-s samples programmable typically every 8 s at 12 Hz 3 bps Ultrasonic Caliper (from EcoScope service or adnvision* azimuthal density neutron tools) Frequency Standoff range 25 khz 3 in at maximum mud weight 1 lb/galus and formation densities above 2.2 g/cm 3 1 in at maximum mud weight 16 lb/galus and formation densities above 2.5 g/cm 3 Accuracy Frequency Standoff range ± 1.5 ms transit time (±.1 inch in water) 67 khz 2 in at maximum mud weight 1 lb/galus and formation densities above 2.2 g/cm 3 1 in at maximum mud weight 13 lb/galus and formation densities above 2.5 g/cm 3 Accuracy ± 1.5 ms transit time (±.1 inch in water)

16 Drilling Dynamics Sensors and Optimization *Mark of Schlumberger Japan Oil, Gas and Metals National Corporation (JOGMEC), formerly Japan National Oil Corporation (JNOC), and Schlumberger collaborated on a research project to develop LWD technology that reduces the need for traditional chemical sources. Designed around the pulsed neutron generator (PNG), EcoScope service uses technology that resulted from this collaboration. The PNG and the comprehensive suite of measurements in a single collar are key components of the EcoScope service that deliver game-changing LWD technology. Copyright 21 Schlumberger 1-DR-169