Saturn 3D radial probe. Enabling, efficient, derisking, and flexible

Saturn 3D radial probe Enabling, efficient, derisking, and flexible

Saturn Formation testing where not previously possible Applications Formation pressure measurement Downhole fluid analysis (DFA) Formation fluid sampling Fluid-gradient determination Far-field permeability measurement and anisotropy determination Well testing design optimization Benefits Enabling: pressure measurement, DFA, and fluid sampling Wide permeability range, extending down to 0.01 md Heavy oil Near-critical fluids Unconsolidated formations Thinly laminated formations Rugose and unstable boreholes Efficient: significant rig-time savings Derisking: reduced station time and assured retraction Flexible: deployable across a wide range of hole sizes, temperatures, and pressures on all conveyance options, from wireline to TLC* tough logging conditions system to openhole tractors 01

Features The industry s largest total surface flow area: 79.44 in 2 8,000-psi differential pressure rating qualified between flowline and hydrostatic pressures Fast setting and retracting time No sump and low storage effect to eliminate mixing of fluids with stationary mud Quantified contamination monitoring algorithm for ensuring representative sampling in oil-base mud 4-ft spacing from monitoring probe above for vertical interference testing Four elliptical ports with fieldreplaceable, customizable filters to prevent flowline plugging Self-sealing drain assembly for excellent seal maintenance during sampling in anyquality borehole Improved mud bypass system to provide superior pressure maintenance in unstable wellbores Combinable with all MDT Forte*, MDT Forte-HT*, MDT* tester modules, and the InSitu Fluid Analyzer* real-time downhole fluid analysis system Conveyance on wireline cable, TLC tough logging conditions system, and UltraTRAC* all-terrain wireline tractor 02

Setting a new standard in downhole formation testing The Saturn* 3D radial probe establishes and maintains true 3D circumferential flow in the formation around the borehole, enabling highly accurate pressure measurement, downhole fluid analysis (DFA), sampling, and permeability estimation in what were previously challenging conditions for conventional wireline formation testing: - rugose or unstable boreholes - extremely low-permeability or unconsolidated formations - heavy oil or near-critical fluid types. The Saturn probe s fast setting and retracting times, zero sump for a low storage effect and elimination of stationary mud mixing, and largest flow area in the industry of 79.44 in 2 facilitate efficient operations across a wide permeability range in a single trip. 03 Reducing stationary time and assuring retraction every time significantly derisks operations. Flexible deployment is supported by wide borehole-size coverage, HPHT rating, and qualification for up to 20 sequential operational cycles in a single descent. q k AdP L u Flow from the formation to a conventional formation tester is narrowed to the intake of the single probe, not from the entire circumference of the borehole wall. Back to basics Successful wireline fluid sampling and DFA begin with accessing a representative sample of the virgin reservoir fluid, ideally in a minimum amount of time. Formation pressure testing similarly requires fluid withdrawal. The fluid extraction is typically conducted with a probe module that includes a packer, telescoping backup pistons, and a flowline. The pistons extend the probe and packer assembly against the borehole wall to provide a sealed fluid path from the reservoir to the flowline. The governing principle behind flowing any fluid from a reservoir for formation testing is Darcy s law, in which flow (q) is a function of permeability (k), drawdown pressure (dp), surface area open to flow (A), fluid viscosity (u), and the length (L) over which the drawdown is applied.

Different probe surface flow areas and the maximum pressure drawdowns that the formation tester can manage are used depending on the formation permeability and fluid viscosity. Typically, the larger the surface area and the higher the maximum drawdown pressure, the higher the flow rate of fluid from the formation that can be achieved for a formation testing operation. Over the years, Schlumberger innovation has increased the maximum allowable differential pressure from 4,596 psi with the standard pumpout displacement unit to 11,760 psi with a high-pressure displacement unit. Concurrently, the available surface area of the probes has increased by nearly 40 times, from the standard probe s 0.15 in 2 to the 6.03-in 2 elliptical probe. This technical progression enables successfully performing formation testing in a wider range of environments. However, as operators attempt to tap into hydrocarbons previously thought to be unproducible low-permeability or unconsolidated reservoirs, highviscosity formation fluids or where reduced drawdown is necessary to test reservoirs in which the saturation pressure of the fluid is close to the reservoir pressure, formation testing is technologically challenged. The Saturn 3D radial probe meets these challenges with a radical redesign of the fluid-extraction module to deploy multiple self-sealing ports around the borehole. With a total surface flow area of 79.44 in 2, Saturn probe technology expands the operating envelope of formation testing for both fluid flow and reservoir environments. The self-sealing drain assembly incorporating the four ports circumferentially extracts fluid from the formation instead localizing flow at a single probe. 04

x4 The Saturn 3D radial probe increases the probe surface area by more than 500 times. Probes not to scale. 79.44 Surface flow area, in 2 8.96 Surface flow area, in 2 2.01 Surface flow area, in 2 1.01 Surface flow area, in 2 0.85 Surface flow area, in 2 0.15 Surface flow area, in 2 05 Saturn 3D radial probe Eliptical probe Extralargediameter probe Quicksilver Probe* focused extraction Large-diameter probe Standard probe

Sealing with confidence Unlike the packer incorporated in a conventional probe assembly or operations using a dual straddle packer in the testing string, the four ports of the Saturn probe self-seal with suction to the borehole wall to receive direct flow from the formation with faster cleanup. Complete pressure surveys in low-mobility formations The technology that makes the Saturn 3D radial probe excel at fluid extraction also delivers a step change in formation pressure testing. Conventional formation tester probes with the largest surface flow area currently available are limited to pressure testing formations with mobilities no lower than about 1 md/cp. Pretesting-only service is the current benchmark for excellent performance in lowpermeability formations, but the mobility limit for those pressure tests is about 0.1 md/cp. Direct rig-time savings in lowpermeability formations As the permeability of a formation decreases, the performance improvement of the Saturn 3D radial probe over conventional probes widens significantly. As shown in comparison with the extralargediameter probe for achieving 5% contamination, the Saturn 3D radial probe improves sampling efficiency beginning at formation mobilities of 500 md/cp, with the performance gap greatly expanding as the mobility decreases. Time to reach 5% contamination, h 25 20 15 10 5 0 Sample enabling in low mobility Saturn 3D radial probe Once mobility approaches 10 md/cp, the extralarge-diameter probe cannot move the formation fluid, whereas the Saturn 3D radial probe is an enabling technology. 1 10 100 Mobility, md/cp 4-in invasion, 300-psi drawdown, kv/kh = 1 Sample efficiency Extralarge-diameter probe Modeled cleanup times for the Saturn 3D radial probe and a conventional extralarge-diameter probe show the increase in sampling efficiency possible. The Saturn 3D radial probe is an enabling technology for sampling at mobilities less than 10 md/cp, at which the conventional probe cannot perform. 06

Flow fluid in three dimensions The Saturn 3D radial probe comprises four elliptical suction ports, distributed at 90 intervals around the circumference of the tool. This placement pulls fluid circumferentially from around the borehole, instead of the conventional probe arrangement of one port as the sole fluid access point. Each of the four Saturn ports has a surface flow area of 19.86 in 2, which is more than 3 times larger than the surface area of an elliptical probe, which is the largest conventional probe. Together, the four Saturn ports total 79.44 in 2 of surface flow area, an increase of more than 500 times over the area of the standard conventional probe. Flow from the formation to a conventional formation tester is narrowed to the intake of the single probe, not from the entire circumference of the borehole wall. 07

Circumferential flow around the wellbore has significant benefits for both sampling cleanup and interval pressure transient testing (IPTT). The Saturn 3D radial probe quickly removes the filtrate from the entire circumference of the wellbore to draw in uncontaminated formation fluid. In addition, the significantly larger flow area of the 3D radial probe can induce and sustain flow in low-mobility formations, formations in which the matrix is uncemented, and the viscous fluid content of heavy oil reservoirs. The four Saturn ports efficiently establish circumferential flow from the formation to quickly remove filtratecontaminated fluid and flow uncontaminated, representative fluid for DFA, sampling, and pressure measurements. 08

Circumferential support for unconsolidated formations The circumferential self-sealing technology of the Saturn 3D radial probe mechanically supports the borehole with the compliant rubber seal of its drain assembly throughout the sampling operation. Pressure drawdown is localized to the four elliptical suction ports, which minimizes the matrix stress while flowing fluid. If any matrix disengages while flowing fluid, the Saturn 3D radial probe is equipped with sandface filtering mechanisms on each of the ports to prevent plugging of the system. Accurate permeability and permeability anisotropy measurement The Saturn 3D radial probe is designed with zero sump, which significantly minimizes wellbore storage. This storage reduction coupled with spacing of the monitoring probe just 1.23 m from the Saturn probe s pressure gauge makes it possible to derive formation permeability and permeability anisotropy across a wide permeability range in a single trip. 09 The mechanical retract mechanism of the Saturn 3D radial probe employs heavy-duty springs to secure the drain assembly when not deployed.

Extending sampling to large-diameter wellbores, HPHT conditions, and lengthy programs Available in both 7-in and 9-in tool diameters, the Saturn probe brings the efficiency of radial fluid flow to boreholes sized up to 14½ in. The high temperature rating of the 7-in Saturn probe at 400 degf and high pressure rating for both Saturn probe sizes at 30,000 psi extends coverage across practically all downhole environments. Qualified for 20 sequential sealings of the drain assembly at maximum differential pressure in a single descent, the Saturn 3D radial probe has achieved up to 60 settings in the field, depending on environmental conditions. This reliable downhole flexibility enables achieving ambitious formation testing objectives. Combinability and conveyance flexibility Full compatibility with the MDT Forte, MDT Forte-HT, and MDT tester modules along with the InSitu Fluid Analyzer realtime downhole fluid analysis system family maximizes configuring the formation testing string to match the wellbore and formation conditions and the test objectives. Deployment capabilities are similarly flexible from wireline to the TLC tough logging conditions system to the UltraTRAC all-terrain tractor for accessing wells at any angle: vertical to highly deviated and horizontal. Reliably out of the hole, every time Sixty-four individual heavy-duty springs mounted around the edges of the Saturn probe assembly and two large-diameter heavy-duty springs around the mandrel ensure reliable, consistent retraction of the elliptical suction ports after every station. The large cumulative closing force of the mechanical spring system keeps operational risk to a bare minimum. 10

Case Study High-quality samples in OBM and tests across wide permeability range, Norwegian Sea Benefits: Enabling Efficient Derisking Flexible When a potential Lower Jurassic reservoir was found to consist of unexpectedly poorer quality, low-permeability rock in comparison with the over- and underlying producing beds in a deepwater field, Statoil wanted to conduct a thorough evaluation by measuring pressure data, collecting fluid samples, and conducting pressure transient and vertical interference tests. However, an initial run of the MDT tester employing conventional single probes could not answer these data needs in the low-permeability zones. For example, a hydrocarbon sample collected in 2.4-mD/cP mobility after 5 h of pumping contained 17-wt% oil-base mud (OBM) filtrate. Sampling efficiency was greatly improved by incorporating the Saturn 3D radial probe in the tester toolstring. Three oil samples and six water samples at mobilities as low as 0.3 md/cp were collected, including fluid extracted from 5 m lower in the same formation as a sample collected with a conventional probe at 17-wt% contamination. However, the Saturn probe reduced the drawdown by half in a 0.6-mD/cP zone to deliver only 5-wt% contamination after 6 h of pumping. The toolstring also incorporated an observation probe at a 1.23-m interval from the Saturn probe for conducting vertical interference tests (VITs) to evaluate permeability and permeability anisotropy and to estimate the flow potential. All four VITs returned valid, interpretable reservoir responses at the probes, with particularly good data acquired in a zone with 120-mD/cP mobility. High-quality pretest pressure measurements were made at all Saturn probe stations, in mobility as low as 0.3 md/cp. 11

Gas/oil ratio, m 3 /m 3 300 200 100 1.0 0.5 0 Low quality Water Oil High quality Highly absorbing fluid flag Three samples at only 5 wt% contamination X Saturn probe Saturn probe derivative X Observation probe Observation probe derivative Volume, L 240 220 200 180 160 140 120 100 80 60 40 20 0 Pressure, bar 460 440 420 400 380 360 340 320 300 Quartz gauge Pumped volume 35-bar drawdown at 12 cm 3 /s 9-bar drawdown at 3 cm 3 /s 0 1 2 3 4 5 6 Elapsed time, h Pressure and pressure derivative, psi 10 1 10 2 10 3 10 3 10 2 10 1 Elapsed time, h The Saturn 3D radial probe sampled a zone at 0.6-mD/cP mobility with contamination reduced to 5 wt% after only 6 h of pumping. Drawdown was 35 bar during cleanup at 12 cm 3 /s and 9 bar during sampling at 3 cm 3 /s. A conventional probe used in a zone 5 m higher in the same formation with 4 times the mobility required almost twice the drawdown and still had 17-wt% OBM filtrate contamination. A pressure transient test with vertical interference monitoring shows well-developed pressure transient responses at both the Saturn probe and the observation probe. The buildup interpretation yields a mobility of 120 md/cp, for which a dual-packer configuration would be challenged to create sufficient drawdown for conducting a valid test. 12

Case Study Oil/water contact delineated in 12¼-in wellbore in low-permeability presalt carbonate An operator needed to accurately define the oil/water contact in a low-permeability zone of a 12¼-in deepwater well offshore Brazil where conventional single probes had returned only tight tests. The low mobility also implied longer pumping times on station, which would increase operational risk. Benefits: Enabling Efficient Derisking Flexible The 9-in version of the Saturn 3D radial probe extends the efficiency of four-port fluid extraction with the industry s largest surface flow area to large-diameter wellbores. Where a conventional probe had previously failed to define the pressure gradient in the transition and water zones, the 9-in Saturn probe reliably sealed in the 12¼-in wellbore. Fluid was extracted at stations with estimated mobilities of 0.03 and 0.06 md/cp in only 3.5 and 6.5 h, respectively, to both save rig time and reduce risk. The purity of the collected samples was confirmed with real-time downhole fluid analysis. 13

Free-Fluid Volume Formation pressure 8,100 psi 9,100 Gamma Ray 0 gapi 150 Bit Size 10 in 20 Caliper 10 in 20 Dry test Dry test Washout InSitu Fluid Analyzer Fluid Fractions Mud After Depth, m 8,800 psi 10,000 Mud Before Cable Tension Water Oil Capillary-Bound Water NMR Porosity 0.3 V/V 0 Free-Fluid Volume 0.3 V/V 0 Free-Fluid Volume Using 3-ms Cutoff Array Induction Density Standoff Correction 2-ft -1 g/cm 0.25 Resistivity A30 3 Standard-Resolution Formation 0.2 ohm.m 2,000 Photoelectric Factor Array Induction 2-ft 20 0 Permeability Resistivity A90 Standard-Resolution Formation Density Drawdown Mobility 0.2 ohm.m 2,000 Array Induction 2 g/cm 3 3 0.01 md/cp 1,000 2-ft Near/Array-Corrected NMR Permeability Resistivity A10 Limestone Porosity 0 1 8,800 psi 10,000 15,000 lbf 0 0.3 V/V 0 0.01 md 1,000 0.2 ohm.m 2,000 0.45 V/V 0.15 X,550 Clay-Bound Water The tight, low-quality pressure points (red) returned by a conventional probe were so scattered that pressure gradients and contacts across the low-permeability water zone could not be determined. The Saturn 3D radial probe acquired multiple valid pressure measurements (yellow) and low-contamination samples from the zone that confirmed the presence of water and delineated the contact to the overlying oil zone. X,560 Dry test Tight test X,570 Lost seal X,580 Dry test Tight test Lost seal No seal No seal Lost seal X,590 14

Case Studies Saturn probe retrieves uncontaminated 7.5-API oil from friable sandstone Benefits: Enabling Efficient Derisking Flexible Accurate fluid description and determination of pressure differentials were needed to guide well placement and completion in an onshore Mexico field to avoid the development of preferential flow along higher-mobility intervals. However, the combination of a poorly consolidated formation, with unconfined compressive strength (UCS) values ranging from 100 to 800 psi, and high-viscosity fluid content meant that the pressure differential generated by conventional formation testing inevitably caused collapse of the wellbore wall and failure of the seal or sanding out of the tool. The operator had to resort to temporarily perforating, completing, and flowing each sand separately to collect samples in coiled tubing deployed bottles on a DST string. The complicated logistics and high costs of this approach were not sustainable. Unlike single-probe conventional formation testers, the Saturn 3D radial probe is ideal for flowing fluid in these challenging conditions of an unconsolidated reservoir with low mobility. The four self-sealing elliptical ports, with the industry s largest surface flow area of more than 79 in 2, quickly establish and maintain flow from the entire circumference of the wellbore instead of funneling fluid from the reservoir to a single access point. The result is quicker cleanup and the efficient performance of pressure measurements. In unconsolidated formations, the compliant rubber surface of the Saturn probe s drain assembly mechanically supports the borehole throughout the sampling operation. Pressure drawdown is localized to the four elliptical ports, which minimizes matrix stress while fluid is flowing. 15

Each self-sealing port incorporates a filter to capture any dislodged matrix and prevent plugging. If sand grains were drawn in with the flowing fluid, the drain assembly incorporates individual port filters to prevent flowline plugging. The Saturn 3D radial probe was deployed in the field to test and sample at multiple stations in several wells, which have up to 12% ovalization. Whereas conventional probes commonly experienced lost seals in the rugose holes, the Saturn probe s selfsealing ports maintained seal integrity to support the borehole in the unconsolidated sandstone reservoirs. There was no evidence of sand grains reaching the pumps. Full pressure surveys were conducted in both water- and oil-base mud environments with only minor storage effects observed in the pressure responses. The pressure surveys in combination with the mobilities determined from every pretest are being used to design completions that will evenly distribute injected steam among designated intervals and avoid channeling. Fluid sampling successfully captured an uncontaminated sample of 7.5-API oil; subsequent laboratory analysis reported a viscosity of approximately 1,030 cp at downhole conditions. Being able to use the Saturn 3D radial probe to collect what were previously unobtainable high-quality samples and pressure data is providing a wealth of information for the operator. The Saturn 3D radial probe collected an uncontaminated sample of 7.5-API oil from an unconsolidated sandstone reservoir without sanding or seal failure. 16

Case Study Saturn probe proves low-permeability laminated pay, offshore northwest Australia Benefits: Enabling Efficient Derisking Flexible An operator identified an interval for further investigation from borehole images obtained with the OBMI* oil-base microimager. However, a wireline formation tester with a conventional probe was unsuccessful at evaluating the thinly laminated sands in the deepwater exploration well. The probe s pressure measurements were ineffective, indicating very low permeabilities, and flow could not be established for fluid sampling. The Saturn 3D radial probe performed well in the low-permeability laminated sands, obtaining valid pressure measurements in submillidarcy formations for pressure transient analysis to accurately determine the permeability. Fluid samples were collected for identification, including a gas sample from a zone with 0.36-mD permeability. The operator s reservoir evaluation was greatly improved by the Saturn probe s results to significantly increase the net pay for the well. 17

X,X13 X,X14 Formation contact area of Saturn 3D probe X,X15 X,X16 Formation contact area of conventional probe X,X17 Pressure measurements and fluid samples were acquired by the Saturn radial probe with its large 79-in 2 contact area in the interval identified from images obtained by the OBMI oil-base microimager. A conventional single probe, with its much smaller contact area, was not able to perform in the very low-permeability laminated sands. 18

Case Study 650% faster flow rate efficiently acquires fluids from dolomite Benefits: Enabling Efficient Derisking Flexible The openhole logs from a dolomitic limestone interval drilled with saline water-base mud in the Middle East did not indicate the presence of hydrocarbon, but the analysis was ambiguous because some zones had resistivity values as low as 0.7 ohm.m. The operator wanted to conduct DFA and collect samples to resolve the identity of the reservoir fluids, but the time allowed at each sampling station was limited to 4 h in consideration of mud losses during the job. Schlumberger deployed an advanced wireline formation tester toolstring that included both the Saturn 3D radial probe and an extralargediameter conventional probe to acquire fluid at multiple stations in a single trip. After DFA at Station I clearly identified 60% 70% oil, Station II was selected for determining the lowest mobile oil. The initial sampling attempt with the extralarge-diameter probe experienced a significant pressure drop, with 2,000-psi drawdown and a low flow rate of 5.2 L/h. The resulting pretest mobility was 1.5 md/cp. After 1.5 h of pumping out, flow was switched to the Saturn 3D radial probe, and the rate increased 650% with only 680-psi drawdown. The performance of the Saturn 3D radial probe for the ratio of rate to pressure drop was a 19-times improvement over that of the extralarge-diameter probe for the 1.5-mD/cP mobility. Flowline resistivity stabilization was achieved with water identification at Station II within the 4-h limit for the well, and the water collected in the sample bottle confirmed the DFA results. 19

Pretest Mobility md/cp Formation Pressure 530 psi 930 0.01 1,000 Thermal Neutron Porosity V/V Formation Density g/cm 3 Delta-T Compressional Slowness us/ft Bulk Density Correction g/cm 3 Photoelectric Factor Resistivity Array Induction 4-ft A60 ohm.m Array Induction 4-ft A30 ohm.m Array Induction 4-ft A20 ohm.m Array Induction 4-ft A10 ohm.m Invaded Zone Resistivity ohm.m Core Interval MDT Quality MDT Station Drillstem Test Interval 0.367 psi/ft (oil) 46 46 70% water 30% oil Station III 48 48 40% water 60% oil Station I 49 Water Station II 50 50 0.477 psi/ft (water) ± 0.021 psi/ft 51 51 52 52 The extralarge-diameter probe was able to collect reservoir fluid at Station I, but after 1.5 h of pumping out at Station II, flow was switched to the Saturn 3D radial probe, which increased the flow rate by 650%. 20

Time, s 16,200 14,400 12,600 10,800 9,000 7,200 5,400 3,600 1,800 No oil was observed by the optical analyzers for the 34 L of fluid extracted at Station II by the extralargediameter probe (left) at a large drawdown and low rate. Once flow was switched to the Saturn 3D radial probe (right), cleanup was achieved at a rate that was about 3.5 times faster. The insets show how the fluid flow in the reservoir is to a single point for the conventional probe but circumferentially for the four self-sealing ports. 21 Extralarge- Diameter Probe 34 L Time, s 16,200 14,400 12,600 10,800 9,000 7,200 5,400 3,600 1,800 Saturn 3D Radial Probe 35 L Pressure, psi Pressure, psi 10 Z,000 9 8 Y,500 Y,000 7 6 5 X,500 X,000 Pressure 4 3 W,500 W,000 Rate 2 1 0 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 Time, s Flow rate, cm 3 /s 20 Y,800 Inflation, 7 L 18 Y,600 16 Y,400 14 Formation pressure Y,200 12 Y,000 X,800 10 8 Flow rate X,600 X,400 X,200 6 4 2 0 0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 Time, s Flow rate, cm 3 /s Comparison of pressure and rate of the extralarge-diameter probe (left) and Saturn 3D radial probe (right) at Station II shows that the Saturn probe increased the flow rate 650% with only 680-psi drawdown, which is one-third of the conventional single probe s drawdown. The resulting ratio of rate to pressure drop delivered an improvement of 19 times over the single probe s performance.

Saturn Specifications Measurement Output Logging speed Mud type or weight limitations Combinability Special applications Mechanical Temperature rating Pressure rating Borehole size min. Borehole size max. Saturn 3D Radial Probe Ultralow-contamination formation fluids, formation pressure, fluid mobility, downhole fluid analysis, permeability anisotropy Stationary None Fully integrates with MDT modular formation dynamics tester and InSitu Family* sensors Low-permeability formations, heavy oil, near-critical fluids, unconsolidated formations, rugose boreholes, large-diameter boreholes, high temperatures 7- and 9-in versions: 350 degf [177 degc] High-temperature 7-in version: 400 degf [204 degc] 20,000 psi [138 MPa] High-pressure version: 30,000 psi [207 MPa] 7-in version: 7.875 in [20.0 cm] 9-in version: 9.875 in [25.08 cm] 7-in version: 9.5 in [24.13 cm] 9-in version: 14.5 in [36.83 cm] Max. hole ovality 20% Outside diameter Tool body: 4.75 in [12.06 cm] 7-in version drain assembly: 7 in [17.78 cm] 9-in version drain assembly: 8.75 in [22.23 cm] Length 5.7 ft [1.74 m] With Modular Reservoir Sonde and Electronics (MRSE): 12.4 ft [3.78 m] Weight (in air) 7-in version: 385 lbm [175 kg] 9-in version: 485 lbm [220 kg] 22