NeoScopeSourceless formation evaluation while drilling

NeoScope service reduces risk by eliminating the need for chemical sources in logging while drilling. The industry’s only sourceless formation evaluation-while-drilling solution, NeoScope service uses unique pulsed neutron generator technology in the shortest multifunction LWD collar available.

“We are pleased with the NeoScope service and the correlation of the sourceless neutron-gamma density with density logs from nearby wells. After this success, we would recommend use of this service on future wells where handling of chemical sources is a concern.”

—Pearl Oil, Thailand

PULSED NEUTRON GENERATOR (PNG) OPERATION

PNG OFF

MUD FLOW STARTS THE

MWD SERVICE TURBINE.

THE MWD TURBINE SPINS

AND PROVIDES POWER TO THE NeoScope

TOOL, WHICH ACTIVATES THE PNG.

PNG ON

WHEN POWERED, THE PNG PRODUCES

HIGH-ENERGY NEUTRONS THAT INTERACT

WITH THE FORMATION.

NeoScope SERVICE MEASURES

SOURCELESS NEUTRON-GAMMA DENSITY,

NEUTRON POROSITY, SIGMA,

AND SPECTROSCOPY.

WHEN MUD FLOW STOPS,

THE PNG TURNS OFF.

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The PNG produces neutrons on demand, eliminating americium-beryllium (241AmBe) radio-isotopic neutron and cesium (137Cs) gamma-ray sources and the associated stringent regulatory transportation and handling procedures. Neutrons are generated only when the NeoScope tool receives power from the turbine in the MWD system. In the absence of mud flow, the PNG stops generating neutrons, and the tool can be handled with no special safety considerations. Fishing, sidetracking, and well abandonment no longer require special or costly procedures associated with BHAs containing nuclear sources.

Exploring New Frontiers In exploration drilling, NeoScope service

■ eliminates the need for chemical sources

■ avoids complex fishing, sidetracking, or abandonment procedures

■ provides comprehensive petrophysical measurements in real time

■ saves rig time through early evaluation to optimize drilling and logging programs.

Developing Unconventional Plays In unconventional plays, NeoScope service

■ offers an extensive suite of sourceless measurements to evaluate reservoir quality

■ provides critical data to optimize completion quality

■ provides sourceless measurements in real time for better well placement

■ removes chemical source transportation risks, handling risks, and costs.

Meeting Everyday Challenges In all drilling operations, NeoScope service

■ saves rig time and risks by eliminating source loading and unloading

■ provides all measurements close to the bit

■ increases efficiency and safety by integrating all sensors in one collar

■ avoids complex sidetracking and lengthy fishing operations.

The Sourceless Solution

NeoScope service uses a PNG to produce neutrons, eliminating the need for chemical nuclear sources. Neutron supply is controlled by the power voltage applied to the PNG. The ability to generate neutron pulses—rather than the continuous stream of neutrons supplied by a chemical nuclear source—provides a number of measurements. These sourceless measurements include neutron-gamma density, neutron porosity, elemental capture spectroscopy, and thermal neutron capture cross section (sigma).

Sourceless neutron-gamma density, a unique sourceless measurementUsing the PNG and a series of detectors, the NeoScope tool determines sourceless neutron-gamma density (SNGD) from the gamma rays induced by the interaction of high-energy neutrons with the formation. SNGD can replace the traditional gamma-gamma-density (GGD) measurement, allowing conventional formation evaluation without the use of a chemical nuclear source. Because of the complex nature of the SNGD response, a prejob calibration is required to maintain the accuracy of the measurement below 0.025 g/cm3 in clean formations. Traditional GGD is limited to 0.015 g/cm3. The SNGD measurement provides higher-quality lithology information than the photoelectric factor (PEF) of the GGD but cannot be focused azimuthally to form an image. The SNGD measurement is also deeper and less dependent on good contact with the formation than the GGD measurement. Log quality control flags guide interpretation of the internal tool diagnostics and measurement quality throughout the drilling process, enhancing the decision-making process.

Sourceless thermal neutron porosity and hydrogen index The high-energy PNG neutrons with a higher count rate than traditional chemical nuclear sources used with the series of NeoScope detectors enable determination of the formation hydrogen index (HI). The high-energy neutrons are slowed down by hydrogen atoms in the formation. The neutron measurements use the count rates from the near and far helium-3 tubes to determine thermal neutron porosity and HI. The HI measurement is less sensitive to environmental conditions than the corresponding thermal neutron porosity.

The industry’s only LWD spectroscopy and sigma Spectroscopy data are acquired by a short-spaced gamma-ray detector performing a spectral analysis. Spectroscopy computations are performed downhole, allowing real-time identification of the elemental composition of the formation, formation grain nuclear response, and lithology determination. Volumetric lithology quantification is important for accurate porosity and saturation determination.

Sigma, which is primarily sensitive to the presence of chlorine, is used to provide a resistivity-independent formation saturation evaluation, to distinguish formation fluids, and to identify low-resistivity pay zones while drilling.

The Science of the Measurement

PNG-BASED MEASUREMENTS

NEUTRON-GAMMA DENSITY

NEUTRON POROSITY

SPECTROSCOPY

SIGMA

OTHER MEASUREMENTS

ARRAY RESISTIVITY

DUAL-ULTRASONIC CALIPER

ANNULAR PRESSURE WHILE DRILLING AND TEMPERATURE

THREE-AXIS SHOCK AND VIBRATION

AZIMUTHAL GAMMA RAY

NEAR-BIT INCLINATION

Pulsed neutron generator, an electronic switchable neutron source

NeoScope neutron-gamma density is based on the detection of neutron-induced gamma rays that result from the collision of high-energy neutrons with the formation.

MD, ft

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X,250

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ROP Averaged Over Last 5 ftft/h 0250

Gamma Ray, AveragegAPI 1500

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ma

Ray

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cato

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2,0000.2Attenuation Resistivity, 22-in spacing

ohm.m

2,0000.2 ohm.m

2,0000.2 ohm.m

2,0000.2Attenuation Resistivity, 40-in spacing

ohm.m

2,0000.2Formation Resistivity

ohm.m

2,0000.2Flushed Zone Resistivity

ohm.m

2,0000.2

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2000.02Attenuation Resistivity, 40-in spacing

Attenuation Resistivity, 34-in spacing

Attenuation Resistivity, 28-in spacing

Attenuation Resistivity, 22-in spacing

Attenuation Resistivity, 16-in spacing

Phase Shift Resistivity, 40-in spacing

Phase Shift Resistivity, 34-in spacing

Phase Shift Resistivity, 28-in spacing

Phase Shift Resistivity, 22-in spacing

Phase Shift Resistivity, 16-in spacing

Phase Shift Resistivity, 22-in spacing

Phase Shift Resistivity, 16-in spacingU0

Gamma Ray ImagegAPI

Image Orientation,°R90

D180

L270

U360

80.0020.00

Resi

stiv

ity Q

ualit

y In

dica

tor

Spec

trosc

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Qual

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dica

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Sigm

a Qu

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ualit

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Indi

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Satu

ratio

n Qu

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Indi

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Perfo

rate

d In

terv

al

6.030284.125

Orientation,°L270

U R90

Borehole Shape 3D

6.030280

500

Ultrasonic Caliper Averagein

500Bit Size

in

500Invasion Diameter

in

Ultrasonic Caliper Average

in

Invasion

Mudcake/Enlargement

015Bit Size

in

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in

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Ultrasonic Caliper, Vertical Diameter

in

015

Ultrasonic Caliper, Horizontal Diameter

in

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Grain Sigma from Elemental Spectroscopy

cu

500Formation Sigma, Average

cu -1545Best Neutron Porosity, Average

pu

2.951.95

Grain Density from Elemental Spectroscopy

g/cm3

2.951.95Neutron Gamma Density, Average

g/cm3

Bound Water Saturation

Irreducible Water Saturation

Total Water Saturation

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Total Water Saturation

ft3/ft3

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Bound Water Saturation

ft3/ft3

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Irreducible Water Saturation

ft3/ft3

Effective Permeability to Hydrocarbon

Intrinsic Permeability

0.0110,000

Effective Permeability to Hydrocarbon

mD

0.0110,000Intrinsic Permeability

mD

6,0004,000

Downhole Annular Pressure

psi

155

Equivalent Circulating Density

lbm/galUS

500Shock Peak

gn

180140

Downhole Annular Temperature

deg/f

2500

Collar Rotational Speed

rpm

Dry Weight Fraction of Anhydrite

Dry Weight Fraction of Siderite

Dry Weight Fraction of Pyrite

Dry Weight Fraction of Carbonate

Dry Weight Fraction of Quartz, Feldspar, and Mica

Dry Weight Fraction of Clay

Dry Weight Fraction of Coal

10Dry Weight Proportions

Volume Fraction of Bound Water in Undisturbed Zone

Volume Fraction of Irreducible Waterin Undisturbed Zone

Volume Fraction of Water in Undisturbed Zone

10Volumetric Proportions

ft3/ft3

Volume Fraction of Hydrocarbon in Undisturbed Zone

Volume Fraction of Siderite

Volume Fraction of Pyrite

Volume Fraction of Carbonate

Volume Fraction of Quartz, Feldspar, Mica

Volume Fraction of Clay

Volume Fraction of Coal

127Bit Size

in

127

Mudcake/Enlargement

Cumulative Fractional Flow of Hydrocarbons

Cumulative Fractional Flow of Water

0.60Flow Pro�le

MD, ft

INTEGRATED SOURCELESS MEASUREMENT INTERPRETATION

SOURCELESS PNG-BASED SNGD, NEUTRON-POROSITY,

SPECTROSCOPY, AND SIGMA MEASUREMENTS

DRILLING ENVIRONMENT

MEASUREMENTSGAMMA RAY, ULTRASONIC CALIPER, AND

PROPAGATION RESISTIVITY MEASUREMENTS

NeoScope service is the industry’s first sourceless formation evaluation technology. It is also the shortest multifunction suite offering in a single 25-ft collar. Measurements include azimuthal natural gamma ray, array resistivity, dual ultrasonic calipers, SNGD, neutron porosity, spectroscopy, sigma, and a full drilling mechanics package.

The compact design minimizes the amount of rathole that must be drilled to obtain extensive formation evaluation measurements. Close-to-the-bit measurements reduce uncertainty in data interpretation.

NeoScope service has a large memory capacity that allows recording of two samples per foot at an ROP of up to 200 ft/h while providing accurate measurements.

A high effective data transmission rate provided by the TeleScope high-speed telemetry-while-drilling service and Orion II telemetry platform ensures that the full suite of NeoScope measurements is available in real time to improve decisions and mitigate risk.

The Techlog wellbore software platform provides 2D and 3D analysis of the extensive NeoScope data suite in real time, requiring only water salinity as an input. This Schlumberger software platform is part of the comprehensive suite of real-time answer products for petrophysical analysis.

NeoScope multifunction formation evaluation service is fully compatible with the ORION II telemetry platform and the IntelliServ® Broadband NetworkTM, bringing recorded-mode-quality measurements and additional QC channels for tool and measurement performance monitoring.

A Comprehensive Formation Evaluation SolutionThe Science of the Measurement

Pulsed neutron generator, an electronic switchable neutron source

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Multifunctional LWD service

Measurement Specifications

Hole size, in [mm] 8.5 to 9.0 [215 to 229] (with 8¼-in stabilizer)Neutron Porosity Range 1 to 100 pu Axial resolution 15 in (11 in with enhanced resolution processing) Accuracy† 0.5 pu below 10 pu, 5.0% from 10 to 50 pu Statistical precision† 0.9 pu at 30 puNeutron-Gamma Density Range 1.7 to 2.90 g/cm3

Axial resolution 35 in Accuracy†,‡,§,‡‡ 0.025 g/cm3 for clean sandstone, limestone, and dolomite 0.045 g/cm3 for shale Statistical precision†,‡ 0.018 g/cm3 at 2.4 g/cm3

Downhole Memory Capacity 1.6 gigabytes Recording time 545 operating h‡‡

Power supply Turbine via TeleScope MWD service Combinability Fully combinable with all Schlumberger toolsOthersGamma ray 0 to 1,000 gAPI; 12-in axial resolution, 16 sectors2-MHz phase shift resistivity 0.2 to 60 ohm.m at 2% accuracy; 60 to 3,000 ohm.m at 0.3 mS/m accuracy§§

400-kHz phase shift resistivity 0.1 to 10 ohm.m at 2% accuracy; 10 to 100 ohm.m at 2 mS/m accuracy§§

2-MHz attenuation resistivity 0.2 to 25 ohm.m at 3% accuracy; 25 to 50 ohm.m at 2 mSm accuracy§§

400-kHz attenuation resistivity 0.1 to 3 ohm.m at 3% accuracy; 3 to 10 ohm.m at 2 mS/m accuracy§§

Shocks 4 accelerometers; 2 kHz bandwidth†††

Continuous inclination 0 to 180°; 0.1° accuracy‡‡‡

Annular pressure 0 to 25,000 psi; 25 psi accuracy; 1 psi resolutionAnnular temperature –40 to 175 degC; 1 degC accuracy; 0.1 degC resolutionUltrasonic calipers 2 sensors 180° apart; 0.1-in resolution; 8 sectors; 3-in max. standoff§§§

Capture spectroscopy Si, Ca, Fe, S, Ti, Gd, H, Cl, K, Mg, and Ba yieldsSigma 5 to 100 cu; 15-in axial resolution; 1 cu precision and accuracy††††

Mechanical Specifications

Collar OD (API), in [mm] 6.90 [171.45]Min. ID, in [mm] 2.00 [50.8]Length, ft [m]†††† 26.4 [8.046]Weight, lbm [kg] 2,700 [1,225]Top thread connection, API 51⁄2 IF BoxJoint yield torque, ft.lbf 46,000Equivalent bending stiffness, ft [m] 24.5 [7.468]Max. operating temperature, degF [degC] 300 [150]‡‡‡‡

Max. flow range, galUS/min [L/min] 800 [3,028]Pressure drop constant (C)§§§§ 3,738Stabilizer Downhole distance, ft [m] 3.7 [1.13] Max. OD, in [mm] 8.25 [209.55] Total flow area (TFA)††††† 14%Max. dogleg severity Sliding, °/ft [°/m] 16/100 [16/30] Rotating, °/ft [°/m] 8/100 [8/30]Max. system shock level 30 min at shock level 3 (50-gn threshold) or accumulated 200,000 shocks above 50 gn

† At 200 ft/h ROP with three-level spatial average (or 27-s time average). ‡ Average uncompensated density for no standoff, circular borehole, and well deviation, allowing borehole contact. § Formation sigma below 40 cu. †† Defined accuracy not applicable for salt and anhydrite formations. ‡‡ At maximum recommended logging speed of 200 ft/h; providing two samples/ft and measurement accuracy in specification. Only recording when operating. §§ Measurement spacing of 16, 22, 28, 34, and 40 in.

††† Transverse, axial, and rotational shocks. ‡‡‡ Above 45° of inclination. §§§ With water-based mud of 10 lbm/galUS. †††† Including lower crossover. ‡‡‡‡ Available up to 175 degC upon request. §§§§ Pressure Drop = [(Mud Density) 0.75 x (Viscosity) 0.25 x (Flow) 1.75] / 3,738. ††††† TFA in in2 is more than 14% of annular flow section (equivalent drill collar).

A Schlumberger expert downloads data at surface. With a large memory capacity, NeoScope service records samples at high ROP while providing extensive, accurate measurements in real time. NeoScope data can also be streamed to remote locations for real-time 2D and 3D petrophysical analysis.

NeoScope

www.slb.com/NeoScopeNeoScope, TeleScope, Orion II, and Techlog are marks of Schlumberger.Other company, product, and service names are the properties of their respective owners.

Note: 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), NeoScope 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 NeoScope service that deliver game-changing LWD technology.

Copyright © 2012 Schlumberger. All rights reserved. 12-DR-0042

NeoScope

Animation: PNG-based measurementsWatch an animation that shows how NeoScope PNG-based technology provides a full suite of petrophysical measurements.

Case Studies: NeoScope service, the only sourceless petrophysical solution while drilling,

■ eliminated the need for chemical sources and saved rig time in two deepwater wells in Angola

■ acquired high-quality, real-time measurements for safer interpretation in a complex exploration well offshore Africa

■ saved 7 days of rig time while delivering detailed sourceless formation evaluation in western Egypt.

TeleScope High-speed telemetry- while-drilling service www.slb.com/TeleScope

Orion II Telemetry platform www.slb.com/Orion2

Techlog Petrophysical analysis software www.slb.com/Techlog

Find out more about NeoScope sourceless formation evaluation while drilling at www.slb.com/NeoScope