Pulsar Multifunction spectroscopy service Introducing environment-independent, stand-alone cased hole formation evaluation and saturation monitoring 1 APPLICATIONS FEATURES AND BENEFITS ■ Stand-alone formation evaluation for diagnosis of bypassed ■ Environment-independent reservoir saturation monitoring ■ High-performance pulsed neutron generator (PNG) hydrocarbons, depleted reservoirs, and gas zones in any formation water salinity ● Optimized pulsing scheme with multiple square and short ● Differentiation of gas-filled porosity from very low porosity ● Production fluid profile determination for any well pulses for clean separation in measuring both inelastic and formations by using neutron porosity and fast neutron cross inclination: horizontal, deviated, and vertical capture gamma rays 8 section (FNXS) measurements ● Detection of water entry and flow behind casing ● High neutron output of 3.5 × 10 neutron/s for greater ■ measurement precision Petrophysical evaluation with greater accuracy by accounting ● Gravel-pack quality determination by using for grain density and mineral properties in neutron porosity elemental spectroscopy ■ State-of-the-art detectors ■ Total organic carbon (TOC) quantified as the difference ■ Metals for mining exploration ● Near and far detectors: cerium-doped lanthanum bromide between the measured total carbon and inorganic carbon ■ High-resolution determination of reservoir quality (RQ) (LaBr3:Ce) ■ Oil volume from TOC and completion quality (CQ) for formation evaluation ● Deep detector: yttrium aluminum perovskite (YAP) ■ Hydrocarbon identification in low-resistivity pay of unconventional reservoirs and complex lithologies ● Compact neutron monitor (CNM), photomultiplier, ■ on the basis of detailed quantitative mineralogy Identification of oil zones in freshwater and mixed- and counting electronics ● or unknown-salinity reservoirs Rigless service deployment ● Excellent spectral energy resolution at high operating ● Formation evaluation in old wells where modern openhole temperatures (175 degC [350 degF]) logs have not been run ● Highest count rate capability in the industry ■ High-fidelity mineralogy and lithology for geochemistry, ● Elimination of stabilization sources stratigraphy, and rock typing ● Calibrated measurement of elemental concentrations for Al, Ca, ■ Carbonates: Ca, Mg, Fe, Mn, and S to differentiate Fe, Gd, K, S, Si, Ti, Ba, Cl, H, Mg, Mn, Na, Br, O, and the metal and determine the volume of calcite, dolomite, anhydrite, Cu, with other elements on request and other carbonate minerals ■ In situ TOC measurement ■ Siliciclastic rocks: Si, Al, Fe, K, Ca, and Mg as the primary ■ Borehole fluid- and completion-compensated sigma and elements to resolve quartz, feldspar, mica, and clay minerals thermal neutron porosity (TPHI) measurements ■ More than 20 measured elemental concentrations routinely ■ Simultaneous acquisition of time and energy domain data available to identify specific minerals, with additional elemental standards available on request ■ Improved elemental precision delivering high-quality data even at faster logging speeds ● Element logs for well-to-well correlation and sequence stratigraphy ■ Extensive laboratory and modeling characterization to ensure accuracy in a wide range of environments ■ Fully combinable hardware with the PS Platform* production services platform, SCMT* slim cement mapping tool, ThruBit* through-the bit logging services, and wireline tractor conveyance ■ Corrosion-resistant housing qualified per the requirements of NACE MR0175 2 Formation Evaluation Pulsar* multifunction spectroscopy service introduces the industry’s first stand-alone cased hole formation evaluation and the new FNXS measurement for reliably differentiating gas-filled porosity from tight zones—all from a single tool. Challenge: Telling apart intermixed low-porosity Pulsar service also provides the new fast neutron cross gas-filled zones and tight zones in a shaly sand section (FNXS) measurement that reliably differentiates A US land well was drilled with an 8¾-in bit size but gas-filled porosity from liquid-filled zones and tight formations. Case Study completed with 4½-in 11.6-lbm/ft casing. As a result Because the fast neutron inelastic scattering response used of the difference between the hole and casing diameters, to calculate FNXS is not dominated by particular elements, the completion has a relatively large cement volume, with which is the case for conventional neutron logging, the FNXS Differentiating Gas and a cement thickness greater than 2 in. The formation lithology measured values for rock matrix and water are in the same Tight Zones in a Shaly Sand is shaly sand, with alternating low-porosity gas-filled zones and range. This makes FNXS insensitive to variation in liquid-filled very low porosity zones. Although openhole logs had been run, porosity but highly sensitive to variation in gas-filled porosity. Despite Cement Thickness the operator was interested in obtaining an interpretation that Results: Differentiating and quantifying gas-filled would provide greater insight to the formation and its porosity from tight zones Greater Than 2 in fluid contents. Logging the shaly sand with a single run of Pulsar service Solution: Introducing a new measurement to identify revealed two zones of interest at X,160 to X,180 ft and and quantify gas-filled porosity X,270 to X,330 ft. Both the environmentally corrected FNXS New Pulsar multifunction spectroscopy service uniquely curve and the gas ratio curve it is calculated from (Tracks 7 provides operators with a stand-alone petrophysical volumetric and 6, respectively) show that only the lower zone contains gas— interpretation incorporating robust, high-fidelity quantified unlike the very low porosity upper zone that conventional cased mineralogy and lithology for cased holes. No openhole logging hole logging would have assumed was also gas bearing. data is necessary for complete formation evaluation from The stand-alone volumetric interpretation performed using a single run of this one tool. In addition to obtaining highly a linear solver with Pulsar service’s sigma, FNXS, and TPHI accurate elemental concentrations—including total organic measurements (Tracks 10 and 11) is validated by the previously carbon (TOC)—Pulsar service acquires the traditional cased obtained openhole logs (Tracks 8 and 9). hole sigma, porosity, and carbon/oxygen ratio measurements With this one-run, one-tool solution to logging cased wells, but at a higher resolution and significantly faster logging speed. the operator can streamline operations to a single log obtained in the more stable cased wells. 3 9.5 9.5 9 9 Dolomite porosity, % Dolomite porosity, % 0 10 0 10 8.5 20 30 8.5 20 30 40 50 40 50 8 Limestone porosity, % 8 Limestone porosity, % 40 50 40 50 0 10 20 30 0 10 20 30 7.5 0 Sandstone porosity, % 50 7.5 0 Sandstone porosity, % 50 40 40 20 30 20 30 7 0 10 7 0 10 10 10 –1 0 –1 0 6.5 6.5 10 20 10 20 FNXS, m FNXS, m 6 6 20 30 20 30 5.5 5.5 30 40 30 40 5 5 40 40 50 50 4.5 4.5 50 50 Gas-filled porosity, % Gas-filled porosity, % 4 4 3.5 3.5 –0.1 –0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 –0.1 –0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 The large annular volume of light cement had to be accounted for in TPHI, ft3/ft3 TPHI, ft3/ft3 quantifying the gas-filled porosity. In the left-hand crossplot of Pulsar 10 Sigma 30 10 Sigma 30 service’s FNXS and thermal neutron porosity (TPHI) measurements, FNXS has the standard wellbore correction applied. However, the cement used in developing the characterization database was heavier, Eective Gas Saturation causing FNXS to clearly read too low compared with the expected Pulsar Fluid Density Pulsar Mineralogy Gas Gas Neutron-Density Water 0 g/cm3 3 4-ft Array Induction Crossover 0 V/V 1 value. An additional offset correction was applied for the effect of the Pulsar Borehole Sigma Openhole NPHI Near/Deep Capture Ratio Near/Deep Burst Count Ratio Resistivity AF90 Openhole Porosity (NPHI) Gas Depth, ft Gas Gas 0 cu 250 0.45 ft3/ft3 –0.15 3 23 9.5 30.5 0.02 ohm.m 2,000 0.45 ft3/ft3 –0.15 0.25 V/V 0 light cement, which adjusted the FNXS value close to the theoretical Pulsar Gamma Ray Pulsar Sigma Pulsar TPHI Near/Far Capture Ratio Near/Far Burst Count Ratio Gas Ratio FNXS 4-ft Array Induction Resistivity AF10 Bulk Density Bulk Density 3 3 –1 3 value for the very low porosity shaly zones. As shown in the right-hand 0 gAPI 150 0 cu 30 0.45 ft /ft –0.15 1 2.6 1.8 2.9 60 45 6 m 8 0.02 ohm.m 2,000 1.95 g/cm 2.95 0.25 V/V 0 Illite Bound Water Quartz Water Gas crossplot, the additional offset produced environmentally corrected FNXS values that are much more consistent with the sandstone envelope and thus are appropriate for use in a quantitative interpretation. X,200 Pulsar service’s FNXS measurement was environmentally corrected X,300 for the large volume of light cement in the annulus to differentiate the dry tight zone at X,160 to X,180 ft from the gas-filled porosity zone at X,270 to X,330 ft. A conventional cased hole pulsed neutron log, as approximated by the near/deep count ratio in Track 5, would read gas in the upper tight zone. 4 Reservoir Saturation Monitoring Pulsar service delivers environment-independent reservoir saturation monitoring in any formation water salinity and without requiring any openhole logging data input. Challenge: Difficulties monitoring in fresh response is not dominated by any elements, the FNXS formation water values for rock matrix and water are in the same range, An operator producing a California heavy oil reservoir by which focuses the measurement’s sensitivity on variation Case Study steamflooding wanted to periodically run cased hole logs in gas or steam content.