Acoustic, or sonic, tools provide a mea-surement of the formation integraltravel time (Δt) in a variety of envi-ronments. Acoustic logs recognize sec-ondary, or vugular, porosity in hard-rock sediments. Acoustic tools can berun in conjunction with density andcompensated neutron tools in badborehole conditions to measure poros-ity, and this third porosity is also usedto identify complex lithology. Certainsonic tools can measure shear Δt invery slow formations.

Digital Sonic Logging ToolThe Digital Sonic Logging Tool (DSLT)is made up with a Sonic LoggingSonde (SLS) and the Digital SonicLogging Cartridge (DSLC), whichuses the Digital Telemetry System, toprovide either compressional Δt mea-surements or Cement Bond Log(CBL) and Variable Density log (VDL)measurements and digital waveformrecording and display. The conven-tional sonic measurements are bore-hole-compensated (BHC) (3- to 5-ft[0.91- to 1.52-m]) transit time andlong-spacing depth-derived BHC(DDBHC) (8- to 12-ft [2.43- to 3.65-m])transit time. These measurements aremade by combining an HSLS-W orHSLS-Z sonde, respectively, with theDSLC. For high-pressure and high-temperature applications, the same mea-surements are available from theHostile Environment Sonic LoggingTool (HSLT).

Slim Array Sonic ToolThe SlimAccess toolstring addressesthe growth and challenges of slimholedrilling activity, especially reentry andcoiled tubing drilling. The monopoleSlim Array Sonic Tool (SSLT) deliversa robust formation slowness usingfirst-motion detection, borehole com-pensation, and slowness-time-coher-ence (STC) semblance techniques. A6-in. [15.24-cm] high-resolution mea-surement identifies thin-bed slowness.A tool extension provides a long-spac-ing sonic measurement in unconsoli-dated formations. Measurement ofCBL amplitudes and VDL waveforms issupported in cased wells. For high-pressure and high-temperature appli-cations, the same measurements areavailable from the SlimXtreme SonicLogging Tool (QSLT).

Applications� Formation porosity from compres-

sional slowness� Shear slowness from STC for hard

rocks� Formation mechanical properties

from shear slowness� Correlation to surface seismic data

with synthetic seismograms� Well placement with respect to cap

rock� Sonic waveforms for fracture iden-

tification� CBL and VDL for cased hole

cement evaluation

Acoustic Logging 85

Monopole Acoustic Tools

QSLT-A SLT-CDSLT

86 Wireline Services Catalog

Measurement Specifications

DSLT and HSLT with BHC or DDBHC Sonde SSLT and QSLT

Output All sondes: Compressional Δt Compressional and shear Δt, porosity, waveforms SLS-C, SLS-D, and SLS-E: and Variable Density waveforms3-ft [0.91-m] CBL, Variable Density waveforms

Logging speed 3,600 ft/hr [1,097 m/h] 3,600 ft/hr [1,097 m/h]Range of measurement 40 to 200 μs/ft [131 to 656 μs/m] 40 to 400 μs/ft [131 to 1,312 μs/m]Vertical resolution

Compressional Δt 2 ft [0.61 m] Standard: 2 ft [0.61 m]Short spacing: 6 in. [15.24 cm]

Shear Δt SLS-F 8 to 10 ft [2.43 to 3.05 m] or 10 to 12 ft 2 ft [0.61 m][3.05 to 3.66 m]: 2 ft [0.61 m]

Cement bond log Amplitude (mV): 3 ft [0.91 m] Amplitude (mV): 3 ft [0.91 m]Variable Density log: 5 ft [1.52 m] Variable Density log: 5 ft [1.52 m]

Accuracy Δt : ±2 μs/ft [±6.6 μs/m] Δt : ±2 μs/ft [±6.6 μs/m]Depth of investigation 3 in. [7.62 cm] 3 in. [7.62 cm]Mud type or weight limitations None NoneCombinability Combinable with most services Combinable with most servicesSpecial applications Run on wireline, drillpipe conveyed, or coiled tubing conveyed

Mechanical Specifications

DSLT HSLT SSLT QSLT

Temperature rating 302°F [150°C] 500°F [260°C] 302°F [150°C] 500°F [260°C]Pressure rating 20,000 psi [138 MPa] 25,000 psi [172 MPa] 14,000 psi [97 MPa] 30,000 psi [207 MPa]Borehole size—min. 45⁄8 in. [11.75 cm] 43⁄4 in. [12.07 cm] 31⁄2 in. [8.89 cm] 4 in. [10.16 cm]Borehole size—max. 18 in. [45.72 cm] 18 in. [45.72 cm] 8 in. [20.32 cm] 8 in. [20.32 cm]Outer diameter 35⁄8 in. [9.21 cm] 37⁄8 in. [9.84 cm] 21⁄2 in. [6.35 cm] 3 in. [7.62 cm]Length SLS-D: 18.73 ft [5.71 m] With HSLS-W sonde: 23.1 ft [7.04 m] 23 ft [7.01 m]

SLS-F: 23.81 ft [7.26 m] 25.5 ft [7.77 m] With inline centralizer: 29.9 ft [9.11 m]

Weight SLS-D: 273 lbm [124 kg] With HSLS-W sonde: 232 lbm [105 kg] 270 lbm [122 kg]SLS-F: 353 lbm [160 kg] 440 lbm [199 kg]

Tension 29,700 lbf [132,110 N] 29,700 lbf [132,110 N] 13,000 lbf [57,830 N] 13,000 lbf [57,830 N]Compression 1,650 lbf [7,340 N] With HSLS-W sonde: 4,400 lbf [19,570 N] 4,400 lbf [19,570 N]

2,870 lbf [12,770 N]With HSLS-Z sonde: 1,650 lbf [7,340 N]