The 3-1/8in RBT evaluates cement bond integrity. A slotted sleeve technology provides superior isolation, rigidity and tool strength, while the 8-segmented piezoelectric crystal sensors detect the minutest of channels. The RBT also incorporates the traditional 3ft amplitude measurement and 5ft VDL.
The RBT measurement is based upon the principle of Sonic Wavetrain Attenuation. A traditional Cement Bond Log (CBL) measures the amplitude of a sonic signal passing along the casing; the signal is reduced where the casing is bonded to the cement. While cement bonds that are either complete, or totally absent, can be clearly identified, signals showing partial bonds can provide insufficient data to determine hydraulic isolation. The RBT overcomes this problem by using 8-receivers positioned around the circumference of the tool. Each receiver provides bond data covering a sector of the casing, generating a 'map' of the cement in addition to a conventional CBL.
The RBT is available either with Ultralink™ or MXII telemetry protocols. The UW RBT is Memory/SRO capable and combinable with any of the complete range of UW tools. The MXII RBT is compatible with both DAS and STIP surface panels, and its low frequency allows it to run easily on all types of wireline, including nickel (sour service) wirelines.
- Radial cement bond evaluation
- Single transmitter with 3 ft (near) and 5 ft (far) receivers
- 8-segmented radial receiver array for radial cement imaging
- Slotted sleeve design for improved rigidity, strength, and acoustic isolation
- Combines with other UW tools (for example, the casing inspection suite)
- Horizontal/deviated hole investigations (for example, combined with the UW inclinometer tool to determine high-side)
The complementary Multiplex II telemetry comprises a sequence of four acoustic analogue channels followed by a series of digital data packets. The RBT001 is compatible with both DAS and STIP surface panels.