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AAPG GEO 2010 Middle East
Geoscience Conference & Exhibition
Innovative Geoscience Solutions – Meeting Hydrocarbon Demand in Changing Times
March 7-10, 2010 – Manama, Bahrain

Memory Cross-Dipole Sonic Tool and Novel Deployment Techniques

Peter J. Williams1; Terry Mayor1; Dan Long2; David Eccles3

(1) Research and Development, Weatherford UK, Loughborough, United Kingdom.

(2) Subsurface Evaluation Services, Weatherford, Houston, TX.

(3) Subsurface Evaluation Services, Weatherford UK, Loughborough, United Kingdom.

Cross-dipole sonic data has broad applications in geophysical, petrophysical and geomechanical studies. The advent of the small-diameter memory cross-dipole tool improves operational efficiency in a broad range of well types. The tool combines monopole and cross-dipole acquisition capabilities. It extends the availability of high-quality cross-dipole data to slim and/or high dogleg wells, and reduces acquisition risk in high angle wells and wells drilled through formations prone to borehole bridging. In spite of the tool’s small size and weight, its novel design provides data quality that matches that of previous generation tools. It is deployed with or without a wireline, and is not constrained by wireline data transmission rates because data is recorded to internal memory. Deploying the tool inside drill pipe on the well shuttle facilitates access into highly deviated wells and past bad hole conditions. This versatility makes cross-dipole data available in a far wider range of wells than has previously been possible.

Operations have been conducted in diverse logging environments around the world, covering a range of borehole sizes and formation velocities. Comparisons with standard cross-dipole tools have demonstrated benefits in respect of well access. The data has been used in velocity calibration, amplitude variation with offset, shear seismic interpretation, anisotropy, Stoneley permeability, rock strength, and hydraulic fracture design.