Abstract
Acoustic measurements have long been used to evaluate rock properties in the near-wellbore region and these methods are well documented. Comprehensive characterization of the wellbore rock relies on the knowledge of compressional and shear slowness in the axial, azimuthal, and radial directions. A recent evaluation in the Gulf of Thailand demonstrates that an understanding of the radial variations may prove extremely valuable in our understanding of completion effectiveness and may provide further insight into changes required in drilling practices or drilling fluid management. Acoustic variations in the near-wellbore region can arise as a result of nonuniform stress distributions, mechanical or chemical near-wellbore alteration from the drilling process, and formation intrinsic anisotropy related to in-situ properties of the formation. This document will explore results from acoustic measurements and interpretation of the near-wellbore resulting in operative information. Combined with measurements of formation properties this information can provide an accurate assessment of the drilling environment and the reservoir. This knowledge can lead to reduced overall drilling costs, improved recovery, and productivity.
