Stephen E. Prensky¹

(1) Consultant, Silver Spring, MD

ABSTRACT: Recent Developments in Logging Technology

Recent advances and developments in wireline and LWD logging technology have been largely evolutionary, following the general outline previously presented (Prensky, 1994). Further improvements in digital electronics and communications technology have permitted improved tool accuracy and reliability, operation at higher temperatures and pressures, greater amounts of downhole processing, and new slimhole designs. With the exception of a few radically new tool designs (see below), recent advances in wireline largely consist of incremental improvements in, and additional designs by competitors to the electromagnetic (resistivity and NMR), nuclear, acoustic, and cased-hole designs (density and resistivity) discussed previously.

At the same time, a number of significant developments have taken place in LWD. A full suite of logging measurements, including acoustic shear slowness, seismic while drilling, NMR, and pulsed neutron, is now commercially available. The emphasis in LWD has been to provide not only additional new measurements but to deliver all of them in real time to facilitate timely decisions needed for safe drilling and accurate well placement (geosteering).

Recent advances include wireline and LWD acoustic dipole, cross, dipole and multipole devices for shear-wave acquisition in soft formations. Second generation pulse-echo NMR devices provide additional measurements, improved evaluation in light and heavy hydrocarbons as well as faster reconnaissance logging. A multi-electrode lateral device and through-casing resistivity device, discussed previously when in they were in the experimental stages, have recently been introduced as commerical designs. High-resolution azimuthal laterolog service and a multi-component induction tool for measuring resistivity anisotropy (Rv and Rh) are now available. In nuclear logging, several through-tubing pulsed-neutron designs now provide both capture and spectroscopy measurements.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado