HEF has interpreted hundreds of logging while drilling image logs (LWD) using gamma ray, density and resistivity images from all over the world. These images are used for a host of possible applications:
• Structural analysis
• Stratigraphic analysis, including distinguishing cross-bedding and brecciated bedding from impermeable layers
• In the case of resistivity images, interpreting the presence and type of natural and drilling-induced fracturing
We offer round the clock support to aid you in real-time decisions, as well as sensible review of memory-recorded images, backed by our extensive experience in working with these image tools.
Stratigraphic Penetration Rate and Direction for Horizontal Drilling
For geosteering applications, HEF produces a selection of very helpful plots that aim to show the stratigraphic position of the bit, as calculated from the bedding dip data and independent of other geosteering methods. This is expressed in two plots. One shows cumulative TST penetration, based on the assumptions that beds are upright, that those beds cut on the low-side of the hole are being cut down-section, and that those beds cut first on the high side of the hole indicate up-section penetration. This plot is invaluable, especially in challenging structures where small changes in borehole dip or in hole azimuth can have rapid effects on whether the bit is going up-section or down-section, and how fast. The other plot shows the gamma ray and bedding dips, rescaled in TST space. The advantage of this plot is it allows for comparison of the gamma rays between offset wells.
LWD resistivity image - This image is in a cross-bedded sandstone in a horizontal well. The cross-bed foresets are the low-angle partial sinusoids that are seen to terminate on a scour surface that runs the length of the example image. The hole is centered on the low-side of the borehole, and as is sometimes the case in horizontal LWD images, the high side is not imaged well. Click on image to enlarge
HEF’s experience and flexibility in helping resolve complex structures has proven to be invaluable and their around the clock availability has been a great advantage for our real-time interpretations of LWD images in the Canadian foothills.
Yvon Lemieux, M.Sc., Senior Geologist, Manitok Energy Inc.