Issue link: https://digital.copcomm.com/i/147928
SCANNING C urrent CT scanning technology has allowed both the industrial and scientific communities to see things that a person cannot see otherwise. Visualizing within hidden places without cutting open an object and possibly destroying the important features inside is now possible. The scientists and engineers at ExxonMobil are using industrial CT scanning to look inside large rock samples, viewing patterns formed by acid injection. One objective of the experiments is to improve the extraction of oil and gas resulting from well stimulation treatments. During such treatments, high volumes of acid are injected into a carbonate formation at specific rates to generate 30-foot-long channels. The channels, also known as "wormholes," act as high-permeability conduits from the reservoir to the wellbore. Experiments are also being conducted to better understand acid fracturing, which is becoming increasingly important in field developments involving lower-quality rock, so that field operations can be executed more effectively and with minimal safety risks. By examining wormhole and fracture patterns that are expected to form in various oil- and gas-bearing rock types, drillers can optimize designs and procedures for specific rock types. ■ CGW Darren McDuff, now at Chevron, was a subsurface engineer in Exxon Mobil's Upstream Research Company in Houston, Texas. ■ DARREN MCDUFF stands next to one of the large limestone blocks that have been acidized and then CT-scanned as part of ExxonMobil's research program. Art Andersen is president of Virtual Surfaces, Inc., a 15-year-old company specializing in 3D scanning, reverse engineering, and digital inspection that caters to both the scientific and manufacturing disciplines. ■ PICTURED HERE is a CT-scanned image of wormhole structure formed by injecting acid through a drilled borehole into a large limestone block. CG W July / August 2013 ■ 59