DARREN MCDUFF stands next to one of the large lime-stone blocks that have been acidized and then CT-scanned as part of ExxonMobil’s research program.
Current 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 Exxon Mobil 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.
Darren McDuff is a subsurface engineer in ExxonMobil’s Upstream Research Company in Houston, Texas.
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.