David Holcomb, Protechnics International & Roland Blauer, Resource Services International Inc.
Using spectral gamma ray imaging to identify issues of fracture stimulation placement has been well documented and enhanced by providing methods to interpret inside or near wellbore phenomena as well as fracturing phenomena occurring within 25 inches of the wellbore. Recent studies by Robinson and Voneiff have confirmed that in most vertical or near vertical wells, fracture heights determined by tracers are equivalent to or within ten percent of fracture heights predicted by 3D models or post-fracture treatment performance testing. " Furthermore, it has been determined that when tracers are proportioned properly throughout proppant slurries and carried as an integral part of non-washing, non-crushing, non-abrasion loss carriers, the counts as determined by spectral gamma ray imaging are directly related to fracture width.* This has successfully been corroborated by correlations made using long-spaced or dipole sonic logging and refined by an algorithm developed to quantify fracture width at the wellbore. Most recently a case study has shown that tracers may be used to confirm that fracture closure may not occur as quickly as is often calculated or assumed.