Accurate assessment of intervals receiving proppant and the determination of near well bore fracture heights are valuable in assessing and optimizing stimulation strategies. Proppant placement evaluation in hydraulic fractures has traditionally involved the detection of radioactive tracers pumped down hole with the proppant. However, as environmental regulations regarding this technique have tightened, and with increased scrutiny by the public and regulatory bodies of the industry in general and hydraulic fracturing in particular, the need for an alternative to radioactive tracers has become paramount.
A new technology for assessing intervals receiving proppant and determining fracture heights utilizing a non-radioactive detectable proppant has been recently introduced. The technology has found global acceptance and has proven to be a robust and accurate method of locating proppant in the near well bore region. In addition to eliminating the safety and environmental concerns with radioactive tracers, this new method also provides a permanent indication of the proppant location near the wellbore. Unlike traditional radioactive tracers which must be logged before the radioisotopes completely decay, this new method will allow investigation of the proppant pack many years or decades in the future, which will provide critical information during remedial or redevelopment work that cannot be determined with conventional approaches.
A review of the current state of regulatory impediments to the use of radioactive tracers in key producing regions around the world is discussed highlighting the need for an alternative diagnostic technology. The technology utilized in the application of the non-radioactive detectable proppant is described and comparisons to other fracture diagnostic technologies are presented. Several case histories are shown which illustrate various applications of the technology in regions around the globe. These case histories include applications performed in Asia, Middle East, Europe and North and South America. In addition to identifying proppant location and fracture height, this technology can be used in other applications such as the evaluation of gravel pack quality. If the current trends in regulatory actions related to hydraulic fracturing continue, it is anticipated that the use of radioactive tracers will be restricted to fewer and fewer locales. At the same time the importance of reliable fracture diagnostics for optimization of hydraulic fracturing both from a well performance and cost control standpoint remains extremely important.
Author(s): Robert J. Duenckel, Terry T. Palisch, CARBO Ceramics, Inc, Xiaoganag Han, Pedro Saldungaray
Paper Number: SPE 166251