Abstract
Traditional fracture-height and/or proppant-placement evaluation following a hydraulic fracture stimulation treatment has relied on the detection of radioactive (R/A) tracers pumped downhole with the proppant. While this technique has proven useful, it raises environmental, safety, and regulatory concerns and issues. In some areas of the world, transport and use of R/A tracers is prohibited.
The proppant placement determination method described in this paper eliminates the downhole placement of R/A materials. A high thermal neutron capture compound (HTNCC) is incorporated into a ceramic proppant during manufacturing in sufficiently low concentration that it does not affect proppant strength or conductivity. Proppant is then detected using standard compensated or pulsed neutron tools, with detection based on the high thermal neutron capture of the compound relative to the surrounding downhole constituents.
Two detection methods use a comparison of before-frac log-count rates and after-frac count rates, with reduced after-frac count rates observed in zones containing proppant. Another detection method, especially useful when formation gas saturations change, involves only the after-frac log.
This paper will describe the methodology and results of an application of the new detectable proppant in the T sand of the Villeta and Caballos formations of Juanambú field in the Putumayo basin of Colombia. The results obtained from this novel technology provided the operator an improved understanding of the geomechanical characteristics of the formations and the achieved fracture dimensions. Additionally, this information will help improve future stimulation treatments. This paper should be beneficial to all completion engineers looking for methods to determine fracture height and/or proppant placement in an environmentally acceptable manner.
