Determining Propped Fracture Width From a New Tracer Technology
Society of Petroleum Engineers, SPE 119545, 2009
An accurate determination of propped fracture geometry will help optimize the benefits derived from a hydraulic fracturing treatment. While advancements in determining propped fracture height have been made recently, there has been no new technology introduced addressing the other aspects of propped fracture geometry. A new tracer technology has been recently introduced and field tested. This technology incorporates a non-radioactive tag into the coating of a resin coated proppant. The tagged proppant is non-hazardous and environmentally safe. The tagged proppant is activated (after it has been placed in the fracture) by a logging tool that contains a neutron source. The activated tag emits gamma rays at a characteristic energy level that can be detected by the logging tool. Analysis of the data (from the logging run) not only identifies the location of the tagged proppant, but can also be used to develop other valuable information including propped fracture width in the near wellbore region. The resin coated proppant containing the tag is manufactured in such a manner as to assure that the concentration of the tag in the coating is held at a constant throughout the coating process. Since the level of gamma ray emission is a function of the amount of tag irradiated by the logging tool, the count rate detected by the tool is proportional to both the concentration of the tag and the concentration of the tagged proppant that has been irradiated. Based on these factors, analysis of the logging data not only yields the location of the tagged proppant, but leads to a more accurate calculation of the propped fracture width as compared to previous methods. This paper will detail the test procedures and resulting data that contributed to the development of this new method to calculate propped fracture width. This method of propped fracture width calculation will then be applied to a variety of actual field applications of the tag technology. The calculated propped fracture width results from the field tests will be presented and discussed in detail.