Technology Update: Real-Time Fluid Tracking Optimizes Treatment Design, Improves Strategy

Abstract

Collecting complete wellbore-temperature profiles during the placement of stimulation and diversion fluids has opened a new window to understanding and modifying matrix-stimulation, fracturing, and conformance treatments. Rapidly collected temperature profiles can identify precisely where fluids are entering the formation, allowing real-time optimization of the treatment through on-the-fly modification of the planned program. Such knowledge is necessary to improve stimulation-fluid placement across the entire treatment interval. The Halliburton StimWatch service identifies stimulation-fluid placement on the basis of changes in fluid properties that introduce variations in temperature gradients as the fluid moves inside the wellbore. This type of analysis provides a detailed understanding of the quality of treatment as applied to the designated intervals through a quantitative assessment of downhole flow rates. Monitoring Benefits Historically, it has been difficult to evaluate the placement of stimulation fluids during a multizone treatment in real time. As a result, the zonal volume of injected fluid is based completely on geological-data interpretation; prejob fluid-placement simulators provide only a theoretical prediction of the injection profile. Unknown and unpredictable downhole events occur during stimulation treatments and can have significant impact on treatment results. To achieve successful stimulation treatments, it is important to obtain the following information throughout the job:Injection profile—which zones are being treated effectively and which zones are not being treated.Effectiveness of a diversion process.Status of squeezed zones.Location of natural fractures. Service Description The StimWatch service follows the treatment as it progresses downhole, monitoring distributed temperature profiles obtained by use of the fiber-optic OptoLog Distributed Temperature Sensing (DTS) system. As changes in wellbore temperature are caused by the injection process, this information is converted into downhole injection profiles for a qualitative indicator of fluid distribution across the pay interval. This is performed without the need for shut-in periods or extensive preconditioning of the wellbore. The DTS fiber-optic-cable assembly can be deployed in a permanent or retrievable configuration. The assembly can be strapped to the completion casing or production tubing as a permanent installation. For retrievable scenarios in horizontal wells, coiled tubing can be used to position the assembly across the perforated interval.