Application of Fluorescent Markers to Determine the Formation Fluid Inflow After MFrac

The primary objective of the technical development and underlying principles described in this article is the creation of physicochemical principles, of which the practical implementation allows users to quickly and accurately conduct production logging of horizontal wells after conducting multi-stage hydraulic fracturing. The main physical phenomenon applied in the described method is the fluorescence of polymer microspheres – marker-reporters ranging in size from several hundred nanometers to several microns and containing quantum dots. Marker-reporters pass from synthesis and injection of proppant/sand into the polymer shell at our company's production facilities to high-precision instrumental determination of their concentration in formation fluid samples using flow cytofluorometry method in the laboratory. This method includes the following stages: Synthesis of marker-reporters containing quantum dots Preparation of polymer-coated proppant / sand with markers Injection of the marked polymer-coated proppant / sand into the well during MFrac, followed by formation fluid filtration through it Formation fluid sampling Sample preparation for obtaining samples to be analyzed with the flow cytometer Determination of marker-reporter concentrations in the samples by flow cytofluorometry data processing, also with our corporate software based on machine- learning principles All the stages mentioned above are constantly being improved and optimized. The description of each stage of the relevant technological process is described below with a "historical reference" to the technological development behind it. The characteristics of the marked polymer-coated proppant Geosplit are also provided herein.