The Release Kinetics of Long-Lasting Tracer Particles in Horizontal Wells

Abstract

In the context of China's ongoing development of unconventional oil and gas reservoirs, horizontal well segmental fracturing technology currently holds a dominant position. Accurate and effective monitoring of fracture parameters and production profiles is imperative for the efficient development of oil and gas resources. Tracer monitoring technology has emerged as a pivotal method for monitoring horizontal wells fractured in tight oil segments. This technology involves the injection of slow-release tracer particles into the fractured fracture, followed by the continuous monitoring of the tracer concentration during the fracture return period and the subsequent production process. The primary advantages of this approach include the ability to characterize fracture parameters of fractured fractures in tight oil horizontal wells and to monitor production profiles during normal production. This method provides a novel approach for real-time and cost-effective monitoring of the production dynamics of horizontal wells. Consequently, this study utilizes independently prepared samples of slow-release tracer particles to conduct an in-depth study of their release kinetic modeling on the basis of microscopic imaging observation. Microscopic observation revealed the existence of micropores, channels, and other structures within the long-acting tracer particles, which contributed to the stable release of the tracer active ingredient. The release kinetic model of the slow-release tracer particles demonstrates its capacity to approximately explain the release process of the tracer particles. The model also reveals that factors such as the diffusion coefficient, the solubility of the tracer components, the radius of the initial tracer components, and the mass of the tracer components per unit volume promote the release process. Conversely, the concentration of the solution to which the tracer particles are exposed has an inhibitory effect on the release process. The findings of this study establish a theoretical framework for the subsequent implementation of slow-release tracer particles in horizontal well fracturing and their comprehensive interpretation.