An Engineered Approach to Design Biodegradables Solid Particulate Diverters: Jamming and Plugging

Abstract

Fluids introduced into a reservoir for stimulation typically take the path of least resistance and therefore frequently go into areas where there are open flow paths. In many cases, those are neither the areas you would want to stimulate for increased production nor areas from which formation damage will need to be removed. The success of a hydraulic fracturing or an acidizing operation depends on maximizing the contact between the fracturing fluid (or acid) and intact rocks. To achieve this goal, existing fluid paths must be effectivelyplugged to divert the fluid towards intact rock for an efficient application.

A typical fluid diversion application can be divided into three major steps; i.e., displacement from surface to downhole, downhole plugging/diversion and corresponding stimulation and production efficiency.The aim of this paper is to review and identify the criticalparameters controlling the downhole plugging and diversion step. In addition, an analytical solution is used for predicting minimum required concentration of solid-particulate diverting agent. The proposed model incorporates multiple operational parameters such as flow rate, fluid viscosity, particle size, and opening size. The validity of the proposed solution is checked byusing experimental testswith single slot-opening. In addition, a coupled Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) model has also been used to verify the proposed analytical solution.The findings will have beneficial implications for acidizing, multistage hydraulic fracturing, and refracturing operations.

By using a scientific approach, better understanding of the controlling parameters along with the verified analytical solution,we can better design and achieve efficient fluid diversion and necessary pressure buildup.The analytical solution verified against both experimental data and advanced numerical simulations (CFD-DEM) can significantly and reliably enhance the diversion job efficiency. Using the analytical solution along with the thorough understanding of underlying mechanisms, we can optimize the particulate system characteristics for a successful diversion process. As an example and by selecting the minimum required concentration, we can eliminate the excessive use of diverting agents, which would reduce costs and adverse effects on equipment resulting from high concentrations.