A novel method to evaluate performance of chemical particulates for fluid diversion during hydraulic fracturing treatment

Abstract

During hydraulic fracturing treatment, each wellbore section or interval does not receive equal treatment fluid because of non-uniformity in in-situ stresses. The application of chemical particulates for fluid diversion plays an important role in achieving a uniform distribution of treatment fluid in single or multistage hydraulic fracturing treatment. The diversion works on bridging and sealing mechanisms. The large particles are responsible to initiate a bridge and small particles help to seal the voids between large particles. This sealing mechanism is responsible for creating an impermeable diverter plug that can resist higher differential pressure across the diverter plug. The pressure withstanding capacity of diverter pack is the most important parameter to be evaluated in order to compare the performance of various diverter blends.The present novel method will help to design and evaluate the effectiveness of near-wellbore diversion stage during hydraulic fracturing treatment. The method utilizes a new empirical model to estimate pressure drop during fluid flow across binary diverter blend. This model is developed by correlating two dimensionless groups, Ergun friction factor, and Modified Ergun Reynolds number. It is able to predict the pressure drop within ±10 % of the experimentally measured values. It will also help to optimize the diverter blends having different particle sizes, and proportions. The diverter blend composed of 60 % of 7 mesh particles and 40 % of 60 mesh particles is recommended for near-wellbore diversion application because it exhibited the highest pressure drop amongst the several diverter blends. When this model is incorporated in the hydraulic fracturing treatment design simulator, it will be able to update the perforation pressure drop for designing a diverter stage. This will help to estimate the increase in treating pressure necessary for the unstimulated zone. Thus, the effectiveness of fluid diversion can be analyzed.