Optimizing Completion and Re-Fracturing Opportunities via Diversion
Authors
Mohammed Omer (Weatherford International) | Oswaldo Perez (Weatherford International) | Fragachan E. Fragachan (Weatherford International)
Publisher
IPTC - International Petroleum Technology Conference
Publication Date
January 13, 2020
Source
International Petroleum Technology Conference, 13-15 January, Dhahran, Kingdom of Saudi Arabia
Paper ID
IPTC-19609-MS
Abstract
The main objective of diversion is to enhance contact of the stimulation fluid with the reservoir. If the diversion is designed by trial and error, without proper understanding of physics behind particle size distribution, and pumped downhole the uncertainty will be high and it will reduce the effectiveness of stimulating job.
Stimulating fluids pumped into a reservoir takes the least resistance path and goes into areas where often the stimulation is not required to increase production. The success of a hydraulic fracturing or acidizing treatment depends on maximizing the contact and distribution between the stimulation treatment and the reservoir. To achieve this goal, existing fluid paths must be efficiently temporarily blocked and divert the treatment fluid towards under-stimulated areas, which should maximize production.
The diversion is being widely used but it is not being focused on optimizing completion via an engineering approach. This paper will present a comprehensive discussion around missing factors associated with jamming and plugging efficiency, particle size, particle shape, frictional parameters, particle concentration, opening geometry, rate during placement, and particles size distribution and ratio. It will clearly highlight the importance of optimizing completion and re-fracturing opportunities via diversion.
Multiple experiments were conducted to quantify the effect of the different factors that dictate the overall goal of a successful diversion treatment. An analytical model based on computational fluid dynamics and discrete element modelling was developed, and calibrated with experimental results to optimize the different parameters that affect an optimum diversion. One of these key paramenters is the displacement rate during diverter injection, including determining the required spacers to minimize particle dispersion, ensuring the diverter pill arrives on formation intact and as designed to effectively create the temporary resistance required to effectively divert to under-stimulated areas.