Abstract
Abstract
This study describes water conformance fundamentals and the uses of relative permeability modifiers (RPM) in stand-alone water control, chemical diverter during acid stimulation, fluid loss control pill (FLCP), and, conformance while fracturing (CWF) treatments. Local examples or references are included when possible. CWF operations, the focus of this study, are explained in more detail including the different approaches on how to pump the HRPM stage depending on the area to be treated. The CWF design process is described with recommendations on candidate selection, core flooding tests, and, reservoir simulation practices.
A total of 37 jobs have been executed from 2014 to 2022. Production results (fluid rate and water cut) for these wells are presented. The data is analyzed by HRPM volume, reservoir, and, water cut variation after CWF. Wells with reduction or slightly increasing water cut are related to volumetric reservoirs, layered formations, and, reservoirs with weak aquifers.
Wells with high water cut located near water intrusion, high water saturation, or active waterdrive, a significant water cut increase was observed despite the use of high HRPM volume. This variability in results demonstrates the need for extensive simulation and laboratory testing before implementation to improve repeatability and hence the chance of success of a CWF job.
All the cases presented uses the pre-pad technique in matrix regime for CWF. Other pumping approaches (Minifrac, Pre-pad, Pad in fracture regime, or HRPM pumped during the entire fracture treatment) cases are recommended for higher water cut cases.
Finally, a proposed treatment to stimulate oil zones that requires hydraulic fracturing with an underlying water zone is described. This technique consists of a double barrier to control water production. A rigid gel disk at or slightly above the water-oil contact (WOC) and an extended CWF treatment in the oil zone.