Excessive water production can detrimentally affect the profitability of hydrocarbon producing wells and limit their economic life. Relative permeability modifiers (RPMs) were introduced to the oil and gas industry more than two decades ago as an option to selectively reduce water production. This type of treatment became appealing to operators because of its simplicity of deployment requiring no zonal isolation (i.e., bullhead-type treatments). However, RPM treatments have their limitations, and proper candidate selection is the key to a high success ratio. This paper discusses the application of a unique RPM system developed for water control.
This RPM system is based on a hydrophobically modified water soluble polymer (HRPM) that, once adsorbed to the surface of the rock, selectively reduces water effective permeability with little to no damage to oil or gas production. The hydrophobic modification to the base polymer chain adds unique associative properties to the system. In contrast to porosity fill-sealants (i.e., crosslinked polymer gels), HRPM treatments only provide a restriction to water flow. The following parameters are discussed: (1) HRPM performance testing, (2) candidate selection criteria, (3) design considerations and best practices for field implementation, and (4) case histories.
To date, more than 3000 treatments have been performed with this HRPM system. A wide variety of case histories are highlighted in this paper discussing different types of reservoirs, wellbore completions, and water production mechanisms, among others. In addition to water control, the application of this HRPM system has been extended to hydraulic fracturing, acid stimulation, and overbalanced workover interventions. Case histories are examined. Often, RPM treatments are applied in reservoir/wellbore conditions outside of their operating capabilities. One of the main objectives of this paper is to assist operators with the candidate selection process for this particular HRPM treatment.