Abstract
Conformance efforts in the Cooper Basin, Australia have been focused on treatments that have the potential to increase hydrocarbon rates. This paper describes the candidate selection process and field application of two different types of conformance treatments that were designed to increase hydrocarbon rates by reducing water rates. In all cases, production of reserves was thought to be impaired by excessive water production. In the cases where water production was decreased as a result of the conformance treatment, the wells produced at significantly higher hydrocarbon rates. Descriptions of both conformance systems (a minimally-penetrating porosity-fill sealant and a hydrophobically-modified relative permeability modifier, RPM) are provided.
The process of identifying wells that have a potential for increased oil-production rates if the water rates are reduced required modification of the traditional candidate-selection criteria. This ultimately changed how the water-production mechanisms were defined. For instance, when supported by production data, channeling was still considered as a plausible water-production mechanism even if the CBL appeared to show good cement bonding to the formation and casing. In addition, RPM technology was considered viable for upwards fining reservoir sections, even if water was coning up into the well. However, special conditions also needed to apply.
In this paper, the details of how treatment candidates were selected, treatment designs, placement techniques, and results are presented. The wells and reservoirs for each case are discussed, illustrating how water production compromised the oil or gas production. The way that these details and the conformance-fluids’ capabilities and characteristics were used to design the conformance treatments is also discussed.
