Dual or twin-well completion with wettability alteration for segregated oil and water production

摘要

A well completion and related method are provided for formations susceptible to simultaneous production of oil and water. In one embodiment, two closely spaced, preferably horizontal wellbores are drilled from a single well into the reservoir. The reservoir rock surrounding one leg (typically the upper leg) is chemically treated to make it hydrophobic, whereas the reservoir rock surrounding the other leg is chemically treated to make it hydrophilic. Separate production tubing and a dual completion is installed in order to enable independent flow from each leg. Drawdown pressures in both legs are controlled to be sufficiently close to each other such that only oil flows into one leg and only water into the other. The water produced is re-injected downhole or brought to the surface.