As conventional petroleum is approaching its maximum production and the world oil demand continues to grow, heavy oil becomes one of the obvious replacement resources. One of the most important problems in heavy oil recovery is dramatic loss of wells’ productivity at the onset of water inflow due to the two fluids’ mobility contrast. Not only the recovery at breakthrough time is very low, but also the water cut increase is extremely rapid.
The paper presents a worldwide survey of heavy oil reservoirs with water problems and their production methods including the in-situ water drainage with down-hole water sink (DWS) completion. It also investigates the mechanisms of productivity reduction and loss of recovery in wells producing heavy oil with bottom water drive.
In the study, the production system (nodal) analysis model simulates well's inflow performance relationship (IPR) with variable water cut. The results capture the difference between heavy and light oil in terms of mobility ratio effect, recovery dynamics prior to and after water breakthrough, and water cut control with production rate. The IPR performance of water drainage with DWS wells is also presented and discussed.