A new IOR technology to homogenize horizontal well injectivity/productivity profile

Abstract

Non-uniform distribution of flow rate along horizontal wells results in early water/gas coning, early breakthrough of water/gas during flooding, etc. For injector wells, injection flow rate profile along the horizontal length leads to low sweep efficiency and to large oil-filled by-passed zones. In the current work, a variable distribution of flow open area along a horizontal well, with or without sand control, is proposed, to correct the flow rate profile along it. An uniform flow profile is achieved by means of unevenly spaced slots or perforations along the liner or sand control device. An analytical model was developed for flow inside and around the horizontal well with unevenly spaced slots or perforations along the liner or along the sand control device. The model couples flows in well and in the reservoir in well vicinity. The analytical model provides an explicit formula for slot/hole density along liners or screens in injection/production horizontal wells. Applications of the model to design horizontal well in cases of injection and production, with or without sand control, with inflow control device are discussed. The technology has been successfully applied in some oilfields onshore and offshore Brazil, where horizontal producer wells were equipped with specially perforated and slotted liners. The purpose is to homogenize flow along horizontal producer or injector wells, in order to delay gas and water coning and improve the sweep. The varying slot/perforation density is calculated by the analytical model, and the calculated option was implemented in some wells.