Abstract
High water cut is often the main factor affecting economical production of an oil well. There are mainly three technologies for reducing water cut: mechanical shutoff in production well, chemical treatment of production well, and injection well profile control. This investigation focuses on low cost rigless methods, comparing their potential effectiveness and economics based on existing applications and computer simulation.
There are mainly two types of rigless methods for water-cut reduction. One is mechanical method when each zone is isolated with packer and choke-sleeve during completion so that choke can be changed for each zone, including shutting the zone off completely, with a slick-line unit. Another is chemical method which depends on injecting agents into production well where the agents selectively reduce high permeability zone permeability or reduce water relative permeability without much damage to oil permeability. Chemical methods may also be used in fractured carbonate reservoir, though it is more difficult to be successful.
Our investigation shows that under suitable conditions, rigless water-cut reduction methods can be cost effective. Computer simulation can be used as a tool to support the selection of a suitable method and help predict the effectiveness of the plan.
Since there are many marginal wells and many of them are limited by high water cut, increased application of cost effective water-cut reduction technologies will improve the economics of these wells and prolong their life, increasing oil production.
