This paper overviews research efforts, to date, toward an expert system and well candidate selection program model, named Candidate Acquisition of Downhole Water Sink Potential or CadWasp. The final program will identify bypassed oil reserves that are accessible through re-entering inactive and orphaned wells with Downhole Water Sink (DWS) installations and prioritize these reserves according to their success potential. DWS uses two completions, one for the water column and one for the oil column to control water coning. The use of DWS technology is the primary target for this system, but the system is built to enable other types of well stimulations/enhancements to be able to target candidates as well.
CadWasp has been designed to identify "most likely to succeed" candidates, not all candidates by searching a massive database from large operational area containing incomplete data. It is presently coupled with the Louisiana Department of Natural Resources Strategic Online Natural Resources Information System (SONRIS) that provided sufficient information for the initial prioritization of candidates by regions, parishes, fields, reservoirs and wells.
CadWasp is written in Java in order to allow its running on a wide number of platforms. To avoid problems with installing and configuring a database management system (DBMS) such as Microsoft Access or mySQL, data is stored locally on the user's hard disk in specially formatted files for use in CadWasp. Most data is accessed via disk based B-Tree data structures, while others are in disk based linked list.
The objective is to identify bypassed reserves that are accessible through re-entering inactive and orphaned wells and prioritize these systems according to their productivity potential, quickly and efficiently. The designed program focuses on the use of Downhole Water Sink technology (DWS), but also may be used for other new technologies.
The DWS technology controls water production and, in some cases (drainage-injection method), may entirely eliminate surface water production.1,2 DWS wells are dual-completed - in the oil and water zones - so that the top completion produces oil and the bottom (water sink) completion is used for draining water. In principle, draining the water from the bottom completion would control water saturation around the well and prevent water invasion into the oil-producing top completion. The DWS technology has potential for producing oil from wells that have entirely watered out. It may also produce oil from thin oil pay zones underlain by a strong water column - unrecoverable by conventional wells.
The system is designed to identify active or marginal wells that may benefit through the use of DWS as a preventative measure rather than a resurrection measure. A candidate selection program model, named Candidate Acquisition of Downhole Water Sink Potential or CadWasp, for short, is being developed to accomplish this. Programmed in JAVA, CadWasp is designed to be flexible and portable for various database templates.
JAVA provided more ease of use, more versatility for changes and added subroutines and more ease of capability of merging with existing programs.
The initial source of data for the design of the screening program was the Louisiana Department of Natural Resources Strategic Online Natural Resources Information System (SONRIS).
