Horizontal Well Drainholes
While several wells in Abu Dhabi have open drainholes, most drainholes are equipped with laterals; often 5.5 inch tubing that extend the length of the drainhole (~2200-4000 feet long either horizontal or at an incline).
Laterals are drilled so that the drainhole can be accurately logged with the correct logging suite. By identifying the producing sections behind the pipe and identifying the water bearing sections, as well as the impervious rock sections, it is possible to perforate the laterals to provide the maximum oil and gas production while minimizing the water production. Further refinement requires installing a slider which can seal off perforations if the water cut increases in a perforated region. The water cut can be significantly reduced by sealing off these water-bearing perforations. Control of drainhole laterals is especially important in reservoirs that create oil and water emulsions because this tends to cause oil losses and high processing costs downstream facilities. This is a significant area of technology since over 74,000 horizontal/lateral wells have been drilled and are in production.