Technology to the rescue: satellite wells and horizontal drilling extends the life of Alaska's oil fields.

• Author: Martin, Gary L.

The best direction to reach black gold is not always straight down. With the high cost of oil, petroleum companies are always looking for better ways to suck the last drop of crude from mother earth. Satellite fields are providing new opportunities to increase production while extending the lifespan of Alaska's oil fields.

Satellite fields are pockets of oil found in areas near larger oil fields, where the processing infrastructure of the major field is used by the satellites to separate gas, water and crude oil.

TECHNOLOGY

Relatively new drilling techniques are now being used to reach these satellite reserves; two of the most common technologies are horizontal and directional drilling. They give producers options when it comes to reaching difficult oil reserves. They also increase a well's productivity and lifespan, while reducing the environmental footprint of an oil and gas operation.

Directional drilling creates a network of separate, interconnected well holes to allow the effluence of other smaller reservoirs.

This is especially true when working with reservoirs having small or isolated buildups of crude located at different drilling depths. Offshore drilling is another environment in which directional drilling can successfully be employed. Multiple targets can be reached from the same offshore platform. ConocoPhillips, the state's largest oil producer, and its sidekick Anadarko Petroleum Corp., took the best lessons learned over 30 years of North Slope oil and improved upon them. Alpine was the first North Slope field developed using exclusively all horizontal-well technology.

THE RIG

Horizontal drilling rigs are essentially the same as the traditional rotary rigs. The primary differences are the rigs used for horizontal drilling are more powerful and can pull more weight. That is why they are more expensive. Time is also a consideration, according to Matt Fox, North Slope development manager for ConocoPhillips. He said: "It takes a bit longer for horizontal wells because you first drill down to the reservoir, which could be about 7,000 feet, then you go out horizontally for up to two miles. In conventional wells all you have to do is drill down to the reservoir."

Since both horizontal- and directional-drilling techniques frequently use existing vertical well shafts, more offshoot wells can be drilled without causing any new havoc to the environment. They also maximize recovery from existing reservoirs by entering a greater...