1 Research is under way to develop new technology for drilling in water depths greater than 3,000 meters (10,000 feet). 2 Multilateral well By drilling extensions off the main well, operators reach multiple oil-bearing rocks. Called multilateral drilling, this new technology lowers costs because it requires fewer wellheads, less casing and less drilling rig time. 3 Horizontal well In some reservoirs, wells can be drilled horizontally for hundreds of meters through the oil-bearing rock, making the well as much as 10 times more productive than a conventional well. 4 Conventional well Traditional vertical wells contact the rock bearing oil and gas only over the limited thickness of the reservoir in the immediate vicinity of the well. Flexibility of the fleet ExxonMobil's worldwide deepwater drilling program requires great flexibility in both the type of rigs we select and the terms of our drilling contracts. This flexibility lets us match a suitable rig to each new drilling program. With our current contract fleet, we can drill in almost any environment and in water depths approaching 3,000 meters (10,000 feet). Deepwater mooring technology Mooring lines are normally deployed from the drilling vessel, with help from an anchor boat that supports most of the weight. But in deep water, those lines can be 3.2 kilometers (2 miles) long and weigh more than 294 metric tons each. If the anchor boat deploys the line too quickly, it pulls the drilling vessel along with it. If the anchor boat goes too slowly, both vessels drift with the ocean currents. To overcome these problems, ExxonMobil engineers developed a proprietary computer program that determines precisely how much weight can be shared between the drilling vessel and the anchor boat as they set out each line.