New Directions in Drilling Aid Environmental Conservation
Oil and gas wells traditionally have been drilled vertically, at depths ranging from a few thousand feet to as deep as 5 miles. Now new technology allows a drill to move laterally or horizontally under the Earth's surface, opening up a range of possible well configurations. That flexibility allows oil exploration operations to protect environmentally sensitive lands, such as wetlands or aquatic habitats, and recover the energy resources needed for our daily lives.
So-called "directional" and "horizontal" drilling techniques enable producers to reach reservoirs that are not located directly beneath the drilling rig. That means wells can be drilled to avoid sensitive surface and subsurface environmental features.
Advanced drilling technology is helping to recover valuable resources beneath Louisiana wetlands, California wildlife habitats and beaches, Rocky Mountain pine forests, and recreational areas on the Texas Gulf Coast.
Some offshore reservoirs, including many off the coast of California, can be tapped from onshore wells.
Horizontal drilling may also allow a producer to contact more of the oil or natural gas reservoir, so that more resources can be recovered from a single well.
Multiple offshoots from a single wellbore can radiate in different directions, or tap into reservoirs located at different depths.
Since the mid-1980s, the drilling of horizontal wells has grown from a few to more than 2,700 wells per year worldwide. In the United States, horizontal drilling now accounts for 5 to 8 percent of the terrestrial well count at any given time.
Additional advancements yield environmental benefits:
Slimhole drilling – a technique gaining widespread use for tapping into reserves in mature fields – significantly decreases waste volumes and takes up as much as 75 percent less surface area than traditional wells, since equipment for slimhole drilling is smaller. In addition, slimhole drilling results in less disruptive, quieter drilling operations that minimize the noise impact on wildlife or humans near the well site.
Coiled tubing technology – a cost-effective way to re-enter under-exploited well sites – has similarly impressive benefits, reducing drilling wastes, minimizing equipment footprints, and reducing operating noise.
New, modular drilling rigs – fabricated from lighter and stronger materials – can be deployed more easily in remote areas than conventional rigs. Built in pieces that can be transported individually and assembled on site. The lower weight of components and the rig itself reduces surface impacts during transport and use. The modular design also allows the rigs to be quickly disassembled and removed when drilling operations are completed.