Offshore drilling is a complex and multifaceted process essential for accessing oil and gas reserves beneath the seabed. Exploration drilling is the initial phase, crucial for identifying potential oil or gas reservoirs. It involves the deployment of mobile drilling units to conduct exploratory drilling on selected sites.
During exploratory drilling, wells are drilled targeting prospects identified through seismic surveys, typically taking 60 to 90 days each to complete. Geologists obtain cutting and core samples to analyze the geological formations and look for signs of petroleum, known as a “show.” If a show is detected, additional tests are conducted to assess the quality and quantity of the oil or gas present and hopefully identify a commercial petroleum discovery.
Once the estimated value of a petroleum discovery is established, the focus shifts to the development phase. Production wells are drilled to begin tapping the discovered resources. Offshore production platforms, built to withstand harsh marine conditions, are fixed directly to the seabed using metal and concrete foundations or tethering cables or subsea infrastructure linked to floating facilities at the surface. Directional drilling techniques allow wells to be drilled at angles to reach distant targets.
Drilling a well occurs in phases or hole sections, starting with the surface hole, followed by the installation of casing to prevent wellbore instability through leaks and caving. Specialized drill bits, rotated by a turntable or top drive on the rig drill floor, cut and grind through the rock, while drilling mud is continuously circulated to lubricate the bit, seal the uncased formation walls, and control pressure. Blowout preventors are installed on fixed rigs or platforms or on the seabed for floating rigs to manage high-pressure kicks and prevent loss of control of the well and potential environmental disasters.
Mobile drilling rigs come in various forms, each suited to different water depths and drilling conditions. Jack-up rigs have legs that are lowered to stabilize the platform above the seabed while semi-submersible rigs operate in deeper waters with the aid of massive anchors or dynamic positioning. Drillships are also equipped with dynamic positioning systems allowing them to operate in very deep water and rough sea conditions. Offshore drilling represents a significant investment and requires meticulous planning, advanced technology and adherence to strict safety and environmental regulations. Mobile drilling rigs are the workhorses that get the wells drilled and accurately tracking their activity provides a key metric in measuring the health of the offshore E&P industry.
The Enverus offshore mobile rig tracker provides the most accurate weekly insight into the activity of the 800 mobile rigs making up the global drilling fleet. Up-to-date rig locations are supplemented with details on drilling contractor, current E&P operator and future contracts plus current activity linked to the Enverus well, block and field attributes.
