«Paper #2-11 SUBSEA DRILLING, WELL OPERATIONS AND COMPLETIONS Prepared by the Offshore Operations Subgroup of the Operations & Environment Task Group ...»
Completion. Used alternately to describe (a) an individual well that is finished to the state of operationally producing hydrocarbons, and (b) the assembly of equipment that controls and connects individual producing wells into a system that directs the hydrocarbons to a processing or storage facility (“Subsea completion” refers to the latter infrastructurebased definition for offshore hydrocarbon production.) CWA. Clean Water Act. US federal legislation, dating from 1972, that prescribes the regulatory structure for protecting US water from pollution. Section 301(a) of the CWA, 33 USC 1311(a), renders it unlawful to discharge pollutants to waters of the United States in the absence of authorizing permits. The EPA is responsible for administration of the CWA.
EPA. US Environmental Protection Agency.
GoM. Gulf of Mexico.
HPHT. High-pressure, high-temperature. Used in reference to an environment where one or both of the following well conditions exist: (1) pressure rating greater than 15,000 psig or (2) temperature rating greater than 350 degrees Fahrenheit.
MMS. US Minerals Management Service (MMS). As of June 2010, it was replaced by the BOEM (BOEMRE).
MODU. Mobile drilling unit.
Packer. A piece of downhole equipment that functions to isolate one compartment in the wellbore from another. When actuated by the well operator, it functions by expanding a packing element outward against the walls of the larger wellbore, thereby leaving the smaller central tube as the only available exit for hydrocarbons.
Platform. An immobile offshore structure from which development wells are drilled and produced. Unlike a MODU, a platform is built for a fixed location.
PSIG. Pounds per square inch as read on a gauge that measures system pressure. If the gauge pressure represents conditions inside a device, then the total pressure is understood to be gauge pressure plus any external environmental pressure such as the surrounding air or water.
Rig. A structure, and all associated equipment, that is used to drill exploration or production wells. In contrast with an offshore platform, an offshore rig is mobile, meaning that it can be moved from one location to another.
Riser. A pipe that connects a subsea well to a drilling, production or processing structure at the surface.
SSSV. Sub-surface safety valve. Part of a subsea completion.
Tree. An assembly of pipes, connectors and valves that sits atop a completed well and connects the hydrocarbon production from the well to gathering or processing systems.
WBF. Water-based fluid. A variety of drilling fluid based on water as the carrier liquid.
B. Appendix 2: World population of oil and gas wells by vertical depth and lateral length
Depth characteristics of world oil and gas wells as measured by total vertical depth (TVD;
vertical axis) and horizontal reach of non-vertical sections (horizontal axis). The colorized bands comprise different categories of extended-reach drilling (ERD) which include both very deep (high TVD) and very long horizontal reach. Directional (non-vertical) drilling to accomplish very long horizontal-reach distances has become the distinguishing attribute of ERD wells (Gheslin, 2009). Red lines show projected future ultra-extended-reach drilling (uERD) wellbores that will become enabled by ultra-high strength steel which is needed for endurance against the pressure, temperature and mechanical stress of the ultra-ERD. Source: Jellison et al.