10,323
edits
Changes
Jump to navigation
Jump to search
Line 21:
Line 21: − +
no edit summary
[[File:M91Ch2FG5.JPG|thumb|300px|{{figure number|2}}Various types of drilling operations, offshore and onshore. Drill ship Jack Ryan courtesy of BP (www.bp.com). Jackup rig courtesy of Maersk Oil and Gas (www.media.maersk.com). Semisubmersible rig and land rig in the Sahara Desert, Libya, courtesy of Woodside Energy Ltd. (www.woodside.com.au).]]
[[File:M91Ch2FG5.JPG|thumb|300px|{{figure number|2}}Various types of drilling operations, offshore and onshore. Drill ship Jack Ryan courtesy of BP (www.bp.com). Jackup rig courtesy of Maersk Oil and Gas (www.media.maersk.com). Semisubmersible rig and land rig in the Sahara Desert, Libya, courtesy of Woodside Energy Ltd. (www.woodside.com.au).]]
The scale and cost of a drilling operation differs between wells onshore and those offshore. An onshore well is drilled with a relatively cheap land rig ([[:file:M91Ch2FG5.JPG|Figure 2]]); offshore, the operation is several times more expensive.
The scale and cost of a drilling operation differs between wells onshore and those offshore. An onshore well is drilled with a relatively cheap [[land rig]] ([[:file:M91Ch2FG5.JPG|Figure 2]]); offshore, the operation is several times more expensive.
In shallow water, typically about 6–45 m (20–150 ft) deep, drilling is conducted by a jackup rig. A jackup is a rig that has three or more legs that sit on the sea floor. In moderately deep water (more than 45 m [150 ft] deep), a floating or semisubmersible rig is used. The semisubmersible rig is kept in place by several anchors.<ref name=Reed_1992>Reed, B., 1992, [[Offshore rigs]], ''in'' D. Morton-Thompson and A. M. Woods, eds., Development geology reference manual: AAPG Methods in Exploration Series 10, p. 65-66.</ref>
In shallow water, typically about 6–45 m (20–150 ft) deep, drilling is conducted by a jackup rig. A jackup is a rig that has three or more legs that sit on the sea floor. In moderately deep water (more than 45 m [150 ft] deep), a floating or semisubmersible rig is used. The semisubmersible rig is kept in place by several anchors.<ref name=Reed_1992>Reed, B., 1992, [[Offshore rigs]], ''in'' D. Morton-Thompson and A. M. Woods, eds., Development geology reference manual: AAPG Methods in Exploration Series 10, p. 65-66.</ref>