California Code of Regulations › Title 14 - Natural Resources › Division 2 - Department of Conservation › Chapter 4 - Development, Regulation, and Conservation of Oil and Gas Resources › Subchapter 1.1 - Offshore Well Regulations › Article 3 - Regulations › Section 1744.2 - Description of Casing Strings

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
Names of strings used by the Division are not always the
						same as those used by the federal government for wells drilled on the Outer
						Continental Shelf. Where there is a difference, the Division name is given
						first followed by the federal name shown in parentheses.
(a) Conductor casing (drive or structural).
					 This casing may be set by drilling, driving, or jetting to a depth of
					 approximately 100 feet to provide hole stability for initial drilling
					 operations. This casing may be omitted, when approved by the Division, if there
					 is geological evidence that hydrocarbons will not be encountered while drilling
					 the hole for the first surface casing and is not needed for hole
					 stability.
(b) First surface casing
					 (conductor). This casing shall be set at a minimum depth of 300 feet or a
					 maximum depth of 500 feet provided that this casing string shall be set before
					 drilling into shallow strata known to contain oil or gas or, if unknown, upon
					 encountering such strata.
(c)
					 Second surface casing (surface). This casing shall be set at a minimum depth of
					 1,000 feet or a maximum depth of 1,200 feet below the ocean floor, but may be
					 set as deep as 1,500 feet, in the event the surface casing is set at a depth at
					 least 450 feet.
(d) Intermediate
					 casing. This casing shall be set if the proposed total depth of the well is
					 more than 3,500 feet. When surface casing is set at deeper than 1,000 feet, the
					 proposed total depth of the well may be extended two (2) feet for each foot of
					 surface casing below 1,000 feet.
Proposed Total Depth of Well or
								Proposed Depth of First Full String of Protective Casing (TVD in Feet Below
								Ocean Floor)
Setting
								Depth for Intermediate Casing (TVD in Feet Below Ocean
								Floor)
Minimum
Maximum
3,500- 4,500
1,500
4,500
4,500- 6,000
1,750
4,500
6,000- 9,000
2,250
4,500
9,000-11,000
2,750
4,500
11,000-13,000
3,250
4,500
13,000-Below
3,500
4,500
(e) Protective casing. This casing shall be
					 set when required by well conditions, such as lost circulation or abnormal
					 pressures. When this string does not extend to the surface, the lap shall be
					 cemented and tested by a fluid entry test to determine whether a seal between
					 the protective string and next larger string has been achieved. The test shall
					 be witnessed and approved by a Division inspector and recorded on the driller's
					 log.
(f) Production casing. This
					 casing shall be cemented as noted in Section
					 1744.3 below and a test of water
					 shut-off made above the zones to be produced or injected into. The test shall
					 be witnessed and approved by a Division inspector before completing the well
					 for production or injection. In injection wells, the Supervisor may approve the
					 demonstration of the shut-off by running of a survey within 30 days after
					 injection commences. The survey must show that injection fluid is confined to
					 the approved injection interval.
When the production string does not extend to the
						surface, the lap between the production string and next larger casing string
						shall be cemented and tested as in the case of protective casing. The surface
						casing shall never be used as production casing unless all lower oil or gas
						zones are properly plugged.
1. Change
						without regulatory effect amending section filed 12-26-2006 pursuant to section
						100, title 1, California Code of
						Regulations (Register 2006, No. 52).