Section 1744.2 - Description of Casing StringsNames 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.
Cal. Code Regs. Tit. 14, § 1744.2
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). 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).