A. Determination of equivalency standard. Improvements proposed over or within close proximity to abandoned wells, shall not be permitted unless the Oil Services Coordinator has determined that the well has been abandoned to the city’s equivalency standard.
1. Improvements are considered permanent structures or other construction that would be difficult or expensive to demolish should the abandoned or reabandoned well leak oil or gas in the future.
2. Pervious improvements, such as landscaping and parking areas with adequate landscape buffers, may be located on top of a previously
abandoned or reabandoned well which has passed the leak test pursuant to Section 16.24.020.
B. Equivalency standard. The following equivalency standard shall be required for construction of improvements over abandoned wells or within close proximity of abandoned wells pursuant to Section 16.24.050(B):
1. A cement plug located at the depth of the last zone produced from the well. All perforations shall be plugged with cement, and the plug shall extend at least 100 feet above the top of a landed liner, the uppermost perforations, the casing cementing point, the water shut-off holes, or the oil or gas zone, whichever is higher. If wellbore conditions prevent placement of the plug at the depth of the last zone produced from the well, approximately 100 feet of cement shall be placed inside and outside of the casing above (but as close as possible to) the last zone produced from the well.
2. A cement plug located at the depth of the base of the fresh water zone in the well. If there is cement behind the casing across the fresh-saltwater interface, a 100 foot cement plug shall be placed inside the casing across the interface. If the top of the cement behind the casing is below the top of the highest saltwater sands, squeeze-cementing shall be required through perforations to protect the freshwater deposits. In addition, a 100 foot cement plug shall be placed inside the casing across the fresh-saltwater interface. If wellbore conditions prevent placement of the plug at the depth of the base of the fresh water zone in the well, approximately 100 feet of cement shall be placed inside and outside of the casing above (but as close as possible to) the base of the fresh water zone in the well. This plug is to be separate and apart from the plug referenced in subparagraph 1 above.
3. A cement plug located at the surface. The hole and all annuli shall be plugged at the surface with a cement plug extending at least 25 feet from the top of the cut off well casing.
4. The intent of these plugs is to ensure that the abandonment is adequate to prevent hydrocarbons from reaching the surface. One continuous plug that significantly exceeds 100 feet located below the surface plug and located in close proximity to the base of the fresh water zone could be adequate to meet (1) and (2). Also, one plug that meets either (1) or (2) and a surface plug that significantly exceeds 100 feet could be found to prevent hydrocarbons from reaching the surface.
5. The city’s consulting petroleum engineer shall determine if these conditions have been met and the abandonment is adequate to prevent hydrocarbons from reaching the surface of the well. The determination shall be based on, at a minimum, a review of a history of all work performed on the well and a detailed wellbore diagram showing the current condition of the well. The well bore diagram shall include details on:
a. Hole size.
b. Casing and liner specifications and setting depths.
c. All cementing operations.
d. Depths of various hydrocarbon zones.
e. Any other data required to analyze the current conditions of the well including casing recovery operations and the presence of junk in the hole.
(Ord. 2015-05-1475 § 8)
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