North Carolina Administrative Code › Title 15A - Environmental Quality › Chapter 05 - MINING - MINERAL RESOURCES › Subchapter H - OIL AND GAS CONSERVATION › Section .1600 - WELL CONSTRUCTION AND COMPLETION › Section 05H .1610 - WELL INSTALLATION FOR INTERMEDIATE CASING

Current through Register Vol. 39, No. 2, July 15, 2024
Intermediate casing shall isolate groundwaters that have
					 not been isolated by the surface casing and isolate flow zones, lost
					 circulation zones, or other geologic hazards in accordance with the
					 following:
(1) if used to isolate
				  groundwaters, the casing shall be set into competent bedrock to a depth of at
				  least 200 feet below the deepest groundwaters. The casing string shall be
				  cemented from the bottom to a minimum of 100 feet above the top of the
				  shallowest groundwaters;
(2) if
				  used to mitigate geologic hazards, such as heaving shale, abnormal pressure,
				  annular flow or other potential flow zones, the casing shall be set to a depth
				  appropriate to mitigate the hazard. The casing string shall be cemented from
				  across such hazards and from the bottom to 200 feet above the base of the
				  previous casing string;
(3) the
				  permittee shall collect correlation logs, core samples, and drill cutting
				  samples to identify groundwaters, zones of formational instability, and
				  competent bedrock to submit to the Department with the submission of Form 12 -
				  Well Drilling Report as required in Rule .1623 of this Section;
(4) if the intermediate wellbore penetrates
				  one or more potential flow zones, the cement used to control annular gas
				  migration from the potential flow zones shall be designed to comply with API
				  Standard 65-Part 2 "Isolating Potential Flow Zones During Well Construction,"
				  which is incorporated by reference, including subsequent amendments and
				  editions. This document may be viewed online for no charge at
http://publications.api.org/
;
(5) a cement bond log (CBL) for the
				  intermediate casing string shall be completed after cement has reached a
				  compressive strength of 500 psi to demonstrate the cementing operation was
				  completed in accordance with this Rule and to locate casing collars and
				  centralizers. Drilling shall not commence until the CBL is complete;
(6) if there is a failure to isolate
				  groundwater zones, the permittee shall submit a plan of remediation to the
				  Department for approval and implement such plan by performing remedial
				  operations prior to continuing drilling operations. If the deficiencies cannot
				  be remedied, the oil or gas well shall be plugged and abandoned in accordance
				  with Rule .1618 of this Section;
(7) a formation integrity test (FIT) shall be
				  completed after drilling out below the base of the intermediate casing, into at
				  least 20 feet, but not more than 50 feet of new formation. The FIT shall be
				  completed in accordance with API Standard 65-Part 2. If the formation fails the
				  FIT, the permittee shall consult with the Department to determine remedial or
				  corrective actions necessary before operations continue; and
(8) the permittee shall identify the top of
				  the cement and submit a plan of remediation to the Department for approval and
				  implementation if operational parameters, such as fluid returns, lift pressure,
				  and displacement indicate to the permittee inadequate coverage of any flow
				  zones, lost circulation zones, or any strata containing groundwater.
Authority
					 G.S.
					 113-391(a)(5)c;
Eff. March 17, 2015.