Current through Register Vol. 35, No. 24, December 23, 2024
A. All wells drilled for the production of
geothermal resources, including low-temperature thermal wells, and all
specialty wells, including injection and disposal wells, shall be cased and
cemented in such manner as to protect surface waters, if any, useable ground
waters, geothermal resources, and life, health and property. Thermal gradient
wells shall be drilled, completed and plugged in such a manner as to protect
surface waters, in any, and useable ground waters. The division may require
casing and cementing as is deemed necessary for such wells.
B. All casing strings reaching the surface
shall provide adequate anchorage for blowout prevention equipment, hole
pressure control, and protection for all natural resources. Although
specifications for casing programs shall be determined on a well-to-well basis,
the following general casing requirements should be used as guidelines in
submitting form G-101, application for permit to drill, deepen, or plug
back-geothermal resources well.
(1) Conductor
Pipe: A minimum of 90 feet and a maximum of 200 feet. In special cases the
division may allow conductor pipe to be run and cemented at deeper depths.
Annular space is to be cemented solid to the surface. An annular
blowout-preventer or equivalent approved by the division shall be installed on
conductor pipe on exploratory wells and on development wells when deemed
necessary by the division. Note: For thermal gradient wells and low-temperature
thermal wells the conductor pipe requirement may be reduced or waived by the
division. The above conductor pipe requirements are not meant to be applicable
to the single or double joint of large diameter pipe often run to keep mud out
of the cellar.
(2) Surface Casing:
Except in the case of thermal gradient wells and low-temperature thermal wells,
the surface casing hole shall be logged with an electrical or radioactivity
log, or equivalent, before running casing. Note: This requirement may vary from
area to area, depending upon the amount of subsurface data available, and may
be waived under certain conditions. Requests for exceptions to the logging
requirement should be noted on form G-101 when applying for a drilling permit.
Surface casing shall provide for control of formation fluids, for protection of
useable ground water and for adequate anchorage for blowout-prevention
equipment. All surface casing shall be, if possible, cemented solid to the
surface.
(a) Length of Surface Casing:
(i) In areas where subsurface geological
conditions are variable or unknown, surface casing in general shall be set at a
depth equalling or exceeding 10 percent of the proposed total depth of the
well. A minimum of 200 feet and a maximum of 1,500 feet of surface casing shall
be set.
(ii) In areas of known high
formation pressure, surface casing shall be set at a depth determined by the
division after a careful study of geological conditions. The division will make
such a determination within 30 days. Drilling shall not commence until such
determination has been made.
(iii)
Within the confines of designated geothermal fields, the depth at which surface
casing shall be set shall be determined by the division on the basis of known
field conditions. Requirements (a)(1) and (a)(2) [now (i) and (ii) of
Subparagraph (a) and (b)of Paragraph (2) of Subsection B of
19.14.27.8 NMAC] above may be
waived for low-temperature thermal wells.
(b) Cementing Point for Surface Casing:
(i) In areas where subsurface geological
conditions are variable or unknown, surface casing shall be set in accordance
with (a) (1) [now (i) Subparagraph (a) of Paragraph (2) of Subsection B of
19.14.27.8 NMAC] above and through
a sufficient series of low permeability, competent lithologic units (such as
claystone or siltstone) to ensure a solid anchor for blowout-prevention
equipment and to protect useable ground water and surface water from
contamination. A second string of surface casing may be required if the first
string has not been cemented through a sufficient series of low permeability,
competent lithologic units and either a rapidly increasing thermal gradient or
rapidly increasing formation pressures are encounted.
(ii) In areas of known high formation
pressure, surface casing shall be set in accordance with (a) (2) [now (ii)
Subparagraph (a) of Paragraph (2) of Subsection B of
19.14.27.8 NMAC] above and through
a sufficient series of low permeability, competent lithologic units (such as
claystone, siltstone or basalt) to ensure a solid anchor for blowout-prevention
equipment and to protect useable ground water and surface water from
contamination. A second string of surface casing may be required, before
drilling into the known high pressure zone is permitted, if the first string of
surface casing has not been cemented through a sufficient series of
low-permeability, competent lithologic units.
(iii) Within the confines of designated
geothermal fields, cementing point shall be determined by the division on the
basis of known field conditions. Requirements (b)(1) and (b)(2) [now (i) and
(ii) of Subparagraph (b) of Paragraph (2) of Subsection B of
19.14.27.8 NMAC ] above may be
waived for low-temperature thermal wells.
(c) Return mud temperatures: Return mud
temperatures shall be entered into the log book after each joint of pipe has
been drilled down. See Rule G-106(b) [now Subsection B of
19.14.25.8 NMAC].
(d) Blowout-prevention equipment (BOPE): BOPE
capable of shutting in the well during any operation shall be installed on the
surface casing and maintained ready for use at all time (see Section H) [see
compiler's note].
(3)
Intermediate casing: Intermediate casing shall be required for protection
against anomalous pressure zones, caveins, washouts, abnormal temperature
zones, uncontrollable lost circulation zones or other drilling hazards.
Intermediate casing strings shall be, if possible, cemented solid to the
surface. This requirement (to circulate cement) may be waived if the production
casing will be cemented to the surface.
(4) Production casing: Production casing may
be set above or through the producing or injection zone and cemented above the
objective zones. Sufficient cement shall be used to exclude overlying formation
fluids from the zone, to segregate zones and to prevent movement of fluids
behind the casing into zones that contain useable ground water. Production
casing shall either be cemented solid to the surface or lapped into
intermediate casing, if run. If the production casing is lapped into an
intermediate string, the casing overlap shall be at least 50 feet, the lap
shall be cemented solid, and it shall be pressure tested to ensure its
integrity. In order to reduce casing corrosion, production casing used to
produce corrosive brine reservoirs shall be of the same nominal inside diameter
from the shoe of the casing to the ground surface.
(5) Casing and Cement Tests: All casing
strings shall be tested after cementing and before commencing any other
operations on the well. Form G-103 shall be filed for each casing string
reporting the grade and weight of pipe used. In the case of combination strings
utilizing pipe of varied grades or weights, the footage of each grade and
weight used shall be reported. The results of the casing test, including actual
pressure held on the pipe and the pressure drop observed, shall also be
reported on the form G-103. See Rule G-203C(2) [now Paragraph (2) of Subsection
C of 19.14.54.8 NMAC].
(a) Casing strings in wells drilled with
rotary tools shall be pressure-tested. Minimum casing test pressure shall be
approximately one-third of the manufacturer's rated internal yield pressure
except that the test pressure shall not be less than 600 pounds per square inch
and need not be greater than 1,500 pounds per square inch. In cases where
combination strings are involved, the above test pressures shall apply to the
lowest pressure-rated casing used. Test pressures shall be applied for a period
of 30 minutes. If a drop of more than ten percent of the test pressure should
occur, the casing or cement job shall be considered defective and corrective
measures shall be taken before commencing any further operations on the
well.
(b) Casing strings in wells
drilled with cable tools may be tested as outlined in Rule 5(a) [now
Subparagraph (a) of Paragraph (5) of Subsection B of
19.14.27.8 NMAC] above, or by
bailing the well dry, in which case the well must remain satisfactorily dry for
a period of at least one hour before commencing any further operations on the
well.
(6) Defective
casing or cementing: If the cementing of any casing appears to be defective, or
if the casing in any well appears to be defective or corroded or parted, or if
there appears to be any underground leakage for whatever other reason, which
may cause or permit underground waste, the operator shall proceed with
diligence to use the appropriate method or methods to eliminate such hazard. If
such hazard of waste cannot be eliminated, the well shall be plugged and
abandoned in accordance with a division approved plugging program.
(7) Logging: All wells, except thermal
gradient wells and low-temperature thermal wells, shall be logged with an
electrical or radioactivity log, or equivalent, from total depth to the surface
casing shoe. This requirement may be waived by the division depending upon
geological or engineering conditions.