Current through August 31, 2023
01.
General. Drillers
constructing low temperature geothermal resource wells (bottom hole temperature
more than eighty-five (85) degrees Fahrenheit and less than two hundred twelve
(212) degrees Fahrenheit) must be qualified under the Well Driller Licensing
Rules. All low temperature geothermal resource wells must be constructed in
such a manner that the resource will be protected from waste due to lost
artesian pressure and temperature. The owner or well driller is required to
provide bottom hole temperature data, but the Director may make the final
determination of bottom hole temperature, based upon information available to
him. (3-18-22)
a. All standards and guidelines
for construction and decommissioning (abandonment) of cold water wells apply to
low temperature geothermal resource wells except as modified by Rule
30, Subsections
030.03,
030.04, and
030.06. (3-18-22)
b. A drilling prospectus must be submitted to
and approved by the Director prior to the construction, modification, deepening
or decommissioning (abandonment) of any low temperature geothermal resource
well. The well owner and the well driller are responsible for the prospectus
and subsequent well construction. (3-18-22)
02.
Well Owner Bonding. The
owner of any low temperature geothermal resource well must file a surety bond
or cash bond as required by Section
42-233, Idaho Code, with the
Director in an amount not less than five thousand dollars ($5,000) nor more
than twenty thousand dollars ($20,000) payable to the Director prior to
constructing, modifying or deepening the well after July 1, 1987. The bond
amount will be determined by the Director within the following guidelines. The
bond will be kept in force for one (1) year following completion of the well or
until released in writing by the Director, whichever occurs first. (3-18-22)
a. Any well less than three-hundred (300)
feet deep with a bottom hole temperature of less than one hundred twenty (120)
degrees Fahrenheit and a shut-in pressure of less than ten (10) pounds per
square inch gage (psig) at land surface must maintain a bond of five thousand
dollars ($5,000). (3-18-22)
b. The
owner of any well three hundred (300) feet to one thousand (1,000) feet deep
with a bottom hole temperature of less than one hundred fifty (150) degrees
Fahrenheit and a shut-in pressure of less than fifty (50) psig at land surface
must maintain a bond of ten thousand dollars ($10,000). (3-18-22)
c. The owner of any low temperature
geothermal resource well not covered by Rule
30, Subsections
030.02.a. and 030.02.b. must
maintain a bond of twenty thousand dollars ($20,000). (3-18-22)
d. The Director may decrease or increase the
bonds required if it is shown to his satisfaction that well construction or
other conditions merit an increase or decrease. (3-18-22)
e. The bond requirements of Section
42-233, Idaho Code, are applicable
to wells authorized by water right permits or licenses having a priority date
earlier than July 1, 1987, if the well authorized by the permit or license was
not constructed prior to July 1, 1987 or if an existing well constructed within
the terms of the permit or license is modified, deepened or enlarged on or
after July 1, 1987. (3-18-22)
03.
Casing. Low temperature
geothermal resource wells must be properly cased and sealed to protect from
cooling by preventing intermingling with cold water aquifers. (3-18-22)
a. Steel casing which meets or exceeds the
minimum specifications for permanent steel casing of Rule
25, Subsection
025.04 must be installed in
every well. The Director may require a more rigid standard for collapse and
burst strength as depths or pressures may dictate. Every low temperature
geothermal resource well which flows at land surface must have a minimum of
forty (40) feet of conductor pipe set and cemented its entire length.
(3-18-22)
b. Casing must be
installed from twelve (12) inches above land surface into the overlying
confining strata of the thermal aquifer. The casing schedule may consist of
several different casing strings (i.e. conductor pipe, surface casing,
intermediate casing, production casing) which may all extend to land surface or
may be overlapped and sealed or packed to prevent fluid migration out of the
casing at any depth (Figure 13, Appendix A). (3-18-22)
i. Low temperature geothermal resource wells
less than one thousand (1,000) feet deep and which encounter a shut-in pressure
of less than fifty (50) psig at land surface must have two (2) strings of
casing set and cemented to land surface. Conductor pipe must be a minimum of
forty (40) feet in length or ten percent (10%) of the total depth of the well
whichever is greater. Surface casing must extend into the confining stratum
overlying the aquifer. (3-18-22)
ii. Low temperature geothermal resource wells
one thousand (1,000) feet or more in depth or which will likely encounter a
shut-in pressure of fifty (50) psig or more at land surface require prior
approval of the drilling plan by the Director and must have three strings of
casing cemented their total length to land surface. Conductor pipe must be a
minimum length of forty (40) feet. Surface casing must be a minimum of two
hundred (200) feet in length or ten percent (10%) of the total depth of the
well, whichever is greater. Intermediate casing must extend into the confining
stratum overlying the aquifer. (3-18-22)
c. Subsection
030.03.b. may be waived if it
can be demonstrated to the Director through the lithology, electrical logs,
geophysical logs, injectivity tests or other data that formations encountered
below the last casing string set, will neither accept nor yield fluids at
anticipated pressure to the borehole. (3-18-22)
d. A nominal borehole size of two (2) inches
in diameter larger than the Outside Diameter (O.D.) of the casing or casing
coupler (whichever is larger) must be drilled. All casing designations must be
by O.D. and wall thickness and must be shown to meet a given specification of
the American Petroleum Institute, the American Society for Testing and
Materials, the American Water Works Association or the American National
Standards Institute. The last string of casing set during drilling operations
must, at the Director's option, be flanged and capable of mounting a valve or
blow out prevention equipment to control flows at the surface before drilling
resumes. (3-18-22)
04.
Sealing of Casing. All casing must be sealed its entire length
with cement or a cement grout mixture unless waived by the Director. The seal
material must be placed from the bottom of the casing to land surface either
through the casing or tubing or by use of a tremie pipe. The cement or cement
grout must be undisturbed for a minimum of twenty-four (24) hours or as needed
to allow adequate curing. (3-18-22)
a. A
caliper log may be run for determining the volume of cement to be placed with
an additional twenty-five (25%) percent on site ready for mixing. If a caliper
log is not run, an additional one hundred (100%) percent of the calculated
volume of cement must be on site ready for placement. (3-18-22)
b. If there is no return of cement or cement
grout at the surface after circulating all of the cement mixture on site, the
Director will determine whether remedial work should be done to insure no
migration of fluids around the well bore. (3-18-22)
c. The use of additives such as bentonite,
accelerators, retarders, and lost circulation material must follow
manufacturer's specifications. (3-18-22)
05.
Blow Out Prevention
Equipment. The Director may require the installation of gate valves or
annular blow out prevention equipment to prevent the uncontrolled blow out of
drilling mud and geothermal fluid. (3-18-22)
06.
Repair of Wells. The well
driller must submit a drilling prospectus to the Director for review and
approval prior to the repair or modification of a low temperature geothermal
resource well. (3-18-22)
07.
Decommissioning (Abandoning) of Wells. Proper decommissioning
(abandonment) of any low temperature geothermal resource well requires the
following: (3-18-22)
a. All cement plugs must
be pumped into the hole through drill pipe or tubing. (3-18-22)
b. All open annuli must be completely filled
with cement. (3-18-22)
c. A cement
plug at least one hundred (100) feet in vertical depth must be placed
straddling (fifty (50) feet above and fifty (50) feet below) the zone where the
casing or well bore meets the upper boundary of each ground water aquifer.
(3-18-22)
d. A minimum of one
hundred (100) feet of cement must be placed straddling each drive shoe or guide
shoe on all casing including the bottom of the conductor pipe.
(3-18-22)
e. A surface plug of
either cement grout or concrete must be placed from at least fifty (50) feet
below the top of the casing to the top of the casing. (3-18-22)
f. A cement plug must extend at least fifty
(50) feet above and fifty (50) feet below the top of any liner installed in the
well. The Director may waive this rule upon a showing of good cause.
(3-18-22)
g. Other decommissioning
(abandonment) procedures may be approved by the Director if the owner or
operator can demonstrate that the low temperature geothermal resource, ground
waters, and other natural resources will be protected. (3-18-22)
h. Approval for decommissioning (abandonment)
of any low temperature geothermal well must be in writing by the Director prior
to the beginning of any decommissioning (abandonment) procedures.
(3-18-22)
