| (iv) The Commission may require a better quality of
cement mixture to be used in any well or any area if conditions indicate
that a better quality of cement is necessary to prevent pollution,
isolate productive zones, potential flow zones, or zones with corrosive
formation fluids or prevent a safety issue in the well.
(E) Compressive strength tests. Cement mixtures for
which published performance data are not available must be tested
by the operator or service company. Tests shall be made on representative
samples of the basic mixture of cement and additives used, using distilled
water or potable tap water for preparing the slurry. The tests must
be conducted using the equipment and procedures in, or equipment and
procedures equivalent to those in, API RP 10B-2, Recommended Practice
for Testing Well Cements. Test data showing competency of a proposed
cement mixture to meet the above requirements must be furnished to
the Commission prior to the cementing operation. To determine that
the minimum compressive strength has been obtained, operators shall
use the typical performance data for the particular cement used in
the well (containing all the additives, including any accelerators
used in the slurry) at the following temperatures and at atmospheric
pressure.
(i) For the cement in the zone of critical cement,
the test temperature shall be within 10 degrees Fahrenheit of the
formation equilibrium temperature at the top of the zone of critical
cement.
(ii) For the filler cement, the test temperature shall
be the temperature found 100 feet below the ground surface level,
or 60 degrees Fahrenheit, whichever is greater.
(F) Cementing report. Within 30 days of completion
of the well, or within 90 days of cessation of drilling operations,
whichever is earlier, a cementing report must be filed with the Commission
furnishing complete data concerning the cementing of surface casing
in the well as specified on a form furnished by the Commission. The
operator of the well or the operator's duly authorized agent having
personal knowledge of the facts, and representatives of the cementing
company performing the cementing job, must sign the form attesting
to compliance with the cementing requirements of the Commission.
(G) Centralizers. Surface casing shall be centralized
at the shoe, above and below a stage collar or diverting tool, if
run, and through usable-quality water zones. In nondeviated holes,
pipe centralization as follows is required: a centralizer shall be
placed every fourth joint from the cement shoe to the ground surface
or to the bottom of the cellar. All centralizers shall meet specifications
in, or equivalent to, API spec 10D Specifications for Bow-Spring Casing
Centralizers; API Spec 10 TR4, Technical Report on Considerations
Regarding Selection of Centralizers for Primary Cementing Operations;
and API RP 10D-2, Recommended Practice for Centralizer Placement and
Stop Collar Testing.
(H) Alternative surface casing programs.
(i) An alternative method of fresh water protection
may be approved upon written application to the appropriate district
director. The operator shall state the reason for the alternative
fresh water protection method and outline the alternate program for
casing and cementing through the protection depth for strata containing
usable-quality water. Alternative programs for setting more than specified
amounts of surface casing for well control purposes may be requested
on a field or area basis. Alternative programs for setting less than
specified amounts of surface casing will be considered on an individual
well basis only. The district director may approve, modify, or reject
the proposed program. The district director shall deny the request
if the operator has not demonstrated that the alternative casing plan
will achieve the intent of this rule as described in subsection (a)(1)
of this section. If the proposal is modified or rejected, the operator
may request a review by the deputy director of field operations. If
the proposal is not approved administratively, the operator may request
a public hearing. An operator shall obtain approval of any alternative
program before commencing operations.
(ii) Any alternate casing program shall require the
first string of casing set through the protection depth to be cemented
in a manner that will effectively prevent the migration of any fluid
to or from any stratum exposed to the wellbore outside this string
of casing. The casing shall be cemented from the shoe to ground surface
in a single stage, if feasible, or by a multi-stage process with the
stage tool set at least 100 feet below the protection depth.
(iii) Any alternate casing program shall include pumping
sufficient cement to fill the annular space from the shoe or multi-stage
tool to the ground surface. If cement is not circulated to the ground
surface or the bottom of the cellar, the operator shall run a temperature
survey or cement bond log. The appropriate district office shall be
notified prior to running the required temperature survey or bond
log. After the top of cement outside the casing is determined, the
operator or the operator's representative shall contact the appropriate
district director and obtain approval for the procedures to be used
to perform any required additional cementing operations. Upon completion
of the well, a cementing report shall be filed with the Commission
on the prescribed form.
(iv) Before parallel (nonconcentric) strings of pipe
are cemented in a well, surface or intermediate casing must be set
and cemented through the protection depth.
(I) Mechanical integrity test of surface casing after
drillout.
(i) If the surface casing is exposed to more than 360
rotating hours after reaching total depth or the depth of the next
casing string, the operator shall verify the integrity of the surface
casing by using a casing evaluation tool or conducting a mechanical
integrity test or equivalent Commission-approved casing evaluation
method, unless otherwise approved by the district director.
(ii) If a mechanical integrity test is conducted, the
appropriate district office shall be notified at least eight hours
before the test is conducted to give the district office an opportunity
to witness the test. The operator shall use a chart of acceptable
range (20% - 80% of full scale) or an electronic equivalent approved
by the district director, and the surface casing shall be tested at
a pump pressure in pounds per square inch (psi) calculated by multiplying
the length of the true vertical depth in feet of the casing string
by a factor of 0.5 psi per foot up to a maximum of 1,500 psi for a
minimum of 30 minutes. A pressure test demonstrating less than a 10%
pressure drop after 30 minutes constitutes confirmation of an acceptable
pressure test. The appropriate district office shall be notified within
24 hours after a failed test. Completion operations may not re-commence
until the district director approves a remediation plan and the operator
successfully implements the approved plan, and successfully re-tests
the surface casing.
(2) Intermediate casing requirements for land wells
and bay wells.
(A) Cementing method. Each intermediate string of casing
shall be cemented from the shoe to a point at least 600 feet (measured
depth) above the shoe. If any productive zone, potential flow zone,
or zone with corrosive formation fluids is open to the wellbore above
the casing shoe, the casing shall be cemented;
(i) if the top of cement is determined through calculation,
from the shoe up to a point at least 600 feet (measured depth) above
the top of the shallowest productive zone, potential flow zone, or
zone with corrosive formation fluids;
(ii) if the top of cement is determined through performance
of a temperature survey, from the shoe up to a point at least 250
feet (measured depth) above the top of the shallowest productive zone,
potential flow zone, or zone with corrosive formation fluids;
(iii) if the top of cement is determined through performance
of a cement evaluation log, from the shoe up to a point at least 100
feet (measured depth) above the top of the shallowest productive zone,
potential flow zone, or zone with corrosive formation fluid; or
(iv) to a point at least 200 feet (measured depth)
above the shoe of the next shallower casing string that was set and
cemented in the well (or to surface if the shoe is less than 200 feet
from the surface); or
(v) as otherwise approved by the district director.
(B) Top of cement. The calculated or measured top of
cement shall be indicated on the appropriate completion form required
by §3.16 of this title (relating to Log and Completion or Plugging
Report).
(C) Alternate method. In the event the distance from
the casing shoe to the top of the shallowest productive zone, potential
flow zone, and/or zone with corrosive formation fluids make cementing,
as specified above, impossible or impractical, the multi-stage process
may be used to cement the casing in a manner that will effectively
isolate and seal the zones to prevent fluid migration to or from such
strata within the wellbore.
(3) Production casing requirements for land wells and
bay wells.
Cont'd... |
