Mr. Erik Milito - The House Committee on Natural Resources ...

ISOLATING POTENTIAL FLOW ZONES DURING WELL CONSTRUCTION 77
Critical Operational Parameters
<strong>The</strong>re are a number of operational parameters, prior to and during the cementing operation, which can affect the ability to
successfully isolate a potential flow zone.
Float Equipment
Cementing Heads
Contingency Plans
Running Casing
Well Control
Surface Systems
Annular Returns
Monitoring
Static Time
WOC
Barrier Removal
Risk Assessment
Are the float valves rated for the anticipated flow rates and volumes of the fluids pumped during circulation
and cementing of the casing string
Float valves shall be rated for the anticipated differential pressure between the minimum anticipated
hydrostatic column above the shoe track and the hydrostatic column in the casing annulus with cement in
place.
Have two independent float valves been installed in the shoe track
Cementing heads shall be pressure tested by the supplier to the maximum working pressure rating of the
head as part of a regular maintenance program.
<strong>The</strong> cementing head selected shall have a working pressure in excess of the maximum anticipated surface
pressure for the job.
As a minimum, are contingency plans in place for the following
— Lost circulation.
— Unplanned shut-down.
— Unplanned rate change.
— Float equipment does not hold differential pressure.
— Surface equipment issues.
Has the maximum casing running speed been determined to minimize swab and surge effects
Is the well stable (no volume gain or losses, drilling fluid density equal in vs out) before commencing
cementing operations
As a minimum, were the following surface systems checked for operability
— Cement mixing and pumping equipment.
— Additive proportioning equipment.
— Bulk delivery system.
— Plug launching systems.
— Treating iron.
— Mix water/drilling fluid deliverability.
— Monitoring and recording systems.
Is there a plan to monitor the annulus during cementing and WOC time
Has the time between drilling fluid circulation/conditioning and commencing cementing operations been
minimized
Has the appropriate WOC time been determined
<strong>The</strong> time from the start of removing the barrier element to securing the exposed annulus shall be
minimized.
If foamed cement is used, operators and all involved contractors shall perform a risk assessment prior to
utilizing foamed cement, and make sure that the results of this assessment are incorporated in the
cementing plan