TECH TIDBITS is an e-newsletter prepared and distributed for the information and benefit of WEST Engineering Services clients. These articles are provided as samples of Lessons Learned from recent work experience. WEST routinely collects finding as rigs are inspected and applies these findings to other rigs and projects, to help our clients reduce their downtime and minimize safety and environmental events while avoiding the costly experiences suffered by others.

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	Volume 14, Zinc Bromide and Bonnet Seal Bonding.  A rig in the Gulf of Mexico experienced premature BOP seal failure after using zinc bromide completion fluid, despite having previous assurances from the OEM that the seals would hold up to the zinc bromide.  Additional testing revealed that the actual completion fluid used contained additional additives that, when all were blended together with the zinc bromide, dissolved the adhesive bonding the bonnet seals to the BOP metal.  The result was an expensive, unplanned stack pull.
	Volume 13, Control System Ball Valves Under Pressure, In several recent cases, control system check valves were found to be leaking pressure because of debris clogging the valves.  If this were to occur during drilling operations, it could result in an unplanned LMRP/BOP pull and significant downtime.
	Volume 12, Riser Connectors and Pilot-Operated Check Valves, A predictive unlatching pressure test on a pilot-operated check valve (POCV)-equipped riser connector that had been recently retrieved from the sea floor required a rather high 2,500 psi unlatching pressure. With the circuit configuration being used, the POCV would not allow the hydrostatic pressure to be released while retrieving the BOP stack to the surface. At the surface, the latch chamber had a combination of latch pressure and hydrostatic pressure that well exceeded the manufacturer's recommended maximum operating pressure. As a result, much higher than normal unlatching pressure was needed to unlatch the connector.
	Volume 11, Pardon Your Elbows, Erosion of pipe can be a serious issue, especially during well control operations. Certain measures, like targeted connections (lead-filled targets, quiet zone targets and long-sweep ells), should be taken to prevent such erosion and the resulting premature failure in diverter and choke/kill lines. WEST frequently sees rigs with original work or modifications to the diverter and choke and kill lines that were done without considering erosion issues. This can lead to piping failure and potential loss of drilling time and money, not to mention the exposure to an environmental or safety incident.
	Volume 10, Controlling Fluids in the Control System , Control fluid cleanliness and condition is considered essential by all control system manufacturers, yet access to the control fluid tanks is uncontrolled on many rigs. Contaminated control fluid can cost big money to fix, especially with today’s sophisticated, deepwater drilling programs.
	Volume 9, Ultrasonic Wind Speed Sensors, Certain ultrasonic wind speed sensors recently installed as part of standard DP packages for newbuild, dynamically positioned, floater rigs have failed for short periods of time during storms.  This could potentially cause the rig to lose position.
	Volume 8, Failure of Subsea Hydraulic Conduit Hose, The LMRP was pulled after recognizing the subsea hydraulic rigid conduit hose was leaking. Like is often the case, numerous factors contributed to the failure, including people, process, and equipment issues.
	Volume 7, Land Rig Surveys Result in High Numbers of Findings with Potentially Serious Consequences , Typical land rig surveys result in the identification of numerous items with a high potential for downtime or critical safety issues. A brief list of the significant items is included along with other helpful recommendations.
	Volume 6, UPS Battery Capacity and Aging, The function of an Uninterrupted Power Supply, or UPS, is to provide a clean back-up power supply for essential and critical systems in the event of a power failure of the primary power source(s). Accordingly, irregularities with the UPS systems could result in system failures with devastating consequences. Minimum battery capacity is covered by regulatory bodies; however, frequency of battery replacement is not.
	Volume 5, PVC Piping and Electrostatic Discharge in Hazardous or Classified Areas , PVC is a common material on rigs; however, use of PVC in hazardous or classified areas can cause build up of static electricity resulting in explosions. WEST has found that many rigs have PVC piping in hazardous areas including drains, vents, waterlines, mud vacuum suctions, and chemical injection lines.
	Volume 4, Downtime Narrowly Averted with Faulty SCR Drilling DC Drive , A slight AC current in an SCR powering a DC motor caused unusual wear in the brushes nearly leading to motor failure. Diligent inspections by rig electricians and installation of alarms can alert crew to this unusual problem.
	Volume 3, Capacities cannot always be determined from a simple review of the equipment list of manufacturers and model numbers. A detailed look at systems can identify mismatched equipment and ensure you can conduct the program you've designed.
	Volume 2, Potential Electrical Protective Relay Problems, Certain serial numbers of the Multilin electrical protective device may require upgrading to prevent spurious trips.
	Volume 1, Introduction to Tech Tidbits, WEST-Hou, Inc. changes name to WEST Engineering Services to better reflect the nature and scope of our services greatly expanded beyond BOP expertise.