WEST recently presented at the AADE conference. The abstract below summarizes the information. If you would like additional details, please contact us. To obtain a complete copy of any of these papers, visit the AADE Library.

AADE-05-NTCE-76 Hydrostatic and Water Hammer Effects on Subsea Control Systems

AADE-05-NTCE-38 Innovations in Rig Surveys Increase Reliability

Hydrostatic and Water Hammer Effects on Subsea Control Systems

The development of 5th generation offshore drilling rigs required increasing the supply pressure to subsea pods from the traditional 3,000 psi to 5,000 psi. This 2,000 psi pressure increase improved pressure as required, but also imparted greater stress factors to the components of the control systems and BOP stack. One example of the problems associated with these stress factors has been the failure of hoses and piping due to the effect of water hammer.

The problems associated with the 2,000 psi increase in supply pressure were compounded as drilling operations moved to increasingly deeper waters. One component of water hammer often overlooked by designers is negative pressure spikes, which in effect forces components to contend with a negative pressure. The effects of negative pressure spikes are more profound in deeper water depths, so some of these potential problems were obscured if the deepwater rig was restricted to operations in shallow water.

This paper will discuss some of the component failures associated with the increased supply pressure and water depth of subsea BOP control systems. Included in this discussion will be a review of laboratory testing of the components under conditions simulating the subsea environment, and suggestions for mitigation of the contributing adverse factors.

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Innovations in Rig Surveys Increase Reliability

The past 20 years have witnessed the increased use of third party surveys to assist operators and drilling contractors in reducing equipment related NPT (Non-Productive Time) that is so costly to both. Due to the increasing complexity and sophistication of both equipment and drilling programs, particularly in the offshore floater arena, it has been necessary for these surveys to become increasingly refined to continue the progress made in NPT reduction. Unfortunately, this growth has sometimes resulted in occasions of frustration and decreased manpower utilization for a variety of reasons.

This paper utilizes a case study approach to illustrate benefits realized from identifying potentially significant issues as a result of innovations in rig survey techniques and systems. These innovations span a wide range, from processes to staffing to technology application