ROV: Improving Remotely Operated(ROV) Intervention Capabilities for Blowout Preventer Override Systems
Authors: Davis John Edward 
Published: May 2011

Events during 2010 have focused attention on increased ROV/BOP Intervention capabilities and standardization of BOP/ROV interfaces in the oil and gas offshore industry. Currently no enforced set standards for ROV intervention panels or manifold types for use on BOP Override systems are specified. The industry offers multiple configurations at present. This abstract will discuss the advantages and disadvantages of the various configurations in existence, trending toward suggested industry standards taking shape as requirements in the near term.

Standards for the offshore industry or a set specification must be made to increase safety and functionality of BOP control systems. To date, ROV override capabilities have been added to existing engineered BOP systems. BOP designed closing times were not a critical consideration, only that the access was there to allow for ROV override.

Increased ROV flow and pressure capabilities: no current minimum flow requirements for Emergency BOP Override pumps are established. Based on stack valving and configuration, a minimum, 7 gpm may be required to shift valving fully to allow BOP operator function. IADC/API minimum requirements may be proposed at 10 gpm at 3000psi. Based on shear pressures exceeding 3000psi, pressures of 5000psi should be considered. Current intervention skids/pump capabilities will be required if ROVs must achieve API 16D BOP minimum closing times.

Remote or isolated accumulation for increased intervention capabilities offers possibilities when ANY ROV of opportunity can trigger a function (such as small inspection type ROVs). Increased volumes will be required. This is critical in functioning stack rams with an ROV of opportunity to achieve API 16D closing times.

We now understand that higher flows and pressures are required along with standardization of stab types. Current recommendations: API 17H Hi-Flow manifolds should be added to essential ROV overrides. ROV skids will have a minimum requirement of 10gpm at 3000psi, but should have capabilities to achieve 5000psi and carry enough fluid volume to perform subsea BOP ram function. Also, any additional isolated accumulator volume would be tied to ANY ROV of opportunity to override the BOP in an emergency situation.

Introduction

As a result of events in early 2010, a need for increased ROV/BOP Intervention capabilities and standardization of ROV/BOP interfaces in the oil and gas offshore industry was highlighted. Based on BOP manufacture or Drilling contractor, ROV intervention points (hotstabs/manifolds) and flow requirements can differ greatly.

ROV intervention points to this date consist of API 17D, API 17H or a custom variant of the two standards for ROV fluid intervention methods. For example, a BOP may have API 17D dual ports manifolds installed with each port operating a separate BOP function, or it may have both ports tied together feeding one function. That same manifold could also be plumbed to only one A or B port leaving the opposite port left open to sea or in the odd case, be bored through proving an increased flow path at the manifold. The same can be said for the API 17H configuration as well, each yielding multiple possibilities for the intervening ROV system to be configured incorrectly. (See Image 1)