**1. Introduction**

The challenge! How do you make this system?

It can be seen from **Figures 1** and **2** that there are a number of significant differences. Perhaps, the most noticeable difference is that the multiplexing BOP control system depicted, in the previous figure, features dual redundancy hydraulic supplies and command paths (blue/ yellow BOP control pods). These are not evident in the direct hydraulic BOP control system shown in **Figure 1** [1–3].

Both command and hydraulic pathways are extended very considerably in the subsea multiplexing version over the direct hydraulic surface BOP control system. Whether it has been considered by the reader at the point of reading the introduction, another very major and significant system design characteristic that is evident is the Class Society rules governing maximum closing times for BOP wellbore functions that represent the underlying design rationale in the development of the control system suited for the use in deep and ultra-deep water locations.

**2. Conceptualizing the initial problems**

**Figure 2.** BOP multiplexing control system.

So, the starting baseline design is a system that is illustrated in **Figure 1**.

Essentially, this system is still in use today on land rigs, jack-ups, and tenders. Certainly, there are a number of design refinements on the basic system but the functionality and practical

Making the Connection for Well Control on Floaters: Evolving Design Rationales for BOP Control…

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At this point, it should also be made clear that the core system requirements for the first landbased control systems and those encountered on sixth-/seventh-/eighth-generation ultra-deep

To exercise efficient and reliable control over the blowout preventer stack in the event of a well influx when the primary well control barrier of the hydrostatic column of drilling fluids in the well has not contained the well influx in the hole. Hence, we can say here that primary

Put another way, we can state that the blowout preventer is the very last mechanical barrier between the well and us and is known as "secondary well control." All exploratory, appraisal,

and development well barriers contain a secondary well control boundary.

**2.1. Introduction**

operability remain.

water rigs are identical.

well control has been lost.

The BOP control system's main purpose is:

**Figure 1.** The fundamental BOP control system for a surface BOP stack.

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**Figure 2.** BOP multiplexing control system.
