With so many theories of what went wrong – and who was in charge – on Deepwater Horizon that fateful night of April 20, Energy Source has decided to enlist the help of ‘on the rig’ expert Mike Clarke, who started his career as a mud engineer on the Diamond M92 rig offshore Louisiana in 1969. After a long working life in the industry, including as a consultant, Mr Clarke is now retired.
Here is his take on how tricky it is to deal with ‘ice crystals’ – the basis of the newest theory, which could be a reason for both the rig blowing up in the first place and the cofferdam not working:
There has been some discussion about ‘ice crystals’ and those looking a little further might have heard mention of ‘hydrates’. When gas leaks out, its pressure drops and it cools, whereas pressurised oil flowing from a well is normally hot. In the presence of water, light hydrocarbon liquids can react with water to form a kind of jelly which is called hydrate. This happens quite often in gas pipelines, but the circumstances 5000 ft down on the sea bed where a mixture of oil and gas is leaking will make this very difficult to control.
Various chemicals can be used to break up hydrates, but normally we would be doing this inside a sealed system of pipes and tanks, where the dosing can be adjusted until we get the right result. The situation here is that it will be difficult to get a continuous flow of the right amount of the right chemical to the right place, and we can’t eliminate mixing of the gushing oil and gas with water until we get it under control, and at least to some degree isolated from the external environment.
Here is Mr Clarke on the relief effort:
There are also some critical comments I could make about the proposed solution involving the metal tank / funnel. Although I’m sure they are doing the best they can, as quick as they can. There needs to be a team working behind the existing team on a much more sophisticated version that is bigger, heavier, better made and more likely to work. It has to seal quite well with the sea bottom which will be very torn up and irregular, so I think it needs to be much bigger, like a bridge caisson.
And on who is in charge – in general- on a rig:
One of the things that jangled in the recent coverage of the blowout and its consequences was the assertion by Tony Hayward that Transocean was responsible for the blowout. In his words, it was their equipment that failed, and he implied that Transocean was operating independently and at arms length from the oil company by which it was contracted.
Every drilling rig has a ‘Company Man’ on board, who is responsible for the conduct of the drilling operations. The Wikipedia article gives an excellent description of how this works. The oil company is in full management control of the drilling operations at all times. The drilling contractor is required to obey the instructions of the representative of the oil company which hired the rig. Early each morning a report on the drilling operation is sent in to the oil company and management issues new instructions.
The ‘company man’:
The ‘Company Man’ is not the only employee of the oil company on board. Frequently, and especially in non routing drilling operations, there are specialists such as a petroleum engineer, a geologist, and frequently the mud engineer, who are employed or separately contracted by the oil company and report directly to the Company Man who has technical control of the drilling operation. Mud materials, cement, casing and other consumables or structures left permanently in place are owned and paid for by the operator, not the drilling contractor which installs them. The drilling contractor will often have little control over the quality of these materials which are ordered by the oil company and supplied through independent procurement operations.
The Blow Out Preventer (BOP) is not one of those items that is left permanently in place on the well. When the well is completed, a wellhead is installed. The BOP remains with the rig and is used elsewhere, next time it drills a well.
Drilling contractors do have failings, but they are responsible for maintaining the equipment in good operating condition. As a general rule the drilling contractor is responsible for the cost of wear and tear, while the oil company is often obligated to cover the cost if losses occur due to the conditions under which the drilling operation is carried out. That generally includes the cost of corrosion damage to the drill string and other equipment due to exposure to formation fluids.