Blowout prevention equipment

The minimum requirements for well blowout prevention equipment for aerated mud drilling operations are basically the same as those for normal mud drilling operations. 

API Recommended Practice S3, Second Edition Recommended Practice for Blowout Prevention Equipment Systems for Drilling Wells, May 1984. 

Blowout control methods for offshore drilling are still basically the same as those used on land. However, in the event of the failure of blowout prevention equipment an oil pollution risk is introduced to a much wider area than would be the case on land. 

OSHA s proposed Confined Spaces in Construction rule (29 CFR 1926 Subpart AA) may impact construction of the ceiiar. Empioyees installing blowout prevention equipment in the cel-iar may need to be protected by the subpart when the rule becomes final. 

An important safety feature on every modern rig is the blowout preventer (BOP). As discussed earlier on, one of the purposes of the drilling mud is to provide a hydrostatic head of fluid to counterbalance the pore pressure of fluids in permeable formations. However, for a variety of reasons (see section 3.6 Drilling Problems ) the well may kick , i.e. formation fluids may enter the wellbore, upsetting the balance of the system, pushing mud out of the hole, and exposing the upper part of the hole and equipment to the higher pressures of the deep subsurface. If left uncontrolled, this can lead to a blowout, a situation where formation fluids flow to the surface in an uncontrolled manner. 

It generally is recommended, and often required, that gas dcicciiuii systems be installed in a fail-safe manner. That is, if power is disconnected or otherwise interrupted, alarm and/or process equipment shutdown (or other corrective action) should occur. All specific systems should be carefully reviewed, however, to ensure that non-anticipated equipment shutdowns would not result in a more hazardous condition tlian the lack of shutdown of the equipment. If a more hazardous situation would occur with shutdown, only a warning should be provided. As an example, a more hazardous situation might occur if blowout preventers were automatically actuated during drilling operations upon detection of low levels of gas concentrations than if drilling personnel were only warned. 

A formation fluid kick can be efficiently and safely controlled if the proper equipment is installed at the surface. One of several possible arrangements of pressure control equipment is shown in Figure 4-351. The blowout preventer (BOP) consists of a spherical preventer (Hydril), blind and pipe rams, and the drilling spool. 

Offshore, well control equipment and associated operations present some differences from that seen and used onshore. In some instances onshore equipment can be employed, but the offshore environment generally dictates a modification of equipment and procedures. There are several different well configurations used offshore, often on the same well at different drilling intervals, and each configuration has specific well control procedures that should be followed. A well may be equipped with a surface blowout preventer stack a subsea blowout preventer stack, riser and diverter system a riser and diverter system with no blowout preventer a diverter only or a riserless system with no well control equipment. 

API Bulletin D13, First Edition Installation and Use of Blowout-Preventer Stacks and Accessory Equipment, API, February 1966. 

Casing head or well head is a large metal flange welded or screwed onto the top of the conductor pipe (drive pipe) or the casing it is used to bolt surface equipment such as blowout preventers or Christmas tree assemblies. 

Well components, including blowout preventer stacks, are equipped with sensors... 

The conductor casing sticks up from the floor of the cellar and the blowout preventer, or whatever other equipment is needed, is installed on top of that casing. 

Oil and gas industries use many risk assessment tools beside the HAZOP. For example, failure modes and effects analysis (FMEA) is particularly common for evaluating how safety critical equipment can fail, such as a subsea blowout preventer used on drilling rigs. The bow tie model is another popular tool. 

Transocean was responsible for operation of the drilling rig and for the safety of operations, and to maintain well control equipment. Transocean purchased, maintained and operated a range of subsea equipment, including the blowout preventer (BOP) and associated control systems. 

The third major player in this drama was Cameron International, a major supplier of equipment for the oil and gas and process industries, who had designed and supplied the blowout preventer (BOP), which failed to operate in the accident. Cameron International is based in Houston, Texas, and has 20,000 employees and annual revenue of 8.5 billion (2012). 

The blowout preventer was critical equipment which was used to isolate the well and regulate the oil and gas pressure. As such it should have been redundantly designed. To be more precise, there should have been a redundant blowout preventer connected in series. This would have reduced the probability of oil and gas leakage to the rig surface. 

One of the most important pieces of safety equipment is the blowout preventor (BOP). The BOP is the equipment installed immediately above the casing/conductor to prevent the escape of pressvu e into the atmosphere. This pressure can be the result of a kick of water, gas, oil, or other formation fluid into the wellbore, which happens because formation pres-siares are higher than the pressure exerted by the column of drilling fluid. 

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