Annular preventer

Figure 4-501 shows a typical diverter system setup. The components of the system are the annular preventer, vent lines, the control system, and the conductor or structural casing. 

Gulf of Mexico, Matagorda Island, Block 669. Blowout, Explosion/Fire Annular preventer failed, closed pipe rams, casing pipe failed at 7,200 psi. 

Annular preventer failed, pipe rams closed, casing ruptured at 49,642 kPa (7,200 psi.) below the BOP. 

Annular preventer leaked, after well "kicked". 

Blowout preventers (BOPs) function is to cut off the flow of potential blowout. In all wells being drilled there are normally three holes or pipes within pipes that are at the surface of the wellhead -conductor pipe, casing pipe, and drill pipe. The drill pipe is the actual hole while the outer two are annulus formed around the inner pipe. Any one of these under varying conditions can be a source of through which oil or gas can escape during drilling. The annular preventer is a valve that appears... 

The bulkhead pan roof has open annular compartments at the periphery to prevent the roof from sinking should a leak develop. 

An effective way of preventing vent loss is to use one of the many types of variable-volume tanks. These are built under API Standard 650. They may have floating roofs of the double-deck or the singledeck type. There are hfter-roof types in which the roof either has a sldrt moving up and down in an annular hquid seal or is connected to the tank shell oy a flexible membrane. A fabric expansion chamber housed in a compartment on top of the tank roof also permits variation in volume. 

The rotary-hearth furnace consists of a heating chamber lined with refractory brick within which is an annular-shaped refractory-lined rotating hearth. Around the periphery of the rotating hearth, sand or circulating hquid seals are employed to prevent air infiltration. It can be made semicontinuous in operation. The hearth speed can be... 

Although plastic sheet and film may be produced using a slit die, by far the most common method nowadays is the film blowing process illustrated in Fig. 4.20. The molten plastic from the extruder passes through an annular die and emerges as a thin tube. A supply of air to the inside of the tube prevents it from collapsing and indeed may be used to inflate it to a larger diameter. 

HARD ROCE Removal of cuttings from hole. Maintain colloidal content high enough to provide gets and viscosities adequate to remove cuttings or prevent settling. Maintain sufficient annular velocity. 

Filter pack. Filter pack is the term used to describe the materials placed in the annular space between the screen and the formation (Figure 1). Aller et al. and Driscoll provide a discussion of the purpose and selection of filter pack materials. The filter pack serves a number of important mechanical functions. During well construction, it helps to keep the well screen centered in the borehole and acts to block the sealant from entering the well screen. The filter pack also improves hydraulic conductivity between the well screen and the formation, prevents formation materials from migrating to the well screen by acting as a filter, and helps support the screen and borehole. ... 

The detector itself may be shielded from background y-rays by means of an annular shield of W or Pb, and absorbers in the form of appropriate metal foils are placed between the detector and the specimen. These reduce the intensity of the continuum of Bremsstrahlung radiation and also prevent back-scattered protons from entering the detector which would degrade the observed spectrum. 

With these features in mind, we envisioned a new family of macrocyclic ligands for olefin polymerization catalysis (Fig. 9) [131, 132], We utilized macrocycles as the ligand framework and installed the catalytic metal center in the core of the macrocycles. Appropriate intra-annular binding sites are introduced into cyclophane framework that not only match the coordination geometry of a chosen metal but also provide the appropriate electronic donation to metal center. The cyclophane framework would provide a microenvironment to shield the catalytic center from all angles, but leaving two cis coordination sites open in the front one for monomer coordination and the other for the growing polymer chain. This could potentially protect the catalytic center and prevent it from decomposition or vulnerable side reactions. 

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