Annulus pressurization

Sensors on the tree allow the control module to transmit data such as tubing head pressure, tubing head temperature, annulus pressure and production choke setting. Data from the downhole gauge is also received by the control module. With current subsea systems more and more data is being recorded and transmitted to the host facility. This allows operations staff to continuously monitor the performance of the subsea system. 

A gas inflow occurs suddenly when entering an abnormal pressure zone. Compute the flowrate of gas if the formation pressure is 7,000 psi, 1 ft has been penetrated in a 50-ft zone with 500 md, gas viscosity is 0.035 cp. Assume no annulus pressure drop, no cutting. Compute the annular temperature drop. 

Annulus pressure transducer (APT) just below flow line detects wave phase at end of round-trip. 

Record the stabilized pressure on drillpipe and annulus pressure gages. 

The fundamental principle of this method is equating the pit volume change with the corresponding change in annulus pressure. We write... 

The limitations of brick liners related to flue gas leakage will be discussed further in the chapter, in the section entitled "Annulus Pressurization."... 

Having keynoted the term "proper construction" as pertaining to brick liners, we must consider far more than the masonry itself. While it is not too difficult to specify materials or seismic design criteria for a given locale which should result in a safe structure, such things as bands, buckstays, breechings, annulus pressurization systems, and many other appurtenances can have a great effect on the service life of a liner. In this section, some of the major appurtenances shall be elaborated upon. 

Reversal and annulus pressure drop Riser height > 2.5 in. 

Annulus pressure drops carrying along the injection gas rate w,v and the oil production. Less gas being injected, the oil column gets heavier and P,i exceeds the upstream pressure. Gas injection in the tubing stops. 

Similar values were attained in a spouted bed of industrial scale. For example industrial-scale drying of 200 kg/h Z-type black dye resulted in 11.8 kg gas/kg water and 4600 kJ/kg water the diameter of the dryer was 1.6 m. The inlet temperature of 330°C in the spouted bed decreased to 100°C in the process of drying. The initial moisture coutent of the wet material was 5%. Gas velocity in the gas inlet nozzle was 30 and 0.75 m/s in the annulus. Pressure drop over the 400-mm bed at this velocity was 5 kPa... 

Abstract— A set of intervertebral pressure transducer (rVPT) and an intradiscal pressure transducer (IDPT) were developed to measure the pressures in the nucleus pulposus and around the annulus. Human lumbar spinal segments were loaded up to 2.0 kN and following parameters were recorded appUed compressive load as a function of time, intradiscal pressure as a function of time, intervertebral pressure as a function of time for anterior and lateral edges of the vertebra, strain as a function of time for anterior and lateral right and left sites of the vertebra, stress-relaxation of the complete segment as a function of time. All show very similar response to loading and stress-relaxation. However, annulus pressure did not respond to stress-relaxation. This was due to functional aspect of annulus. 

However, annulus pressure does not respond to stress-relaxation (Fig. 9). This is due to the functional aspect of the annulus, i.e. it distributes the pressures evenly in all directions when the non-degenerated nucleus of the intervertebral disc is loaded in compression. It is further observed that the annulus only responds to stress-relaxation in the direction in which bulging of the disc takes place. Annulus fibres also respond to stress-relaxation. 

It is concluded that 1) the response of the normal young lumbar spine to loading is time dependent. 2) the normal disc and the vertebral body show a significant amount of stress- relaxation. 3) the nucleus and the annulus pressures have a linear relationship with applied compressive load. Earlier it was postulated that pressure in nucleus is three times the annulus pressure [4]. However, these findings suggest that there is a one-to-one relationship between the annulus and the nucleus pressures. 

A. Control the injection rate. Maintain surface annulus pressure at or below 500 psi during treatment. 

Prepare well for injection down 2.875" tubing and hold annulus pressure during treatment. 

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