BOP rated working pressure

1 determining working pressure when there are several different views

(1) limit the wellhead strength is the internal pressure strength of casing, resistance to internal pressure strength so BOP working pressure greater than casing

It is not necessary.

(2) when the pressure in the well over the formation fracture pressure, the formation fracturing downhole blowout occurred, casing internal pressure strength and high

Also be of no avail, so that the work of the BOP pressure must not be larger than the limit set pressure.

(3) determining working pressure as possible blowout consequences.

When a shallow well, such as blowout, the mud in the well will be light spray, wellhead pressure formation pressure minus the gas column pressure,

This is the maximum wellhead pressure, BOP rated working pressure must be larger than this value.

(3-1 cases) to drill a well S km, is expected to 3 km formation pressure Ppe for 1, g/cm'for 30, should be much use

The working pressure of BOP. A gas density is 0 2.4g/cm4 o Pg

Solution: the gas column pressure = 9 8pgH=9. 8 X 0.24 X 3 two 7.1 MPa

Expect the formation pressure 9 8PpeH=9. 8X1.3X3=38. two, MPa 2

Wellhead pressure of two 38.2-7.1=31. 1 MPa

Should choose the rated working pressure of 35 MPa BOP.

When the well is deep, after the blowout, the mud in the well not all light spray. BOP rated working pressure is just equal to the total

A certain percentage of light spray head pressure can be. This percentage is called design coefficient, it is an experience of digital, according to the

The specific conditions of selected. Is actually according to well are part of the mud column count wellhead pressure.

A case of 3-2 to drill a 5 km deep wells, the formation pressure is expected Ppe is 1.9 g/cm', the design factor of 8000 is well

Is left with 20 barge mud, try to determine the BOP rated working pressure. Natural gas density according to the 0.24 Pg g/cm'.

Solution: it is expected that the formation pressure of two 9.8XPpcH=9.$X1.9X; 5=93. 1 MPa

Natural gas column pressure = 9 8pgH=9. 8 X 0.24 X 5=11.8 MPa

Wellhead pressure = 93.1-11. 8=81. 3 MPa,

BOP rated working pressure) 81 3X0. 8 ".1 MPa,

So a total of 70 MPa BOP.

(fishing that should be according to the worst case selection of BOP working pressure. This method is the most secure.

(5) domestic regulations, according to the formation pressure the highest full well the selection of BOP rated working pressure. That is, BOP rated working pressure is equal to or greater than the formation pressure is the highest in the borehole, see Appendix two.

The BOP group, including BOP, four, pipe should be selected according to the pressure. As each piece of work pressure is different, the whole

The system working pressure is equal to the pressure of the lowest working pressure parts. The choke line, a throttle valve according to the liquid flow (party after

To) part, its working pressure according to the group BOP half the work pressure of consideration.