Difference between revisions of "BHP from the fluid level"

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(Equation to calculate the BHP from the fluid level)
(Flowing well fluids segregation)
 
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When the well is flowing with the pump this is how fluids segregate in the well bore:
 
When the well is flowing with the pump this is how fluids segregate in the well bore:
 
*Oil, gas and water are produced through the tubing from the reservoir to the surface   
 
*Oil, gas and water are produced through the tubing from the reservoir to the surface   
*Gas is in the annulus from the surface to fluid level, Hd
+
*Gas is in the annulus from the surface to the fluid level, Hd
 
*Oil and gas are between the fluid level Hd, and the pump setting depth, Hd
 
*Oil and gas are between the fluid level Hd, and the pump setting depth, Hd
*Water, oil and gas are between pump and the top of the perforations, Hperfs
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*Water, oil and gas are between pump, Hd and the top of the perforations, Hperfs
 
*Water is in the rathole
 
*Water is in the rathole
  
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:<math>SG_w</math> = water specific gravity, dimensionless
 
:<math>SG_w</math> = water specific gravity, dimensionless
 
:<math>WCUT</math> = well water cut, fraction
 
:<math>WCUT</math> = well water cut, fraction
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{{#seo:
 
{{#seo:

Latest revision as of 12:08, 27 April 2020

Bottom hole pressure from the fluid level

BHP from the fluid level notations

Fluid level is the interface between the gas and liquid phases occurred in the annulus of the well.

Echometer is used to measure the fluid level in the wells.

Fluid level is used to calculate and monitor the bottom hole pressure of the wells.

Math and Physics

The physics is based on the principal hydrostatics law:

P=\frac{\rho g h}{101325}

Flowing well fluids segregation

When the well is flowing with the pump this is how fluids segregate in the well bore:

  • Oil, gas and water are produced through the tubing from the reservoir to the surface
  • Gas is in the annulus from the surface to the fluid level, Hd
  • Oil and gas are between the fluid level Hd, and the pump setting depth, Hd
  • Water, oil and gas are between pump, Hd and the top of the perforations, Hperfs
  • Water is in the rathole

Equation to calculate the BHP from the fluid level

P_{wf}=P_{ann}+\frac{(H_{perfs}-H_{pump})(SG_o(1-WCUT)+SG_w WCUT)+(H_{pump}-H_d)SG_o}{10.32}

Note that for the deviated wells TVD depths should be used.

Nomenclature

g = 9.81, m/s^2
h = depth, m
H_d = fluid level, m
H_{perfs} = top of the perforations, m
H_{pump} = pump setting depth, m
P = pressure, atm
P_{ann} = annulus presssure, atm
P_{wf} = well flowing bottomhole pressure, atm
\rho = density, kg/m^3
SG_o = oil specific gravity, dimensionless
SG_w = water specific gravity, dimensionless
WCUT = well water cut, fraction