RESERVOIR ENGINEERING - WATER CONING

Water Coning In A Vertical Oil Well

INPUT   DATA

Title  

Oil column thickness ft
Perforated interval ft
Wellbore radius ft
Drainage radius ft
Permeability mD
Oil relative permeability  
Oil density lb/ft3
Water density lb/ft3
Formation volume factor  
Oil Viscosity cp

Data for Anisotropic rock(Optional)
Vertical permeability mD

     Reset

OUTPUT   VARIABLES

Critical Oil Flow Rate STB/day
 ♦  Meyer-Garder's Method  
 ♦  Chaperon's Method  
 ♦  Schol's Method  
 ♦  Hoyland-Papatzacos-Skjaeveland  

Critical Oil Flow Rate (Anisotropic) STB/day
 ♦  Chaperon's Method  
THEORY  &   FORMULAE

Water Coning In A Vertical Oil Well

For an reservoir with an underlying water-zone, and the perforated interval at the top of the oil-zone, a number of researchers have proposed methods for determining the Critical oil flow rate (Qoc).

The four commonly-used methods are:

   -   Meyer-Garder’s Method

   -  Chaperon's Method

   -  Schol's Method

   -  Hoyland-Papatzacos-Skjaeveland's Method

All these methods apply to the isotropic reservoir case where horizontal permeability equals vertical permeability, except for Chaperon's more general anisotropic case.

The equations for each method is given below:

   Meyer-Garder’s Method

        

   Chaperon's Method

        

   Schol's Method

        

  Hoyland-Papatzacos-Skjaeveland's Method

        

Where:

   Qoc = critical oil well rate, STB/day
   h = oil column thickness, ft
   hp= perforated interval, ft
   kh= horizontal permeability, md
   kv= vertical permeability, md
   ko= effective oil permeability, md
   (ko= rock permeability x oil relative permeability)
  re = drainage radius of well, ft
  rw = wellbore radius, ft
  Bo = formation volume factor of oil
   μ o = oil viscosity, cp
   ρ o = oil density, lb/ft3
   ρ w = water density, lb/ft3

Note that the critical rate is the oil rate below which water breakthrough will never occur; this rate may be too low for practical and economic reasons.

BIBLIOGRAPHY