Page 322 - Intelligent Digital Oil And Gas Fields

Smart Wells and Techniques for Reservoir Monitoring 267

schematic with a representation of coupling wellbore nodes with reservoir
cells. It is recommended to set up an ICV valve per reservoir cell; in those
scenarios where the cell is bigger than the segment where the ICV is com-
pleted, it is suggested to create a local grid refinement (LGR) to connect one
cell with one segment.
The Perkins equation (7.3) is coupled with the numerical models with a
surface-network capability assuming that these parameters are known: molar
rates of hydrocarbon components, water rate at stock tank conditions,
temperature at the outlet of the valve (used in flash calculations), valve
control, and the flow valve coefficient profile. The simulator solves the pres-
sure equation across the valve with the following procedure solution
algorithms:
• Determine the number of hydrocarbon phases and the compositions and
compressibility factors of each phase using the phase-equilibrium
calculation.
• Determine the densities of oil, gas, and water phases (flash calculations).
• Determine the specified type of mass rate.
• Calculate density of the fluid mixture.
• Compute interpolation values of valve coefficient as described in
Section 7.6.
• Determine the pressure differential across the valve.
Fig. 7.13 shows a schematic representation of how the fluids flow through
the ICV, the reservoir produces through perforated casing to the annulus,
and valves control flow from the annulus into the tubing contained inside
the casing. Annular flow in the casing is blocked by packers and between
three perforated sections of the wellbore.
The VLP of the wells could be represented using hydraulic tables from
nodal analysis or any industry-standard analytic multiphase flow correlation
(e.g., Beggs and Brill, Hagedorn and Brown, etc.), which can be applied to
the connection between ICV nodes and the vertical section of the wellbore.
The VLP is required to complete the surface calculation of production rate
and pressure, and to estimate the pressure drop across the vertical section.

7.6.4 Modeling ICDs for Oil Wells

The ICDs are designed to control the down-hole flow distribution by cre-
ating a frictional pressure drop across the orifice; it is the ICD that acts as
setting up several chokes in front of the casing. This device is created to
reduce the pressure drop at the heel of a horizontal well or reduce the