Downhole flow meter
AssigneeSchlumberger Technology Corporation
InventorsTerizhandur S. Ramakrishnan, Gary M. Oddie, Sam Smonian
Life of this patent
Estimating the term…
Abstract
This invention comprises the use of a variable orifice valve as a flow controller and flow meter. Pressure measurements are taken upstream and downstream of the variable orifice valve by way of a differential pressure measurement mechanism. The differential pressure measurement mechanism may comprise two separate absolute pressure measurement devices or a single differential pressure measurement device. Flow rate through the valve is determined from the pressure drop across the valve. In wellbores having multiple zones, a variable orifice valve together with a differential pressure measurement mechanism may be deployed for each zone. The flow rate through each of the zones and at the surface can then be monitored and controlled.
Claims32
A method for measuring the flow rate of a fluid in a wellbore, comprising:
- flowing the fluid through a variable orifice valve having one or more orifices between an annular region outside a tool string and a region inside the tool string;
- measuring the pressure differential of the fluid across the variable orifice valve;
- and
- calculating the flow rate through the variable orifice valve by use of the pressure differential measurement.
A method for measuring the flow rate of a fluid in a wellbore, comprising:
- flowing the fluid through a variable orifice valve;
- measuring the pressure differential of the fluid across the variable orifice valve;
- determining the flow coefficient and the total area of variable orifice valve openings that are exposed to flow;
- and
- calculating the flow rate through the variable orifice valve by use of the pressure differential measurement, the flow coefficient, and the total area,
- wherein the determining the flow coefficient and the total area step comprises determining the flow coefficient and the total area for each setting of the variable orifice valve.
A method for measuring the flow rate of a fluid in a wellbore, comprising:
- flowing the fluid through a variable orifice valve;
- measuring the pressure differential of the fluid across the variable orifice valve;
- determining the flow coefficient and the total area of variable orifice valve openings that are exposed to flow;
- calculating the flow rate through the variable orifice valve by use of the pressure differential measurement, the flow coefficient, and the total area;
- and
- calibrating the flow coefficient and the total area, wherein the calibrating step comprises calibrating the flow coefficient and the total area for each setting of the variable orifice valve.
A method for measuring the flow rate of a fluid in a wellbore, comprising:
- flowing the fluid through a variable orifice valve;
- measuring the pressure differential of the fluid across the variable orifice valve;
- calculating the flow rate through the variable orifice valve by use of the pressure differential measurement;
- determining the flow coefficient and the total area of the variable orifice valve openings that are exposed to flow (“the total area”);
- determining the expansibility factor and the fluid density of the fluid flowing through the variable orifice valve;
- calculating the flow rate through the variable orifice valve by use of the pressure differential measurement, the flow coefficient, the total area, the expansibility factor, and the fluid density;
- and
- calibrating the flow coefficient and the total area, wherein the calibrating step comprises calibrating the flow coefficient and the total area for each setting of the variable orifice valve, and, wherein the calibrating step comprises determining the product of the flow coefficient and the total area by utilizing the equation Q = C A ϵ 2 Δ P ρ
- to solve for (C), wherein (Q) is the flow rate, (C) is the flow coefficient, (A) is the total area, (ε) is the expansibility factor, (ΔP) is the pressure drop across the valve, and (ρ) is the upstream fluid density.
A method for measuring the flow rate of a fluid in a wellbore, comprising:
- flowing the fluid through plural variable orifice valves;
- measuring the differential pressure of the fluid across each of the variable orifice valves, and
- calculating flow rate in a tubing string based on the differential pressure measurements across corresponding variable orifice valves.
Dependencies are inferred from the claim text.