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Downhole Chemical Injection Mechanical Flow Meter

IP.com Disclosure Number: IPCOM000247094D
Publication Date: 2016-Aug-04
Document File: 4 page(s) / 408K

Publishing Venue

The IP.com Prior Art Database

Abstract

Proposed Title: Downhole Chemical Injection Mechanical Flow Meter Abstract of the Invention: The invention proposed is a downhole chemical injection mandrel with an integrated measurement device capable of obtaining temperature, pressure, and flow measurements. A common downhole pressure-temperature measurement device is used to obtain a differential pressure measurement, which then allows for calculation of flow velocity and volumetric flow rate of the injected fluid. Pressure measurements may be made using either a single differential measurement device, or multiple absolute pressure measurement devices. Remote measurement of flow rate, as well as temperature and pressure, enables informed decisions on chemical composition and greater control of flow rate at the surface. Additionally, multiple instances of the device could be used in a wellbore for injection of chemicals. Technical Summary The primary implementation of the invention is the integration of pressure-temperature measurement device(s) connected to the flow path in the chemical injection mandrel. The flow path incorporates a change in the cross-sectional area to accelerate the fluid, thus creating a difference in pressures as resulting from the well-known Venturi effect. This allows for determination of the fluid velocity and, consequently, flow rate. When the chemical injection valve opens to allow fluid flow, the static pressure measurements at the first and second openings will differ as a function of the known difference in cross-sectional areas. Knowing this difference allows for determination of the fluid velocity at either location of pressure measurement, and thus for the fluid's volumetric flow rate. Implementation of this into a chemical injection mandrel requires the following components: 1) Chemical injection mandrel 2) Chemical injection valve 3) Fluid flow path with a change in cross-sectional area 4) Access ports connecting the fluid flow path to the pressure measurement devices 5) Pressure/Temperature measurement devices 6) Surface communication line (including, but not limited to, electric and fiber optic lines)

Figure 1: Chemical Injection Mandrel and Valve with integrated pressure, temperature, and flow measurement using P/T measurement device and the Venturi effect

Alternate Method 1: Pitot tube One possible implementation of this is the integration of a Pitot tube into the flow path in the chemical injection mandrel. When the chemical injection valve opens and fluid flow begins, the implementation of one of many possible Pitot tube configurations can then be used to derive fluid velocity through the differential between the static pressure and the stagnation pressure. Use of a standard pressure/temperature measurement device as part of the static pressure measurement allows the temperature measurement described in the primary method. 1) Chemical injection mandrel 2) Chemical injection valve 3) Fluid flow path 4) Pitot tube or a Pitot-static tube to measure static and stagnation pressures. 5) Surface communication line

Figure 2: Chemical Injection Mandrel and Valve with integrated pressure, temperature, and flow measurement using P/T measurement device with a Pitot-tube configuration

Alternate Method 2: Position-sensing using a piston-spring assembly and the Venturi effect for flow measurement Similar to the primary method, this method relies on the Venturi effect and a fluid flow path with a change in cross-sectional area. In this case, each access port contains a spring with a piston attached to its end. Movement of the piston is measured through any of a number of existing position-sensing methods, including, but not limited to, Hall Effect sensing, magnetostriction, and linear variable displacement transducer (LVDT). With a known spring constant and piston area, any movement of the piston through compression or extension of the spring allows for determination of the static pressure in the access port. Calculation of the static pressures in the access ports again allows for determination of the fluid velocity and fluid flow rate. In this method, however, an additional sensor would be required for temperature measurements. 1) Chemical injection mandrel 2) Chemical injection valve 3) Fluid flow path with a change in cross-sectional area 4) Access ports connecting the fluid flow path to the pressure measurement devices 5) Spring 6) Piston 7) Position sensing device 8) Surface communication line (including, but not limited to, electric and fiber optic lines)

Figure 3: Chemical Injection Mandrel and Valve with integrated flow measurement using position-sensing of a piston-spring assembly

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Proposed Title:                                 Downhole Chemical Injection Mechanical Flow Meter

Abstract of the Invention:

The invention proposed is a downhole chemical injection mandrel with an integrated measurement device capable of obtaining temperature, pressure, and flow measurements. A common downhole pressure-temperature measurement device is used to obtain a differential pressure measurement, which then allows for calculation of flow velocity and volumetric flow rate of the injected fluid. Pressure measurements may be made using either a single differential measurement device, or multiple absolute pressure measurement devices. Remote measurement of flow rate, as well as temperature and pressure, enables informed decisions on chemical composition and greater control of flow rate at the surface. Additionally, multiple instances of the device could be used in a wellbore for injection of chemicals.

Technical Summary

The primary implementation of the invention is the integration of pressure-temperature measurement device(s) connected to the flow path in the chemical injection mandrel. The flow path incorporates a change in the cross-sectional area to accelerate the fluid, thus creating a difference in pressures as resulting from the well-known Venturi effect. This allows for determination of the fluid velocity and, consequently, flow rate.

When the chemical injection valve opens to allow fluid flow, the static pressure measurements at the first and second openings will differ as a function of the known difference in cross-sectional areas. Knowing this difference allows for determination of the fluid velocity at either location of pressure measurement, and thus for the fluid’s volumetric flow rate. Implementation of this into a chemical injection mandrel requires the following components:

1)      Chemical injection mandrel

2)      Chemical injection valve

3)      Fluid flow path with a change in cross-sectional area

4)      Access ports connecting the fluid flow path to the pressure measurement devices

5)      Pressure/Temperature measurement devices

6)      Surface communication line (including, but not limited to, electric and fiber optic lines)

Figure 1: Chemical Injection Mandrel and Valve with integrated pressure, temperature, and flow measurement using P/T measurement device and the Venturi effect

Alternate Method 1: Pitot tube

One possible implementation of this is the integration of a Pitot tube into the flow path in the chemical injection mandrel. When the chemical inject...