Fluid mixing system

• US 20020093875A1
• Filed: 11/29/2000
• Published: 07/18/2002
• Est. Priority Date: 11/29/2000
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (SLB)
• Original Assignee: Schlumberger Technology Corporation (SLB)
• Inventors: Rondeau, Joel, Vigneaux, Pierre
• Granted Patent: US 6,491,421 B2
• Time in Patent Office: Days
• US Class Current: 366/8
• CPC Class Codes: B01F 2101/28 Mixing cement, mortar, clay, plaster or concrete ingredients
• CPC Class Codes: B01F 2101/49 Mixing drilled material or ingredients for well-drilling, earth-drilling or deep-drilling compositions with liquids to obtain slurries
• CPC Class Codes: B01F 2215/0409 Relationships between different variables defining features or parameters of the apparatus or process
• CPC Class Codes: B01F 23/59 Mixing systems, i.e. flow charts or diagrams
• CPC Class Codes: B01F 25/53 in which the mixture is discharged from and reintroduced into a receptacle through a recirculation tube, into which an additional component is introduced
• CPC Class Codes: B01F 35/21 Measuring
• CPC Class Codes: B01F 35/2111 Flow rate
• CPC Class Codes: B01F 35/21112 Volumetric flow rate
• CPC Class Codes: B01F 35/2112 Level of material in a container or the position or shape of the upper surface of the material
• CPC Class Codes: B01F 35/2117 Weight
• CPC Class Codes: B01F 35/213 of the properties of the mixtures, e.g. temperature, density or colour
• CPC Class Codes: B01F 35/2132 Concentration, pH, pOH, p(ION) or oxygen-demand B01F35/2133 takes precedence
• CPC Class Codes: B01F 35/2134 Density or solids or particle number
• CPC Class Codes: B01F 35/2211 Amount of delivered fluid during a period
• CPC Class Codes: B01F 35/881 by weighing, e.g. with automatic discharge
• CPC Class Codes: B28C 7/022 by measuring the consistency or composition of the mixture, e.g. with supply of a missing component
• CPC Class Codes: E21B 21/062 by mixing components
• CPC Class Codes: E21B 33/13 Methods or devices for cementing, for plugging holes, crevices or the like
• CPC Class Codes: G05D 11/132 by controlling the flow of the individual components G05D11/133 takes precedence
• CPC Class Codes: G05D 11/135 by sensing at least one property of the mixture G05D11/139 takes precedence

Abstract

A method for continuously mixing a borehole fluid such as cement includes using a measurement of the solid fraction of a cement slurry as it is being mixed to determine the ratio of the solid and liquid components to be added to the slurry. A system for mixing the includes a liquid material (water) supply including a flow meter; a solid material (cement) supply; a mixer which receives the liquid and solid materials and includes an output for delivering materials from the mixer to a delivery system; a device for measuring the amount of material in the mixer; and a flow meter in the output; wherein measurements from the flow meters and the device for measuring the amount of material in the mixer are used to control the amount of solid and/or liquid material added to the mixer.

Claims

1. A system for mixing fluids comprising:

i) a liquid material supply including a flow meter;

ii) a solid material supply;

iii) a mixer which receives the liquid and solid materials and includes an output for delivering materials from the mixer to a delivery system;

iv) a device for measuring the amount of material in the mixer; and

v) a flow meter in the output;

wherein measurements from the flow meters and the device for measuring the amount of material in the mixer are used to control the relative amounts of solid and liquid material added to the mixer.

2. A system as claimed in claim 1, wherein the fluid comprises a cement slurry, the liquid material including water and the solid material including cement.

3. A system as claimed in claim 2, wherein the measurements are used to determine the solid fraction of the slurry in the mixer, the solid fraction being used to control the amount of solid material added.

4. A system as claimed in claim 1, wherein the flow meters are selected from mass flow meters and volumetric flow meters.

5. A system as claimed in claim 1, wherein the flow meters are selected from Coriolis meters and electromagnetic meters.

6. A system as claimed in claim 1, wherein the mixer comprises a mixing section and a mixing tub, mixed materials being fed from the mixing section to the mixing tub, and a portion of the materials in the tub being recirculated to the mixing section.

7. A system as claimed in claim 6, wherein the device for measuring the amount of material in the mixer measures the amount of materials in the tub.

8. A system as claimed in claim 7, wherein the device comprises a level sensor in the tub.

9. A system as claimed in claim 7, wherein the device comprises a load sensor which measures the weight of the tub.

10. A system as claimed in claim 7, wherein the device measures the variation in the amount of materials in the tub over time.

11. A system as claimed in claim 6, wherein recirculation of material takes place upstream of the flow meter in the output.

12. A system as claimed in claim 2, wherein the supply of solid material comprises separate supplies of cement and dry additives, a flow meter being provided to measure the rate of flow of the dry additives.

13. A system as claimed in claim 11, wherein the supply of dry additives comprises multiple separate supplies of additives, each with its own flow meter.

15. A method as claimed in claim 14, wherein the fluid comprises a cement slurry

16. A method as claimed in claim 15, wherein the solid and liquid components are continuously delivered to a mixer and the slurry is continuously removed from the mixer for use, the method comprising:

i) measuring the flow rate of liquid components into the mixer;

ii) measuring the amount of slurry in the mixer;

iii) measuring the flow rate of slurry removed from the mixer; and

iv) using the measurements of flow rate and amount of slurry to calculate the solid fraction of the slurry.

17. A method as claimed in claim 16 wherein the solid components include additives that are delivered to the mixer separately from cement, the method further comprising measuring the flow rate of the additives delivered to the mixer.

18. A method as claimed in claim 17, wherein the mixer includes a tub, the measurement of the amount of slurry in the mixer comprising a measurement of the amount of slurry in the tub.

19. A method as claimed in claim 17, wherein a portion of the slurry in the tub is recirculated into the mixer as solid and liquid components are added.

20. A method as claimed in claim 19, wherein the recirculation takes place upstream of the measurement of the flow rate of slurry removed from the mixer.

14. A method of mixing a borehole fluid comprising solid and liquid components that are mixed to form the fluid, the method comprising measuring the solids fraction of the fluid and using the measured solids fraction to determine the ratio of solid and liquid components mixed to form the fluid.