Patent ID: 6786629
Filing Date: 2004-09-07
Classification: B01F,B28C,E21B,G05D

Abstract:
A system for mixing a cement slurry in a well cementing operation, comprising:i) a liquid material supply including means for controlling the flow of liquid therefrom in response to a first control signal, and a first flow meter for determining the flow rate of liquid supplied therefrom and generating a first flow rate signal; ii) a solid cement supply including means for controlling the flow of solid cement supplied therefrom in response to a second control signal; iii) a mixer which receives the liquid and solid cement from the liquid material supply and solid cement supply respectively and mixes them to form a slurry, and includes and output for delivering materials from the mixer, a second flow meter being located in the output for determining the flow rate of slurry from the mixer and generating a second flow rate signal; iv) a device for determining the variation over time of the amount of slurry in the mixer and generating a mixer content signal; v) a delivery system connected to the output of the mixer for delivering the slurry to a well; and vi) a monitoring system which determines the ratio of solid cement and liquid in the mixer from the first and second flow rate signals and the mixer content signal, and generates the first and second control signals to operate the means for controlling the flow of liquid and means for controlling the flow of cement so as to control the relative amounts of solid cement and liquid material added to the mixer according to the determined ratio of solid cement and liquid in the mixer.