Patent ID: 11896940
Assignee: HALLIBURTON ENERGY SERVICES, INC.
Field: Chemical engineering (Chemistry)
Classification: CPC B  E | IPC B  E

Claim 10:
11. A method of controlling proppant concentration in a hydraulic fracturing slurry, comprising:
a) transmitting to a non-transient computer readable memory of a blender control unit, a target slurry volumetric flow rate ({dot over (V)}sl-target), a target input value of a slurry volume fraction (Cs-target), and inputs of a known density of a fracturing fluid (ρfl) and known density of a proppant (ρpr);
b) sending from a transmitter of the blender control unit, a command signal to actuate a first valve to deliver the fracturing fluid to a blender;
c) sending from the transmitter of the blender control unit, a second command signal to actuate a second valve to deliver the proppant to the blender at a non-zero proppant mass flow rate ({dot over (m)}pr);
d) measuring, using a first volume flow rate sensor, a volumetric flow rate ({dot over (V)}fl) of the fracturing fluid input to the blender and transmitting a signal corresponding to the measured {dot over (V)}fl to a signal receiver of the blender control unit;
e) measuring, using a second volume flow rate sensor, a volumetric flow rate ({dot over (V)}sl) of the hydraulic fracturing slurry output from the blender and transmitting a signal corresponding to the measured {dot over (V)}sl to the signal receiver of the blender control unit;
f) executing computer readable instructions, stored in the memory of the blender control unit to calculate, in a central processing unit of the blender control unit a volumetric flow rate of proppant input ({dot over (V)}pr) to the blender according to the formula: {dot over (V)}pr=({dot over (V)}sl−{dot over (V)}fl), and, a slurry volume fraction according to the formula: Cs=({dot over (V)}sl−{dot over (V)}fl)/{dot over (V)}sl;
g) determining, in the central processing unit, a difference (Δ{dot over (V)}sl) between the {dot over (V)}sl-target and the {dot over (V)}sl, and, a difference (ΔCs) between the Cs-target and the Cs; and then
h) if the Δ{dot over (V)}sl is not less than an acceptable slurry volumetric flow rate margin of error (ER-{dot over (V)}sl) or the ΔCs is not less than an acceptable slurry volume fraction margin of error (ER-Cs), then the central processing unit sends instructions to cause the command signal to further actuate the first valve to incrementally change the {dot over (V)}fl or to cause the second command signal to further actuate the second valve to incrementally change the {dot over (m)}pr, and then the central processing unit repeats steps (d)-(h), and
i) if the Δ{dot over (V)}sl is less than ER-{dot over (V)}sl and the ΔCs is less than the ER-Cs, then the central processing unit sends an output signal to a display unit of the blender control unit to indicate that the target input values have been achieved.