Systems and methods to operate hydraulic fracturing units using automatic flow rate and/or pressure control

A method of operating a plurality of hydraulic fracturing units, each of the hydraulic fracturing units including a hydraulic fracturing pump to pump fracturing fluid into a wellhead and an internal combustion engine to drive the hydraulic fracturing pump, the method comprising:

• receiving, via a supervisory controller, one or more operational parameters associated with pumping fracturing fluid into the wellhead, the one or more operational parameters including one or more of a target flow rate, a maximum flow rate, a target pressure, or a pressure range for fracturing fluid supplied to the wellhead;
• determining, via the supervisory controller, whether the plurality of hydraulic fracturing units have a capacity sufficient to achieve the one or more of the target flow rate or the target pressure;
• initiating operation of at least one of the plurality of hydraulic fracturing units;
• increasing a flow rate from the at least some of the hydraulic fracturing units according to a controlled increasing flow rate schedule toward the one or more of the target flow rate or the target pressure, the controlled increasing flow rate schedule causing operation of the hydraulic fracturing units such that a flow rate of fracturing fluid does not exceed the maximum flow rate and a fracturing fluid pressure substantially remains within the pressure range;
• and
• operating the at least some hydraulic fracturing units to maintain one or more of the target flow rate or the target pressure.

A hydraulic fracturing control assembly to operate a plurality of hydraulic fracturing units, each of the hydraulic fracturing units including a hydraulic fracturing pump to pump fracturing fluid into a wellhead and an internal combustion engine to drive the hydraulic fracturing pump, the hydraulic fracturing control assembly comprising:

• an input device configured to facilitate communication of:
• operational parameters to a supervisory controller, the one or more operational parameters including one or more of a target flow rate, a maximum flow rate, a target pressure, or a pressure range for fracturing fluid supplied to the wellhead;
• one or more sensors configured to generate one or more sensor signals indicative of one or more of a flow rate of fracturing fluid or a pressure associated with fracturing fluid;
• and
• a supervisory controller in communication with one or more of the plurality of hydraulic fracturing units, the input device, or the one or more sensors, the supervisory controller being configured to:
• receive one or more operational parameters associated with pumping fracturing fluid into a wellhead, the one or more operational parameters including one or more of a target flow rate or a target pressure for fracturing fluid supplied to the wellhead;
• determine whether the plurality of hydraulic fracturing units have a capacity sufficient to achieve the one or more of the target flow rate or the target pressure;
• and
• increase a flow rate from at least some of the hydraulic fracturing units according to a controlled increasing flow rate schedule toward the one or more of the target flow rate or the target pressure, the controlled increasing flow rate schedule causing operation of the hydraulic fracturing units such that a flow rate of fracturing fluid does not exceed the maximum flow rate and a fracturing fluid pressure substantially remains within the pressure range.

A hydraulic fracturing system comprising:

• a plurality of hydraulic fracturing units, each of the hydraulic fracturing units comprising:
• a hydraulic fracturing pump to pump fracturing fluid into a wellhead;
• a gas turbine engine mechanically linked to the hydraulic fracturing pump;
• one or more sensors configured to generate one or more sensor signals indicative of one or more of a flow rate of fracturing fluid or a pressure associated with fracturing fluid;
• and
• a supervisory controller in communication with one or more of the plurality of hydraulic fracturing units, the input device, or the one or more sensors, the supervisory controller being configured to:
• receive pump characteristics for each of the plurality of hydraulic fracturing pumps, wherein the plurality of pump characteristics comprises one or more of a minimum flow rate, a maximum flow rate, a harmonization range, and a pump condition for each of the plurality of hydraulic fracturing pumps;
• receive one or more operational parameters associated with pumping fracturing fluid into a wellhead, the one or more operational parameters including one or more of a target flow rate or a target pressure for fracturing fluid supplied to the wellhead;
• determine whether the plurality of hydraulic fracturing units have a capacity sufficient to achieve the one or more of the target flow rate or the target pressure;
• increase a flow rate from at least some of the hydraulic fracturing units according to a controlled increasing flow rate schedule toward the one or more of the target flow rate or the target pressure, the controlled increasing flow rate schedule causing operation of the hydraulic fracturing units such that a flow rate of fracturing fluid does not exceed the maximum flow rate and a fracturing fluid pressure substantially remains within the pressure range.