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Integrated one pump control of pumping equipment

Integrated one pump control of pumping equipment description/claims

The present invention relates, in general, to process control, and more particularly to controlling a pumping process. Specifically, the present invention relates to methods and systems for improving the efficiency of a pumping process by controlling the operation of the pumps involved based on certain parameters characterizing the pump.

Pumps are used in a variety of industries to deliver fluids. For example, pumps may be used in conjunction with subterranean operations to deliver cement slurries, stimulation fluids, drilling fluids, or other fluids at a desired pressure or flow rate. In order to inject the requisite amount of fluid in a short period of time, multiple pumps are commonly used with the pumping load distributed among them. In a multiple pump set up each pump will handle part of the load and the pumps are adjusted so as to achieve the desired output.

Currently, the pumps are manually adjusted so that each pump operates at a particular level. Because there is no intelligent control system for deciding the level of operation of each pump, the pumps are assigned a certain load without taking into account the pump's characteristics such as its efficiency or horse power. As a result, some of the pumps operate at their maximum capacity while others are being under utilized.

The current methods of pump control have several disadvantages. One disadvantage of the current methods is that those pumps that are operating at their maximum capacity will be subject to wear and tear and have a shortened life span while other pumps are being under utilized. This problem is exasperated by the fact that a pump failure can be very costly to an operator who may have to halt the operations while the pump is being repaired or replaced.

Another drawback of the current methods is that a pump's horse power is not taken into account when assigning a load to the pump. As a result, one pump may run well under its maximum horse power and be underused, while another pump is running close to its maximum horse power thus shortening its life span.

Also, in some instances such as a fracturing application, the flow rate or pressure of the fluid entering a pump may change with time. Because the current pump control process is a static one, the pump operation is not modified with the change in the fluid flow through the pump. As a result, the pump will continue to operate at a preset operating level even when the fluid flow is reduced. Consequently, a pump may not get enough pressure and flow rate and be starved. When a pump is starved, it will suffer wear and tear.

Another disadvantage of the current methods is that any sensor readings monitoring the operation of the pumps will produce noisy readings. The effect of this noise is reduced in some instances by passing the sensor reading through a filter. However, the filter produces a lagged signal and the filters often fail to respond to the high frequency of changes in the sensor readings.

Another drawback of the current methods is that in case of a problem with a pump it may take a considerable amount of time before the rate and pressure of the dropped pump is compensated. Still another problem with the current methods is that the operators on the field have no idea which pump or pumps would be able to compensate for the dropped pump load.

The present invention relates, in general, to process control, and more particularly to controlling a pumping process. Specifically, the present invention relates to methods and systems for improving the efficiency of a pumping process by controlling the operation of the pumps involved based on certain parameters characterizing the pump.

In one embodiment the present invention is directed to a pumping apparatus comprising a pump unit; a pump controller coupled to the pump unit; a pump modulator coupled to the pump controller; and a master controller coupled to the pump modulator. The value of an output parameter from the pump unit is fed back to the pump controller which generates a first driving signal to the pump unit to drive the value of the output parameter closer to a first desired value received from the pump modulator. The value of an output parameter from the pump unit is also fed back to the pump modulator which generates a second driving signal to the pump controller representing the first desired value to drive the value of the output parameter closer to a second desired value. The master controller compares a first input and a second input and generates a third driving signal to the pump modulator representing the second desired value.

In another embodiment the present invention is directed to a method for driving a plurality of pump units comprising: generating a first drive signal from each of a plurality of pump controllers to a corresponding pump unit; generating a second drive signal from a pump modulator to each of the plurality of pump controllers; generating a third drive signal from a master controller to the pump modulator; and driving the master controller with a signal representing an actual value of an output parameter and a desired value of the output parameter.

In yet another embodiment, the present invention is directed to a method for estimating an output parameter of a pump comprising generating an estimated value of a first parameter and an estimated value of a second parameter using a system model; calculating a difference between the estimated value of the second parameter and a measured value of the second parameter; feeding the difference between the estimated value of the second parameter and the measured value of the second parameter to a controller; generating a disturbance signal corresponding to the first parameter; and feeding a sum of the disturbance signal corresponding to the first parameter and a desired value of the first parameter to the system model.

This type of intelligent system will increase the life of the pumps between maintenance thereby lowering costs and improving job efficiency. Another advantage of the present invention is the capability to develop a pattern on how long each part in a pumping unit can last if they are run at their maximum efficiency, and potentially replace them right before they fail. The present invention also allows monitoring for pump cavitations to prevent damage and make the operations safer.

The features and advantages of the present invention will be apparent to those skilled in the art from the description of the preferred embodiments which follows when taken in conjunction with the accompanying drawings. While numerous changes may be made by those skilled in the art, such changes are within the spirit of the invention.

These drawings illustrate certain aspects of some of the embodiments of the present invention, and should not be used to limit or define the invention.

FIG. 1 illustrates a flow diagram for a one pump control system in accordance with an embodiment of the present invention.

FIG. 2 illustrates a block diagram of operation of the pump modulator in accordance with an embodiment of the present invention.

• Provisional Patent
• Utility Patent

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