A leading well fracturing company needed to have a system to control multiple pumps from one computer using previously designed code made to control one pump at a time. The application needed to be able to launch multiple executables of the other application and monitor and control the system.
Using the system design software LabVIEW, Data Science Automation (DSA), a certified member of the Control Systems Integrators Association (CSIA) with experience in the development of oil and gas industry field applications, was able to create an application that launched the other application and tied into the data and controls to monitor and control the Real-Time (RT) targets. This allowed the end-user to control up to 16 well fracturing pumps on a single computer.
This process was needed when the well fracturing company wanted to have its equipment automated. The operators of the equipment needed a way to have one operator control the group of pumps from a single location and have the ability to set a flowrate and maximum pressure and have the equipment determine the best solution to get the job done.
The multiple fracturing pump control (MFPC) application that was created allows for more than one controller to be online at a time. Each pump control application has the operator select a color for the group of pumps under their control. Once the operator selects the pumps that they want to control, the pumps are locked out and other MFPC operators are not allowed to connect to those pumps until the operator releases control by programmatically disconnecting from it. Each pump has a Compact Field Point (cFP) or a Compact RIO (cRIO) on it that had been previously configured with the correct parameters for the operation of the pump and the feedback needed to monitor the control. A single pump control application was also created in LabVIEW before the MFPC was designed. The single pump control code only needed slight modifications to enable the new MFPC application to function.
The operator uses a well setup screen, shown in Figure 1, to customize the well layout. This includes the direction of the wellhead and the pumps they will be controlling on the “missile” (pump manifold). The missile is the main piping that was connected to all the pumps and the wellhead. The operator also needs to set the maximum pressure allowed to prevent a blow out as a safety measure. The operator can adjust the maximum acceptable pressure by use of the pressure setup screen as shown in Figure 2. This setting is used on all pumps controlled by the pump control application and can be upwards of 10,000 PSI. The algorithm on the real-time controllers looks at the input pressure and predicts the next set of pressure readings to determine if the pressure might exceed the set limit. This feature helps the crew avoid bursting the pipes and avoid injury.
|Figure 1. This is the well setup screen that allows the operator to select the position of the pumps that their MFPC will control.|
|Figure 2. This is the pressure setup screen that allows the operator to select maximum pressure setting for the pumps under that MFPC’s control.|
|Figure 3. This is the rate screen that allows the operator to set a new rate and commit it to allow the rate to be transferred to the pumps.|
Once the pumps are selected and the pressure limit set, the MFPC application allows operators to select a rate at which they would like to operate. The application creates a solution to operate the pumps that checks for harmonics based on the types of pumps being used and their operating settings. The operator can also select an individual pump and remove it from the solution if the pump is not running at acceptable performance. The operator can also lock an individual pump into a gear and throttle level if desired. Once the application is started, the operator can select the rate screen, shown in Figure 3, and modify the rate to a new rate. The rate only takes effect after the operator clicks on the commit button.
Each group of pumps is assigned a color, and the operators of the individual applications select a color from the color selection screen. Once a color is selected by the operator, that color appears disabled and grayed-out to all of the other MFPC operators on their selection screen to avoid pumps being ganged to the wrong MFPC application.
The main screen shown in Figure 4 shows the connected pumps and displays the values for each pump, if it is locked out or not, and the connection status. The controls can be clicked on to bring up the desired controls. The HHP and RATE controls at the top can be clicked on to bring up the scoreboard that provides the totals of all the pumps on the network and the pumps under the MFPC’s control. This allows the operators to manage their workload with the other operators. By clicking on the warning light an error and warning panel is displayed to provide a description of the warning and the pump number it is associated it. Clicking on the pressure brings up the pressure setup screen and clicking on the rate indicator brings up the rate selection screen. The dropdown menu in the center of the upper main screen allows the user to select any of the main functions as well as neutral and shutdown functions. The warning and scoreboard screens are shown in Figure 5.
|Figure 4. This is the main screen that shows the controls and active pumps along with a locked pump. The two pumps are in park with no output pressure or rate.|
|Figure 5. Above are the error and scoreboard screens. The warnings show an error on an emergency stop that has lost an input pressure signal. The scoreboard shows the total HHP and RATE for all pumps connected to the network while also showing grouped pumps.|
DSA says having the initial code for controlling the single pump made it easy to tie in the new multiple MFPC application. Using some of the standard LabVIEW architecting, only slight modifications to the existing code were needed to the existing single pump control code.
As a result, this MFPC application makes it easier for the operator to control multiple pumps from a single location that can be a safe distance from the high-pressure piping. The previous method for controlling these pumps was for the operator to stand next to the pump and use levers and controls to adjust the pump output.
Overall, the application designed by DSA using LabVIEW was able to provide the end-user with the ability to reduce the number of operators and place the operator a safe distance from the more dangerous area of the well site. It also allowed for better control of the process and, with additional system components, make the entire process much safer.
Data Science Automation is a software and systems engineering firm specializing in developing highly technical PC and network-based solutions for research and industrial clients. DSA has three operating divisions for process automation, business automation and technical training with offices in Pittsburgh, Philadelphia, Cleveland, Dayton and Indianapolis. For more on DSA, visit www.dsautomation.com.
The Control System Integrator Association (CSIA) is a global non-profit professional association for control system integration companies to advance system integration for the success of members and their clients. For more information, visit to www.controlsys.org.
This article was adapted from “Developing a Fracturing Pump Controller using NI LabVIEW, Compact FieldPoint, and Compact RIO,” a DSA paper that won the NI LabVIEW FPGA (field programmable gate array) Innovation Award and was a finalist in the National Instruments (NI) 2012 Graphical System Design Achievement Awards (Energy Category).