Realizing the returns of an integrated control and monitoring architecture

The oil and gas industry depends heavily on advanced technology as evidenced in better geologic devices; computer-aided modeling; and major advances in drilling, particularly horizontal drilling. These advances in technology have made it possible to enhance recovery or even produce hydrocarbons from oil and gas wells not previously viable.

One trend today is the convergence of computing power requirements for hydraulic fracturing operations. Similar to business professionals who require a suite of software applications to perform daily activities, oil and gas operators must manage a host of challenges in their pressure pumping operations. These challenges include ensuring worker safety, redundant operations to maximize uptime, integration that extends beyond engineering, application standardization while controlling costs, data acquisition processing for doing advanced computations, and the tight coordination of a complex network of equipment.

Another perennial issue operators deal with is worker safety. While nearly half of all fatal injuries are attributed to motor vehicle accidents, many other injuries are attributed to workers being struck by tools and moving machinery. Additionally, an increase in the rate of injury or fatalities increases for inexperienced workers, typically operators with less than one year of service in the field.

Within upstream oil and gas, traditional process control and automation systems have many constraints that require operators to interface at control devices, placing them near high-pressure equipment systems. Because traditional process control offers fixed functionality and, in some cases, requires a ratio of one operator per hydraulic fracturing pump unit, this can translate to a high number of operators based on the number of pumpers on a frac site. At a distance of only a few feet from the pumpers, noise can be loud and pose additional challenges for communications. In some cases, frac site communications can mean operators communicate via two-way radio to ensure the right coordination of equipment. Ensuring reliability of information so that what is being communicated is understood and acted upon correctly is crucial.

Reducing risk

At a well location, the wellsite leader is the most visible safety leader, so proactive planning by management helps workers understand the risks and establish priorities for ensuring safety. One approach to minimizing risks is to prevent operators from coming into contact with moving machinery, high-pressure areas, and tools. Through an advanced control and monitoring platform, personnel are removed from the danger zones. The National Instruments (NI) LabVIEW and CompactRIO platform provides high-performance embedded processing coupled with rugged hardware capable of withstanding the harsh, remote environments of a well site. The benefit to service companies is having the user interface and embedded logic in one platform, which is traditionally not an option. Because embedded logic such as field-programmable gate array (FPGA) code can be stored on the control device, operators are able to monitor frac pump operations from the safety of the data van. Essentially, the FPGA-based control platform provides flexible hardware through software-defined, reprogrammable circuitry. FPGAs have been used for more than 30 years as digital glue logic between different components on the same printed circuit board (PCB). The reconfigurable logic within the FPGA fabric has been ideal for implementing complex state machines and application-specific digital circuitry that operate independently from processor clock cycles, with higher reliability and determinism. Over the years, the performance of FPGAs has increased dramatically, with significant reductions in power and cost. For this reason, the use of FPGAs in embedded measurement and control designs has expanded from simple glue logic to handling signal processing tasks such as custom digital filters, fast Fourier transforms, and logic for proportional integral derivative control. A primary benefit of FPGAs for processing is that several algorithms can now run in parallel, unlike the sequential architecture of a processor.

A host of challenges in oil and gas pressure pumping operations has led to a convergence of computing power requirements at hydraulic fracturing well sites. (Images courtesy of Lime Instruments)

Through a FPGA-based control platform, oilfield service companies can provide a step-function of safety for applications in the oil patch, thus putting their safety programs in the best position for reducing risks. Using proven digital computing technology, advanced control systems serve as autonomous control devices for wellsite jobs that historically pose safety-related risks. In addition, an integrated control and monitoring platform is able to address a host of applications, including pump frac control.

Pump monitoring and frac pump control

Located in Houston, Lime Instruments is a global provider of turnkey redundant control and instrumentation systems for the oil and gas well services industry. In addition to pressure pumping, Lime also provides control and monitoring systems for coiled tubing and both conventional diesel horsepower and turbine-driven systems. In order to be successful in pressure pumping with an integrated control system, service companies need pump, blender density, hydration, chemical, and data acquisition system control.

Through a common platform of NI LabVIEW and CompactRIO architecture, Lime is able to design systems that enable service companies to address frac systems individually as well as in a coordinated system. Lime's advanced oil well monitoring system is designed to monitor the performance of vital pump components during operation. Using the NI platform, each frac pump system is mounted on a tractor rig with a high-horsepower diesel engine and mated to a triplex or quintuplex pump. Both the engine and the transmission come equipped with an electronic interface that monitors critical functions and provides diagnostic information as the unit is running. The engine and transmission output the monitoring data via an SAE J1939 communication protocol.

Using the NI LabVIEW and CompactRIO architecture, each frac pump system is mounted on a tractor rig with a high-horsepower diesel engine and mated to a triplex or quintuplex pump.

To ensure operation, these systems offer redundant operator controls for reliability, Ethernet cables for wired control, wireless controls with dynamic IP addressing, and high-performance control and monitoring built on embedded real-time FPGA technology. The system is constructed with NEMA 4X and Zone approved packages and can withstand operating temperature ranges from -40°C to 70°C (-40°F to 158°F).

Integration that extends beyond engineering

The use of an advanced computing platform has the ability to change the way oilfield service companies address their engineering and operational practices on a well site. The system essentially acts as a data aggregator of all information and activities related to a particular location. This data can extend across a service company to benefit various functions, departments, and roles beyond those contained at the well site. Maintenance can use data to understand which transmissions or pumps need repair or service. Staff accountants can use the data to understand how much materials have been used as well as how much revenue they can expect from the job. Purchasing departments can manage resources such as sand and water to understand when to order and stay on top of the job. The data generated by this advanced platform enable service companies to run their operations at optimal efficiency.

Acknowledgement

The authors gratefully acknowledge the contributions and work of Rob Stewart, president and CEO of Lime Instruments. Please visit for more information.