An Internet of things turns to the right
The drilling lexicon is dominated increasingly by the cloud, the Internet of things, centralization, intelligent systems, and other similarly techie terminology. As much as tongs and slips, these are tools of the trade. They extend our expertise, and improve performance by collecting every conceivable piece of data about a rotary rig’s operation, and in real time sieve it down to useable, actionable information. Much of the current emphasis is on pressure control and automation. This year’s review of rig innovations presents the leading edge of that advance with contributions from a spread of industry leaders—National Oilwell Varco, Schlumberger, Weatherford, Weir and Schramm.
INTEGRATED MPD CONTROL
Managed pressure drilling (MPD) is a proven tool for dealing with narrow downhole pressure limits in challenging wells. A common concern with MPD, however, is that it can introduce invisible nonproductive time into drilling operations, due to the array of complicated systems that must effectively interact with one another. For example, a typical MPD operation involves distributed control systems, additional human-machine interfaces, and stand-alone components that have limited integration with the rig.
National Oilwell Varco (NOV) is addressing the challenge, onshore and offshore, with a drilling system that combines holistic drilling performance optimization with an MPD system. Its new MPowerD MPD system includes a centralized control system that is permanently installed on the rig’s main drilling control network (Fig. 1) to provide robust, direct access to high-speed data from other drilling machines that influence wellbore pressure. The system integrates MPD functionality for precise, automatic, coordinated control of the main drilling machines, including the rig’s mud pumps, drawworks, top drive and MPD equipment.
MPD operations are placed on the driller’s control screen to enable more consistent process execution and safety, while the integrated, highly automated control system manages the electric MPD chokes. The system also allows for critical sub-activities, such as connections, to be customized and automated for consistent, high-level performance, minimized connection times, and maximized MPD system accuracy.
The integrated MPD system was installed recently for the first time on a deepwater drilling rig equipped with NOV’s CYBERBASE drilling control system, and a second ongoing installation is expected to begin work in early 2019.
MPD advances also include a first-of-its-kind land rig, designed and built from scratch to accommodate an advanced MPD system. The modular, extended-reach design is a collaborative effort between NOV and a customer, to address specific drilling campaign challenges. The rig integrates a high level of automation—including electric valves in the return system—to allow the driller to select main flow paths from the driller’s chair. Use of the integrated MPD control system gives the driller an unprecedented overview of the drilling process and ownership and control of key MPD parameters and set points.
The driller-operated MPD control system improves performance and consistency while significantly reducing cost by decreasing personnel requirements. Rather than having dedicated MPD field personnel on location, the MPD service is provided by the drilling contractor, while the OEM provides maintenance and remote support, leveraging equipment expertise with existing technology infrastructure.
NOV said it is important that the industry continues to push for integration of MPD systems with existing drilling control networks. Achieving the goal will provide essential MPD data on the primary driller’s screen. This allows monitoring and control of MPD parameters as part of standard operating procedures, versus trying to control the disparate pieces of a complicated system. The company believes true integration of MPD control systems will provide better overall performance, and relevant data for post-run optimization, at a more sustainable price, driving greater adoption and increased acceptance of this performance-enhancing drilling tool.
RIG CONTROL SYSTEM
Schlumberger’s PRECISE automated drilling system played an integral role in the industry’s move toward AC-powered, variable frequency drive (VFD) rig technology in the mid-2000s. At that time, the power systems required new controls to benefit from the precision that they offered. The automated drilling system’s modules were developed to control rig equipment from a wide variety of providers, while advanced power management features effectively ended blackouts.
Today, the system enables full control and direction of rig functions from a single control source, Fig. 2. Engineered to help achieve more efficient operations with less downtime, it is configurable to any number of human machine interfaces.
The automated drilling system interfaces with critical rig components, using remote I/O installed on the drawworks, top drive, mud pumps and drill floor. All controls can be accessed from the driller’s cabin through a combination of touch screens, discrete operators, and simple joystick controls. Each system also features an integrated talkback system to further improve rig site communication reliability.
In addition to equipment control, power management, advanced auto-driller and slip-stick capabilities, the system improves drilling performance by empowering the driller. For example, drilling choke control enables the driller to react faster under critical circumstances, such as well control situations, where pumps and choke must be managed simultaneously to achieve greater accuracy.
Drilling choke control integration eliminates the need for added panels or displays for the choke, speeding installation and saving space in the cabin. The system is easier to deploy to address wellbore instability, kicks and mud losses. The driller can input backpressure set points in the PRECISE system, and the MPD system automatically adjusts to the setting. Because the driller can directly control the MPD system, the need for wellsite MPD personnel also is reduced.
In directional and horizontal drilling, the automated drilling system increases drilling efficiency by operating in conjunction with a fully automated slide drilling system. The Slider Plus system creates rocking torque that, in turn, increases ROP during slide drilling. The directional driller simply enters the target tool face, and the system takes over by automatically maintaining tool face within acceptable limits and optimizing sliding ROP—providing more skill at the rig without adding more people.
Schlumberger said that maximizing the value of rig investment is a priority for every drilling contractor. For this reason, automation plays a paramount role in delivering the required drilling performance. Emerging automated drilling rig capabilities include the company’s drilling operations advisor service, which uses real-time downhole and surface data to analyze trends and patterns of the motor assembly, for recommending steering instructions that guide the bit along the well plan. The driller can then follow recommended steering and parameter-setting instructions using the PRECISE system. The directional advisor streamlines the directional drilling process, such that one directional driller in a remote operations center can simultaneously direct motor operations on multiple rigs.
MPD CONTROL AND AUTOMATION
Automation benefits have resulted in the use of MPD techniques as a technical and cost-reward solution for hard-to-reach assets. The approach not only saves time but also enhances the safety capabilities of the operation.
Weatherford said the evolving industry shift toward MPD-ready rigs creates a significant need for a reliable software system with conditioned-based maintenance (CBM) that interacts with the equipment, and simultaneously delivers precise control of annular pressure during any drilling operation.
Industry studies have demonstrated the operational benefits of MPD through the application of the constant bottomhole pressure (CBHP) method, embedded automated kick detection, and control capabilities. MPD technology relies substantially on applying surface backpressure (SBP), using automated chokes to precisely control the annular pressure profile in a closed loop circulation system. During drilling, CBHP connections, mud displacement, and fluid anomaly incidents, the SBP is dynamically adjusted in response to operational changes that yield annular pressure changes, such as circulation rate, top drive speed, and rate of penetration.
Weatherford’s OneSync integrated MPD drilling software platform is used in combination with interactive models, and surface and downhole data measurement, in a unified computing system to enhance real-time analysis of drilling performance. The automated MPD software has been used successfully in numerous onshore and offshore wells around the world.
By employing real-time models, such as hydraulics, well control, pore and fracture pressure estimation, and surge and swab, the system quantifies the boundaries and aids in understanding the real operational limits. Additional software platform applications deliver the common integration baseline that enables both operations within the pre-drilling, while-drilling and post-drilling analysis.
The company’s intelligent MPD system enables automated, repetitive, dynamic formation integrity tests (FIT), and pore pressure tests (PPT), without the need to stop circulation. Dynamic FIT and PPT are performed to safely confirm the upper and lower boundaries of the downhole pressure envelope, respectively, without causing downtime. In a dynamic FIT on an intact formation, the integrity of the entire open hole is confirmed by stepwise increasing the surface pressure until a predetermined set point, while the return flow is continuously monitored. If a loss is observed, the pressure is unloaded, and the downhole pressure where the micro-loss occurred provides the direct and precise measurement of the leak-off pressure. In a dynamic PPT, similarly, the surface pressure is stepwise reduced from an initial set point until a micro-influx is observed. (The well must be statically underbalanced for an influx to be observed.)
The MPD software tracks the system’s performance and health through a CBM system. CBM is optimal, when equipment has an age-related failure mode that can be measured and used for prediction. The equipment can either remain in service, on condition that it meets the relevant safety case performance standard, be taken out of service immediately, or be repaired on an opportunity basis.
CBM is premised on being able to identify a point of “potential failure” and having evidence that suitable monitoring and action can be carried out before functional failure occurs. The effectiveness of CBM is, therefore, dependent on failure mode identification, and measurement using primary, secondary and tertiary methods or sensors.
RCD performance monitoring has been included in MPD software, to predict bearing assembly seal life. Data captured during every job will eventually allow us to optimize bearing maintenance through data management and analysis. For example, if operations are performed at 70% dynamic pressure rating (DPR), and given adequate data, it will be possible to predict bearing assembly sealing life. Example data analytics now included are shown in Figs. 3 and 4.
Predictive RCD monitoring also allows establishment of a time interval for performing internal seal replacement, thereby avoiding a major overhaul, and redressing. This approach will yield significant cost savings to operators while improving operations, reducing NPT, and lowering operating costs.
MPD INTELLIGENT SYSTEMS
Weir Oil & Gas said innovative technology continues to impact the oil and gas industry, adjusting processes and creating increased efficiencies. One area that has long demanded a smarter approach is MPD and flowback operations. Outdated methods for monitoring vent-gas performance and measuring levels within the mud-gas separator, frac flowback tanks, and containment systems are less dependable, less accurate, and less efficient than they could be.
To address the challenge, the company redefined how pressure drilling is managed with a line of Pressure Control Intelligent Systems. The systems replace manual procedures with a safer, faster, more accurate, and more reliable Internet of Things (IoT) approach. The approach allows real-time information to be stored and applied with a variety of operational, analytic and reporting capabilities. Each system component includes sensors that transmit real-time information to a centralized onsite control unit. The data are relayed via a secure, cloud-based portal, accessible from desktop or mobile device, and stored in Weir’s electronic data warehouse for historical reference. If an issue were to arise with fluid levels or flowrates, onsite operators are alerted through local alarms, while remote stakeholders are notified on devices, giving teams more time to respond.
The systems were engineered for challenging or environmentally sensitive areas, and to help prevent the occurrence of kicks and overflows. They are designed to take the guesswork out of MPD and flowback operations by providing more reliable, local, real-time data and automated controls. Enhanced accuracy and control helps improve performance, simplify diagnostics, minimize environmental impact, and decrease non-productive time.
Weir’s modular Mathena surface control systems (Fig. 5) provide options for integration, as well as the ability to separately collect, monitor, analyze and notate the data. The modules include a mud gas separator intelligent system (Fig. 6) that provides precise measurements and automatically controls liquid levels within the mud gas separator. An industry first for drilling operations, the system helps prevent both gas overflow to the shakers and mud overflows to the vent line from occurring.
A vent gas analyzer and intelligent flow meter system provide integrated data to accurately measure gas flowrates and gas volume for methane and hydrogen sulfide. The information is used to improve reservoir evaluations, and provide more accurate information for EPA reporting of carbon footprint or methane release. An intelligent tank system provides precise measurement of liquid levels in secondary containment units. Designed to maximize safety and minimize environmental impact, it’s the industry’s first active, real-time monitoring system for containment levels. The Mathena technology also includes a frac flowback system that monitors flowrate data and level change within frac tanks.
Weir said the systems have been used in every major basin in North America and are providing increased visibility into operations, optimizing drilling performance and reducing overflow incidents. For example, a customer in the Rocky Mountain region was experiencing frequent incidents during high-pressure, nitrogen-aerated drilling operations. During these incidents, operators only had 16 min. to respond before the overflow from the system would be discharged through the igniter.
The mud-gas separator system was installed to monitor the levels on the mud-gas separator from top to bottom. The 16-min. response time became 3.5 hr, and the customer added the MGS-ISL to its remaining drilling fleet in the region. The solution eliminated overflows and non-compliance with environmental regulations, along with the associated vacuum trucks, shutdown and non-productive time, saving the customer hundreds of thousands of dollars over the course of a single year.
RIG AUTOMATION
Electronic interlocks on Schramm rigs are adding another level of safety by isolating or limiting functionality, Fig. 7. Advances in digital control and data acquisition make it much easier, for example, to prevent rotation during specific operations. Limiting torque, setting speed limits, and controlling rod joint make-up torque also helps avoid mistakes and improve crew performance. Exceeding pre-set operating parameters can trigger alarms, while the electronic systems make it easier to understand the machine feedback—such as automatic calculation of pressures and weight. The input also improves crew skills and competence. Because the control panel can be located away from the rig, safety is enhanced while improving visibility of rig functions and the drill crew activity. With a heated, cooled and protected cab, operators work in a safer, friendlier environment.
Schramm’s long-time focus on rig automation is shown in two current units. The T500XD rig is a 500,000-lb hookload, walking pad rig; the T250XD is a trailer-mounted, 250,000-lb hookload unit for top hole and horizontal drilling in excess of 10,000 ft. In addition to electronic interlocks and related technology, their capabilities include precise control of weight on bit, automated pipe-handling systems, and enhanced operator data acquisition systems designed to easily interface to third party performance monitoring devices. 
