The XACT acoustic telemetry network features sensing tools that are incorporated into the drill string every 4,000-5,000 ft. These tools act as both repeaters to help carry acoustic signals along the pipe up to surface and as separate measurement points. Because the signal is sent through the pipe, the network enables data collection at any point that drill pipe is in the well.
Obtaining any downhole data, in real time and particularly during completion installation operations, can be a challenge for deepwater operators using conventional methods such as mud pulse telemetry. XACT Downhole Telemetry has developed an acoustic telemetry network that can be incorporated into standard drill strings to provide real-time telemetry and distributed measurements along the length of the wellbore any time the drill pipe is downhole.
“Being able to send acoustic signals through drill pipe, which is in the hole for almost 90% of all operations, means that you now have the potential to access data 90% of the time,” said Andy Hawthorn, Director of Applications at XACT.
The system consists of nodes that resemble drill collars and pick up and handle like drill pipe. They are incorporated into the drill string every 4,000 to 5,000 ft. These nodes act as repeaters for the acoustic telemetry but also individually measure internal and external temperature and pressure, weight, torque and bending moment. A high-voltage charge is sent across a piezoelectric stack, which generates an acoustic signal that is carried up the drill string to the surface.
Once the signal reaches the surface, it is captured by the XACT Electronic Acoustic Receiver, which is attached to the top drive or frac head. The receiver then wirelessly sends the data to an onsite computer, from which the data is integrated with other surface data and shared with real-time operations centers or other offices.
Because the acoustic signal travels up the wall of the drill pipe, the network is independent of formation, fluid and flow. While electromagnetic telemetry systems can experience transmission problems in some formations, the XACT network has been designed to transmit effectively in all formation types, according to the company.
Measurement systems that are dependent on fluid flow to gather or transmit data cannot provide data when tripping or when the pumps are off. Mr Hawthorn said industry data indicates that 75% of kicks occur off bottom or while tripping. The XACT telemetry network’s ability to work in low- or no-flow situations also means it is effective in managed pressure, underbalanced and total loss situations.
Because each node takes separate measurements in addition to boosting the signal, the network provides distributed measurements that allow the users to observe what is happening downhole through every section of the well, rather than relying on only bottomhole and surface measurements, or analyzing data after the fact.
“Our system is about providing more intelligence about downhole conditions in real time than exists today,” said Jason Roe, XACT President and CEO. “It enables decisions that operators don’t currently have the ability to make in real time. Right now, it’s just analyzed after the fact and applied to the next well. This system allows you to analyze downhole conditions and apply solutions immediately to efficiently and reliably drill and complete your well in a cost-effective manner.”
The network is also fully through-bore so operators can cement, frac, drop balls and pass wiper darts with the system in the wellbore.
BP and Shell sponsored the development of the acoustic telemetry network. Working closely with these major operators not only allowed XACT access to multiple wells for testing and proving the system, but it also helped the company know exactly what problems operators are facing and to develop a solution that addresses those problems. “The last thing you want to be is a solution looking for a problem, and as well complexity continues to increase, so does the need for better understanding of downhole conditions in real time,” Mr Roe said.
XACT’s acoustic telemetry network has been used in multiple deepwater wells for real-time applications, including cementing, liner running and during a frac pack installation, in the deepwater Gulf of Mexico. These applications have largely targeted areas where downhole data was previously not available in real time.
Looking to the near-term future, the company is working to make the network fully bidirectional by building on the current network capabilities.
“The beauty of this telemetry system is that when you induce signals in the pipe, they naturally travel both directions,” Mr Hawthorn said. “What we’re working on as a part of the network evolution is bi-directionality so we can talk down to tools, as well as receive data.” This would allow operators to send signals through the telemetry network to change the settings or configurations of tools or other mechanical devices when needed.
XACT Downhole Telemetry, in conjunction with BP, recently completed the first operational field trial of the SandSentry Acoustic Telemetry Network in the deepwater Gulf of Mexico.
The SandSentry measurement and telemetry tools provide downhole measurements of weight, torque, bending, pressure and temperature, and wirelessly transmit this information to surface regardless of flow, depth or formation type. The system provides real-time downhole measurements in challenging environments where data is currently not available, while offering simple integration opportunities into existing rig operations.
In late October, two collar-based, full through-bore SandSentry tools were deployed during a deepwater Gulf of Mexico completion operation. These tools were designed to meet the harsh conditions and challenging loads seen in today’s deepwater well construction environments. They demonstrated their ability to transmit and receive downhole data during flow and no-flow operations and exceeded acoustic-performance expectations, including demonstrating transmission ranges of greater than 5,000 ft between measurement nodes while operating at reduced transmission power settings.
“We are thrilled with the success of our first deepwater deployment of the SandSentry Acoustic Telemetry Network,” Jason Roe, President and CEO of XACT, said. “We are very thankful to BP Ventures and BP Upstream Technology for their commitment to XACT and to BP’s Gulf of Mexico Region for the opportunity to demonstrate our system’s capability. We look forward to continuing our close working relationship and to further demonstrate how our Network can reduce risk and improve efficiency in operators’ well construction processes.”
Mark Barrilleaux, Completions Advisor for BP, added, “BP has been at the forefront of real-time well monitoring technology, and we are excited to be a part of yet another innovative project in this area. This successful field trial demonstrates the clear potential of XACT’s acoustic telemetry system, and we look forward to commercial application of this technology.”
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