Category: Oil & Gas

17 Aug 2018

OptaSense designation “Qualified Supplier” of North Sea

OptaSense recently earned the designation “Qualified Supplier” by Achilles JQS, the leading industry initiative for pre-qualifying suppliers in the Nordic market. This prestigious designation ensures that buyers in the North Sea oil and gas market can trust OptaSense to provide reliable service that meets all Nordic environmental and regulatory requirements.

14 Jun 2018

The Future Starts Here

OptaSense, a QinetiQ company, is featured in a new exhibition, The Future Starts Here, which opened last month at London’s prestigious Victoria & Albert Museum. The exhibition focuses on technologies that are shaping the way in which we live and interact as a society.

 

A featured project within the V&A exhibition is San Francisco-based Stamen Design’s Big Glass Microphone, which is an interactive visualization of OptaSense’s Distributed Acoustic Sensing (DAS) data from a system installation at Stanford University, California. OptaSense’s fiber optic sensing system is installed on five kilometers of fiber optic cable in the ducting below Stanford’s campus, as part of a research and development project for using DAS to detect seismic activity and potentially provide early warning of earthquakes.

 

Stamen Design’s project looks at how fiber optic infrastructure all around us can be leveraged as a sensor array. OptaSense converts fiber optic cables along pipelines, railways, roads and other assets into an array of ‘microphones’ by converting light into sound. On Stanford’s campus, the primary sensing goal is to detect seismic activity, but incidental day-to-day activity is also detected around the campus, like vehicles, students walking and cycling around, and even a fountain water feature. Big Glass Microphone is a data visualization of the distinct shapes that different kinds of surface events have on the sensing fiber optic cable. Using this information, an interactive visualization of the movements of people and vehicles within the campus was created.

 

The project is an offshoot of a collaborative research effort between OptaSense and the Stanford School of Earth, Energy and Environmental Sciences for an on-campus fiber optic seismic observatory, designed to sense ambient noise and seismic energy, enabling scientists to conduct research in passive seismology. Located adjacent to a major geologic fault zone, the San Andreas Fault, the seismic array is used to image subsurface properties that provide scientists a better understanding of the complex geology in the San Francisco Bay Area.

 

Big Glass Microphone gives a glimpse at how this unique “listening” device can also be used to provide ‘smart’ monitoring of infrastructure assets over long distance in real time, using ubiquitous sensors that are all around us, like fiber optic cables. OptaSense provide this monitoring technology already on around 20,000 miles of pipelines, railways, roads and other infrastructure around the world. Fiber optic sensing is a technology that is revolutionizing critical infrastructure monitoring, providing many applications from a single sensing platform.

 

“We’re proud to have OptaSense exhibited at one of the world’s leading museums for design and innovation,” said Jamie Pollard, CEO of OptaSense. “Technology can have a massive impact on people’s quality of life, and fiber optic sensing is a prime example. This exhibit demonstrates our earthquake detection potential but we’re also monitoring infrastructure assets all around the world, making people’s drive to work, or their energy consumption safer and more efficient. This exciting technology will become more and more widely known in the coming years.”

 

The Future Starts Here runs until November 4, 2018, then will continue at other locations around the world. For more information in the exhibition, visit www.vam.ac.uk. To learn more about OptaSense, visit www.optasense.com.

26 Feb 2018

SPE Hydraulic Fracturing Technology Conference

Join us at SPE Hydraulic Fracturing Technology Conference and Exhibition January 23-25 in booth 624 to learn more about our Distributed Fiber Optic Sensing (DFOS) and how it helps you monitor cluster efficiency and cross-well strain in real time to optimize fracture stimulation and reservoir understanding.

 

SPE Hydraulic Fracturing Technology Conference and Exhibition

23 – 25 Jan 2018 The Woodlands Waterway Marriott Hotel & Convention Center The Woodlands, Texas, USA

Booth # 624

13 Jul 2017

Real-time Cluster Efficiency

Distributed fiber optic sensing for uniform fracture stimulation

Evaluating stimulation performance and well spacing early in development can increase a projects Net Present Value. This is especially true when developing stacked intervals.  For example, studies have shown that plug-and-perf completions often produce under-performing perforation clusters and undesired inter-well communication.

To address under-performing perforation clusters, operators are combining Distributed Acoustic Sensing (DAS) and Distributed Temperature Sensing (DTS)measurements to calculate the amount of fluid and proppant placed in each cluster on the fly to enable optimized decision-making throughout a project ensure more effective fracturing on current and future wells.

Recent observations from fiber optic DAS and DTS indicate that a majority of treatment volume is limited to only one or two dominate clusters near the heel-side of a treatment stage—leaving the remaining stage clusters under stimulated.

With a large majority of perforation clusters failing to contribute to production, you can’t help but ask: Where’s my proppant going and why?

Assessing cluster efficiency, fluid distribution and diverter effectiveness

There are many possible reasons for uneven reservoir stimulation, such as stress shadowing interference between fractures, local heterogeneity, the effectiveness of zonal isolation between stages, stimulation design (pumping schedules and fluid/proppant selection), and the variation in natural fracture systems surrounding the well.

Fiber optic monitoring, such as DAS and DTS can be used to assess cluster efficiency, fluid and sand distribution and diverter effectiveness.

On a recent spacing pilot in the Anadarko Basin, home to several stacked interval reservoirs, a five-well project equipped with OptaSense Distributed Fiber Optic Sensing offered another explanation for the heel-side bias. For this project fiber optic derived DAS and DTS measurements provided the operator an opportunity to monitor fluid movement during fracture stimulation and warm-back before the well was produced.

Monitoring distribution

During treatment, acoustic and temperature data confirmed inadvertent diversion away from toe-side clusters, and acceleration of the already-dominant heel-side clusters. Using algorithms applied to DAS data, proppant volumes per cluster were calculated revealing highly uneven proppant distribution among multiple clusters even when fluid is uniformly distributed

The DAS measurements captured in this pilot project suggested a strong heel bias was present in a majority of stages. The uneven distribution, caused by interference between adjacent fractures within a given stage and from preceding fracture stages, resulted in a consistent geometric predominance for fracture growth toward the most heel-ward perforation cluster.

A variety of completion variables, such as perforation designs, fluid systems, diverter and proppant size, were tested to identify the optimal treatment for improved fluid distribution.

Simulating distribution

Using these measurements, the operator used calculated proppant placement to monitor diversion efficiency in real-time during the fracture and took action to modify the treatment, which resulted in more even fluid and treatment distribution. After modeling the improved distributions derived from fiber optic monitoring, a new well completion and stimulation design resulted in more equal fracture heights and half lengths, as well as increased the overall effective fractures in the wellbore.

Multiple optimizations in pressure pumping strategy were discovered during the variable testing using real-time DAS and DTS. The pumping schedule was altered to test different rations of slick water and high viscous fluids, ratios in proppant sizes and concentrations of proppant within the various fluids.

Optimizing distribution

Using DAS and DTS to estimate fluid and proppant placement enabled the operator to identify the root problem and implement an effective proppant and fluid treatment (aligned with an optimized pressure pump schedule) that mitigated the uneven stimulation. The result, improved cluster efficiency and more uniform proppant/fluid distribution on current and future stages and wells.

15 Dec 2016

Enabling Cost-Effective Sweep Efficiency with DAS-VSP

Offshore brownfield exploitation generally involves operating in remote, environmentally sensitive areas that have geologic basins with complex overburden, structure and stratigraphy.

In these geologically challenging areas, Ocean Bottom Node (OBN) seismic acquisition is the technology of choice for a number of reasons; the most important being its ability to capture a high quality seismic image, which is critical for characterizing time-lapse response of the reservoir.

Due to the high acquisition cost, many mature reservoirs using an OBN approach for time-lapse imaging are surveyed several years apart, resulting in the missed opportunity to effectively manage and understand the reservoir.

To eliminate this risk, a supermajor operating in the Gulf of Mexico contacted the OptaSense team with the goal of identifying a low-cost alternative that would enable comparable or better quality seismic surveys at more frequent intervals.

Rethinking borehole seismic

Technology plays crucial role in providing the information to make sound exploration decisions. Given the complexity and high cost of deepwater development, there is great value in being able to identify the best spots to drill wells and manage production methods for field exploitation. This skill hinges on generating an accurate picture of the subsurface. Seismic technology lies at the heart of this process and was a key research priority for our client.

Vertical Seismic Profiling (VSP) has long been considered a possible solution for deepwater seismic imaging; however, high cost and practicality have made it unfeasible for many operators. Since the introduction of Distributed Acoustic Sensing (DAS) VSP technology, these concerns have essentially been eliminated.

Putting DAS to the test

Concept testing for the low-cost, on-demand DAS-VSP solution included several aggressive objectives, one being surveying reservoirs lying below thick salt formations which are notoriously challenging to image. Additional objectives included demonstrating repeat DAS acquisition using multimode fiber, acquiring DAS on active production and injection wells, and providing quick on-demand service for time-lapse monitoring of sweep efficiency.

To meet these objectives, OptaSense recommended running their DAS-VSP borehole seismic acquisition service, capable of acquiring 2D, 3D and 4D VSP data, and the fourth generation ODH-4 DAS interrogator unit (IU) for its unmatched imaging and measurement performance.

The ODH-4 provides a 6 dB improvement in signal-to-noise ratio over its predecessor—delivering the highest fidelity VSP measurements available. In addition to higher quality seismic imaging, the ODH-4 offers increased sensitivity, finer spatial sampling (1.02m) and finer spatial resolution of (4.02m gauge length) to capture high-caliber image resolution.

Subsalt imaging

Oil and gas is commonly trapped subsalt, or near salt flanks.Incidentally, imaging near and below the large salt structures is naturally problematic for any surface or OBN seismic program. One of the best known methods to properly image these areas is a VSP survey, which enables access to these obscure locations. However, these wellbores commonly have high deviation and high entry to access costs, making the use of conventional geophones unfeasible.
The ODH-4 IU instead transformed the operators existing fiber optic cable attached to production casing into an array aperture to acquire VSP data across the entire wellbore.

Multimode fiber acquisition

By retro-fitting our DAS technology to pre-existing multimode fibers, OptaSense provided permanent, on-demand DAS-VSP access at no extra cost to the operator. Although DAS was originally developed for single-mode fibers, most legacy fiber optic installations are multimode.

By continuously pioneering the evolution of DAS technology, OptaSense has proven quality DAS measurement can be acquired on either single-mode or multimode fiber—enabling on-demand acquisition of quality seismic surveys from wellbores with existing fiber.

VSP acquisition on active production and injection wells

With OptaSense DAS-VSP borehole seismic acquisition service, the operator successfully acquired VSP data on actively producing and injecting wellbores during acquisition operations. Such a practice would be unthinkable with geophones.

In some cases, a mature field may not have suitable placement for, or the existence of, an observation well. This can impact an operator’s ability to monitor production, as well as optimize future well placement. Our DAS-VSP eliminates the requirement of observation wellbores for VSP imaging, while providing on-demand, direct monitoring of production and injection zones.This ensures operators receive the subsurface insight required to control current operations and optimize future placement of injector and producer wells.

OptaSense DAS-VSP also provides the ability to acquire data on active wellbores without shutting in operations—resulting in greater VSP imaging coverage at favorable economic costs.

On-demand 4D time-lapse

Due to cost, 4D VSP acquisition at shorter intervals may not be feasible. However, the OptaSense DAS-VSP service is flexible, quickly mobilized and offers favorable economics for repeat acquisition monitoring.
Through the use of our DAS-VSP 4D time-lapse service, the operator effectively monitored conditions throughout the reservoir over time—increasing recovery, optimizing cost, reducing risk and extending the life of the field.

Unmanned VSP services

Manned operations for recording instruments can amount to significantly increased risk and cost depending on the duration and location of the program. Through the use of a suitable internet connection OptaSense can provide unmanned VSP services through remote monitoring of OptaSense equipment and data. This significantly reduced cost and HSE exposure for our client by reducing lodging, substance and day rates for an onsite operator, in exchange for a daily remote monitoring fee.

Exceeding expectations

The quality of the DAS-VSP acquired using our ODH-4 IU surpassed our client’s expectations. This included data collected on multimode fiber, actively producing and injecting wellbores and those positioned subsalt.

Imaging objectives for 4D reservoir monitoring continues to be successfully met and our client is looking forward to expanding DAS-VSP service for regular time-lapse monitoring of their asset. In just a short period of monitoring, our client is moving forward with DAS-VSP service as an integral part of sustainable field development. They have realized added value with the service’s seamless application and the capability to remotely monitor the equipment and program. Our client highly advocates the installation of fiber optic cables for new offshore wells, and utilizing existing fibred wells to take full advantage of DAS for VSP acquisition.