Fiber Deployment Research Articles

Experimental Demonstration of Multigigabit Data Communication Using Surface Waves on Twisted-Pair Cables

The demand for higher broadband speeds is ever increasing whereas the deployment of full fibre to the premises is slower than initially predicted and remains costly. Solutions exploiting the existing, ubiquitous, copper network and increasing its capacity would be highly beneficial in the near term. One approach is to use surface wave (SW) transmission mode to transmit signals over the existing copper cabling network. We present proof-of-concept experimental SW data transmission on twisted pair cables. A surface wave launcher for low GHz carrier frequency operation is designed and optimised. Experimentally, we demonstrate data rates in excess of 12 Gb/s in a 1.15-3.25 GHz band over a 6.1 m twisted pair cable with an average bit error rate of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.25 \times 10 ^{-5}$ </tex-math></inline-formula> , without coding or feedback implementation. Furthermore, higher frequency bands are tested with data rates up to 3.4 Gb/s displaying their potential for surface wave transmission. S-parameter measurements allow capacity estimations of SW data transmission on longer cable lengths using water-filling algorithms. Our calculations predict over 13 Gb/s capacity on a 100 m cable using a 3.5 GHz transmission bandwidth, this may be further extended by further increases to the bandwidth used for SW transmission.

New Algorithm for a Fixed Right Shift Code to Support Different Quality of Services in Smart and Sustainable Optical Networks

Smart and sustainable cities require a network that can ensure many exchanges of information. In this sense, the deployment of optical fiber seems essential in order to guarantee urban interconnection. In this work, a new algorithm for the right shift code to be used in optical fiber communication (OFC) is proposed. The algorithm was designed to support different quality of services (audio, video, and data) for smart cities. This algorithm was based on varying the code weight for a certain number of users and transmitting a service to them. This algorithm was used for a spectral amplitude-coding optical code division multiple-access (SAC-OCDMA) system. Two detection scheme approaches were used, which are the single photodiode (SPD) detection technique and the direct detection (DD) technique. The performance was analytically studied for the proposed system in terms of BER, SNR, and the maximum number of users. The obtained results, when our system used SPD, showed an improvement in the number of users, about 2.5% at 622 Mbps and 1.4% at 1.25 Gbps and 2.5 Gbps. It can support a number of users up to 151 for video services at BER = 10−12, 300 for audio services with BER = 10−3, and 162 for data services at BER = 10−9 at a data rate of 1.25 Gbps. Furthermore, the system was simulated and showed transmission distances of 30 km at 1.25 Gbps and 6 km at 2.5 Gbps for video services, 80 km at 1.25 Gbps and 30 km at 2.5 Gbps for audio services, and 44 km at 1.25 Gbps and 13 km at 2.5 Gbps for data services. Our proposed system is suggested to be implemented in a fixed fifth-generation passive optical network (F5G PON).

Deformation and Damage Characteristics of Deep Rock Specimens Based on 3D-DIC and FBG

Abstract Specimen-scale testing of loaded rock parameters is an important research component of rock mechanics testing. In this paper, a method combining 3D-DIC and FBG (fiber Bragg grating) technology is proposed and applied to the study of deformation and damage characteristics of deep limestone and sandstone specimens under uniaxial loading conditions in the Panxie mine area of Huainan coalfield. The selection of optical fiber, the bonding method, and the process of rock specimen fabrication are introduced in detail. Two different fiber Bragg grating sensor arrays were constructed by using both multi-inclination type and orthogonal type deployment of fiber grating to dynamically monitor the strain response of rock specimens throughout the whole process. The results show that both 3D-DIC displacement monitoring and fiber Bragg grating strain captured the rock deformation and failure process well with identical outcomes. Under a continuous load of 0.3 kN/s, the local cracks of the rock specimen and the damage to the rock specimen resulted in different degrees of sudden changes in the fiber strain value. According to the differences in the degrees of brittleness and texture densities of the rock specimens, the local cracks evolution to transfixion of the limestone registered a certain time accumulation and produced more local cracks, while the sandstone at the same stage produced fewer local cracks within a shorter duration. The effective combination of regional noncontact testing and high-precision point contact can dynamically and accurately capture the rock deformation and damage characteristics at the specimen scale. In addition, the combined monitoring method of 3D-DIC and fiber grating can provide assistance in the prediction of rock crack expansion and potential fracture surfaces.

The Implementation of Dispersion Effect on Rise Time Budget and Power Link Budget on Optical Links at PT Telkom Akses Rungkut Surabaya Website Based

Along with the development of an increasingly rapid era, it is directly proportional to the development of technology. Optical fiber is a transmission medium used in telecommunications. The quality of information transmissions through this cable transmission medium is influenced by a number of variables, including attenuation and dispersion. The rising time budget value is determined by the dispersion, and the power link budget is determined by measuring the attenuation that influences the light's path during data transmission and causes dispersion. The results showed that the chromatic dispersion value of the measurement results on this optical link was influenced by bending, the length of the distance on the path, the splicing of optical fibers, and due to the deployment of optical fibers. The system still performs at the required levels, i.e., at a power link budget of less than -15 dBm and a rise time budget of less than 70 ps, hence the optical link results have no impact on the system's performance. The results of the implementation of the website in this study display the results of measurements and calculations that were previously carried out where the results of these measurements and calculations can be seen in a table that has been integrated between databases to store data values ??with an online map which is then displayed the value on the map or online maps on the website containing data from the measurement results and parameter calculations on optical fiber owned by PT. Telkom Access.

A comprehensive study on radio over fiber systems: present evaluations and future challenges

Abstract In order to serve the explosive demands of triple play services or multimedia services with high quality of data transmission in Fifth Generation (5G) communication systems which has availability of large spectrum unlike Fourth Generation (4G), low latency, improved transmission, and increased reliability, an access networks with optical fiber distribution network and wireless enabled technology is urgently needed and therefore, a prominent technology known as Radio over Fiber (RoF) is suggested by researcher/Scientists due to a perfect blend of flexible fiber technology and wireless mobility. RoF technology is helping the data transmission systems from last thirty years with great success and has numerous advantages such as scalability, transparency, antenna site complexity reduction, low installation cost, accessibility of radio carrier by diverse antenna sites dynamically. Millimeter waves (Mm waves) integration in 5G wireless RoF systems comes out to be an encouraging candidate to cater the bandwidth hungry current as well as future generation internet application such as high definition TV (HDTV), online games, video conferencing, and voice over IP (VoIP) etc. For the prolonged reach, economical installations, and improved performance, optimal Mm wave generation methods should be incorporated in 5G such as employing multi carrier generation technique (MCG). Deployment of single mode fiber (SMF) in 5G offers high speed, large capacity, improved security, etc., but also has a prominent limitation of nonlinear effects and it is unwanted phenomenon which degrade the system performance by introducing intermodulation distortion, distortion of signal phase, harmonic distortion, and interference in the neighbouring channels. Minimum modifications of architecture and minimum cost should be spent on the compensation of nonlinear effects or Kerr’s effects in RoF systems and recently mode division multiplexing has emerged as an ultimate solution. In this review article, detailed discussion of an evolutionary technology, i.e., RoF is presented with a literature review, present evaluations, and future challenges. Our utmost goal is to enrich the young researchers with precious aspects for RoF technology on single platform and also encourage them to conduct the technology advancement research works in various fields such as nonlinear compensation, Mm wave generation, dispersion compensation, cost reduction, complexity reduction, and security enhancements for 5G RoF systems.

Benefits of counterpropagating Raman amplification for multiband optical networks

Multiband (MB) optical fiber transmission systems can unlock additional capacity in existing optical fiber infrastructures, enabling them to keep up with the increase in traffic demand while postponing costly optical fiber deployments. However, due to the worse transmission characteristics of MB systems than C-band-only transmission, the network’s overall spectral efficiency decreases when increasing the transmission bandwidth. The extent of this performance degradation is paramount to determining the commercial viability of deploying MB systems. By estimating the generalized signal-to-noise ratio using the GNPy library, this work analyzes the impact of using counterpropagating Raman amplification to improve the performance of an S + C + L -band transmission system comprising a total bandwidth of 15.5 THz. Raman amplification is proposed to mitigate the worse system performance resulting from the stimulated Raman scattering effect and the worse noise figure of the S-band optical amplifier. We show that the optimized deployment of a counterpropagating Raman pump makes it possible not only to improve but also to equalize the network-wide optical performance of the S + C + L -band transmission system, which potentially reduces the complexity of routing and wavelength assignment algorithms. The capacity, spectral efficiency, and number of feasible lightpaths of the S + C + L -band system are compared with C- and C + L -band systems with and without Raman amplification on two reference networks. Results show that the spectral efficiency of the S + C + L -band system with Raman amplification is similar to the C-band-only system without Raman amplification. These results provide evidence that this strategy can be effectively used to compensate for the worse transmission characteristics of MB systems, the higher noise figure of the S-band optical amplifier, the SRS effect, and the additional losses from the band demultiplexer and coupler required at every amplification stage to separate the transmission bands. Overall, the simulation results highlight that a single optical fiber can approximately carry the same data when using a 15.5 THz transmission band (and Raman amplification) as three parallel fibers using C-band-only transmission (without Raman amplification).

Advanced Modeling of Surface Waves on Twisted Pair Cables: Surface Wave Stopbands

At the network access layer, optical fiber deployment continues at pace but copper cables containing twisted pairs (TWPs) will remain for some time and face an increasing bandwidth and data rate demand. Surface waves have been proposed to address these requirements. This article reports and investigates the existence of stopbands reaching over 50-dB insertion loss on 1-m-long, typical final drop cables under surface wave excitation at a few gigahertz. Coupled mode analysis shows that lack of helical symmetry enables the formation of a stopband in systems containing TWPs. A representative core model containing a single TWP alongside a straight wire is thoroughly studied. Numerical simulations and measurements confirm the crucial dependence of the stopband frequency on the twist rate of the TWP. Further investigation into the role of the dielectric coating and the distance of the straight wire is performed as well. Finally, in systems with multiple TWPs, we find that the twist rate associated with any pair can create a stopband effectively limiting surface wave propagation. Thus, careful design and deployment strategies are required for use of surface waves on legacy copper networks.

A Review of Distributed Fiber–Optic Sensing in the Oil and Gas Industry

Fiber&#x2013;optic sensors have been widely deployed in various applications, and their use has gradually increased since the 1980 s. Distributed fiber&#x2013;optic sensors, which enable continuous and real&#x2013;time measurements along the entire length of an optical fiber cable, have undergone significant improvements in underlying industries. In the oil and gas industry, distributed fiber&#x2013;optic sensors can provide significantly valuable information throughout the life cycle of a well and can monitor pipelines transporting hydrocarbons over great distances. Here, we review the deployment of fiber&#x2013;optic Rayleigh&#x2013;based distributed acoustic sensing (DAS), Raman&#x2013;based distributed temperature sensing (DTS), and Brillouin&#x2013;based distributed temperature and strain sensing (DTSS) in the oil and gas industry. In particular, we describe the operation principle and basic experimental setups of the DAS, DTS, and DTSS, highlighting their applications in the upstream, midstream, and downstream sectors of the oil and gas industry. We further developed a prototype of a fiber&#x2013;optic hybrid DAS&#x2013;DTS system that simultaneously measures vibration and temperature along a multimode fiber (MMF). The reported hybrid sensing system was tested in an operational oil well. This work also discusses the challenges that might hinder the growth of the distributed fiber&#x2013;optic sensing market in the petroleum industry, and we further point out the future directions of related research.

Investigation of Strain Fields Generated by Hydraulic Fracturing with Analytical and Numerical Modeling of Fiber Optic Response

Summary The use of fiber optics in reservoir surveillance is bringing valuable insights into fracture geometry and fracture-hit identification, stage communication, and perforation cluster fluid distribution in many hydraulic fracturing processes. However, given the complexity associated with field data, its interpretation is a major challenge faced by engineers and geoscientists. In this work, we propose to generate distributed strain sensing (DSS)/distributed acoustic sensing (DAS) synthetic data of a crosswell fiber deployment that incorporates the physics governing hydraulic fracturing treatments. Our forward modeling can be used to add value to the interpretation task. The forward modeling is based on analytical and numerical solutions. The analytical solution is developed integrating two models: 2D fracture (e.g., Khristianovic-Geertsma-de Klerk known as KGD) and Sneddon’s induced stress. DSS is estimated using the plane strain approach that combines calculated stresses and rock properties (e.g., Young’s modulus and Poisson’s ratio). On the other hand, the numerical solution is implemented using the displacement discontinuity method (DDM), a type of boundary element method, with net pressure and/or shear stress as the boundary condition. In this case, the fiber gauge length concept is incorporated deriving displacement (i.e., DDM output) in space to obtain DSS values. In both methods, DAS is estimated by the differentiation of DSS in time. The analytical technique considers a single fracture opening and is used in a sensitivity analysis to evaluate the impact that rock/fluid parameters can promote on strain time histories. Moreover, advanced cases including multiple fractures failing in tensile or shear mode are simulated applying the numerical technique. Results indicate that our models are able to capture typical characteristics present in field data: heart-shaped pattern from a fracture approaching the fiber, stress shadow, and fracture hits. In particular, the numerical methodology captures relevant phenomenon associated with hydraulic and natural fractures interaction, which is often interpreted purely in terms of opening fractures. We can anticipate that the developed forward modeling, when embedded in a classification or regression artificial intelligence framework, will be an important tool adding substantial insights related to field fracture systems that ultimately can lead to production optimization. Also, the development of specific packages (commercial or otherwise) that explicitly model both DSS and DAS, incorporating the impact of fracture opening and slippage on strain and strain rate is still in its infancy. This paper is novel in this regard and opens up new avenues of research and applications of synthetic DAS/DSS in hydraulic fracturing processes.

Towards an Understanding of the Effect of Adding a Foam Core on the Blast Performance of Glass Fibre Reinforced Epoxy Laminate Panels.

This paper presents insights into the blast response of sandwich panels with lightweight foam cores and asymmetric (different thicknesses) glass fibre epoxy face sheets. Viscously damped elastic vibrations were observed in the laminates (no core), while the transient response of the sandwich panels was more complex, especially after the peak displacement was observed. The post-peak residual oscillations in the sandwich panels were larger and did not decay as significantly with time when compared to the equivalent mass laminate panel test. Delamination was the predominant mode of failure on the thinner facesheet side of the sandwich panel, whereas cracking and matrix failure were more prominent on the thicker side (which was exposed to the blast). The type of constituent materials used and testing conditions, including the clamping method, influenced the resulting failure modes observed. A probable sequence of damage in the sandwich panels was proposed, based on the transient displacement measurements, a post-test failure analysis, and consideration of the stress wave propagation through the multilayered, multimaterial structure. This work demonstrates the need for detailed understanding of the transient behaviour of multilayered structures with significant elastic energy capacity and a wide range of possible damage mechanisms. The work should prove valuable to structural engineers and designers considering the deployment of foam-core sandwich panels or fibre reinforced polymer laminates in applications when air-blast loading may pose a credible threat.

A Critical Assessment of A-D Strips® Used in Degradation Studies of Artworks Made from Cellulose Acetate

ABSTRACT Acid-detecting strips (A-D Strips®) available from the Image Permanence Institute (IPI) and third-party suppliers outside the USA were originally developed to detect volatile acids from deteriorating film stock made from cellulose acetate (CA) by using a five-step colour scale to represent acetic acid concentration. The strips are shown here to be sufficiently sensitive for the detection of acetic acid as a volatile organic compound (VOC) generated by degrading CA in objects in storage. In confined spaces, the local air concentration of VOCs can deviate significantly from background levels due to low air circulation and interaction with solid materials and can be explored by this means. The usefulness of placing a number of A-D Strips® with CA-based artworks stored in closed containers, instead of or during the deployment of SPME fibres to monitor the degradation of these plastics, is assessed critically. The useful level of indicative and semi-quantitative information they can offer in such practical situations is presented. It is proposed that an interpretation of acetic acid concentration on an eight-step colour scale of measurement of b* in CIELAB1976 colour space with a hand-held spectrophotometer, or visual comparison with the IPI-provided colour scale is more useful than a direct calculation of concentration, because placement around stored objects introduces significant measurement errors. This paper gives guidance on the limitations and benefits of using A-D Strips® as a low-cost passive monitoring tool for CA-based objects, whether visibly degraded or not. The guidance is also relevant for monitoring VOCs derived from wood-based crating materials used in museum storage areas, which also generate acetic acid.

Transparent multichannel wireless bridge for optical fiber links based on a two-stage upconversion

A bridge architecture enabling seamless wireless interconnection within an optical fiber link is studied. Optical baseband data is remodulated by local oscillators using two stages to allow efficient and cost-effective upconversion. Proof-of-concept experiments show the feasibility of the approach. Direct operation with standard optical signals and ease of integration in the conventional optical fiber infrastructure define the transparency property of this subsystem, which represents a potential solution to restore data traffic in scenarios where fiber deployment is uneconomical or a disaster has taken place.

Fiber Optic-Based Thermal Integrity Profiling of Drilled Shaft: Inverse Modeling for Spiral Fiber Deployment Strategy.

The current state of practice to interpret the thermal integrity profiling (TIP) data of drilled shaft is the so-called effective radius method. It uses the concrete pouring log and average temperature to construct a relationship between temperature distribution and effective radius that can be used to reconstruct a drilled shaft model. While this effective radius method is computationally inexpensive and has good operationality, it is not good at predicting the dimensions and shape of shaft defects. Upgrading the sensor used in conventional TIP from thermocouples/thermal wires to fiber optic sensors, the spatial resolution of the measured temperature will be enhanced. By using the newly proposed spiral fiber deployment strategy, we can improve the reconstruction of shaft defects in the integrity testing of drilled shafts. The corresponding inverse modeling of defected shaft reconstruction for spiral deployment is proposed in this paper based on the temperature distribution pattern that is learned from forward modeling. Through inverse modeling, the details of defects in drilled shafts can be reconstructed numerically. An analysis of the results shows that the prediction by inverse modeling has good agreement with the forward modeling set up initially. This work helps the evolution of the TIP from the nondestructive testing stage to the quantitative nondestructive evaluation stage.

Fault‐tolerant wireless‐optical broadband access network with cluster‐controlled architecture

SummaryThe ever increasing demand in wireless connectivity has led PON networks suffer from limitations in mobility and wide area coverage. Wireless networks suffer by bandwidth limitations. Hybridization uses the best characteristics of all networks: wireless networks and optical networks. A lightweight wireless mesh network is a wireless‐optical broadband access network (WOBAN), which has a front end and background effective bandwidth optical network. WOBAN has already suffered from two large network feature faults as well as feeder and fiber breaks. Cluster‐based protection (CBP) mechanism is proposed in order to increase traffic recovery reliability and reduce backup fiber deployment. With minimal fiber distribution cost, CBP efficiently manages single and simultaneous failures from many segments. Long‐term evolution (LTE) technique‐based CBP is implemented in WOBAN. Faults are analyzed by injecting wireless/distribution fiber/multiple feeder fiber. The novel fault tolerant network is built using an efficient automated failure detection and rerouting (AFDRR) algorithm. An efficient automated failure detection and rerouting (AFDRR) algorithm is used for developing the novel fault‐tolerant network. Implementation of orthogonal frequency division multiplexing (OFDM) technology‐based AFDRR‐CBP on WOBAN‐LTE network with the same scenario is analyzed through simulation. The performance measures are compared among CBP‐WOBAN‐LTE network, AFDRR‐CBP‐WOBAN‐LTE network, and OFDM‐based AFDRR‐CBP‐WOBAN‐LTE networks. From the result obtained, it will be revealed that the suggested methodology throughput ratio will increase up to 24.4% when compared to other methodology.

Deploying Fiber in Appalachia: a Study of Fiber Deployment, Challenges, Funding, and the Impacts of Broadband Connectivity in Eastern Kentucky

We present insights from a fiber network deployment in Eastern Kentucky. The Peoples Rural Telephone Cooperative (PRTC) operates FTTH services in Jackson and Owsley counties. PRTC is part of a group of 5 companies in the region that maintains a 360-mile fiber ring, across 9 counties in the Eastern Kentucky Concentrated Employment (EKCEP) Local Workforce Area (LWA). A similar group operates Appalachian Wireless cellphone service in the region, which has been in operation for over 25 years and has approximately 130,000 customers. In this paper, we provide a brief history of PRTC, a case study of the deployment of the fiber network, and a summary of the impacts of the fiber deployment. PRTC has been operating in the region, in Jackson and Owsley counties, since 1950. Originally constituted as an entity that would provide the region with POTS, the company has steadily evolved through the decades, rebuilding its networks many times to stay up to date with current technologies. The latest example being the deployment of a fiber network for the region that provides fiber internet to residents, at network speeds available in many “well-connected” urban areas of the country. The degree of adoption – as of March 2021, 5709 customers across the 2 counties, and an additional 1030 customers in neighboring counties – indicates that there is indeed a market for such services where we are often told that demand is soft or does not exist. The impacts of the deployment are immediately observable. Over 1100 Tech or related jobs have been added in the region through 2 workforce hubs in EKCEP. Educational access has improved with individuals being able to attend online classes. Veteran telehealth services are being provided through a specialized pilot with the Lexington, KY VA hospital with a customized videoconferencing room at the Jackson County Public Library. The local library and schools have fiber connectivity (the school system has been fiber connected since 2005). We present more details about these impacts in the full paper. There are several takeaways from our study: 1) like the building of the electric and telephone infrastructures in relatively remote areas, the digital divide isn’t going to get “magically solved” unless there is a concerted effort through public-private initiatives and partnerships, beginning with significant Federal investment; 2) the customer base of PRTC (and Appalachian Wireless) indicates that once the initial investment deployment hurdle is overcome there is indeed a base of customers for these services, which in turn challenges the expressed point-of-view of larger telecom operators; 3) local operators and community leaders have a strong sense of what is needed in their communities, and with appropriate support can deploy the services that are needed; 4) at the same time, even for creative entrepreneurial enterprises such as PRTC there is a significant burden presented by the complexity of current Government funding mechanisms – PRTC has demonstrated great creativity and foresight in utilizing all available resources – but simplifying the funding mechanism would greatly benefit entities nationwide looking to expand network capacity; and 5) the larger impacts of deploying broadband are observable over a short term, indicating that the long-term ROI is well beyond money recovered through services sold. Although our study looks at a specific context, we believe that many of the insights apply to other contexts nationwide as well as throughout the world. We expect to return to this specific context again after 5 years and then 10 years to study the long-term impacts of the fiber deployment. We do not yet have enough data on specific impact areas that may see significant effects long-term: 1) to what extent has the fiber network impacted entrepreneurship? Are there additional insights as far considering other dimensions therein such as small business funding? 2) beyond that which is presented in the paper, what is the impact of the improved network connectivity on local businesses? Are there services that have been enabled through enhanced services? 3) What is the impact on digital literacy? Digital literacy ranges from access to online services (ex: filing taxes, applying for jobs) to civic engagement (ex: being able to participate in an online commentary process); and 4) We have anecdotal evidence that there are people returning to the area while maintaining their remote WFH jobs. Is this a trend, how will this look in the long-term?

Techno-economic assessment and design optimization of compressed air energy storage using filament wound carbon fiber reinforced plastic pressure vessels

The deployment of filament wound carbon fiber reinforced plastic (CFRP) pressure vessels for small to medium scale CAES systems is techno-economically assessed and proposed as a cost-effective and location-independent installable solution. The cost of filament wound CFRP vessels is estimated for different vessel sizes and internal pressures via a Monte-Carlo design method that considers the uncertainties in raw material cost, design safety factor, and fabrication expenses. The guidelines for the optimum design of the CAES system in terms of sizing, operational pressure, and the number of required vessels are reported to minimize the cost of filament wound CFRP vessels. Results suggest that filament wound CFRP pressure vessels utilized in CAES systems are more cost-effective compared to conventional metallic tanks and pipes. Moreover, smaller radius filament wound CFRP vessels, i.e., in a sense, pipes, are more economical compared to larger radius ones. Finally, for a given compressed air volume, a single vessel is cheaper than multiple vessels to store a specific amount of energy such that the use of multiple vessels incurs a cost penalty ranging from roughly 10% for small radius vessels up to 50% for large radius vessels.

As Road To Real-Time Fracturing Optimization Is Paved, Shale Producers Approach On-Ramps Cautiously

To say that the shale sector is on the cusp of a new era, one where fast-flowing streams of real-time well data and on-the-fly fracture designs are the norm, is not something one does lightly. It’s a bold declaration. It represents a step change that engineers have been told is just around the corner for several years. They’ve been promised software that will churn out truly optimized recipes of proppant concentration, rate, total volume, etc. to match each fracture stage’s piece of the rock. In a neat world, this nets better production from good stages while injecting less capital into bad stages—the ultimate win-win for a sector that spends 60–70% of well costs on the completion. We can pluck example after example from industry literature to prove the incremental existence of such tailor-made well pads. However, the mostly small-scale cases are far from representative of the aggregate. For some, the absence of scale fuels skepticism over whether real-time optimization will ever amount to much more than avoiding screenouts and other costly operational drags. Then again, history is not always the best predictor of the future. In this context, it discounts a slate of technologies and methods that didn’t exist 5 years ago or were still coming into their own. Some of these innovations are now part of the toolbox that operators are using to reach for the brass ring that is real-time optimization at scale. “Much like self-driving cars, we see the future of a self-driving oil field that’s self-optimizing and operated autonomously—an element of this would be automating the fracturing process,” said Rob Fast, the chief technology officer of the Bakken Shale producer Hess Corp. He added that this vision of the future could be coming soon. Hess and its service provider are scheduled to start the first field trials of an automated fracturing system sometime in June. While sharing details of the upcoming test, Fast emphasized that “this project is a collaboration project that combines automation and optimization and provides advanced measurements to optimize completions and well spacing.” Fast was speaking during the SPE Hydraulic Fracturing Technology Conference plenary where he said the decision to invest in automated fracturing comes after Hess spent more than a decade producing some of the industry’s most in-depth tight reservoir studies. Through that work, the operator has apparently concluded that right sizing fractures will require a reliable set of eyes and ears in the subsurface. That translates to an array of permanent fiber-optic cables and permanent downhole pressure gauges, along with temporary “dip in” fiber deployments. Traditionally, such a big data-giving diagnostic program would be deemed a “science project,” the widely used euphemism for the sector’s illuminating but hard-to-scale look-back studies. But Hess sees dividends if the diagnostic jewelry helps achieve a new ambition to complete 40% fewer wells in the Bakken while still maintaining current recovery estimates. “Serious beef,” Fast said of the sought-after target.

Distributed acoustic sensing for shallow seismic investigations and void detection

During the past few decades, fiber-optic-based distributed acoustic sensing (DAS) has emerged as an affordable, easy-to-deploy, reliable, and noninvasive technique for high-resolution seismic sensing. We have determined that fiber deployments dedicated to near-surface seismic applications, commonly used for the detection and localization of voids, can be used effectively with conventional processing techniques. We tested a variety of small sources in different geologic environments. These sources, operated on and below the surface, were recorded by horizontal and vertical DAS arrays. Our results and comparisons to data acquired by vertical-component geophones demonstrate that DAS may be sufficient for acquiring near-surface seismic data. Furthermore, we tried to address the issue of directional sensing by DAS arrays and use it to solve the problem of wave-mode separation. Records acquired by a unique acquisition setup suggest that one can use the nature of standard DAS systems as uniaxial strainmeters to record separated wave modes. Finally, we applied two seismic methods on DAS data acquired at a test site: multichannel analysis of surface waves (MASW) and shallow diffraction imaging. These methods allowed us to determine the feasibility of using DAS systems for imaging shallow subsurface voids. MASW was used to uncover anomalies in the S-wave velocity, whereas shallow diffraction imaging was applied to identify the location of the void. The results we obtained illustrate that by using these methods we are able to accurately detect the true location of the void.

Adding Indoor Capacity without Fiber Backhaul: An mmWave Bridge Prototype

Today, a large portion of the mobile data traffic is consumed behind the shielding walls of buildings or in the Faraday cage of trains. This renders cellular network coverage from outdoor cell sites difficult. Indoor small cells and distributed antennas along train tracks are often considered as a solution, but the cost and the need for optical fiber backhaul are often prohibitive. To alleviate this issue, we describe an out-of-band repeater that converts a sub-6 GHz cell signal from a small cell installed at a cell tower to a mmWave frequency for the fronthaul to buildings or distributed antenna sites, where the signal is downconverted to the original frequency and emitted for example inside a building. This concept does not require fiber deployment, provides backward compatibility to equipment already in use, and additional indoor capacity is gained while outdoor networks are offloaded. The architecture and hardware prototype implementation are described, and measurements are reported to demonstrate the functionality and compatibility with commercial infrastructure and mobile terminals.

Development of a Soft Robot Based Photodynamic Therapy for Pancreatic Cancer

Photodynamic therapy (PDT) has received increased attention over the past decades with the potential to noninvasively treat cancer via light exposure. Due to the limited light penetration depth within the tissue (typically less than 1 cm), the PDT optical fiber typically needs to be placed close to the cancerous region to ensure the treatment outcome. In this article, we present a novel soft robot laparoscope design that enables accurate and safe deployment of the PDT optical fiber for pancreatic tumor treatment. To achieve this, the proposed soft robot is able to produce three degrees of freedom motions: linear translation, in-plane bending, and axial rotation. A micro camera is integrated with the soft robot to provide intraoperative image guidance during the procedure. The robot forward kinematics model was obtained via a generalized calibration method, and the differential kinematics was derived analytically. Benchtop characterization results indicated that the soft robot was able to achieve 1.4 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 0.4 mm position and 1.5 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 1.1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> orientation accuracy, respectively. The robot was experimentally validated in two <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in vivo</i> mice models, and the results indicated that the proposed system successfully reduced the tumor size from 15.3 and 11.8 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{mm}^3$</tex-math></inline-formula> to 12.1 and 4.4 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{mm}^3$</tex-math></inline-formula> , respectively.