Field Crews Research Articles

Under predicted climate change: Distribution and ecological niche modelling of six native tree species in Gilgit-Baltistan, Pakistan

Abstract This study presents the tree species distribution and habitat suitability maps in Gilgit-Baltistan, Pakistan at 1 km spatial resolution. This study is based on bioclimatic and topographical variables and 440 samples of six native trees species: Abies pindrow, Betula utilis, Cedrus deodara, Picea smithiana, Pinus wallichiana, and Quercus ilex. Data is collected through field survey. Exclusively for each tree species, a multicollinearity test was performed among 24 independent or environment variables (21 bioclimatic and 3 topographic). The highly correlated independent variables (r ≥ 0.9, Pearson correlation coefficient) were eliminated from the independent variables list. In this study, we employed the Maximum Entropy (MaxEnt) model to produce current (2015–2016) as well as RCP4.5 and RCP8.5 climate-change scenarios by 2050 for tree species spatial distribution results. The jackknife test was carried out to depict the importance of variables with the highest gain and it was observed that overall elevation, precipitation, and temperature are the factors with the highest gain. The results of the MaxEnt model for each tree species were satisfactory with ROC (receiver operating characteristic) AUC (area under the curve) curve training and testing values greater than 0.9 and 0.84 respectively. Based on 10-percentile training presence threshold-dependent values, the overall accuracy of True Skill Statistics (TSS) was more than 80%. The maximum area coverage of all tree species existed under “inadmissible natural surroundings (0–0.2 probability)” and least area fell under “exceptionally appropriate environment (0.6–0.7 probability)” to “profoundly reasonable living space (0.7–1.0 probability)”. A tree species diversity map prepared through equal weighted average overlay analysis, using all six developed tree species probability outputs. The field observation might possess certain limitations because it was difficult for the field crew to access the areas with rough terrain, long distances, harsh weather conditions, and locations of forest in steep, narrow valleys. Overall, this study contributes to enlarge tree species distribution research datasets applicability in Pakistan and over the Hindu Kush Himalayan (HKH) mountains region. It may also provide interesting insight, which could be used for the habitat corridor suitability modelling of endangered species, and ground intervention to protect and expand tree species distributions.

Prevention of bacterial contamination of stored hydrants: Utility recommendations for hydrant inlet orientation and capping

To avoid contamination of the drinking water distribution system and obtain reliable bacteriological testing results, a rigorous and protective hygiene approach must be followed when storing, repairing or installing hydrants. However, in North America strategies to avoid or eliminate microbial contamination of hydrants during storage, transport and installation are often insufficiently defined in utility standards and manuals. In the summer of 2015, Edmonton (Alberta, Canada) utility field crews encountered several instances where water samples collected from newly installed hydrants were total coliform (TC) positive and thus did not meet the regulatory requirements to be put into service. The present study evaluated whether stored hydrants were contaminated with TC. The study also evaluated the efficacy of an intervention targeting two common hydrant storage practices at preventing microbiological contamination: pointing the hydrant inlet downwards and capping hydrants by the manufacturer. We swabbed 24 hydrant inlets and recorded inlet orientation and capping status prior and after the intervention. The swabs were processed using IDEXX Colilert tests for total coliform and E. coli detection. Positive samples were further identified by Biomerieux 20E API testing. Out of the 24 tested hydrants, twenty were oriented with the inlet pointing downward. Ninety percent of the downward pointing hydrants were TC negative, while the remaining 10% were TC positive. Seventy five percent of the hydrants not pointing downward were TC positive, while the remaining 25% were not contaminated. The results showed that hydrant inlet orientation had a statistically significant effect on hydrant contamination with TC (Fisher Exact Test two-tailed p-value=0.018). The results also highlighted that capping, while efficacious in protecting water mains from contamination in the field, did not have a statistically significant impact on bacterial contamination of hydrants as capped and uncapped hydrants were TC negative 86% and 70% of the time, respectively. All TC were identified as Pantoea spp. indicating that the most likely source of contamination was environmental not fecal in nature. We were unable to identify the source of the bacterial contamination but recommend that hydrant disinfection practices related to new mains be expanded upon in standards in the future, as the cost of a failed bacteriological test can be exorbitant (>US$10,000). Results highlighted that contamination of distribution system network components with environmental TC interferes with detection of real point source contamination resulting from actual system failures. It can also result in delayed appropriate remedial actions and an impairment in the evaluation of risk to the public. Results also highlight the importance of educating field crews about bacterial contamination and its sources to benefit utilities, reduce false positives, improve performance and empower crews to make informed decisions.

A Stepwise Approach to Assess the Occupancy State of Larval Lampreys in Streams

Abstract Pacific Lamprey Entosphenus tridentatus is an ecologically and culturally important anadromous species of conservation concern for which fisheries managers use information on occupancy state in streams to assess species status and inform stream management decisions. Here we developed a stepwise approach that incorporates the potential for nondetection and a preselected expected maximum probability of stream occupancy if field crews do not document larval Pacific Lamprey during sampling. Our approach includes seven steps: define the occupancy question; select the maximum acceptable probability of occupancy, if the species is not documented during sampling; define an assumed detection probability for the target organism; calculate required sampling effort; select sampling units; conduct sampling; and interpret sampling results into probabilistic occupancy conclusions. We examined detection probability of our approach for larval lamprey using data from multiple occupied streams in the Pacific Northwest. We illustrated our approach by evaluating Balm Grove Dam as a barrier to Pacific Lamprey migration in Gales Creek, Oregon. Bayesian estimates of detection probability in occupied streams ranged from 0.15 to 0.94, with an overall median of 0.70 (95% credible interval: 0.60–0.79). Assuming detection probability is at least 0.15 (i.e., lowest estimate), 19 reaches are required for the expected maximum probability of occupancy to be not more than 0.05, if the species is not documented through our sampling approach. Although detected downstream, we detected no larvae upstream of Balm Grove Dam; thus, we conclude that the maximum probability of occupancy upstream of Balm Grove Dam was not more than 0.05 at an assumed detection probability of 0.4, suggesting the dam as a barrier to adult migration. We provide an occupancy assessment tool with standardized sampling requirements that incorporates the potential for nondetection and the flexibility to select an expected maximum probability of occupancy if researchers document no larvae, to aid management and restoration in a single stream.

Visual and passive acoustic observations of blue whale trios from two distinct populations

Visual and passive acoustic observations of blue whale trios from two distinct populations

Precision of VS30 values derived from noninvasive surface wave methods at 31 sites in California

We study the inter- and intra-method variability of VS30 results by inverting/forward-modeling individual dispersion data for 31 seismographic stations located in California where combinations of surface-wave methods were applied and the minimum recorded wavelength from each method satisfies the 30-m depth criteria. These methods consist of noninvasive geophysical (active and passive surface-wave techniques) multi-station approaches, including the Multi-channel Analysis of Surface Waves (MASW; Rayleigh and Love waves), Spectral Analysis of Surface Waves (SASW), Microtremor Array [using Extended Spatial Autocorrelation (ESAC) processing methods], and Refraction Microtremor (ReMi) methods. Depending on the apparent geologic or seismic complexity of the site, field crews applied one or a combination of these methods whenever economically feasible to estimate the one-dimensional shear-wave velocity (VS) profile and calculate VS30, the time-averaged VS to a depth of 30 m. For each of the 31 sites, we find both types of variability in VS30 estimates generally remain insignificant (arithmetic mean of 5% difference). We also find similar results (3%) when we evaluate individual-method based VS30 estimates against composite-method based estimates. We note that VS30 values vary insignificantly when using a combination of complementary methods, e.g., active MASW data combined with passive MAM data, and that the most reliable results are also based on close fitting of the theoretical dispersion data to the representative (experimental) dispersion data.

Inspiring the next generation through the AMADEE-18 MARS analog simulation

The Austrian Space Forum in cooperation with the Oman Astronomical Society conducted a high-fidelity Mars Analog field simulation in the Dhofar region, Sultanate of Oman in February 2018. Directed by a Mission Support Center in Austria, a carefully selected and trained field crew of 15 researchers conducted experiments from various disciplines (e.g. engineering, planetary surface operations, astrobiology, geophysics/geology, life sciences) preparing for future human Mars missions. Mars analog research in a representative environment is also an excellent tool to enhance the visibility of planetary sciences and to engage with the next generation of researchers. To reach out to young students from 6 to 25 years, special programs and initiatives were set-up. This paper focuses on the Junior Researchers Program, where four high school and undergraduate student teams realized their experiments in a scientific mission, starting with defining their research questions, building their experiment hardware and finally analyzing and publishing the outcomes.

A Model-Based Design System for Terrestrial Laser Scanning Networks in Complex Sites

With the rapid increase of terrestrial laser scanner (TLS) applications, especially for the high-accuracy modelling of large-volume objects, a design system is needed to provide solutions for both scanner and target placement that can meet the project requirements in terms of completeness, precision, economy, and reliability. In this paper, a hierarchical strategy driven by an improved optimization method is developed to solve the TLS viewpoint planning problem. In addition, the placement of the targets is determined by optimizing the target arrangement criterion, and the number of target locations is minimized by accepting the close to optimal target arrangements. Finally, the quality of the design, including the sensitivity of the object coverage to viewpoint placement and the precision of the point cloud are provided. Two building complexes located on University of Calgary campus are used as the experimental datasets in this research. The designs for scanner placement are compared with the “brute force” strategy in terms of the optimality of the solutions and runtime. The results showed that the proposed strategy provided scanning networks with a compatible quality but with more than 80% time savings in design. The number of targets necessary for registration from our system is surprisingly small, considering the volume and complexity of the networks. Through the quality assessments, the sensitivity of the object coverage to the scanner placement indicates how careful the field crew should be when placing the scanner for data capture, and the point cloud precision indicates if the network design can meet the project requirements.

A modified biopsy needle with pole for repeatable tissue extraction from free‐ranging crocodiles

ABSTRACTBiopsy sampling is a powerful tool for furthering our understanding of animal populations. Knowledge of diets and trophic energy flows, genetic structure and connectivity between populations, and uptake of environmental contaminants can all be elucidated through analysis of animal tissues, which is particularly useful for animals that are elusive and difficult to observe. Crocodylians are an aquatic group for which biopsy sampling is an appropriate tool; however, sample collection usually requires undertaking the arduous and dangerous process of capturing individual crocodiles. We describe a biopsy system that employs a modified version of a standard biopsy needle and pole kit to consistently extract crocodile tissue with greatly reduced effort and increased safety. This system takes advantage of the behavioral trait of crocodiles to “freeze” under the glare of a high‐powered spotlight, enabling an approach to within a few meters. We field‐tested the system in 2 remote river systems in northwestern Australia, during July–August 2015, collecting tissue samples from 69 crocodiles (Crocodylus porosus; size range = 0.9–4.4 m total length) with approximately 95% success. The pole biopsy system increases sample collection efficiency by removing the need to handle individual crocodiles. Moreover, this decreases stress on the crocodile population and significantly reduces the number of field crew required. © 2019 The Wildlife Society.

New Method for Detecting Oil Contaminants in Asphalt Mixtures through Chemical Testing

In this study, an analytic method was developed for detecting potential oil contaminants in asphalt mixtures using gel permeation chromatography (GPC) and Fourier-transform infrared spectroscopy (FTIR). This study was initiated when the authors were contacted by a major contractor whose field crew reported spots of loose asphalt pavement and suspected the pavement surface was being contaminated with spills of petroleum-based oils or other soluble chemicals. Oil contamination would change the content and performance grade of the asphalt binder in the mixture, thus compromising the properties and performance of the asphalt pavement. The proposed method involved extracting asphalt binders from potentially contaminated asphalt mixtures using the solvent tetrahydrofuran (THF), testing the extracted binders using GPC and FTIR, and comparing their results with those of the pure asphalt binder and oil contaminants. This study first verified the proposed method by testing artificially contaminated asphalt binders at different contamination contents and then evaluated seven potentially contaminated asphalt mixtures from the job site, as well as six possible oil contaminants. The study shows that the GPC results yielded convincing evidence whether or not asphalt mixtures were contaminated and that the FTIR results were effective in detecting specific oil contaminants using their characteristic peaks.

Can Field Crews Telecommute? Varied Data Quality from Citizen Science Tree Inventories Conducted Using Street-Level Imagery

Street tree inventories are a critical component of urban forest management. However, inventories conducted in the field by trained professionals are expensive and time-consuming. Inventories relying on citizen scientists or virtual surveys conducted remotely using street-level photographs may greatly reduce the costs of street tree inventories, but there are fundamental uncertainties regarding the level of data quality that can be expected from these emerging approaches to data collection. We asked 16 volunteers to inventory street trees in suburban Chicago using Google Street ViewTM imagery, and we assessed data quality by comparing their virtual survey data to field data from the same locations. We also compared virtual survey data quality according to self-rated expertise by measuring agreement within expert, intermediate, and novice analyst groups. Analyst agreement was very good for the number of trees on each street segment, and agreement was markedly lower for tree diameter class and tree identification at the genus and species levels, respectively. Interrater agreement varied by expertise, such that experts agreed with one another more often than novices for all four variables assessed. Compared to the field data, we observed substantial variability in analyst performance for diameter class estimation and tree identification, and some intermediate analysts performed as well as experts. Our findings suggest that virtual surveys may be useful for documenting the locations of street trees within a city more efficiently than field crews and with a high level of accuracy. However, tree diameter and species identification data were less reliable across all expertise groups, and especially novice analysts. Based on this analysis, virtual street tree inventories are best suited to collecting very basic information such as tree locations, or updating existing inventories to determine where trees have been planted or removed. We conclude with evidence-based recommendations for effective implementation of this type of approach.

Assessing spectral measures of post-harvest forest recovery with field plot data

Information regarding the nature and rate of forest recovery is required to inform forest management, monitoring, and reporting activities. Delayed establishment or return of forests has implications to harvest rotations and carbon uptake, among others, creating a need for spatially-explicit, large-area, characterizations of forest recovery. Landsat time series (LTS) has been demonstrated as a means to quantitatively relate forest recovery, noting that there are gaps in our understanding of the linkage between spectral measures of forest recovery and manifestations of forest structure and composition. Field plots provide a means to better understand the linkage between forest characteristics and spectral recovery indices. As such, from a large set of existing field plots, we considered the conditions present for the year in which the co-located pixel was considered spectrally recovered using the Years to Recovery (Y2R) metric. Y2R is a long-term metric of spectral recovery that indicates the number of years required for a pixel to return to 80% of its pre-disturbance Normalized Burn Ratio value. Absolute and relative metrics of recovery at 5 years post-disturbance were also considered. We used these three spectral recovery metrics to predict the stand development class assigned by the field crew for 284 seedling plots with an overall accuracy of 73.59%, with advanced seedling stands more accurately discriminated (omission error, OE = 15.74%) than young seedling stands (OE = 49.84%). We then used field-measured attributes (e.g. height, stem density, dominant species) from the seedling plots to classify the plots into three spectral recovery groups, which were defined using the Y2R metric: spectral recovery in (1) 1–5 years, (2) 6–10 years, or (3) 11–15 years. Overall accuracy for spectral recovery groups was 61.06%. Recovery groups 1 and 3 were discriminated with greater accuracy (producer’s and user’s accuracies > 66%) than recovery group 2 (< 50%). The top field-measured predictors of spectral recovery were mean height, dominant species, and percentage of stems in the plot that were deciduous. Variability in stand establishment and condition make it challenging to accurately discriminate among recovery rates within 10 years post-harvest. Our results indicate that the long-term metric Y2R relates to forest structure and composition attributes measured in the field and that spectral development post-disturbance corresponds with expectations of structural development, particularly height, for different species, site types, and deciduous abundance. These results confirm the utility of spectral recovery measures derived from LTS data to augment landscape-level assessments of post-disturbance recovery.

Liberation of future crop trees from lianas in Belize: Completeness, costs, and timber-yield benefits

Lianas (woody climbing plants) often abound in tropical forests after selective logging and other disturbances. Liana cutting is an often-prescribed but seldom applied silvicultural treatment designed to foster the growth of future crop trees (hereafter: FCTs). Small-scale studies indicate that this treatment is effective, but little is known about its efficiency (i.e., proportions of lianas missed) or financial cost effectiveness at operational scales. To fill these gaps, we worked in a commercial forest concession in Belize where FCTs and trees to be felled were liberated from lianas in 500–1000 ha annual timber harvest blocks. We found that field crews assigned this and inventory-related tasks spent 11.8% of their time cutting lianas from FCTs at a cost of $0.11 per tree. Workers failed to cut 31.9% of the lianas that infested the 701 FCTs they were supposed to liberate; most of the missed lianas grew into the FCT crowns from neighbors or hung down far from the bole [an additional 48 FCTs (6%) were completely missed]. In a logging block treated 9-years prior to this study, 39% of the liberated Swietenia macrophylla FCTs 29–56 cm DBH were still liana-free whereas in an untreated stand, 94% of similar-sized conspecific control FCTs were liana-infested. Based on tree ring data for the same 9-year period, the liberated FCTs grew 38–63% faster than control FCTs. If the mean growth benefit is sustained over the entire 40-year cutting cycle, each liberated FCT will yield an average of 1.51 m3 (639 board feet) more roundwood than comparable FCTs in unliberated forest. Over this 40-year period with an annual discount rate of 4.5%, this added volume gives the $0.11 investment per tree a net present value of US $161.38 and a profitability index of 1467 for export quality timber. These results argue for the application of this inexpensive and effective treatment in managed forests where lianas abound.

A Multi-objective Swarm Intelligence Approach for Field Crews Patrol Optimization in Power Distribution Systems Restoration

A fault on a power distribution system may cause electricity interruption for several consumers, so a good restoration plan is required to decrease such interruptions duration and, consequently, assure the quality of service. Among the measures for service restoration, there is the dispatch of inspection and maintenance crews. The routing of these teams can be classified as a case of the multiple traveling salesman problem. Although involved in series of decision problems, the power distribution system maintenance crews routing is addressed, in the most part of the literature, as a single-objective problem, an instance of a multi-objective one, or as a multi-objective aggregating approach, which generates a single solution in an optimization run, in contrast with the set of equally good solutions, known as Pareto set, the result of a multi-objective problem. In this paper, a Pareto based multi-objective discrete particle swarm optimization approach was applied with the aim of reducing the patrol duration and also the total crews displacement. Wherein the concept of epsilon-dominance was used to update the set of non-dominated solutions, resulting in a good spreading and convergence of them. To promote an uniform exploration of the Pareto set, the selection of the local leaders of the archive was based on square root distance metrics. The Dijkstra algorithm was employed to find the shortest path between two consecutive points of the route of each team. As a result, a set of solutions were obtained for the routing of maintenance crews for power distribution system restoration.

Using maternal mule deer movements to estimate timing of parturition and assist fawn captures

ABSTRACTMovement patterns of maternal ungulates have been used to determine parturition dates and aid in locating fawns, which may be important for understanding reproductive rates (e.g., pregnancy and fetal), but such methods have not been validated for mule deer (Odocoileus hemionus). We first determined timing of parturition using vaginal implant transmitters (VITs) and then predicted timing of parturition using VITs in conjunction with Global Positioning System collar data in the Piceance Basin of northwestern Colorado, USA, during 2012–2014. We examined daily movement rate to determine differences in movement rate among days (7 days pre‐ and postpartum) and for movement patterns indicative of parturition. Mean daily movement rate (m/day) of 102 maternal deer decreased by 46% from 1 day preparturition ( = 1,253, SD = 1,091) to parturition date ( = 682, SD = 574), and remained at this low rate 1–7 days postpartum. We applied an independent data set to validate predicted parturition dates based on daily movement rate. We estimated day of parturition correctly (i.e., day 0), within 1–3 days postparturition, and ≥4 days postparturition of field‐reported dates for 10 (29%), 21 (60%), and 4 (11%) maternal females, respectively. For novel data sets, we predict that a mule deer female whose daily movement rate decreases by ≥46% and remains low ≥3 days postparturition particularly when preceded by a sudden increase in movement—has given birth. However, we caution that disturbance of deer by field crews should be minimized, and if birth sites are not found, neonatal mortality will be underestimated. Our results can help determine timing and general location of parturition as an aid in capturing fawns when the use of VITs is not feasible, with the ultimate objective of estimating pregnancy, fetal, and fawn survival rates if birth sites are found. © 2018 The Wildlife Society.

Iterative deblending of simultaneous-source data using smoothed singular spectrum analysis

Simultaneous-source acquisition helps the field crews obtain a faster seismic data recording by allowing multiple sources to be fired simultaneously. However, the simultaneous source ignition causes strong interferences in the recorded data, which greatly affects the subsequent seismic data processing and imaging workflows. An effective separation of simultaneous sources is considered as the key in successfully utilizing the simultaneous-source acquisition technology. In this paper, we propose a novel smoothed singular spectrum analysis (SSA) approach to remove blending noise in an iterative inversion manner. Compared with the traditional SSA approach, the smoothed SSA approach applies a Gaussian smoothing operator onto the Hankel matrix in the frequency domain, and can attenuate more blending noise than the traditional SSA method. We use both synthetic and field data examples to demonstrate the successful performance of the proposed method.

Accuracy of Volunteer-Derived Data from a Single-Day Inventory Event Built Around a Crowdsourced Tree Mapping Application

Freely available ecosystem service models, like those incorporated in the i-Tree suite of tools, have helped scientists and practitioners estimate the environmental functions and economic benefits associated with their urban forest. Traditionally, professional inventory crews have been used to collect the inventory data needed for these models, but several cities have established crowdsourcing platforms to allow volunteers to map and inventory trees. Students in this study hosted and participated in an Arbor Day inventory collection event, using a newly released crowdsourcing application for mapping trees and estimating ecosystem services. The students located, identified, and measured trees on the University of South Florida campus (Tampa, Florida, U.S.) after a brief training session. After the one-day event, a more rigorously-trained field crew attempted to relocate the inventoried trees to assess the accuracy and variability of the data collected. Of the 339 trees inventoried at the original event, only 57.8% (n = 196) had coordinates that were accurate enough to re-measure. Of the 196 re-measured trees, 91.3% (n = 179) were correctly identified. However, only 47.9% (n = 91) of trees had dbh measurements within a one inch (2.5 cm) threshold for accuracy. Results of this experiment offer insights for communities looking to host special inventorying events to increase participation in crowdsourcing tree inventory initiatives.

Evaluating Inter-Rater Reliability and Statistical Power of Vegetation Measures Assessing Deer Impact

Long-term vegetation monitoring projects are often used to evaluate how plant communities change through time in response to some external influence. Here, we evaluate the efficacy of vegetation monitoring to consistently detect changes in white-tailed deer browsing effects. Specifically, we compared inter-rater reliability (Cohen’s κ and Lin’s concordance correlation coefficient) between two identically trained field crews for several plant metrics used by Pennsylvania state agencies to monitor deer browsing impact. Additionally, we conducted a power analysis to determine the effect of sampling scale (1/2500th or 1/750th ha plots) on the ability to detect changes in tree seedling stem counts over time. Inter-rater reliability across sampling crews was substantial for most metrics based on direct measurements, while the observational based Deer Impact Index (DII) had only moderate inter-rater reliability. The smaller, 1/2500th ha sampling scale resulted in higher statistical power to detect changes in tree seedling stem counts due to reduced observer error. Overall, this study indicates that extensive training on plant identification, project protocols, and consistent data collection methods can result in reliable vegetation metrics useful for tracking understory responses to white-tailed deer browsing. Smaller sampling scales and objective plant measures (i.e., seedling counts, species richness) improve inter-rater reliability over subjective measures of deer impact (i.e., DII). However, considering objective plant measures when making a subjective assessment regarding deer browsing effects may also improve DII inter-rater reliability.

Vehicle-Based Methane Surveys for Finding Natural Gas Leaks and Estimating Their Size: Validation and Uncertainty.

Managing leaks in urban natural gas (NG) distribution systems is important for reducing methane emissions and costly waste. Mobile surveying technologies have emerged as a new tool for monitoring system integrity, but this new technology has not yet been widely adopted. Here, we establish the efficacy of mobile methane surveys for managing local NG distribution systems by evaluating their ability to detect and locate NG leaks and quantify their emissions. In two cities, three-quarters of leak indications from mobile surveys corresponded to NG leaks, but local distribution companies' field crews did not find most of these leaks, indicating that the national CH4 activity factor for leaks in local NG distribution pipelines is underestimated by a factor of 2.4. We found the median distance between mobile-estimated leak locations and actual leak locations was 19 m. A comparison of emission quantification methods (mobile-based, surface enclosure, and tracer ratio) found that the mobile method overestimated leak magnitude for the smallest leaks but accurately estimated size for the largest leaks that are responsible for the majority of total emissions. Across leak sizes, mobile methods adequately rank relative emission rates for repair prioritization, and they are easily deployed and offer efficient spatial coverage.

Design of Daily Training Protocol for Field Crews Wearing Chemical Protective Clothing for Firefighting and Analysis of Activity

Design of Daily Training Protocol for Field Crews Wearing Chemical Protective Clothing for Firefighting and Analysis of Activity

Ten Years of Continuous Technology Development and Field Application of a Coiled-Tubing Tube-Wire Telemetry System: Past, Present, and Future

Summary For more than 50 years, coiled tubing (CT) has been an intervention technology used primarily to maintain or increase production. In the last 10 years, CT telemetry systems have been used for such applications as milling, stimulation, well cleanouts, gas lifting, camera services, logging, and perforating. These systems have resulted in increased certainty, improved safety and efficiency, and reduced time and cost. In this article, a review of a CT telemetry system with 0.125–in. tube wire, including the technology development and field applications, is presented for the first time. Unlike conventional CT for which surface–measured parameters, such as CT weight and length and pumping pressure, are the only parameters available to monitor the operation's progress, CT telemetry systems provide real–time monitoring of downhole data such as pressure, temperature, depth, and others. The CT telemetry system described in this article consists of the surface hardware and software, a 0.125–in. tube wire inside the CT connecting the surface equipment and the downhole tools and sensors, and a versatile bottomhole assembly (BHA), designed in three sizes (i.e., 2.125–, 2.875–, and 3.5–in.). The 0.125–in. tube wire has the dual purpose of powering the downhole sensors and transferring the real–time downhole data to the surface. The sensors available are a casing–collar locator (CCL), two pressure and temperature transducers (capable of measuring downhole data inside and outside the BHA), and tension, compression, and torque gauges. In addition, cameras with front and lateral views and flow–through capabilities could be used. One of the advantages of this CT telemetry system is its versatility: Switching between applications is as simple as changing parts of the BHA, significantly reducing the operational time and cost, and increasing safety. Another advantage stems from the acquisition of real–time downhole data, enabling the CT field crew to intervene promptly on the basis of dynamic downhole events. A state–of–the–technology review of the 0.125–in. tube–wire CT telemetry system is presented for the first time. The many benefits of the real–time monitoring of the downhole parameters during such CT applications are summarized. These applications include logging, zonal isolation, collapsed–casing identification, scale removal, cleanout and perforation, milling, confirmation of jar activation during fishing jobs, and others. Many of these applications were performed together, and the real–time monitoring of downhole data increased the job efficiency, control, and safety, and reduced the operational costs by simplifying the operational procedures and equipment. The article summarizes the results stemming from 10 years of global experience with the 0.125–in. tube–wire CT telemetry system. A new case history involving the 0.125–in. tube–wire CT telemetry system and a vibratory tool is also presented for the first time. With the current trends to automate drilling operations, the details presented in this article show that the CT telemetry systems are poised to become standard technologies for all CT operations in the not–so–distant future.