Impact of Repeated Acute Exposures to Low and Moderate Exercise-Induced Hypohydration on Physiological and Subjective Responses and Endurance Performance

This study aimed to examine whether repeated exposures to low (2%) and moderate (4%) exercise-induced hypohydration may reverse the potentially deleterious effect of hypohydration on endurance performance. Using a randomized crossover protocol, ten volunteers (23 years, V˙O2max: 54 mL∙kg−1∙min−1) completed two 4-week training blocks interspersed by a 5-week washout period. During one block, participants replaced all fluid losses (EUH) while in the other they were fluid restricted (DEH). Participants completed three exercise sessions per week (walking/running, 55% V˙O2max, 40 °C): (1) 1 h while fluid restricted or drinking ad libitum, (2) until 2 and (3) 4% of body mass has been lost or replaced. During the first and the fourth week of each training block, participants completed a 12 min time-trial immediately after 2% and 4% body mass loss has been reached. Exercise duration and distance completed (14.1 ± 2.7 vs. 6.9 ± 1.5 km) during the fixed-intensity exercise bouts were greater in the 4 compared to the 2% condition (p < 0.01) with no difference between DEH and EUH. During the first week, heart rate, rectal temperature and perceived exertion were higher (p < 0.05) with DEH than EUH, and training did not change these outcomes. Exercise-induced hypohydration of 2% and 4% body mass impaired time-trial performance in a practical manner both at the start and end of the training block. In conclusion, exercise-induced hypohydration of 2% and 4% body mass impairs 12 min walking/running time-trial, and repeated exposures to these hypohydration levels cannot reverse the impairment in performance.

Challenges of Gas Wells Killing Operation with Emphasis on Reservoir & Completion Integrity Issues

Well killing always remains a most radical part during the life cycle of gas production wells with reservoir and completion integrity issues. In moderate permeability gas reservoirs, it will be more challenging due to below issues; Low pressure gas reservoir with moderate reservoir permeability where hydrostatic head of water is almost double the formation pressure Well with the sustainable annulus pressures (Production & first cemented annulus) Well with complex layered scale / asphalting deposition Completion jewelry component integrity breached Recycle reservoir with pressure maintenance Noise logs / corrosion logs generally conducted in order to assess the downhole completion jewelry and potential leak source prior any attempt for killing the well. To achieve the desired accessibility extensive scale analysis for better designing of scale clean out operation carried out specially to access the SPM. Variation of reservoir permeability considered for designing of optimized kill fluid for Depleted horizontal gas reservoir to cater challenge of complete losses. Effective fluid loss solutions designed and implemented to avoid abnormal fluid losses. Further more Polymer based gels used to kill and prevent the gas peculation to surface. Wells having completion and reservoir integrity issue isolated by considering cement zonal isolation, salt plugs, thru-tubing bridge plugs and nipple less plugs. All these barriers having their advantages and disadvantages with reference to work over objectives and their application limitations with respect to well conditions and detail study conducted for each candidate prior execution. Depletion Gas well killing and securing operation considered to be complex in nature and may result serious concern of rig intervention or well future objectives in case of improper execution. Gas wells having reservoir integrity issues and in case of 1st cemented Annulus pressure can be isolated by using thru-tubing bridge plugs. For retrieval of dummy from SPM must be done after setting of downhole plug to avoid any heavy suction for wire line operation. Cement plug operation is not suitable for such wells due to severe losses and fluid circulation limitation. Adequate selection of kill gel fluid as per reservoir characteristics will improve the killing efficiency.

Awareness of Fluid Losses Does Not Impact Thirst during Exercise in the Heat: A Double-Blind, Cross-Over Study

Background: Thirst has been used as an indicator of dehydration; however, as a perception, we hypothesized that it could be affected by received information related to fluid losses. The purpose of this study was to identify whether awareness of water loss can impact thirst perception during exercise in the heat. Methods: Eleven males participated in two sessions in random order, receiving true or false information about their fluid losses every 30 min. Thirst perception (TP), actual dehydration, stomach fullness, and heat perception were measured every 30 min during intermittent exercise until dehydrated by ~4% body mass (BM). Post exercise, they ingested water ad libitum for 30 min. Results: Pre-exercise BM, TP, and hydration status were not different between sessions (p > 0.05). As dehydration progressed during exercise, TP increased significantly (p = 0.001), but it was the same for both sessions (p = 0.447). Post-exercise water ingestion was almost identical (p = 0.949) in the two sessions. Conclusion: In this study, thirst was a good indicator of fluid needs during exercise in the heat when no fluid was ingested, regardless of receiving true or false water loss information.

The history of UGS Strachocina investment as an example of success achieved by cooperation between a western company and Polish oil and gas companies

In 2006 Oil and Gas Institute, Underground Gas Storage Department was given the task of designing the UGS Strachocina working volume, production and injection rates enlargement. Gas storage Strachocina is located in the south eastern part of Poland, near Sanok. The UGS Department ran some analysis before that date, which gave us the answer that the old vertical well technology would not be enough to achieve investment success. We knew that we needed to use horizontal well technology in which we had no experience at all. At that time there were only a few horizontal wells drilled in Poland. We decided to start cooperation with the company Baker Hughes, and asked them to help us to design the drilling technology and well completions. We knew that we needed to drill 8 horizontal wells in difficult reservoir conditions. Based on Baker Hughes’ recommendations, the EXALO Polish drilling company’s experience and the Institute’s knowledge of storage reservoir geology, the trajectories of 8 new wells were designed. Working with Baker Hughes, we designed the well completion based on expandable filters, the second time this type of completion technology had been used in the world at that time. During drilling, we were prepared for drilling fluid losses because of the extensive Strachocina reservoir’s natural fracture system. The investment was in doubt during the drilling of the first two horizontal wells because of huge drilling fluid losses and the inability of drilling the horizontal section length as designed. We lost 4000 cubic metres of drilling fluid in a one single well. During the drilling of the 2nd well, we asked Baker Hughes to help us to improve the drilling technology. Our partners from Baker Hughes prepared the solution in 3 weeks, and so we were able to use this new technology on the 3rd well drilled. It turned out that we could drill a longer horizontal section with less drilling fluid loss. The paper will show the idea of the project, the team building process, the project problems solved by the team, decisions made during the UGS Strachocina investment and the results. It will show how combining “western” technology and experience with “eastern” knowledge created a success story for all partners.

How much water is in a mouthful, and how many mouthfuls should I drink? A laboratory exercise to help students understand developing a hydration plan

Preventing impairments in athletic performance is an important concept for students that are preparing for careers that involve working with athletes. Gaining hands on, laboratory-based experience in measuring exercise induced dehydration can help students understand how to help athletes prevent dehydration induced impairment in performance. This article describes a laboratory exercise for junior and senior students in a sports nutrition class, in which the students measure changes in body mass (as a measure of dehydration) due to 40 min of moderate-intensity exercise and 40 min of vigorous-intensity exercise. The students also measure how much water is in a mouthful from a sports bottle and from a drinking fountain. The students then calculate how many mouthfuls are necessary to replace exercise induced fluid losses. This laboratory exercise has been well received by students and has improved performance on the test regarding hydration.

Triple MPD Technique for Drilling and Intelligent Completion Deployment on an Abandoned Deepwater Well

This is a case study of a presalt well that required the use of 3 different MPD techniques to achieve its goals. The well was temporary abandoned when conventional techniques failed to reach the final depth. Total fluid losses in the reservoir section required changing the well design and its completion architecture. The new open hole intelligent completion design had to be used to deliver the selective completion in this challenging scenario. From the hundreds of wells drilled in the Santos basin presalt, there are some wells with tight or no operational drilling window. In order to drill these wells different MPD techniques are used. In most cases, the use of Surface Backpressure (SBP) technique is suitable for drilling the wells to its final depth. For the more complex cases, when higher fluid loss rates occur, the use of SBP and Pressurized Mud Cap Drilling (PMCD) enables the achievement of the drilling and completion objectives. After the temporary abandonment of this specific well in 2018, the uncertainty of the pore pressure could not ensure that the SBP and PMCD techniques would be applicable when reentering the well. To avoid difficult loss control operations, the completion team changed the intelligent completion design to include a separated lower completion, enabling its installation with the MPD system. Besides the previously used MPD techniques, the integrated final project considered an additional technique, Floating Mud Cap Drilling (FMCD), as one of the possible contingencies for the drilling and completion phases. Well reentry and drilling of the remaining reservoir section included the use all the previously mentioned MPD techniques (SBP, PMCD and FMCD). The lower completion deployment utilized the FMCD technique to isolate the formation quickly and efficiently, without damaging the reservoir. The planning and execution of the well faced additional difficulties due to the worldwide pandemic and personnel restrictions. The success from the operation was complete with no safety related events and within the planned budget. At the end, the execution team delivered a highly productive well with an intelligent completion system fully functional, through an integrated and comprehensive approach. MPD use on deepwater wells is relatively new. Different operators used several approaches and MPD techniques to ensure safety and success during wells constructions over the last decade. This paper demonstrates the evolution of MPD techniques usage on deepwater wells.

Buzios Presalt Wells: Delivering Intelligent Completion In Ultra-Deepwater Carbonate Reservoirs

This paper describes the challenges faced on the deployment of intelligent well completion (IWC) systems in some of the wells built in Buzios field, mostly related to heavy fluid losses that occurred during the well construction. It also presents the solutions used to overcome them. This kind of event affects not only drilling and casing cementing operations, but may also prevent a safe and efficient installation of the completion system as initially designed. The IWC design typically used in Brazilian pre-salt areas comprises cased hole wells. Perforation operations must be performed before installing the integral completion system, as it does not include a separation between upper and lower completion. Therefore, the reservoir remains communicated to the wellbore during the whole completion installation process, frequently requiring prior fluid loss control as to allow safe deployment. Rock characteristics found in this field make it difficult to effectively control losses in some of the wells, requiring the use of different well construction practices that led to the development of some new well designs. The well engineering team developed a new well concept, where a separated lower completion system is installed in open hole, delivering temporary reservoir isolation. This new well architecture not only delivers reduced drilling and completion duration and costs, but also provides the IWC features in wells with major fluid losses. This is possible by the use of multiple managed pressure drilling (MPD) techniques when required, which were considered since the initial design phase. Safe and effective construction of some wells in pre-salt fields was considered not feasible before the adoption of MPD solutions, both for drilling and completions. Other important aspects considered on the new well design are the large thickness and high productivity of Buzios field reservoirs, as well as the need of some flexibility to deal with uncertainties. Finally, the new completion project was also designed to improve performance and safety on future challenging heavy workover interventions. The well construction area has gradually obtained improved performance in Buzios field with the adoption of the new practices and well design presented in this paper. The new solutions developed for Buzios field have set a new drilling and completion philosophy for pre-salt wells, setting the grounds for future projects. The improved performance is essential to keep these deepwater projects competitive, especially in challenging oil price scenarios. One of the groundbreaking solutions used is the possibility of installing the lower completion using managed pressure drilling techniques.

Automated Pattern Recognition in Real-Time Drilling Data for Early Karst Detection

Drilling in carbonate formations often poses a real challenge to operators, contractors and service companies. Severe fluid losses, gas kicks and other unwanted situations increase drilling risks. These risks are closely related to drilling through karsts — vugs, cavities and fractures. Therefore it is important to detect karsts early enough to avoid drilling into them or, once drilling in a karstification region is detected, to prepare risk mitigating actions. Some geophysical methods can be used for karsts detection, however, they have limitations and cannot guarantee early detection of karsts. One of the recent studies has shown that certain patterns in real-time drilling data can serve as indicators of zones with a higher likelihood of encountering karsts. In this paper, we demonstrate how these patterns can be detected in an automated manner with an adaptive differential filter algorithm. The method has been validated on real drilling data.

A Big Question for Digital Experts: What Is the Driller Trying To Do?

Digital drilling experts spend a lot of time wondering “what was the driller thinking?” They are not being sarcastic. The question matters for those doing analysis or writing control algorithms because the significance of readings, such as level of torque at any moment, depends on what the driller is doing at the time. The interpretation is different if the rig is drilling, where significant torque is required, or reaming, where the resistance is likely minimal. “During the reaming process, a spike in torque indicates something altogether different from a similar spike while drilling. So, the machine must recognize at least these two states: drilling and reaming,” said Fred Florence, a drilling consultant. He is among a group of drilling automation advocates who put rig state on a short list of issues that must be addressed to make it possible to create drilling systems where multiple devices can read and react in sync to changing drilling conditions. In other words, they want to know the information in the driller’s head now, said Moray Laing, director of digital value well construction engineering for Halliburton. That means an automated device needs to know what the driller is doing and also be aware of concerns that could require quick reactions. “Unless we can give it the same situational awareness of a human, it will not be able to manage the complexity of the process,” said Darryl Fett, Total’s manager of research drilling and wells in Houston. Rig state differences also plague those trying to analyze drilling data who need to know what else was going on at the time. They struggle with multiwell data where different methods of calculating the rig state were used. Drillers leave a record of their work in drilling logs. But this after-the-fact report typically lacks the precise timing sought by digital analysts using high-frequency data to analyze events that can happen suddenly. “A data scientist working on drilling will tell you that one of their biggest pains is someone will ask them to build a model on lost circulation and here is some data,” Laing said. That analysis is not possible unless someone can offer details about when the fluid losses began, how long they lasted, and other bits of context that might matter, such as the drilling fluid properties at the time. When asked for a basic explanation of the rig state, Crispin Chatar, drilling subject matter expert for Schlumberger, compared it to bringing a car that has been overheating to the shop. The mechanic will ask what was happening when the trouble began. Did the trouble start while driving fast on a freeway? While stuck in traffic? Did it happen after the radiator fluid warning light went on? “Every single engineer who works in drilling optimization, drilling analytics, or any one of our remote operation centers uses rig state to quickly and clearly understand what is going on at the well-site in terms of drilling operations or what the system might be seeing downhole,” Chatar said.

‘Level-off’ cement plugging method to cure lost circulation verified with case studies

Controlling lost circulation during drilling operations in a reservoir prone to fluid losses is typically remedied by cement squeezing or plug setting as the last resort. The aim being to minimize or stop drilling fluid losses and to regain full returns at surface, and to maintain wellbore integrity. Different placement methods of cement plugs have been discussed in detail in the literature, except for the ‘level-off’ method, which can be effective for curing complete loss circulation cases. Following modeling and calculations of this cement plug placement method, its design and execution procedures are discussed, together with two successful field cases in highly fractured carbonate reservoirs in the Middle East. Using drill pipe and a Retrievable-Test-Treat-Squeeze (RTTS) packer, set with some spacing from the loss zone, the method entails that the cement slurry is allowed to drop by gravity in order to cure lost circulation. As the column of fluid, mud and slurry in the well exceeds formation pore pressure, i.e., overbalanced conditions, a volume of acid-soluble cement slurry is allowed to slowly drop and freely penetrate the formation, i.e., through its fractures or caverns. During the penetration of this viscous slurry into the loss zone, the cement slurry can set and the fracture or fissure openings are plugged. Presented are detailed design calculations for the level-off placement technique, determination of required cement slurry and displacement volumes, and recommended displacement and RTTS packer setting depths. The expected depth of the top of cement plug is estimated. The design parameters are compared with field cases and explanations are given for possible discrepancies. Success of the operation is discussed in terms of final mud loss after cement plugging and Non-Productive Time mitigation. Detailed field procedures and execution are also presented. The level-off job is already practiced by the industry, but it is not published in the literature, in some cases they have different methods with causing some errors. To the best of authors’ knowledge, this is the first detailed description and stepwise calculation of the level-off cement placement technique in the literature.