Academic literature on the topic 'Structural Propping'
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Journal articles on the topic "Structural Propping"
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Zhu, Qingzhong, Bo Wang, Xin Zhao, Chunchun Liu, Qing Yu, Liwen Zhang, Tao Hou, and Guangjie Sang. "Effect of Coalbed Methane Well Fracturing on Slope Stability of Open-Pit Coal Mine: A Case Study of Shengli East No. 2 Open-Pit Coal Mine." Advances in Civil Engineering 2020 (July 16, 2020): 1–16. http://dx.doi.org/10.1155/2020/4708274.
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The impact of hydraulic fracture from CBM well fracturing on slope stability of the Shengli East No. 2 open-pit coal mine is analyzed by numerical simulation and limit equilibrium methods. The interference effect of coalbed methane (CBM) well fracturing on slope stability of the open-pit coal mine promotes the coordinated development of CBM, and open-pit coal is discussed before and after coal mining. It shows that nearly horizontal fractures are formed in the coal seam due to CBM well fracturing, of which the dynamic facture length and propping fracture length are 137.2 m and 105.2 m, respectively. Moreover, the dynamic fracture height is 137.2 m and propping fracture height is 130.6 m. At the location of perforation, the dynamic fracture width is 0.873 cm and average propping fracture width is 0.111 cm. The CBM well fracturing barely imposed any effect on slope stability before open-pit coal mining. The maximum vertical displacement at the toe of slope induced by fracturing is 0.293 mm. In situations with and without CBM well fracturing, vertical stress distributions in the toe, top, and interior of slope have no obvious difference. There is some extent of vertical stress increase within the interior of slope, which is merely 0.2 MPa higher than that in the condition of initial in situ stress equilibrium. The presence of hydraulic fractures has little effect on the overall displacement of slope during coal mining; and there is no obvious difference between the slope stability during coal mining and the slope stability impacted by fracturing. According to the results of limit equilibrium method and numerical simulation, the overall slope stability coefficient is 1.5–1.97, which accords with the requirements of the Design Code for Open-Pit Mine of Coal Industry (GB50197-2015). Therefore, more attentions should be paid to the ways of excavation and sloping during coal mining, avoiding slope instability caused by excavation.
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Parthasarathy, Arunachalam, Smriti Mahalingam, Subhiksha Sridharan, Sai Pavan Kalyan Chethala, and R. Vidjeapriya. "Comparative Analysis of 3D Steel and Glulam Trusses Using ABAQUS." IOP Conference Series: Materials Science and Engineering 1197, no. 1 (November 1, 2021): 012006. http://dx.doi.org/10.1088/1757-899x/1197/1/012006.
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Abstract This study aims at developing an innovative and sustainable 3D truss system that can be applied in a variety of scenarios where intermediary propping is a hindrance. One prominent and pertinent application of such a system is in archaeological sites where long spans and no intermediary propping are desired. Previous research and studies have developed an innovative 3D steel truss for the same application. This study aims to further the innovation by providing a more sustainable alternative through Glulam and Glulam-Bamboo hybrid variations which are able to withstand similar loads as that of the steel truss but offering more sustainability and less impact on the environment as well as a light weight alternative. The results of such an alternative truss system are discussed here. One obvious problem faced with the alternative wood system was the large deflections observed and also certain regions with impermissible stresses. In addition, the proposed joint in the Glulam truss has been modelled and analyzed. It was found that the Glulam truss with lateral restraints at every quarter length of the span showed the best results in terms of deflection and stress developed. Also, the Glulam-Bamboo hybrid truss without any lateral restraints proved to be an equally effective alternative from a structural standpoint. The proposed joint system for the glulam truss also proved to be effective. The study concludes with a cost benefit analysis (CBA) between the steel, glulam and Glulam-Bamboo hybrid systems, which compares the viability of the proposed designs from an economic standpoint. The CBA shows that about 46% and 48% of costs are minimized on employing Glulam, Glulam- Bamboo respectively, instead of using Steel for the truss.
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Blanco, Haydee, Yosbel Boffill, Ignacio Lombillo, and Luis Villegas. "Monitoring Propping System Removal in Domes and Tie-Rod Slackening from a Historical Building." Journal of Structural Engineering 145, no. 5 (May 2019): 04019033. http://dx.doi.org/10.1061/(asce)st.1943-541x.0002297.
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Ivanova, Maria N. "Inequality, financialization, and the US current account deficit." Industrial and Corporate Change 28, no. 4 (March 19, 2019): 707–24. http://dx.doi.org/10.1093/icc/dtz005.
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Abstract The US has run a persistent current account deficit since 1982. Its growth particularly accelerated in the early 2000s, and the deficit peaked at about 6% of US GDP in 2006. Coincidentally, the distribution of income and wealth has grown progressively unequal, while the so-called financialization of the US economy has deepened. This article argues that the concomitant processes of persistent current account deficits, rising inequality, and deepening financialization are not merely coincidental but can be traced to common causes arising from the global restructuring of US production through foreign direct investment and offshoring, which has underlain the structural transformation of the US economy since the 1980s. On the one hand, the US is the world’s biggest exporter of capital and recipient of foreign investment income; on the other hand, it is the biggest importer of foreign goods, often produced with the involvement of US capital. Ultimately, deindustrialization at home—a major factor behind the loss of middle-wage, middle-class jobs, and thus of rising income inequality—and the transnationalization of US production have boosted corporate profits, thereby propping up and accelerating the financialization of the US economy.
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Tan, Yong, Bin Wei, Xin Zhou, and Yanping Diao. "Lessons Learned from Construction of Shanghai Metro Stations: Importance of Quick Excavation, Prompt Propping, Timely Casting, and Segmented Construction." Journal of Performance of Constructed Facilities 29, no. 4 (August 2015): 04014096. http://dx.doi.org/10.1061/(asce)cf.1943-5509.0000599.
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Kathalikkattil, Amal Cherian, Kamal Kumar Bisht, Núria Aliaga-Alcalde, and Eringathodi Suresh. "Synthesis, Magnetic Properties, and Structural Investigation of Mixed-Ligand Cu(II) Helical Coordination Polymers with an Amino Acid Backbone and N-Donor Propping: 1-D Helical, 2-D Hexagonal Net (hcb), and 3-DinsTopologies." Crystal Growth & Design 11, no. 5 (May 4, 2011): 1631–41. http://dx.doi.org/10.1021/cg101587h.
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Wang, Ping, TianLi Gu, Zhanwu Gao, Jiayong Fan, Hai Huang, Zhan Qu, Qiang Han, and Zongxiao Ren. "Stability Evaluation of Proppant in Fractures of Gas Storage in Yulin Gas Field." Advances in Civil Engineering 2022 (May 28, 2022): 1–12. http://dx.doi.org/10.1155/2022/2044561.
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In nearly a hundred years of construction, underground gas storage has become the main natural gas storage and peak regulation means in the world. For the gas storage, the large production and high flow rate of the gas well in the actual production process will cause the backflow of proppant filled in the supporting fracture, which will bring great harm to the gas field production. In this article, when the proppant fracture reaches a stable state in the process of gas injection and production, the stress of proppant particles is analyzed, the critical velocity of proppant reflux is calculated, and then the critical production model is established; calculate the permeability change during proppant migration, then calculate the fluid velocity and production, and determine the fluid velocity range of injection and production wells in gas storage. The parameter sensitivity of velocity and flow model is analyzed. The results show that with the increase of closure stress, the critical gas flow and critical gas velocity of proppant backflow gradually increase, and the proppant filling layer is more stable. The smaller the thickness and width of the filling layer, the greater the critical gas flow and critical gas velocity of proppant backflow, the more stable the proppant filling layer, and the lesser the chance of backflow. The higher the saturation, the lower the critical gas velocity, and the more prone the proppant to reflux. It has important guiding significance for realizing the optimization of gas well production and maintaining efficient production efficiency.
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Kwietniewski, M., D. Miedzińska, and T. Niezgoda. "Fem Analysis of Proppant Sticking in Rock Cracks." Archives of Civil Engineering 64, no. 2 (September 28, 2018): 55–65. http://dx.doi.org/10.2478/ace-2018-0016.
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AbstractThe problem of effective gas extraction from Polish shale rocks is an interesting research subject for scientists. A properly selected proppant, which protects cracks from closing during the fracturing process, inestimably contributes to an increase of extraction. Grains of proppant are transported along with a fracturing medium to reach the deepest regions of the crack. The proper support of the crack provides an easy flow of gas, therefore it is important in terms of extraction efficiency. This paper shows the interactions of a proppant grain with the crack surface in shale rock. FEM analysis was conducted to observe the stress region, which is generated as a result of pressing the grain into the crack surface. A model of a sphere which was pressed into the rock model with constant velocity was applied. The received results of stress depend on material properties and a range of proppant grain pressing.
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Kühnel, K., R. Krick, R. A. Busse, A. Scacioc, and M. Thumm. "Structural and functional characterization of the two phosphoinositide binding sites of PROPPINs." Acta Crystallographica Section A Foundations of Crystallography 69, a1 (August 25, 2013): s316. http://dx.doi.org/10.1107/s0108767313097262.
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Masłowski, Mateusz, and Małgorzata Labus. "Preliminary Studies on the Proppant Embedment in Baltic Basin Shale Rock." Rock Mechanics and Rock Engineering 54, no. 5 (March 3, 2021): 2233–48. http://dx.doi.org/10.1007/s00603-021-02407-0.
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AbstractProppant embedment is a serious issue that reduces fracture width and conductivity. The paper presents the results of experiments on embedment phenomena on a shale rock from the region of the Baltic Basin, which is regarded as an unconventional gas deposit. A novel laboratory imaging procedure was implemented to the proppant embedment visualization. The tests were performed for conditions corresponding to the average reservoir conditions occurring in the studied deposit formation. The parameters characterizing damage of the surface of the fracture faces by the grains of proppant material, after the application of axial compressive stress to two shale core samples with proppant placed in between, are presented. The tests were carried out for rock samples pre-saturated with fracturing fluid. The obtained results of relatively low total effective penetration depth of proppant grains into the walls of the fracture (0.293 mm), and high effective width of fracture with proppant material after hydraulic fracturing (87.9%), indicate the proper selection of proppant and fracturing fluid for the properties of the rock and the reservoir conditions. The results of the experiments present a range of embedment parameters, that have not been widely described before. The test procedure presented in the article is a good method for assessing the vulnerability of a deposit rock to embedment phenomenon.
Dissertations / Theses on the topic "Structural Propping"
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Rockstroh, Benjamin Andreas. "An investigation into the effects of early propping removal on the deflection of reinforced concrete beams." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29285.
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In today’s fast paced construction industry, there is an ever present need to increase productivity and to complete projects as quickly as possible. Reinforced concrete is a popular and widely used construction material. However it has the unfortunate drawback in that the concrete requires time to set and gain sufficient strength before loads may be applied and the formwork and props can be removed. It is therefore desirable to keep propping times to a minimum. If the propping is removed too early, there is a risk of the member deflecting excessively and exceeding the maximum allowable limits, or in severe cases it could even lead to a structural failure or collapse. The SANS 2001 code provides recommended propping times for beams and slabs, which can be used as a guideline by building contractors and structural designers. These propping times present a universal approach, which does not consider all the factors that affect deflection. This simplified approach may be considered to be conservative as shorter propping durations could be possible without a loss in performance. The aim of this dissertation is to look into the effects of early propping removal on the longterm deflections of concrete members. This was done by modelling the deflection of a typical reinforced concrete beam at different ages of loading, using three code-based deflection calculation methods. The codes that were used are the South African National Standard (SANS), Eurocode (EC2) and American Concrete Institute code (ACI 318). A detailed literature-based investigation was conducted to determine the factors which affect deflection in reinforced concrete members, as well as the theory behind the code-based deflection calculation procedures. This was followed by the modelling of deflections using the abovementioned methods. Three case studies were performed to determine the effects of early propping removal under different scenarios. The first case study only deals with the effects of early age loading on long-term deflection. As an added point of interest, two different concrete mixes were used, made with two different types of cement. The second case study compares the effect that different levels of relative humidity have on the long term deflection at early ages of loading. Lastly, the effects of concrete strength on long-term deflections at early ages of loading was modelled. The results of the first case study indicated that a reduction in propping time is possible without causing excessive deflections. In the second and third case study is was observed that both the relative humidity and concrete strength respectively have an effect on the long term deflection and therefore also influence the propping time. The study concluded that based on the obtained estimated deflection values using the codebased methods, the propping times provided in the SANS 2001 code may in certain applications be conservative. According to the results obtained from the code-based deflection calculation procedures, it is possible to reduce the propping duration. It was suggested that an alternative method should be developed which would allow structural designers to determine the required propping time more accurately.
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Choi, Myungsub. "Propping and pyramids in family business groups: Evidence from Korean chaebols." Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/120476/1/Myungsub_Choi_Thesis.pdf.
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Using a sample of Korean family business groups (chaebols) during the 2006-2011 period, I study the mechanism of propping through related party transactions following the 2008 financial crisis, and its effects on firm performance and investments. I find chaebols use intra-transactions to mitigate the negative effects of the crisis. Using a discrete classification of firms into four pyramidal layers, chaebol families use related party sales to prop up firms in the third layer following the crisis, perhaps at the expense of central firms. In doing so, controlling chaebol families transfer the cost of propping to outside minority shareholders.
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Scacioc, Andreea [Verfasser], Karin [Akademischer Betreuer] Kühnel, and Michael [Akademischer Betreuer] Thumm. "Structural, biochemical and computational studies on PROPPINs, proteins important in autophagy / Andreea Scacioc. Betreuer: Karin Kühnel. Gutachter: Karin Kühnel ; Michael Thumm." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2015. http://d-nb.info/1080361839/34.
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Scacioc, Andreea. "Structural, biochemical and computational studies on PROPPINs, proteins important in autophagy." Doctoral thesis, 2014. http://hdl.handle.net/11858/00-1735-0000-0028-8675-3.
Full textBook chapters on the topic "Structural Propping"
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Murphy, Terence Patrick. "From Veselovskian Motif to Proppian Function." In The Fairytale and Plot Structure, 29–33. London: Palgrave Macmillan UK, 2015. http://dx.doi.org/10.1057/9781137547088_4.
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Murphy, Terence Patrick. "A Proppian Analysis of Charles Perrault’s Cinderella." In The Fairytale and Plot Structure, 34–50. London: Palgrave Macmillan UK, 2015. http://dx.doi.org/10.1057/9781137547088_5.
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"propping structure." In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik, 1051. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_164120.
Full textConference papers on the topic "Structural Propping"
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Liu, Yinghui, Ernesto Fonseca, Claudia Hackbarth, Ralph Hulseman, and Kenneth N. Tackett II. "A New Generation High-drag Proppant: Prototype Development, Laboratory Testing, and Hydraulic Fracturing Modeling." In SPE Hydraulic Fracturing Technology Conference. SPE, 2015. http://dx.doi.org/10.2118/spe-173338-ms.
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Abstract A new generation alumina ceramic proppant has been developed for higher drag and thus improved settling performance compared to conventional sand or ceramic proppant. Slickwater hydraulic fracture treatments in unconventional gas and tight oil developments are less expensive and less likely to leave residue than cross-linked gel formulations, but due to the lower viscosity, proppant transported with slickwater tends to settle out, likely contributing to screenout of proppant and shorter fracture half length with limited propped height. This novel proppant technology is designed to address the challenges of better proppant placement and increased propped height and half length in slickwater fracturing. This paper describes prototype development of the novel proppant technology, laboratory testing, and hydraulic fracturing modeling. The new proppant is shaped such that it tumbles and flutters during sedimentation in water and this movement greatly reduces settling rate. Finite element structural analysis was conducted to optimize the geometry to achieve higher crush strength while maintaining the conductivity. Laboratory sedimentation tests show a significant increase in settling time of new generation proppant compared to 30-50 sand poppant which had similar size and weight. Hydraulic fracturing modeling shows potential for a significant increase in proppant coverage area. With structurally designed and optimized shapes, this high drag proppant has better transport/placement due to lower settling rates, and enhanced proppant flowback control. Finally, a practical manufacturing process has been identified to enable cost-effective manufacturing of this material.
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Burukhin, Alexander Alexandrovich, Sergey Kalinin, Jonathan Abbott, Marina Bulova, Yong K. Wu, Michael Crandall, Ignatius Kadoma, Michael Begich, and Siegmund Papp. "Novel Interconnected Bonded Structure Enhances Proppant Flowback Control." In SPE International Symposium and Exhibition on Formation Damage Control. Society of Petroleum Engineers, 2012. http://dx.doi.org/10.2118/151861-ms.
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Zhou, Jia, Paul Carman, Hong Sun, Richard Wheeler, Harold Brannon, D. V. Satya Gupta, and Ray Starks. "Revolutionary Particle Fluid System Unlocks of Fractured Reservoir Potential." In SPE Hydraulic Fracturing Technology Conference. SPE, 2015. http://dx.doi.org/10.2118/spe-173369-ms.
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Abstract Post-treatment production analyses for hydraulic fracturing treatments with conventional crosslinked gel or slickwater often indicate that the treatments do not achieve the designed stimulation effectiveness, which could be attributed to non-optimal proppant placement and/or significantly damaged fracture conductivity. Although conventional crosslinked fluids are observed to provide good proppant suspension in laboratory environments, they might not provide the desired proppant transport under downhole conditions. Crosslinked fluids are known to be difficult to clean up, and thus are notorious for imparting gel damage to proppant pack and formation. Slickwater can be used to mitigate gel damage by reducing the effective polymer loadings, but consequential extreme proppant settling and banking problems reduce the chance of achieving fracture performance. Several proppant placement techniques have been developed to generate highly conductive paths for hydrocarbons to flow from an unconventional reservoir to the wellbore, such as hybrid fracturing, reverse hybrid fracturing, and channel fracturing, each of which predominantly rely upon high viscosity fluids to carry the proppant to the designated location. This paper presents a non-traditional fracturing fluid system and application technique with near perfect proppant suspension and transport, high fracture conductivity, and self-diverting characteristics. The revolutionary fracturing fluid system employs engineered packing of particle domains for proppant suspension mechanics that are significantly different from crosslinked polymer systems which use polymer chain overlap and inter-chain crosslinking to generate viscosity governed proppant transport. The unique gel particle structure perfectly suspends proppant for several hours at reservoir conditions to facilitate better transverse and vertical placement of proppant in the fracture and significantly increases the fractured surface area, which is one of most important factors in unconventional reservoir production. The self-diverting tendencies offer the potential to maximize created fracture area while simultaneously reducing the treating fluid volumes without the addition of costly diverting additives. The degradability of the fluid can be controlled at reservoir conditions by fluid pH and/or breaker loading to yield near 100% regained proppant pack conductivity. This paper discusses the evolution of the technology, and laboratory results for this unique fluid system. The system can unlock reservoir potential in areas requiring high fractured surface area and high regained conductivity, such as unconventional liquid-rich formations.
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Gomaa, A. M. M., D. V. S. V. S. Gupta, and P. Carman. "Proppant Transport? Viscosity Is Not All It's Cracked Up To Be." In SPE Hydraulic Fracturing Technology Conference. SPE, 2015. http://dx.doi.org/10.2118/spe-173323-ms.
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Abstract Post-treatment production analyses for hydraulic fracturing treatments with conventional crosslinked gel often indicate that the treatments do not achieve the designed stimulation effectiveness, which could be attributed to non-optimal proppant placement and/or significantly damaged fracture conductivity. Although conventional crosslinked fluids are observed to provide good proppant suspension in laboratory environments, they might not provide the desired proppant transport under downhole conditions. Crosslinked fluids are known to be difficult to clean up, and thus are notorious for imparting gel damage to proppant pack and formation. Surfactant gels have been developed to mitigate some of the issues. Viscosity measurements are used as the main tool to judge and optimize the performance of both polymer and surfactant based fracture fluids, especially their ability to transport proppant. While efficient proppant transport is essential for successful hydraulic fracturing, recent laboratory work has shown that viscosity alone may not accurately assess proppant transport. The objective of the paper is to investigate and determine the minimum rheological properties required for efficient proppant transport. Thus, combinations of rotational and oscillatory measurements were conducted to better predict the proppant transport characteristics. Also, proppant settling tests were conducted at static and dynamic conditions. A strong correlation was established between fluid's elasticity and its ability to suspend the proppant with a required minimum elastic modulus (G') value to be greater than viscous modulus (G”). Experimental results show that for two fluids that both have a close viscosity value (similar power law parameters); one fluid with G'>G” while the other one G'< G”, the fluid that has G'>G” behaves as semi-solid material where it deforms instead of flowing when shear stress is applied, while the fluid that has G”>G', flows when shear stress is applied and time to flow depends on viscosity. A proppant particle in a fluid undergoes shear stress due to its density. Therefore, for the fluid G”>G', proppant settles as the fluid moves around it and the speed of settling depends on fluid viscosity, whereas for the elastic fluid (G'>G”), fluid elasticity does not allow the proppant to settle. This observation was confirmed for both polymer and surfactant based fracturing fluids. Additives can be divided into categories that may enhance or reduce fluid elasticity based on their effect on the internal structure of the fluids. For example, breakers tend to significantly reduce the fluid elasticity, even when viscosity reduction is minimized. Data obtained from this study can be used as a guideline to optimize and select the fluid that has ability to carry proppant for field treatment design.
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Busteed, John E., Jesus Arroyo, Francisco Morales, Mohammed Omer, and Francisco E. Fragachan. "Is High Viscosity a Requirement for Fracturing Fluids?" In SPE International Hydraulic Fracturing Technology Conference & Exhibition. SPE, 2022. http://dx.doi.org/10.2118/205244-ms.
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Abstract Uniformly distributing proppant inside fractures with low damage on fracture conductivity is the most important index of successful fracturing fluids. However, due to very low proppant suspension capacity of slickwater and friction reducers fracturing fluids and longer fracture closure time in nano & pico darcies formations, proppants settles quickly and accumulates near wellbore resulting in worse-than-expected well performance, as the fracture full capacity is not open and contributing to production. Traditionally, cross-linked polymer fluid systems are capable to suspend and transport high loading of proppants into a hydraulically generated fracture. Nevertheless, amount of unbroken cross-linked polymers is usually left in fractures causing damage to fracture proppant conductivity, depending on polymer loading. To mitigate these challenges, a low viscosity-engineered-fluid with excellent proppantcarrying capacity and suspension-in excess of 30 hours at static formation temperature conditions - has been designed, enhancing proppant placement and distribution within developed fractures, with a 98% plus retained conductivity. In this work experimental and numerical tests are presented together with the path followed in developing a network of packed structures from polymer associations providing low viscosity and maximum proppant suspension. Challenges encountered during field injection with friction are discussed together with the problem understanding characterized via extensive friction loop tests. Suspension tests performed with up to 8-10 PPA of proppant concentration at temperature conditions are shared, together with slot tests performed. Physics-based model results from a 3D Discrete Fracture Network simulator that computes viscosity, and elastic parameters based on shear rate, allows to estimate pressure losses along the flow path from surface lines, tubular goods, perforations, and fracture. This work will demonstrate the advanced capabilities and performance of the engineered fluid over conventional fracturing fluids and its benefits. Additionally, this paper will present field injection pressure analysis performed during the development of this fluid, together with a field case including production results after 8 months of treatment. The field case production decline observed after fracture treatment demonstrates the value of this system in sustaining well production and adding additional reserves.
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Pawar, Gorakh, Ilija Miskovic, and Manjunath Basavarajappa. "Evaluation of Fluid Behaviour and Mixing Efficiency in Predefined Serpentine Micro-Fracture System." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-65124.
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Scientific research and development in the field of microfluidics and nanofluidics technology has witnessed a rapid expansion in recent years. Microfluidic and nanofluidic systems are finding increasing application in wide spectrum of biomedical and engineering fields, including oil and gas technology. Fluid flow characterization in porous geologic media is an important factor for predicting and improving oil and gas recovery. By developing understanding about the propagation of hydraulic fracturing fluid constituents in irregular micro- and nano-structures, and their multiphase interaction with reservoir fluids (e.g. mixing of supercritical CO2 with oil or gas) we can significantly improve efficiency of the current oil and gas (O&G) extraction process and reduce associated environmental impacts. In present paper, mixing of hydraulic fracturing fluid constituents in three dimensional serpentine microchannel system is simulated in CFD environment and results are used to evaluate mixing efficiency for different fracturing fluid compositions. In addition, pressure drop along the length of serpentine micro-channel is evaluated. Serpentine micro-channels considered in this study consist of periodic symmetrical and asymmetrical proppant particles, placed on both sides of the channel over the full length of the channel, to simulate realistic geometrical constraints usually seen in geological fractures. The fluid flow is characterized as a function of the proppant particle radius by varying size of adjacent proppant particles. Further, the flow is characterized by varying distance between adjacent proppant particles. Overall, this study will be primarily helpful to gain fundamental understanding of fracturing fluid mixing in micro-fractures, similar to real geologic media. In addition, this study will provide an insight into variations of fracturing fluid mixing efficiency, and pressure drop in micro-fracture systems as a function of geometry of the proppant particles at different flow rates.
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Lv, Qichao, Tongke Zhou, Yingting Luan, and Zhaoxia Dong. "Rheology and Dynamic Filtration of Foam Fracturing Fluid Enhanced by Cellulose Nanofibrils." In International Petroleum Technology Conference. IPTC, 2021. http://dx.doi.org/10.2523/iptc-21361-ms.
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Abstract Foam fracturing is an effective method for the development of unconventional reservoirs. However, due to lamellar film, high pressure differences within foam films, and the strong diffusivity of the internal phase, foam is prone to suffering from unstable phenomena such as rupture, drainage, disproportionation, etc., thus leading to uncontrollable foam flow behavior in the tube and formation. In this work, cellulose nanofibrils (CNFs) were used to enhance foam fracturing fluid. The target is not only to obtain a stable foam system, but also to control its rheology, proppant-carrying and leak-off behavior. The stability of the N2 foam fracturing fluid with CNFs was firstly explored via static tests by measuring its foam volume and liquid drainage. Then, the viscosity of foam fracturing fluids with different foam quality was measured using a tube viscometer under conditions of use, to evaluate the rheology of foam with CNFs. Subsequently, the proppant-carrying capacity was evaluated by observing suspension state of proppants in foam over time. The microscopic images of the foam with proppants were collected to analyze the interaction between bubbles and proppant. Finally, the dynamic filtration behavior and core damage of foam with CNFs were investigated by using a dynamic filtration apparatus. The results of the static tests showed that the stability of foam was significantly enhanced by the addition of CNFs, and the liquid drainage and gas diffusion could be effectively inhibited. Upon foam evolution, bare surfactant foam formed a polyhedral structure rapidly, while the CNFs enhanced foam maintained spherical and dense for a long time. The viscosity of foams with and without cellulose nanofibrils showed a shear thinning behavior. With the addition of CNFs, the viscosity of foam was improved by 3 - 6 times compared with bare surfactant foam and its value was increased with foam quality changing from 60% to 80%. The results of proppant-carrying tests indicated that the proppants suspension in foam was improved obviously as the cellulose nanofibrils were added. For CNFs-stabilized foam, the aqueous film of bubbles became thicker and the mechanical strength of foam structure was improved, thus enhancing the proppant suspension in the foams. Moreover, the filtration control performance of CNFs foam was also improved compared with bare surfactant foam. The filtration coefficient of CNFs foam fracturing fluid decreased with increasing CNFs concentration at a filtration pressure difference of 3 MPa, and core damage was maintained at a relatively low level. Additionally, the filtration coefficient of CNFs-stabilized foam and its core damage could be reduced with the increase of foam quality from 60% to 80%. The stability, rheology, proppant-carrying and dynamic filtration control of foam fracturing fluid enhanced by cellulose nanofibrils were explored in this work. The results show that the addition of CNFs effectively improves the stability of the foam, thus enabling the rheology, proppant-carrying and the dynamic filtration to be well controlled, which provides a high-performance and eco-friendly foam fracturing fluid.
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Nguyen Huu, Truong. "Fracture Treatment Design in the Lower Miocene Reservoir, Offshore Viet Nam." In IADC/SPE Asia Pacific Drilling Technology Conference. SPE, 2021. http://dx.doi.org/10.2118/201056-ms.
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Abstract In the past decades, most oil explotation in the White Tiger oil field was produced from the basement reservoir. However, in recent years, these pay zones consist of basement reservoirs, Oligocene reservoirs, and Miocene reservoirs of which oil field s have been declined in oil production rate due to several issues such as complex fracture network, high heterogeneity formation, high water cut, and the reduction of reservoir pressure. The huge issues in the most production wells at basement reservoir were high water cut and it has been significantly increasing during oil production yearly. Therefore, the total amount of oil production in all pay zones sharply decreased with time. At present, the lower Miocene reservoir is one of the best tight oil reservoirs to produce oil extractrion. The lower Miocene reservoir has been faced some issues such as high heterogeneity, complex structure, catastrophic clay swelling, low connectivity among the fractures, low effective wellbore radius and the reservoir that is hig h temperature up to 120°C, the closure pressure up to 6680psi, reservoir pressure up to 4500 psi, reservoir depth up to 3000m. Another reason low conductivity consists of both low reservoir porosity ranging from 1% of the hard shale to 10% of the sandstone formation, and the low permeability raining from 1md to 10md. By considering the various recovery methods, the integrated hydraulic fracturing stimulation is the best tool to successfully stimulate this reservoir, which method allows an increase in oil production rate. In the post fractured well has been shown an increase in productivity over 3 folds in comparison with the base case with fracture half-length nearly 75m, and fracture conductivity about 5400md.ft, which production rate is higher than the production rate of the base case. In addition, the proppant mass is used of 133,067 lbs of which the first main stage is to pump sinter lite bauxite proppant type of 20/40 into the fractures and the next big stage is to pump sintered ball bauxite proppant size of 16/30 into the fractures, which not only isolate proppant flow back but also increase fracture conductivity at the near wellbore as wel as high productivity rate after fractured well. To improve proppant transport, fract uring fluid systems consist of Guar polymer concentration of 11.2 pptg with these additives to form a total leak-off coefficient of 0.00227 ft/min0.5.
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Briner, Andreas, Alexey Moiseenkov, Romain Prioul, Safdar Abbas, Sergey Nadezhdin, and Nihat Gurmen. "Hydraulic Fracture Initiation and Propagation Model Provides Theoretical Ground for Hybrid-Type Fracturing Schedules in Unconventional Gas Reservoir in the Sultanate of Oman." In SPE Middle East Unconventional Resources Conference and Exhibition. SPE, 2015. http://dx.doi.org/10.2118/spe-172950-ms.
Full textAbstract:
Abstract A recent series of tight gas discoveries in the Amin formation of the greater Fahud area represents some of the most exciting exploration success of this decade in the Sultanate of Oman. The structures have been evaluated as containing very significant amounts of gas locked in a challenging deep and hot environment requiring hydraulic fracture stimulation. Since their discoveries, the two primary challenges have been difficult breakdown of the formation and limited proppant placement during stimulation attempts. The early experience in the exploration and appraisal campaigns from 2009 to 2014 has led to fracture designs with conservative proppant amounts that could limit the full potential of the field. Several geomechanical studies have been commissioned in the past to guide completion strategies in well placement, perforation, and fracture stimulation design. The objectives of this study were to model hydraulic fracture initiation and breakdown in the three Amin zones (upper, middle, and lower) to provide some theoretical understanding of the impact of the different parameters on the observed field breakdown pressures. In agreement with field observations, the model showed that lowering the viscosity of the pad has a major impact in lowering the breakdown pressures. Consequently, current best practices include formation breakdown and hydraulic fracture propagation with low-viscosity fluids followed by proppant placement with high-viscosity fluids. When applied to tight gas formations in the Sultanate of Oman, the hybrid fracturing evolves from conventional designs for the purpose of successful fracture initiation, while still placing a successful job.
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Pei, Yanli, and Kamy Sepehrnoori. "Efficient Modeling of Depletion Induced Fracture Deformation in Unconventional Reservoirs." In SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/206318-ms.
Full textAbstract:
Abstract The change of fracture conductivity during reservoir depletion significantly affects the well performance and stress evolution in unconventional formations. A common practice is to model fracture deformation using the traditional finite element method with very dense unstructured grids representing complex fracture geometries. However, the associated computational cost is high, so previous studies mainly use empirical correlations to catch the fracture conductivity loss or neglect fracture deformation during the production period. This work proposes a novel coupled flow and geomechanics model with embedded fracture methods to capture the fracture deformation accurately yet efficiently in unconventional reservoirs. Under a single set of structured grids, an embedded discrete fracture model (EDFM) is employed to characterize fluid flow through discrete fractures by introducing non-neighboring connections, and an extended finite element method (XFEM) is applied to simulate discontinuities over fracture walls by adding phantom nodes. In addition, a modified proppant model is incorporated to represent interactions between proppants and hydraulic surfaces, and an iterative coupling scheme is implemented to link the fracture-related fluid flow and solid mechanics. Being validated against the classical benchmark problem, the coupled model is used to investigate the impacts of proppant strength, closure stress, and bottomhole pressure on fracture deformation, well production, and in-situ stresses. Numerical results indicate that weaker proppant support induces more fracture aperture and production losses, resulting in greater stress changes and higher residual pressure in the depletion region. In comparison, the fracture deformation for a well-propped scenario is modest and barely affects the well performance and stress redistribution. Less stressed formation corresponds to lower closure stress on fracture walls, which triggers limited fracture closure and stabilizes well production. Moreover, a moderate bottomhole pressure decline rate avoids significant fracture closure while preserves relatively high initial production rates. The coupled flow and geomechanics model with embedded fracture methods resolves computational difficulties in modeling complex fracture deformations and delivers more insights on production forecast and stress changes crucial to refracturing and infill operations.