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Research on Hull Form Optimization of KCS Ship Based on NM Theory
Feng, Baiwei (Key Laboratory of High Performance Ship Technology, Wuhan University of Technology, Ministry of Education, Wuhan, Hubei / School of Naval Architecture, Ocean and Energy Power Engineering, Wuhan University of Technology Wuhan, Hubei) | Zhou, Hui (Key Laboratory of High Performance Ship Technology, Wuhan University of Technology, Ministry of Education, Wuhan, Hubei / School of Naval Architecture, Ocean and Energy Power Engineering, Wuhan University of Technology Wuhan, Hubei) | Ma, Chao (Key Laboratory of High Performance Ship Technology, Wuhan University of Technology, Ministry of Education, Wuhan, Hubei / School of Naval Architecture, Ocean and Energy Power Engineering, Wuhan University of Technology Wuhan, Hubei)
ABSTRACT To meet the requirements for green ships in the IMO ship Energy Efficiency Design Index, based on the self-developed ship form optimization platform (SHIPMDO-WUT), the KCS ship is regarded as the initial hull to reduce its wave-making resistance at a certain speed. The hull form modification is then implemented by the radial basis function (RBF) interpolation technology and the resistance evaluation is carried out by the NM (Neumann-Michell) potential flow theory solver to minimize the wave-making resistance combining with the NSGA-II algorithm. Finally, after completing the optimization of ship resistance performance at the speed of Fr=0.3, the optimized ship is selected for analysis, and the resistance reduction effect of the optimized ship is analyzed through STARCCM+ software. The research results show that: (1) The hull form modification module based on radial basis interpolation technology can produce a smooth hull profile; (2) For the KCS ship, under the premise of meeting the engineering constraints, the automatic optimization method of the hull surface based on numerical simulation can obtain a new ship form with better performance of resistance. INTRODUCTION Ship hull form optimization is one of the effective methods to achieve energy saving and emission reduction. With the development of computer technology and Computational Fluid Dynamics (CFD), its evaluation capability has been enhanced, simulation-based design (SBD) has been listed as a hot issue in the research of numerical simulation technology by the International Tugboat Conference (ITTC), and many scholars at home and abroad have conducted extensive research on ship hull form optimization. Kim (2009) modified Wigley hull profile based on parametric hull representations and NURBS surfaces and Peri et al. (2001) utilized Bรฉ zier Patch to complete the modification of hull geometry. Based on the Rankine source method, Zhang and Percival et al. (2012) obtained an optimized ship hull form with minimum wave-making resistance. Wan Decheng et al. (2020) carried out local deformation of bow, waterline and aft of luxury cruise ship by the FFD (Free-Form Deformation) method, combining with the Neumann-Michell (NM) potential-flow-based solver NMShip-SJTU to complete the optimization of wave-making resistance at the two specified speeds. Shen Tong et al. (2013; 2015) used the radial basis function interpolation method and combined with the hydrodynamic solver Shipflow to optimize the wave-making resistance of KCS and S60 ships, and obtained the ship type with better resistance performance, but the displacement of the optimized ships was reduced, which reduced the ship operation economy to some extent. Hu Chunping et al. (2012) completed the full parametric modeling of KCS by using parametric modeling software CAESES, and combined with hydrodynamic calculation software to complete the study of automatic optimization of KCS profile. Zhan et al. (2012) used a fusion deformation method to generate a series of bulbous bows, realized the automatic optimization of the bulbous bow profile, and got the ship type with less wave-making resistance.
- Research Report > New Finding (0.34)
- Research Report > Experimental Study (0.34)
- Transportation > Marine (1.00)
- Energy > Oil & Gas > Upstream (0.47)
Impact of Completion Design on Various Infill Scenarios: A Data Driven Permian Case Study
Darneal, Chad (ConocoPhillips Company) | Friehauf, Kyle (ConocoPhillips Company) | McLin, Kristie (ConocoPhillips Company) | Rajappa, Bharath (ConocoPhillips Company) | Zhou, Hui (ConocoPhillips Company) | Hoang, Phuong (ConocoPhillips Company) | Hammond, Justin (ConocoPhillips Company) | Swan, Herbert (ConocoPhillips Company)
Abstract An ongoing challenge in unconventional reservoirs is the significant production degradation (loss of production) realized from child wells drilled adjacent to depleted parent wells. One strategy hypothesized to reduce the realized degradation is to modify the completion design in the child well. The main objective of this case study will be to test this hypothesis and quantify the impact completion design has on child well degradation; specifically, the case focuses on the stage architecture component of completion design defined as the combination of cluster spacing, number of clusters per stage, and stage length. This paper covers an integrated, multi-disciplined review of a unique development situation in the Permian where three different depletion scenarios surround a single well at various well spacings. This data rich review will characterize the SRV (Stimulated Rock Volume) and DRV (Drained Rock Volume) from each of four completion designs within the different depletion scenarios. Data sets include fiberoptic DAS/DTS (Distributed Acoustic/Temperature Sensing) and microseismic during stimulation, along with downhole pressure gauges, chemical tracers, downhole camera for perforation erosion, additional fiber-optic DAS/DTS production logs, and interference (well communication) tests. A single well with four different completion designs surrounded by three different depletion scenarios creates a rare opportunity to analyze the impact completion design has on child well degradation. Eight different forms of data acquisition technologies were used to increase understanding of completion variable impacts to SRV and DRV as well as validate several new cost-effective data acquisition technologies that were successfully trialed for this pilot. The SRV-related data shows fracture interference with offset depletion, but the amount of interference did not conclusively change among the various completion designs tested. Similarly, DRV-related data shows child well degradation when exposed to parent well depletion, but the amount of degradation did not conclusively change among the various completion designs tested. This suggests that factors other than stage architecture are the dominant drivers of well performance. Detailed analysis from the cross-functional team provides multiple perspectives on the results acquired as they pertain to the overall motivating objectives of the pilot.
- North America > United States > Texas > Permian Basin > Delaware Basin (0.99)
- North America > United States > Texas > Fort Worth Basin > Barnett Shale Formation (0.99)
- North America > United States > New Mexico > Permian Basin > Delaware Basin (0.99)
- Information Technology > Communications > Networks (0.50)
- Information Technology > Artificial Intelligence (0.34)
Mechanical Behavior of Bolted Rock Joints Under Constant Normal Stiffness Shear Loading Condition
Cui, Guojian (University of Chinese Academy of Sciences) | Zhang, Chuanqing (University of Chinese Academy of Sciences) | Zhou, Hui (University of Chinese Academy of Sciences) | Lu, Jingjing (University of Chinese Academy of Sciences) | Zeng, Zhiquan (PowerChina Huadong Engineering Corporation Limited) | Cheng, Guangtan (Shandong Agricultural University)
Abstract The mechanical behaviors of rock joints with and without rock bolt are essential for ensuring the safety of rock engineering and determining support scheme in jointed rock masses. This paper experimentally investigated the shear behavior of unbolted and bolted artificial rough joints using direct shear tests under different boundary conditions, where the effects of the initial normal stress, normal stiffness, and joint surface roughness were studied. Both strain-softening and strain-hardening characteristics were observed for shear stress curves, depended on normal boundary conditions and bolting state. Generally, bolted joint showed better shear resistance capacity than unbolted one regardless of boundary conditions, and conventional shear tests would underestimate the shear resistance capacity of rock joints when shear dilatancy was restricted by surrounding rock masses. Bolt contribution in jointed rock masses tended to decrease with the increase of normal stiffness or initial normal stress and increase with the increasing joint surface roughness. Moreover, the failure characteristics of the joint surface after shear tests were identified. Introduction Shear failure of rock joints is frequently encountered in geotechnical engineering, which might induce some severe disasters, such as fault slip rockburst and landslide, and therefore shear behavior of rock joints has a remarkable influence on the stability and safety of rock engineering projects. Rock bolting, an effective reinforcement technique, was broadly used in the fractured rock mass for enhancing the shear resistance of rock joints. Understanding the mechanical behavior of rock joints with and without rock bolt subjected to shearing is essential to determine the reinforcement effect and optimize corresponding support design schemes in practical engineering. Thereby, it's of considerable significance to study and compare the shear behaviors of rock joints with and without rock bolts. Shear behaviors of rock joints are generally evaluated using direct shear tests in the laboratory. A large number of experimental studies have been carried out on both bolted and unbolted rock joints to reveal the parametrical influence on the reinforcement effect and shear behavior, including rock mass conditions, rock joint surface morphology, bolt diameter and type, loading conditions, etc [1-14]. Spang and Egger experimentally investigated the influence of bolt diameter, bolt inclination angle with respect to the shear direction of the joint plane, and normal stress [1]. Li et al. compared the shear behavior of fiberglass (FG) bolt, rock bolt (steel rebar bolt), and cable bolt for the bolt contribution to bolted concrete surface's shear strength, and bolt failure mode [2]. Wang et al. evaluated the acoustic emission counts and characteristics of bolted rock-like joint specimens with different roughness and bolt elongation rates [7]. Wu et al. conducted a series of direct shear tests on six standard roughness profile joints and two natural joints and found that shear strength increased as the increase of joint roughness and established a dimensionless mathematical model to predict the shear behavior of bolt jointed with different joint roughness conditions [9]. Chen et al. concluded that rock bolts could increase the shear strength and shear stiffness of joint specimens [10]. Jalalifar and Aziz demonstrated that the strength of the concrete, bolt rib profile configuration, and bolt pretension load affected the shear resistance, shear displacement and failure mechanism of the reinforced medium when subjected to double shear tests [11]. Chen developed a new method to apply the pull and shear loads to the rock bolt at the same time [12].
An accelerating strategy in stochastic inversion
Yu, Bo (State Key Laboratory of Petroleum Resources and Prospecting, CNPC Key Lab of Geophysical Exploration, and China University of Petroleum) | Zhou, Hui (State Key Laboratory of Petroleum Resources and Prospecting, CNPC Key Lab of Geophysical Exploration, and China University of Petroleum) | Wang, Lingqian (State Key Laboratory of Petroleum Resources and Prospecting, CNPC Key Lab of Geophysical Exploration, and China University of Petroleum) | Chen, Hanming (State Key Laboratory of Petroleum Resources and Prospecting, CNPC Key Lab of Geophysical Exploration, and China University of Petroleum) | Huang, Weilin (State Key Laboratory of Petroleum Resources and Prospecting, CNPC Key Lab of Geophysical Exploration, and China University of Petroleum) | Shang, Guojun (State Key Laboratory of Petroleum Resources and Prospecting, CNPC Key Lab of Geophysical Exploration, and China University of Petroleum)
Stochastic seismic inversion can integrate diverse datasets to estimate the spatial distribution of subsurface elastic properties. High-resolution stochastic inversion results are significant in the development stage of an oil field. Nevertheless, existing statistical inversion approaches are commonly restricted by the heavy calculation burden. To address this issue, we propose a strategy to accelerate stochastic inversion. Based on a Bayesian linearized inversion theory, we propose a feasible and efficient stochastic inversion. Using the proposed method, we can not only obtain as good stochastic inversion results as the conventional stochastic inversion methods, but also avoid the heavy calculation burdens of forward simulation and computation the inverse of a complex kernel matrix. We test this method by a section of field data, and compare it with the conventional stochastic inversion method. The test result illustrates the effectiveness of this method. Presentation Date: Monday, October 12, 2020 Session Start Time: 1:50 PM Presentation Time: 2:15 PM Location: Poster Station 9 Presentation Type: Poster
Multi-scale full-waveform inversion constrained with patch-ordering smoothing
He, Huili (China University of Petroleum, Beijing) | Zhou, Hui (China University of Petroleum, Beijing) | Wang, Lingqian (China University of Petroleum, Beijing) | Fang, Jinwei (China University of Petroleum, Beijing) | Jiang, Shuqi (China University of Petroleum, Beijing)
In the process of patch-ordering Preconditioning and regularization is adopted to stabilize the smoothing, we decompose the inverted model into inverse problem in full waveform inversion. However, overlapping patches, construct a permutation matrix to order conventional isotropic smoothing blurs layer interfaces such these patches into a regular smooth sequence, and use a as faults and salt boundaries. In this paper, we propose a simple smoothing filter to obtain a stable reconstructed result patch-ordering smoothing operator for multi-scale full (Ram et al., 2013). Finally, we apply the proposed multiscale waveform inversion to improve the stability and lateral FWI constrained with patch-ordering smoothing to the continuity of the inversion result. Our algorithm is to apply 2D Overthrust model. The inversion result shows that the patch-ordering smoothing based on velocity magnitude interfaces are faithfully preserved and sharpened with our information obtained from each frequency-band velocity proposed method. Our algorithm is also able to delineate the inversion result.
- Research Report > New Finding (0.35)
- Research Report > Experimental Study (0.35)
Stability analysis of multiple-relaxation-time lattice Boltzmann model for wave simulation
Jiang, Chuntao (1China University of Petroleum, Beijing) | Zhou, Hui (1China University of Petroleum, Beijing) | Xia, Muming (1China University of Petroleum, Beijing) | Jiang, Shuqi (1China University of Petroleum, Beijing) | Tang, Jinxuan (1China University of Petroleum, Beijing) | An, Yong (1China University of Petroleum, Beijing)
The lattice Boltzmann method (LBM) has emerged as an effective and innovative numerical method based on kinetic theory for computational fluid dynamics and acoustic wave propagation. The multiple-relaxation-time LBM (MRTLBM) is much more stable and flexible than the traditional Bhatnagar-Gross-Krook LBM (BGK-LBM) owing to its adjustable free relaxation parameters (FRPs) in the case of low kinematic shear viscosity (low-KSV). Here acoustic wave propagation is simulated by BGK-LBM and MRTLBM with different FRPs in the case of low-KSV to display the superior stability of MRT-LBM. Meanwhile, how the FRPs of MRT-LBM affect the seismic waveform and the numerical stability separately in the case of low-KSV are analyzed. Presentation Date: Monday, October 12, 2020 Session Start Time: 1:50 PM Presentation Time: 3:55 PM Location: Poster Station 12 Presentation Type: Poster
A regularization strategy for Q-compensated reverse time migration using excitation imaging condition
Zhang, Mingkun (China University of Petroleum) | Zhou, Hui (China University of Petroleum) | Chen, Hanming (China University of Petroleum) | Jiang, Chuntao (China University of Petroleum) | Jiang, Shuqi (China University of Petroleum) | Wang, Lide (China University of Petroleum)
Q-compensated reverse time migration (Q-RTM) plays an important role for attenuate media imaging. The highfrequency of the seismic data growth exponentially during the absorption compensation, however, pose a challenge to Q-RTM. In order to overcome the limitation, we developed a stable and efficient Q-RTM method, in which a regularization term is introduced into the decoupled constant-Q fractional Laplacians viscoacoustic wave equation, to suppress the high-frequency instabilities during the attenuation compensation. Meanwhile, a Q compensated excitation amplitude image condition is conducted to decrease the computation complexity. We tested our method on the BP gas chimney model, and the numerical examples demonstrate that this method can effectively overcome the instability during the attenuation compensation, and obtain a prospective effects for Q-RTM. Presentation Date: Monday, October 12, 2020 Session Start Time: 1:50 PM Presentation Time: 2:40 PM Location: Poster Station 7 Presentation Type: Poster
Local cross-correlation imaging condition for reverse time migration
Zhou, Hui (China University of Petroleum) | Zhang, Mingkun (China University of Petroleum) | Wang, Yufeng (China University of Geosciences (Wuhan)) | Chen, Hanming (China University of Petroleum) | Jiang, Chuntao (China University of Petroleum) | Jiang, Shuqi (China University of Petroleum)
The cross-correlation imaging condition requires that the source and receiver wavefields should be synchronously available. Opposite propagation directions of those wavefields, nevertheless, pose a challenge between computer memory and computation complexity. We present a local cross-correlation imaging condition, a transition between the excitation amplitude and the crosscorrelation imaging conditions, for reverse time migration (RTM) to relax the limitation. For one spatial node, we merely correlate the forward and backward records in a local time window, which is corresponding times of the direct wave at this node during the source wavefield simulation. This method only demands to store a complete waveform of the direct wave in each spatial nodeโs record, and it does not require remodeling the source wavefield. We demonstrate this method on two-layer and BP synthetics. Numerical simulations show that this method can generate high-accuracy images and reduce the storage cost significantly. It may be widely used in RTM and other adjoint-state methods. Presentation Date: Tuesday, October 13, 2020 Session Start Time: 1:50 PM Presentation Time: 1:50 PM Location: Poster Station 2 Presentation Type: Poster
- Information Technology > Hardware > Memory (0.36)
- Information Technology > Mathematics of Computing (0.34)
Abstract Calcium-based brines, principally calcium chloride and calcium bromide, find widespread use as completion fluids and base fluids for reservoir drill-in fluids (RDF). The high ionic strength of these brines, combined with the chemical compatibility issues inherent with divalent ions, such as calcium, makes identifying additives for developing functional fluids challenging. While additives, such as hydroxyethyl cellulose, can provide viscosity to calcium brines, imparting the suspension properties needed for the transport of solid bridging agents or drill cuttings can be particularly problematic in divalent brines. Even the widely used and potent suspension agent, xanthan gum, in addition to being difficult to degrade, suffers from gelation and precipitation under certain conditions in high-calcium environments. In this study, nanocellulose, which has previously shown promise as a suspension additive in freshwater and low-salinity brines, was evaluated in high-density brine fluids. Extensive laboratory evaluation of the commercially sourced nanocellulose was conducted in sodium chloride, calcium chloride, and calcium bromide brines. Rheological determinations were made of simple systems containing only brine plus the novel additive, as well as fully formulated RDF containing the additive with sized calcium carbonate bridging solids, alkalinity, and filtration control additives. This data was compared before and after aging at various temperatures and was further compared to other biopolymers that are used today in divalent brines. Stability of the fluids and the capability of the formulated fluids to suspend solids were also examined. Fluid-loss control of full formulations was compared under API conditions. Single-phase return permeability studies were conducted. While results in sodium brines were mixed, nanocellulose was shown to outperform existing biomaterials in calcium brines. Nanocellulose was shown to be readily hydrated in the challenging high-density divalent environment and provided superior suspension to currently used fluid components at similar concentrations. Rheological performance of nanocellulose was found to be synergistic with bridging solids. In one particularly interesting example, it was also shown to complement a synthetic polymer in a high-temperature calcium bromide application. Nanocellulose provides superior rheological performance and reduced formation damage potential compared to conventional materials in difficult high-density calcium chloride and bromide brines. The improved rheological profile and enhanced thermal stability of fluids formulated with nanocellulose, combined with a greater diversity of removal options, can facilitate expansion of the utility of calcium-based brines in well construction and completion applications.
- Europe (1.00)
- North America > United States > Colorado (0.28)
Compensating time-stepping error in fractional Laplacians viscoacoustic wavefield modeling
Wang, Ning (State Key Laboratory of Petroleum Resources and Prospecting, CNPC Key Lab of Geophysical Exploration, China University of Petroleum, Beijing) | Zhou, Hui (State Key Laboratory of Petroleum Resources and Prospecting, CNPC Key Lab of Geophysical Exploration, China University of Petroleum, Beijing) | Zhu, Tieyuan (Department of Geoscience and Institute of Natural Gas Research, Pennsylvania State University)
ABSTRACT The decoupled fractional Laplacian (DFL) viscous wave equations are commonly solved using the pseudospectral (PS) method, which usually introduces a high spatial accuracy but only second-order temporal accuracy. To eliminate the time-stepping errors, here we adopt the -space concept to the solver of DFL viscoacoustic wave equation. Different from the existing -space methods, the proposed k-space method for DFL viscoacoustic wave equation contains two correctors, which are designed to compensate for the time-stepping errors in the dispersion-dominated operator and the loss-dominated operator, respectively. Both theoretical analyses and numerical experiments show that the proposed k-space approach is superior to the traditional PS method mainly in three aspects. First, the proposed approach can effectively compensate for the time-stepping errors. Second, the stability condition is more relax, which makes the selection of sampling intervals more flexible. Finally, the k-space approach allows us to conduct high-accuracy wavefield extrapolation with larger time steps. These features make the proposed scheme be appealing for seismic modeling and imaging problems. Presentation Date: Tuesday, September 17, 2019 Session Start Time: 8:30 AM Presentation Start Time: 8:55 AM Location: 304A Presentation Type: Oral
- Geophysics > Seismic Surveying > Seismic Modeling (0.90)
- Geophysics > Seismic Surveying > Seismic Processing > Seismic Migration (0.31)