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Application of the Laplace Transform to Discrete Time-Rate Data for the Analysis and Forecasting of Well Performance Behavior in Unconventional Reservoirs

Application of the Laplace Transform to Discrete Time-Rate D...

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作者： Chingulprasan, Nat Texas A&M University

学位级别：硕士

The numerical Laplace transformation of discrete data has been discussed extensively in the petroleum literature in applications related to well-test analysis. This approach has been shown to be a useful tool for the deconvolution of variable-rate pressure responses, although the success of this method heavily relies on the algorithms used to transform the discretely sampled data into the Laplace domain and then to invert these results (numerically) back into the time domain (Onur and Reynolds, 1998). Onur and Reynolds [1998] note that the major limitation for the numerical Laplace transformation of discrete data is the need for an "extrapolation" of the data function in the real domain (both for "early" (near zero) times and "late" times (beyond existing data)). The most important distinction of the present work is that it focuses on rate functions, which are inherently decreasing and positive functions. The fact that the function of interest is decreasing and positive is not an issue in terms of the mathematics of this scenario, but there are several challenges — e.g., the applicability of various extrapolation schemes. Simply stated, the primary objective of this research is to examine the application of existing algorithms for discrete-data Laplace Transforms, and to develop an appropriate workflow utilizing the numerical Laplace transform of discrete data for the analysis and forecasting of well performance behavior. The concept of this research is both simple and straightforward — for a given discrete data set of time and rate values, we use the Laplace transformation to generate the following: ● The Laplace transform smoothed rate function ● The Laplace transform smoothed cumulative function ● The Laplace transform smoothed rate derivative function ● A Laplace transform smoothed D-parameter function ● A Laplace transform smoothed b-parameter function The traditional approach to this problem is to use numerical integration (most typically, the Trapezo

关键词： Laplace Transform Unconventional Derivative Differentiation algorithm integration algorithm discrete data

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Mitchellandgauthierassoc :: Advanced Continuous Simulation Language 1981

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2016年

Mitchellandgauthierassoc :: Advanced Continuous Simulation Language 1981 by published by

关键词： acsl advanced array communication interval continuous derivative exec version independent variable initial initial condition initial conditions integration integration algorithm language macro mitchellandgauthierassoc model definition output output stream plot simulation standard form step size variable variables

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Constitutive modeling and simulation of perforation of targets by projectiles

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AIAA JOURNAL 2008年第2期46卷 304-316页

作者： Voyiadjis, George Z. Al-Rub, Rashid K. Abu Palazotto, Anthony N. Louisiana State Univ Dept Civil & Environm Engn Baton Rouge LA 70803 USA USAF Inst Technol Dept Aeronaut & Astronaut Wright Patterson AFB OH 45433 USA

The effective use of existing finite element codes in the direct simulation of hypervelocity impacts by projectiles is limited by the dependence of the size of localized failure regions on the mesh size and alignment. This gives rise to a nonphysical description of the penetration and perforation processes. A micromechanical constitutive model that couples the anisotropic thermoviscodamage mechanism with the thermohypoelastoviscoplastic deformation is presented here as a remedy to this situation. Explicit and implicit microstructural length-scale measures, which preserve the well-posed nature of the differential equations, are introduced through the use of the viscosity and gradient localization limiters. Simple and robust numerical algorithms for the integration of the constitutive equations are also presented. The proposed unified integration algorithms are extensions of the classical rate-independent return-mapping algorithms to the rate-dependent problems. A simple and direct computational algorithm is also used for implementing the gradient-dependent equations. This algorithm can be implemented in the existing finite element codes without numerous modifications, compared with the current numerical approaches for integrating gradient-dependent models. Model capabilities are preliminarily illustrated for the dynamic localization of inelastic flow in adiabatic shear bands and the perforation of a 12-mm-thick Weldox 460E steel plate by a deformable blunt projectile at various impact speeds.

关键词： Kinetic Energy Penetrator integration algorithm Numerical algorithms Viscosity Adiabatic Shear Band Thermal Stresses Von Mises Yield Criterion Arbitrary Lagrangian Eulerian Smoothed Particle Hydrodynamics Viscoplasticity

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Approximate expressions for the spectrum of constant amplitude polynomial phase signals

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CHINESE JOURNAL OF ELECTRONICS 2007年第4期16卷 688-690页

作者： Lv Xiaolei Xing Mengdao Zhang Shouhong Xidian Univ Key Lab Radar Signal Proc Xian Peoples R China

An integration algorithm is presented for approximate closed-form expressions for the spectrum of constant-amplitude Polynomial-phase signals (PPS) with a given degree. The algorithm introduces a slowly varying function as the amplitude of PPS. The slowly varying function is then approximated by Hermite polynomial expansion and the Fourier transform of PPS with the slowly varying amplitude, i.e., the expression of spectrum is thus expressed as a sum of constituent integrals with integrands containing a Hermite polynomial multiplied by polynomial phase factors. The expression for spectrum of the constant-amplitude PPS is just the first term of the constituent integrals which are approximately expressed by means of obtaining the inverse of a banded coefficients matrix in a system of linear equations. Simulation results are provided to indicate that the expressions derived by using the integration algorithm have high precision.

关键词： integration algorithm polynomial-phase signals (PPS) constant-amplitude hermite polynomials

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An interface to numerically model undrained soil-structure interactions

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COMPUTERS AND GEOTECHNICS 2021年 138卷 104327-104327页

作者： Liu, Wenlong Tian, Yinghui Cassidy, Mark J. Univ Melbourne Fac Engn & Informat Technol Dept Infrastruct Engn Parkville Vic 3010 Australia

The traditional Coulomb friction model is commonly used to illustrate interactions at the soil-structure interface, but it assumes zero tangential resistance when the normal stress on the interface is in tension. This is not realistic for modelling the undrained behaviour of geo-structures deeply embedded in the seabed because the soil adheres to the structure due to the suction generated. This note proposes a new interface model that captures the undrained behaviour of soil at the structural interface, including the ability to maintain frictional shear stresses under tensile normal stress. Based on simple elastic-perfectly plasticity theory the constitutive behaviour of the interface and the algorithm required to numerically implement it into a finite element program are fully described. Computational cases are presented to verify the model's implementation and demonstrate how the new interface model performs for cases of undrained behaviour encountered in offshore geotechnics.

关键词： Interface model Soil-structure interaction Interface roughness Undrained behaviour integration algorithm

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Review of attitude representations used for aircraft kinematics

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JOURNAL OF AIRCRAFT 2001年第4期38卷 718-737页

作者： Phillips, WF Hailey, CE Gebert, GA Utah State Univ Dept Mech & Aerosp Engn Logan UT 84322 USA Sverdrup Technol Inc Eglin AFB FL 32542 USA

A detailed survey is presented of the literature on attitude representation dating from the early work of Euler and Hamilton to recent publications in fields such as navigation and control. The scope is limited to the development of the aircraft kinematic transformation equations in terms of four different attitude representations, including the well-known Enter angles, the Euler-axis rotation parameters, the direction cosines, and the Euler-Rodrigues quaternion. The emphasis is directed at the application of the quaternion formulation to aircraft kinematics. Results are presented that reinforce observations that the quaternion formulation, typically implemented to eliminate singularities associated with the Enter angle formulation, is far superior to the other commonly used formulations based on computational efficiency alone. A development of quaternion constraints necessary to independently constrain roll, pitch, yaw, bank angle, elevation angle, and/or azimuth angle is presented. For verification of simulation codes, a general closed-form solution to the quaternion formulation, for the case of constant rotation, is also presented. Additionally, a discussion is provided of numerical integration methods and numerical errors for the quaternion formulation. This discussion is especially important for simulations that may still utilize a common error reduction scheme originally developed for analog computers.

关键词： Aircraft Kinematics Quaternions Angular Motion Aerodynamic Moments Earth Numerical integration Pilot Airspeed integration algorithm Numerical algorithms

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Integrating heterogeneous OO schemas

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JOURNAL OF INFORMATION SCIENCE AND ENGINEERING 2000年第4期16卷 555-591页

作者： Chen, YJ GMD GmbH IPSI Inst D-64293 Darmstadt Germany

A key problem in providing enterprise-wide information is the integration of databases that have been independently developed. A major requirement is to accommodate heterogeneity and at the same time preserve the autonomy of component databases. This article addresses this problem and presents a strategy to integrate heterogeneous OO schemas. As compared to the existing methodologies, this approach integrates local schemes into a deduction-like global schema. In this way, more semantic relationships of component schemas can be captured, and more complete integration can be obtained. In addition, an efficient algorithm is proposed which can do the integration almost automatically, based on the correspondence assertions supplied by designers. This algorithm is efficient in the sense that the characteristics of assertions are utilized to avoid useless matchings.

关键词： federated databases correspondence assertion schema integration derivation assertion integration algorithm

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ALTERNATIVE VARIABLE TRANSFORMATION FOR SIMULATION OF MULTIBODY DYNAMIC-SYSTEMS

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1995年第2期18卷 375-377页

作者： YANG, LF National Chung-Cheng University Taiwan Republic of China

An alternative variable transformation is proposed and analyzed for the simulation of multibody dynamic systems. The developed alternative variable transformation matrix intended to work directly with the multibody equations of motion without altering the inherent dynamic characteristics also eliminates the need for expensive computation of inversion of a large mass matrix required for the simulation of multibody dynamic systems. From the analytical derivation of an articulated multibody model, it was found that the computation can be saved (3n + 1/4 )-fold due to the computational merits associated with the band matrix.

关键词： Closed Loop System Numerical integration Nonlinear Programming Trajectory Optimization integration algorithm Numerical Simulation Multibody Dynamics

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A Machine Learning Classification algorithm for Vocabulary Grading in Chinese Language Teaching

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TEHNICKI VJESNIK-TECHNICAL GAZETTE 2021年第3期28卷 845-855页

作者： Zhang, Yinbing Song, Jihua Peng, Weiming Guo, Dongdong Song, Tianbao Beijing Normal Univ Sch Artificial Intelligence 19 XinJieKouWai St Beijing 100875 Peoples R China Huaibei Normal Univ Sch Math Sci 100 Dongshan Rd Huaibei 235000 Anhui Peoples R China Beijing Technol & Business Univ Sch Comp Sci & Engn 11 Fucheng Rd Beijing 100048 Peoples R China

Vocabulary grading is of great importance in Chinese vocabulary teaching. This paper starts with an analysis of the lexical attributes that affect lexical complexity, followed by an explanation of the extraction of lexical attribute information combined with the constructed word-formation knowledge base, the construction of mapping functions corresponding to lexical attributes, and the quantitative representation of the attributes that form the basis for vocabulary grading. Based on this, a machine learning classification algorithm is creatively applied to the Chinese vocabulary grading problem. Using the comparative analysis of vocabulary grading models based on common machine learning classification algorithms, the importance measurement analysis of Chinese vocabulary attributes based on different feature selection methods is performed, and a vocabulary grading model is constructed based on the machine learning classification algorithm and feature importance selection of different feature selection algorithms. A comparison of the experimental results demonstrated that the classification model based on the support vector machine (SVM) algorithm and top six attribute groups by the importance of feature selection received the best effect. To improve vocabulary grading, a variety of feature selection algorithms were used to fuse the importance of lexical attributes on average. Then an experiment was conducted for vocabulary grading combined with the Bagging + SVM integration algorithm and top six attribute groups by the importance of feature selection. The experimental results demonstrated that the combination scheme achieved a better effect.

关键词： integration algorithm machine learning classification algorithm vocabulary grading word-formation knowledge base

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Computations of axisymmetric plug-nozzle flowfields: Flow structures and thrust performance

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JOURNAL OF PROPULSION AND POWER 2002年第2期18卷 254-260页

作者： Ito, T Fujii, K Hayashi, AK Univ Tokyo Dept Aeronaut & Astronaut Bunkyo Ku Tokyo 1138654 Japan Inst Space & Astronaut Sci Kanagawa 2298510 Japan Aoyama Gakuin Univ Dept Engn Mech Tokyo 1578527 Japan

Plug-nozzle flowfields are analyzed by the numerical simulations. The method of characteristics is used to design the plug contour, and several types of plug nozzles are considered by truncating the length of the nozzle at different positions. Plug-nozzles' altitude-compensating features are confirmed by the computed results, and the base pressure turns out to play an important role to maintain the thrust performance of the nozzle for high-truncation configurations. The altitude clearly influences the base-pressure distributions under the assumption that the chamber pressure is constant during the ascent. The computed thrust difference between the contoured and the conical nozzle linearly increased as a function of the pressure ratio. The thrust performance of the contoured plug nozzle is estimated to be about 5-6% higher than the conical plug nozzle. Various conditions of external flows over the plug nozzle are also imposed, and the result shows that the external flow does not influence the pressure distribution on the nozzle surface for the pressure ratios higher than the designed point.

关键词： Contoured Plug Nozzle Mach Number Numerical Simulation Chamber Pressure Oblique Shock Wave Baldwin Lomax Turbulence Model Primitive Variable Navier Stokes Equations integration algorithm Propulsion System

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