bluuebunny/crossref_metadata_2025_split huggingface dataset:
Method for Calculating Forces Produced by Irregular Waves
Authors: Wheeler J.D. 
Published: December 2007

This new method for calculating wave forces on offshore structures is based on an extension of Airy theory for two-dimensional waves and uses a linear filtering technique to calculate wave forces as a function of time for wave profiles of arbitrary shape and length.

Introduction
Interest in wave-force predictions has been increasing in recent years with the increasing worldwide investment in offshore operations and the movement into deeper water. The larger structures required in deeper water increase the need for rapid and accurate waveforce predictions. This paper presents a method for computing wave forces from an ocean-wave profile by a linear filtering technique and compares these computed forces with measurements. The linear filter employed is developed from a modification of small-amplitude wave theory suggested by wave-tank studies and used to calculate water velocities and accelerations. In the linear filtering method, a wave train of any length and any degree of irregularity can be used in design and dynamic studies of offshore structures. Further, the change of the wave profile shape with time (dispersion) can be allowed for. Velocities and accelerations calculated with the linear filter and introduced into an equation proposed by Morison et al. permits calculation of wave forces. Force coefficients required in Morison's equation were determined by fitting calculated forces to observed hurricane wave-force measurements. Consequently, the force coefficients should be used only with the calculation procedures presented in this paper; further, their application has been limited to calculation of forces on members similar in size and surface properties to the test member used to obtain the measured properties to the test member used to obtain the measured forces.
The force predictions are compared with force measurements made in about 400 waves at various heights along a 44-in.-diameter piling in 99 ft of water during Hurricane Carla in 1961. The procedure gives acceptable prediction of maximum forces at all heights above bottom. Force profiles in the four largest measured waves are reproduced with reasonable fidelity, and the peak forces in these largest waves are closely reproduced. Additional force measurements made in shallow water (34 ft) are not referred to in this paper. The wave theory used is less applicable in shallow water, leading to considerable scatter in fitting results. The force measurements indicate that wave forces fall off sharply near the surface of the water. Reproduction of the actual flow regime near the wave surface requires further modification of any way theory. This additional modification is not discussed here.
Procedure Used to Predict Wave Forces Procedure Used to Predict Wave Forces Force Equation
The horizontal force per foot of vertical piling length is calculated as a function of time t and height z above the ocean bottom as:
(1)
Eq. 1, proposed by Morison et al., represents the total force as a sum of drag and inertial forces.
JPT
P. 359
Wave Forces: Data Analysis and Engineering Calculation Method
Authors: Dean R.G. , Aagaard P.M. 
Published: December 2007

This method for calculating the force of ocean waves on offshore drilling structures utilizes a mathematical model for the flow field of highly nonlinear waves; the method is considered applicable to a broad range of wave conditions commonly encountered in offshore design.

Introduction
An extensive body of knowledge is developing in the area of ocean wave forces on cylinders. Excellent summaries appear in Refs. 1 and 2; important contributions of mathematical models used in wave-force calculations are described in Refs. 3 through 5; and wave-force measurement installations are described in Refs. 6 and 7. From theoretical and experimental work has come a variety of wave-force calculation methods for use in engineering; one such example is presented in Ref. 8. Most published methods are presented in Ref. 8. Most published methods are based on the analysis of relatively few waves of low to moderate height and mathematical models that involve major simplifications in the representation of real ocean waves. There has been a need, therefore, to improve the mathematical model and to use information from larger waves. A mathematical model was developed and proved to be a substantial improvement over the available models. Using this model and data from large-amplitude waves measured in the Gulf of Mexico, Standard Oil Co. of California developed the method reported here for use in design of offshore structures.

Selection of a Mathematical Model
The mathematical model used in the wave-force calculation method was picked to be compatible with specification of design wave conditions in terms of a single wave; the calculated forces are used in a space-frame loading program to calculate the loads on a complete structure. Although this deterministic, single-wave approach appears to conflict with the fact that the sea is non-deterministic and can be described only statistically, for the following reasons the deterministic approach was chosen.
Natural periods of structures considered when the method was developed were much shorter than the period range of significant wave energy; hence, wave loads could be treated as static loads. Nonlinear wave theories could be used for calculating the single wave, whereas time series representations used in the statistical models were not developed to the point that nonlinear wave characteristics could be modeled. Statistical characteristics of a sea that are of importance to the static load case could be approximated in selection of design wave heights and calculation of wave forces.
Considerable progress is being made on calculation methods using time-series description of waves and forces, and such methods will be used when longer period structures, requiring dynamic analysis, are studied.
JPT
P. 368
Implementing Environmental Management System on Oilfield Operation in Sumatra: Field Operation Case Study
Authors: Kosasih Achmad , Shobirin Mohammad 
Published: December 2007

Summary
Given the progressively increasing level of government and public environmental awareness, environmental management has emerged as a key component in the overall management of hydrocarbon exploration, development, and production. This paper examines how Lasmo Oil (Malacca Strait) Ltd. (LOMSL) has set up and implemented its environmental management system to comply with Indonesian regulatory requirements and to understand and deal with environmental and community issues proactively in its areas of operation. Initiated in 1989, the current achievements of the LOMSL are described. The results show that by setting up an environmental management system and positively implementing a comprehensive environmental management program, LOMSL has managed to solve its major environmental problems. We found that to establish and to maintain a satisfactory level of environmental performance, broad-ranging consideration must be given to aspects of a regulatory and institutional, socioeconomic, and ecological nature. Management commitment and participation is also identified as essential if a sustained level of high-quality environmental management is to be achieved.

Introduction
LOMSL's history of operation in Malacca Strait started in early 1980. Seismic and exploration drilling were initiated, and in 1984, under the name of HOMSL, the first oil field, the Lalang field, started to produce oil.
Currently, LOMSL operations consist of six fields: the offshore Lalang field (production began in June 1984 from 15 wells), the offshore Mengkapan field (production began in Dec. 1986 from 10 wells), the onshore Melibur field (production began in Dec. 1986 from 32 wells), the onshore Kurau field (production began in Jan. 1988 from 29 wells), the onshore Padang Selatan field (production began in Dec. 1990 from 11 wells), and the onshore MSBV field (production began in Aug. 1993 from 1 well).
Since LOMSL started operation in the Malacca Strait, management has made a strong commitment to managing the environment properly. One person was dedicated to health, safety, and environmental matters. An environmental impact assessment for Lalang field was developed before operation of the field in 1984, even though there was no government regulation effective at that time that required an environmental impact assessment study for a project development.
Application of Probability to the Design of Single-Point Moorings
Authors: Haring R.E. , Adams R.B. , Beazley R.A. , Kipp K.L. 
Published: December 2007

HARING, R.E., MEMBER AIME, ESSO PRODUCTION RESEARCH CO., HOUSTON, TEX. ADAMS, R.B., ESSO STANDARD OIL (AUSTRALIA) LTD., SYDNEY, AUSTRALIA BEAZLEY, R.A., ESSO RESEARCH and ENGINEERING CO., LINDEN, N.J. KIPP, K.L., ESSO PRODUCTION RESEARCH CO., HOUSTON, TEX.

Abstract
A procedure has been developed to analyze mooring forces and to aid the selection of design parameters for single-point mooring systems. The parameters for single-point mooring systems. The results of a study indicate that a conventional SPM buoy could be used successfully to permanently moor a 52,000-dwt tanker in 260 ft of water under moderate sea conditions. The procedure utilizes scaled-model data and environmental observations to derive force-probability functions, which define The probability of exceeding any given force in the mooring system.

Introduction
There has been a steady increase in the application of monomoorings in loading terminals for exporting crude oil from shore storage and in discharging terminals for handling products and importing crude to refineries. Almost all the monomoorings have been single-point mooring buoys. Their general characteristics are illustrated in Fig. 1. The buoy itself is circular and of all-welded construction. It is subdivided into watertight compartments with provisions to handle the anchor chains, rotating manifold, and bow mooring hawser attachment. About 60 systems of this type have been installed or are under construction in the free world. Their main application has been in water depths less than 150 ft and in relatively calm, sheltered areas. Increased use of super tankers has stimulated further interest in loading buoys for deeper water.
In at least two instances single-point mooring buoys have been used for floating, crude-oil storage vessels. As offshore oil fields are discovered in areas far from existing crude-oil markets or gathering systems, the use of single-point mooring systems for floating storage vessels will increase. The most important considerations in the design of single-point mooring systems for this application will be the continuous exposure to environmental forces, the more severe conditions typical of the open ocean, and water depths greater than are found at existing installations. A design procedure should allow the engineer to identify the probability of exceeding specified forces induced in the mooring system by the ocean environment. Mooring systems are usually designed well within the nominal strengths of their components to allow for fatigue, corrosion and short-duration high stresses. Therefore, even if the induced forces exceed the design forces, failure will not necessarily result. Rather, this condition alerts the marine operator to the need for corrective action or suspension of operations to prevent continued exposure of the system to excessive forces.
SPEJ
P. 219
Viscous Fluids Characterize the Crushed Zone
Authors: Rochon Jean , Creusot M. R. , Feugas Daniel , Thibeau Sylvain , Bergerot J-L. 
Published: December 2007

Summary
The crashed zone surrounding a perforation tunnel, which contributes to the overall skin effect, is well documented. Many authors have proposed equations to predict the pressure drop caused by both laminar and high-velocity flow through the crushed zone. However, determining the thickness of the crushed zone and its permeability always has been a major problem.
We obtained cylindrical single-shot core samples perforated under API conditions. We evaluated the damage surrounding the perforation tunnels in the laboratory using a new technique. The core is saturated with a low-viscosity refined oil. The low-viscosity oil is flushed at a constant flow rate by another refined oil, which has a much higher viscosity. The differential pressure is monitored as the miscible front moves radially outwards. The rate of change of the differential pressure is affected as the high-viscosity oil invades zones with different permeabilities.
Our interpretation of the pressure differential was done analytically. We obtained results in terms of effective crushed-zone thickness and crushed-zone permeability alteration. Such results can be used to calculate the contribution of the crushed zone to the skin effect.
The success of this nondestructive laboratory technique leads us to evaluate the possibility of injecting a viscous fluid into a real well to investigate in-situ formation damage.
Simple Method Predicts Downhole Shaped-Charge Gun Performance
Authors: Ott R. E. , Bell W. T. , Harrigan J. W. , Golian T. G. 
Published: December 2007

Summary
A simple method is proposed for predicting downhole shaped-charge gun performance based on the use of API RP 43, Edition 5, Sec. 1 data. API Sec. 1 has been the preferred method for assessing perforating gun system performance because of the simplicity of the test and its use of standard field guns fired at maximum shot densities and positioned as they would be in an actual well. The validity of the proposed method is demonstrated, allaying past concerns regarding the translation of data from Sec. 1 nonrock, nonstressed concrete targets to downhole conditions. The new method is based on an observed linear relationship between Edition 5, Sec. 1 and Sec. 2 penetration information. The applicability of the well-known Thompson relationship between formation compressive strength and perforator penetration to Edition 5, Sec. 2 and therefore to Sec. 1 data is shown. Incorporating necessary corrections for casing entrance hole size, downhole effective formation stress, and casing configurations different from those in the API test completes the translation of surface data to downhole conditions.
Pore Pressure Estimation From Velocity Data: Accounting for Overpressure Mechanisms Besides Undercompaction
Authors: Bowers Glenn L. 
Published: December 2007

Summary
A new method for estimating pore pressure from formation sonic velocity data is presented. Unlike previous techniques, this method accounts for excess pressure generated by both undercompaction, and fluid expansion mechanisms such as aquathermal pressuring, hydrocarbon maturation, clay diagenesis, and charging from other zones.
The method is an effective stress approach; the effective stress is computed from the velocity, and the result is subtracted from the overburden stress to obtain pore pressure. To include multiple sources of overpressure, a pair of velocity-vs.-effective-stress relations are introduced. One relation accounts for normal pressure and overpressure caused by undercompaction. The second is applied inside velocity reversal zones caused by fluid expansion mechanisms.
Example applications of the method are presented from the U.S. gulf coast, the Gulf of Mexico, and the Central North Sea. Some other pore pressure estimation approaches are also examined to demonstrate how these techniques have unknowingly accounted for overpressure mechanisms other than undercompaction.
It is also explained how velocity-vs.-effective-stress data can be used to identify the general cause of overpressure in an area. For instance, the empirical correlation of Hottman and Johnson indicates that overpressure along the U.S. gulf coast cannot be due only to undercompaction.
Environmentally Acceptable Water-Based Mud Can Prevent Shale Hydration and Maintain Borehole Stability
Authors: Simpson J. P. , Walker T. O. , Jiang G. Z. 
Published: December 2007

Summary
This paper presents laboratory and field results showing that an environmentally acceptable water-based mud (WBM) can be formulated to act like an oil-based mud (OBM) in preventing hydration, pore-pressure increase, and weakening of shale by effectively developing sufficient osmotic force to offset the hydraulic forces acting to cause water flux into the shale. We also show that this methyl glucoside system has other performance characteristics similar to OBM's, such as lubricity, filtration control, and tolerance for common WBM contaminants, thus meeting the needs for drilling high-angle or even extended-reach wells.
Visualization of Reservoir Simulation Data With an Immersive Virtual Reality System
Authors: Williams B. K. 
Published: December 2007

Summary
This paper discusses an investigation into the use of an immersive virtual reality (VR) system to visualize reservoir simulation output data. The hardware and software configurations of the test-immersive VR system are described and compared to a nonimmersive VR system and to an existing workstation screen-based visualization system. The structure of 3D reservoir simulation data and the actions to be performed on the data within the VR system are discussed. The subjective results of the investigation are then presented, followed by a discussion of possible future work.
Identification of Well-Test Models by Use of Higher-Order Neural Networks
Authors: Kumoluyi A. O. , Daltaban T. S. , Archer J. S. 
Published: December 2007

SummaryIn a well test, the central objective is to "prove" the formation in terms of a sustainable economic flow rate. This objective is related to the characterization of the reservoir and the estimation of its parameters, tike permeability and skin, by knowledge of only the input and output signals, such as pressure and flow rate, and, in certain cases, other reservoir characteristics, such as the drainage area and the distance to faults.Interpretation efforts, therefore, can be performed in two phases: (1) the identification of "reasonable" theoretical reservoir models representing the field data, and (2) the estimation of pertinent parameters of the selected theoretical reservoir model. The second phase is well established in the literature, whereas many problems are associated with model selection, such as uncertain data, incomplete data, and the ambiguity of the models (i.e., more than one model might be representing the field data).One can identify the theoretical models based on similarities of the curvature of both the type curves (from both simple analytical models and complex numerical models) and the field data. The whole process can be conceived as a pattern-recognition task. In this paper, we present an approach by which it is possible to identify an appropriate welltest model in a consistent and objective manner, thereby reducing some of the problems associated with the task. The approach is based on the application of higher-order neural networks (HONN's).Conventional neural networks are used in general for both optimization and classification tasks. For classification purposes, these networks will find appropriate mappings to any set of patterns with dependence on both spatial and temporal positions. That is, such networks find it extremely difficult and often impossible to deal with patterns invariant to some transformation groups, such as scaling, translation, and rotation. Well-test models are inherently translation invariant with respect to the field data and are also scale invariant. Thus, we propose the use of HONN's, by which we can encode the invariant properties of patterns into the architecture of the network, thereby constraining some of its weights (parameters). Constructing such networks enables us to identify well-test models in an automated and robust manner. Moreover, these networks are both pattern and training-rule independent. Additionally, the training time for such networks is extremely fast compared to conventional neural networks.Our system has been used to identify various models, such as naturally fractured reservoir, homogeneous reservoir, multilayer reservoir, dual porosity, commingled, and fractured wells. We performed all implementation using VISUAL C++ 1.0 and Microsoft Foundation Classes 2.
Migrating Legacy Petroleum-Engineering Applications to Open-Systems Environments
Authors: Little Todd , Chien David , Corbell Rory , Rahi Ahsan M. , Sinclair Craig 
Published: December 2007

Summary
We present a case study involving the software life cycle of a suite of commercial petroleum-engineering reservoir-simulation legacy applications. As with typical petroleum legacy applications, these are designed for DOS or VMS environments, written in FORTRAN, based on the Graphics Kernel System (GKS) for graphics, and have hierarchical menu trees.
We replaced the hierarchical user interface with a C++ toolkit to provide a Motif look and feel, while keeping the remainder of the application in FORTRAN. As a result, the application developers well versed in FORTRAN can continue to augment the engineering portion of the application, allowing training in C, C++, X, and Motif to be spread out over time.
This migration path has had several major benefits over a complete rewrite of the software. We have been able to produce an open-systems application significantly faster than what would be required for a software rewrite. Additionally, this path has preserved compatibility with the legacy application and, therefore, provided enhanced reliability.
Integrating Knowledge-Based Techniques Into Well-Test Interpretation
Authors: Harrison I. W. , Fraser J. L. 
Published: December 2007

Summary
The goal of the Spirit Project was to develop a prototype of nextgeneration well-test-interpretation (WTI) software that would include knowledge-based decision support for the WTI model selection task. This paper describes how Spirit makes use of several different types of information (pressure, seismic, petrophysical, geological, and engineering) to support the user in identifying the most appropriate WTI model. Spirit's knowledge-based approach to type-curve matching is to generate several different feasible interpretations by making assumptions about the possible presence of both wellbore storage and late-time boundary effects. Spirit fuses information from type-curve matching and other data sources by use of a knowledge-based decision model developed in collaboration with a WTI expert. The sponsors of the work have judged the resulting prototype system a success.
Tools, Processes, and Systems: An Integrated Approach to Petroleum Software Training
Authors: Ames L. C. , Reese R. D. 
Published: December 2007

Summary
The petroleum industry has fewer analysts, engineers, and technicians than it did a decade ago. To handle this increased workload, the remaining individuals use a variety of computing options. The question under consideration here is how to most effectively train the right people to use the appropriate computing tools to solve corresponding problems.
As we have planned our software training at Oil and Gas Consultants Intl. Inc. (OGCI), we have found it useful to divide computing skills into three levels—tools, processes, and systems. These levels are progressively more complex; they build on each other, and represent increasingly higher levels of analysis. This paper draws from our experience training nearly 800 people around the world, in 1993 alone, to better use petroleum software. We use the multi-level approach to highlight training challenges and to suggest possible improvements.