bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wellsite Interpretation of Multicomponent Induction Log Data in Anisotropic Media
Authors: Kriegshäuser B. F. , Fanini O. N. , Yu L. , Gupta P. , v. d. Horst J. 
Published: December 2007

Abstract
Electrically anisotropic reservoirs are encountered frequently in hydrocarbon exploration. For accurate saturation estimation and optimum hydrocarbon recovery from these reservoirs, it is essential to detect and properly describe their electrical properties. For example, in laminated sand/shale sequences or sands with different grain size distributions the resistivity parallel to the formation bedding is usually smaller than the resistivity perpendicular to the bedding. Conventional induction logging tools with transmitter and receiver orientation parallel to the borehole axis provide insufficient information to accurately evaluate hydrocarbon saturations in anisotropic reservoirs. These reservoirs usually show low resistivities from conventional induction logs, where the hydrocarbon content can be economically significant and are called "low resistivity pay." Under the sponsorship of Shell Technology EP, Baker Atlas developed and field-tested a new induction logging tool that comprises three mutually orthogonal transmitter-receiver configurations yielding all necessary data to derive the horizontal and vertical resistivities of an anisotropic formation.
Interpretation of these measurements is complicated because the magnetic field responses of horizontal induction coils are more sensitive to shoulder bed and borehole effects than conventional, vertical induction sensors. To provide a fast, yet reliable, interpretation of the formation parameters, we developed an enhanced apparent parameter estimation procedure that also applies shoulder bed corrections to the measured field data.
We match the data acquired at each logging depth with responses of an anisotropic, whole-space model optimizing both horizontal and vertical resistivities in a least-squares sense. This process incorporates information about formation dip and azimuth as well as borehole trajectory and tool rotation. Then, we integrate both horizontal and vertical resistivities over layer intervals derived from the horizontal magnetic field data. After that, we apply shoulder bed corrections to the measured data, based on the synthetic layered host model response and the corresponding whole-space responses. Finally, we match the shoulder bed corrected data at the center of each layer with synthetic responses of an anisotropic, whole-space model. These newly derived resistivities in both horizontal and vertical direction are then used to refine both, the layered earth model and the shoulder bed corrections. The process comprising whole-space response matching and refining shoulder bed corrections is repeated until convergence is achieved. This interpretation scheme developed with synthetic data and tested with field data has proven to be fast and efficient, thus allowing us to provide reliable estimates of both horizontal and vertical resistivities at the wellsite.
Application of Array Resistivity Measurements in Horizontal Wells
Authors: Frenkel M. A. , Geldmacher I. M. , Georgi D. T. , Mezzatesta A. G. , Rabinovich M. B. , Tabarovsky L. A. , Meyer W. H. , Fidan M. 
Published: December 2007

Abstract
When interpreting array resistivity measurements in horizontal wells, the objectives are quite different from traditional data interpretation in vertical or near vertical boreholes. While the emphasis for the latter is put on resolving the invasion profile and "true" formation resistivities, the former measurements are aimed at the identification of any nearby geometry, e.g., cap rock or oil-water contacts in the vicinity of the wellbore. In order to accomplish this, new algorithms have been developed ranging from real-time "geosteering" applications to sophisticated inversion-based processing.
Early resistivity tools were complex devices that utilized bucking coils and guard electrodes to "focus" the measurement onto a particular region in the formation, for example, shallow and/or deep. These analog focusing methods were designed for and worked well in quasi-horizontally layered formations penetrated by a near vertical well. In the last decade array tools offering a multitude of electrode or coil arrangements have been introduced. By combining data from different electrodes or receiver coils and transmitters, it is possible to mathematically focus in on a particular formation area, such as illuminating the invasion profile and obtaining a better estimate of the formation resistivity. In horizontal and highly deviated wells, the array data still can be used to characterize the invaded zone, but, more importantly, the array data can be used to probe the layered structure above and below the well. Interpreting the response of today's array resistivity tools in these situations is critical to the drilling and formation evaluation process. In horizontal wells, the response of resistivity tools in even a simple layered formation is complicated and may differ significantly from our vertical well-based intuition. However, forward modeling of the expected formation earth model and inversion techniques, from the simplest to the most sophisticated approach, can assist both the driller and the petrophysicist in extracting required information.
In this paper we demonstrate the use and effectiveness of the array resistivity tools in horizontal and near-horizontal wells. We focus on the use of the array data collected by the logging-while-drilling (LWD) Multiple Propagation Resistivity (MPR) tool as well as the wireline or pipe-conveyed driven High-Definition Induction Log (HDIL) and High-Definition Lateral Log (HDLL). For each tool the interpretation process is illustrated with field examples.
Full Tensor Upscaling of Geologically Complex Reservoir Descriptions
Authors: Wen X. -H. , Durlofsky L. J. , Lee S. H. , Edwards M. G. 
Published: December 2007

Abstract
The upscaling of geostatistical models characterized by oriented layering is considered. Such models are representative of a broad class of geologically complex reservoir characterizations as they display full tensor permeabilities on both the fine and coarse scales. The significant errors that result from the improper numerical treatment of the full tensor permeability are demonstrated. The application of existing upscaling approaches to these oriented systems is shown to lead to coarse models of lower accuracy, for both flow and displacement calculations, than in the case of models with horizontal layers. Two alternate upscaling procedures are presented in an attempt to improve the accuracy of these coarse scale reservoir descriptions. The first technique involves the use of a border or "skin" region, while the second approach entails the use of a rotation procedure, in which the gridblock permeability is computed in a coordinate system approximately aligned with the principal directions of the upscaled permeability tensor. Both methods are shown to generally result in improved accuracy in displacement calculations, though the rotation procedure appears to be the more accurate overall. The approaches presented here can be used in conjunction with sophisticated gridding techniques to achieve more accurate and robust coarse scale models.
Calculation of Convective and Dispersive Flows for Complex Corner Point Grids
Authors: Sammon Peter H. 
Published: December 2007

Abstract
Complex corner point grids are often encountered in reservoir simulation. Such grids can be severely faulted and the corner point cells near faults, and elsewhere, can be distorted. Also, extensive refinements may be used. Since such grids are usually presented without specific information regarding inter-cell contact, it is up to the reservoir simulator to decide when to connect blocks together to permit fluid flow, and also, in many cases, how to build the more extensive computational template required to model dispersive fluxes. The latter can be particularly complicated since directions both perpendicular to, and parallel with, the usual flow directions have to be resolved. Nevertheless, dispersive mixing is often a required feature, such as when modelling gas storage reservoirs where cushion gas and fuel gas commingle, or when examining convective mixing as a primary drive mechanism, such as for the VAPEX process.
A corner point grid cell starts with eight points, and can be described as the volume contained within surfaces that are stretched across the corner points associated with each of its six faces. Face contact (or near-contact) can be specified as the requirement for flow to occur from cell to cell. The contact can be full (the four face corner points are shared by each cell), or partial. The first case is easy to detect, while the latter is more complicated, breaking down into sub-cases that will be described in this paper. Once contacts are established and overlap areas are determined, suitable transmissibilities can be defined.
Refined grids need to be seamlessly incorporated into all of the above. These can be difficult to work with if several layers of refinement are present.
Once connectivities have been determined, an extended computational molecule has to built around each cell to allow for the computation of dispersive fluxes to take place. Since directions have to be resolved both parallel with, and perpendicular to, the Darcy phase velocities, an enlarged template is required. An algorithm will be described for processing lists of cell contacts to devise a suitable template for resolution of parallel and perpendicular flows. Once the template has been built, a method for computing the required longitudinal and transverse dispersive fluxes will be given.
Results of computations made using the above algorithms for building flow connections will be described. In particular, the effects of longitudinal and transverse dispersion will be shown.
Phase Behavior of Gas Condensate/Water System
Authors: Kokal Sunil , Al-Dokhi Mohammad , Sayegh Selim 
Published: December 2007

Abstract
Gas condensate reservoirs are an essential part of Saudi Arabia's hydrocarbon resources. A good understanding of the effect of water on the phase behavior properties of these hydrocarbons is essential for carrying out accurate forecasts of the performance of these reservoirs using numerical simulators. In addition, the scaling and corrosion tendencies of the produced water are strongly influenced by mass transfer with the hydrocarbon phase.
This paper presents unique experimental phase behavior data for a typical Saudi Arab gas condensate three-phase (water/condensate/gas) system. The objective of this work is to quantify the effect of water on gas condensate fluid properties.
The results show that appreciable amount of carbon dioxide and methane partition from the gas condensate phase into the aqueous phase. Another important observation was the mass transfer of water into the condensate phase. The mass transfer between the condensate and aqueous phases results in a decrease in the gas/condensate ratio. The carbon dioxide in solution makes the brine acidic, and can dissolve carbonate minerals from the formation, for example, calcium carbonate. In addition, the acidic or sour brine will be quite corrosive. The experimental results are compared with equation-of-state and other correlations published in the literature.
Sand Consolidation Using High-Temperature Alkaline Solution
Authors: Mamora D. D. , Nilsen K. A. , Moreno F. E. , Guillemette R. 
Published: December 2007

Abstract
In the period 1991-1996, sand consolidation using high-pH steam was successfully tested in 13 vertical and 7 horizontal wells in the Wilmington field, California. Savings (for not running gravel-packs) amounted to $90,000 per vertical well and $150,000 per horizontal well.
An experimental study was carried out to better understand and optimize the process. The apparatus consisted of a vertical 18 in. long aluminum cylindrical cell with an ID of 1.5 in. into which loose Wilmington Tar Zone sand was tamped. The top half of the cell was thermally insulated while the bottom half was cooled by means of a cooling jacket. Steam was injected at the top of the cell and fluids produced at the bottom of the cell. Temperatures along the cell axis, and inlet and outlet pressures were measured. The cell contents were removed after each experiment and analyzed to determine if sand consolidation occurred. Thin sections of samples before and after the steam treatment were analyzed using an electron microprobe to determine any change in shape, size, and composition of the sand grains. Steam at 250-260 °C and 700800 psig was injected at rates of 5 cc/min and 20 cc/min. Steam with pH of 7 and 12 were used, the latter obtained by addition of sodium carbonate to the feedwater.
Results showed sand consolidation did not occur for steam with pH of 7. However, for steam of pH 12, the sand was consolidated particularly at the top part of the cell in only 3-4 hours. Photomicrographs showed both needle-like and equant crystals of sodium aluminum silicate being formed between the consolidated sand grains. Contrary to the previous postulate that precipitation of dissolved quartz or feldspar "cements" the sand grains, the results indicate that the mechanism of sand consolidation is probably more complex. Further research is being undertaken to fully understand and optimize the process.
Measurement of Waxy Crude Properties Using Novel Laboratory Techniques
Authors: Karan Kunal , Ratulowski John , German Philip 
Published: December 2007

Abstract
Transportation and production of waxy crude oils poses a variety of challenges including wax deposition, increased viscosity and pressure drop at temperatures below the cloud point, and high re-start pressure for gelled oil in the pipeline at temperatures below the pour point.
The driving force for this study is an investigation of live oil transportation through a 600 km long sub-sea pipeline where ambient temperatures range from 0 to 5°C and pressures up to 3000 psia. The design and operation of such a system warrants unique set of input data. Measurement of such data involves the development of novel experimental techniques.
In this paper, newly developed experimental techniques and apparatus used for measuring key waxy crude properties is presented. A novel experimental apparatus was used to visually determine live oil pour points at pressures up to 3000 psi. The gel strength measurements for pipeline restart pressures for both dead and live oils were conducted using a model pipeline test (MPT) apparatus. Measurements of the live oil wax appearance temperature (WAT) were performed using a state-of-the-art High Pressure Cross Polar Microscope (HP-CPM) and a laser-based solids detection system.
Reliability Qualification Testing for Permanently Installed Wellbore Equipment
Authors: Veneruso A. F. , Hiron S. , Bhavsar R. , Bernard L. 
Published: December 2007

Abstract
Reservoir monitoring and intelligent completions require installation of permanent downhole equipment for use by operations personnel to monitor and control wells with flow-control devices. Reliability qualification testing (RQT) is essential for the success of these systems. This equipment is permanently installed in the severe downhole environment; it is rarely retrieved to surface for analysis, and it is impractical to run long-duration laboratory and field tests to qualify the system for its long lifetime before installation.
RQT helps achieve overall system reliability by closing the loop from equipment design, component qualification, and testing to personnel training and field operations. A mission profile provides a realistic basis and framework for the specifications and testing. The challenge is for the entire system to achieve an operational reliability of at least 90% during 5 years or more in the hostile downhole environment at temperatures as high as 150°C and pressures that reach 15,000 psi. Reliability testing identifies weak links, measures progress, and builds confidence to avoid risks and surprises. However, designing and building the special test facilities requires a significant investment and a long-term commitment to run and maintain them.
Case histories illustrate the challenges and benefits achieved with the RQT approach. Examples from more than 10 years of experience with downhole safety valves and permanent gauge installations show surprisingly similar reliability and testing problems to those experienced in automotive and aerospace applications. These examples demonstrate how RQT provides an objective set of techniques to develop and deploy reliable long-life systems.
Start-up Automation of a Petroleum Offshore Platform
Authors: de Campos Mário César , Satuf Eduardo 
Published: December 2007

Abstract
It is difficult to control and manage the start-up of a petroleum offshore platform. In order to solve this problem an intelligent system can play an important role, since available qualified operator and design knowledge can be easily implemented to assist the operator during start-up. This paper describes a system applied to the start-up of a petroleum offshore platform. The intelligent system has many heuristic rules to implement the automation of procedures, like the opening of many on-off valves while simultaneously monitoring process variables. This system can shorten the start-up time by 30%. This intelligent system is operating since June 1999 in the Petrobras’ P-19 platform, the Brazilian Oil Company, in Campos Basin, Brazil. This paper follows reference [1] that presented the operating interface of this intelligent system.
East Texas Hydraulic Fracture Imaging Project: Measuring Hydraulic Fracture Growth of Conventional Sandfracs and Waterfracs
Authors: Mayerhofer Michael J. , Walker Ray N. , Urbancic Ted , Rutledge James T. 
Published: December 2007

Abstract
This paper presents detailed analyses of hydraulic fracture microseismicity and engineering data created during the joint operator Cotton Valley Hydraulic Fracture Imaging Project in East Texas. The project was a joint operator consortium with the goal of evaluating hydraulic fracture growth of conventional "sandfracs" and waterfracs with very low sand concentrations. A variety of fracture diagnostic tools were used on ten fracture stages in three wells including microseismic and downhole tiltmeter fracture mapping, fracture modeling, stress tests, radioactive tracers, pressure transient well tests, and production logging. We also introduce a methodology that uses full triaxial waveform analysis of the microseismic signals to obtain seismic source parameters, which characterize failure modes during hydraulic fracturing. This information could potentially be used for a detailed description of fracture geometry, growth and complexities and may give some indications about created versus propped fracture lengths. The paper compares the microseismic created lengths and propped lengths with those from frac models.
Experimental Study on Fracture Initiation by Pressure Pulses
Authors: Yang David W. , Risnes Rasmus 
Published: December 2007

Abstract
A new testing device has been developed which can be utilized to study the dynamic fracture initiation by pressure pulses. Instead of using propellant gas, the device employs a falling weight to impact on the piston that compresses the borehole fluid and transmits a dynamic pressurization to the simulated wellbore. The device is instrumented to measure the pressure pulses in the simulated borehole and in the confining chamber. The fracture pattern can directly be observed and examined. A systematic work has been done to calibrate the set-up and to identify the factors for controlling the pressurization rate.
Altogether 63 tests with commercially available or artificial rock samples have been conducted by using the developed setup. The transition from the hydraulic-fracture pattern to the multiple-fracture pattern has been observed. Three series of tests have been conducted to confirm the transition and determine the relation between the transition and rock strength.
Besides presenting the experiment results, the paper also briefly discusses how to use the data in designing the dynamic fracturing treatments for enhancing well productivity or injectivity.
CONTROL: PCP – An Intelligent System for Progressing Cavity Pumps
Authors: Carvalho P. G. , Morooka C. , Bordalo S. , Guilherme I. 
Published: December 2007

Abstract
This paper describes an intelligent system for the management and control of petroleum wells operating with progressing cavity pumps (PCP), named CONTROL: PCP.
The purpose of CONTROL: PCP is to maintain the operational conditions of PCPs within the established limits, reduce the operational costs, maximize the useful life of the equipment, and, consequently, increase the profitability of the petroleum wells. The architecture of the system involves expert knowledge for handling an existing database.
Interpretation and Application of Acoustic and Transient Pressure Response to Enhance Shale (In)Stability Predictions
Authors: Tare Uday A. , Mese Ali I. , Mody Fersheed K. 
Published: December 2007

Abstract
The main objective of this work is to discuss the initial results of an ongoing experimental study. The study has investigated the role of chemical potential of drilling fluids on transient pore pressure, acoustic, static properties, and strength of shale formations subjected to compressive confining stress. The motivation behind this study is to develop real time wellbore (in)stability logging capability.
Wellbore (in)stability in shales is a major problem costing the petroleum industry, according to conservative estimates, $700 million annually. Understanding and modeling mechanisms of shale (in)stability is an ongoing industry effort. Drilling a hole into a formation in equilibrium induces stress concentration near the borehole. A chemical interaction will occur if parameters such as chemical potential, ionic concentration, etc., of the drilling fluid and the shale formation fluid are not in equilibrium. Any differences in these parameters will alter the near wellbore pore pressure which in turn will influence the borehole equivalent stress-state and the shale mechanical strength thus affecting wellbore (in)stability. Tests conducted at compressive uniaxial and triaxial stress conditions in the past have indicated the strong influence of these chemical parameters on shale strength.
In this study, transient pressure, compressional and shear wave velocities, deformation and strength of shale cores were measured as a function of time when exposed to a drilling fluid. The experiments were conducted under conditions simulating a borehole portion under geostatic stress and the wellbore surface exposed to a circulating drilling fluid.
The uniqueness of this study comes from the fact that the mechanical property, acoustic velocity and transient pressure for each sample are measured simultaneously as a function of time during the experiment. This eliminates the anisotropy-associated differences obtained when different samples are used to determine the relationship between these characteristic parameters of shale formations. This comprehensive testing program will enhance our understanding of the relationship between acoustical, mechanical and chemical properties of shale as a function of time when exposed to a drilling fluid.
Interpretation of static and dynamic rock properties utilizing acoustic velocity data as a function of the transient pressure of shales under identical stress state will facilitate real time wellbore (in)stability predictions using MWD/LWD information. Thus, this application provides better real-time management of (in)stability problems in the field.