bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reservoir Characterization by Integrating Well Data and Seismic Attributes
Authors: Yang An-Ping , Gao Yaming , Henry Steve 
Published: December 2007

Abstract
Fueled by the continuing development of computer technology, traditional techniques for reservoir characterization have evolved into a multi-disciplinary process. In particular, geostatistical techniques have provided a framework for integrating all available engineering and geoscience data. In this paper, we will demonstrate a seismic-guided geostatistical method on a realistic seismic data set. A cross section from a three-dimensional reservoir facies model was used to test the capabilities of this method. Synthetic seismic data were generated from the geologic cross section and then input to a seismic inversion process to estimate acoustic impedance. Five porosity logs derived from the known model were used as hand data. Using this hard data, and utilizing varying correlation coefficients between the hard data and soft data, a set of gridded maps were generated using a geostatistical method.
Comparisons of the results with the known model clearly indicate the potential of this type of approach to provide meaningful reservoir characterizations consistent with the available data. The integration procedure illustrated in this paper can be used as a basis by engineers and geoscientists to develop specific procedures for their applications. The demonstrations in characterization quality improvement can be used to justify the need for integrating seismic data into the reservoir description process.
Integrated Geostatistical Reservoir Description Using Petrophysical, Geological, and Seismic Data for Yacheng 13-1 Gas Field
Authors: Yang C. T. , Chopra A. K. , Chu J. , Huang X. , Kelkar M. G. 
Published: December 2007

ABSTRACT
Seismic data are routinely and effectively used to delineate the structure of a reservoir. However, the use of seismic data in reservoir modeling has been limited. This paper introduces a new approach of incorporating 3-D seismic data in reservoir porosity modeling. This approach employs a stochastic seismic inversion technique to generate the seismic impedance. The inversion technique uses a modified stochastic hillclimbing method. Correlation between porosity and the inverted impedance is established at well locations. The resulting relationship is used to generate 3-D porosity models. The generation of these models involves a stochastic co-simulation of inverted seismic impedance of loc-derived porosity.
This modeling technique is applied to the Yacheng 13-1 Gas Field. The results are compared with porosity models generated using well-log data only, as well as with using seismic amplitude and well-log data since a good correlation between seismic amplitude and well log data is also observed after transforming the data into similar scales.
The results demonstrate a protocol for early integration of geological and geophysical data in a gas reservoir. This approach will allow easy revision and refinement of the description with additional data, such as new well data or new interpretation of the existing data.
Optimizing Horizontal Well Locations Using 3-D, Scaled-Up Geostatistical Reservoir Models
Authors: Goggin David. J. , Gidman June , Ross Steve E. 
Published: December 2007

ABSTRACT
This paper demonstrates how horizontal well locations may be optimized by maximizing recovery and minimizing the number of wells. The study is unique in that we had a large number of wells penetrating a reservoir interval which had been developed by only two horizontal wells. We combined structural and stratigraphic information with processed log data available from 67 vertical wells drilled for a deeper reservoir target. 3-D, 161 cell layer geostatistical models of porosity, permeability, and inital water saturation were built from the log data. Variations in porosity and initial water saturation were kriged, while permeability heterogeneity was captured through conditional simulation.
Scaled-up, 42 cell layer versions of the geostatistical models were built for full-field simulation. The 3D scale up process preserves effective permeability and connectivity of the main flow units in the full-field model. Proportional volumetric averages of porosity and saturation were also preserved.
Two existing horizontal wells were history-matched on the scaled-up model. Thirty-year production forecasts for more than twenty proposed horizontal well locations were tested. Proposed well locations were tested individually, in pairs, and in triple combinations. Well locations were designed to tap high permeability flow units, and maximize the distance to the oil-water contact. Results from paired well combinations show the impact of well-to-well production interference on incremental oil recovery. Using these results, we were able to maximize incremental recovery for a minimum number of proposed horizontal well locations.
Fractured Reservoir Characterization and Performance Forecasting Using Geomechanics and Artificial Intelligence
Authors: Ouenes A. , Richardson S. , Weiss W. W. 
Published: December 2007

Abstract
A new approach in fractured reservoir characterization and simulation that integrates geomechanics, geology, and reservoir engineering is proposed and illustrated with actual oil reservoirs. This approach uses a neural network to find the relationship between, reservoir structure, bed thickness and the well performance used as an indicator of fracture intensity. Once the relation established, the neural network can be used to forecast primary production, or for mapping the reservoir fracture intensity. The resulting fracture intensity distribution can be used to represent the subsurface fracture network. Using the fracture intensity map and fracture network, directional fracture permeabilities and fracture pore volume can be estimated via a history matching process where only two parameters are adjusted.
Characterization and Simulation of Naturally Fractured Tight Gas Sandstone Reservoirs
Authors: Harstad Hugo , Teufel Lawrence W. , Lorenz John C. 
Published: December 2007

Abstract
Significant gas reserves are present in low-permeability sandstones of the Frontier Formation in the Green River Basin, Wyoming. Successful exploitation of these reservoirs requires an understanding of the characteristics and fluid-flow response of the regional natural fracture system that controls reservoir productivity. Fracture characteristics were obtained from outcrop studies of Frontier sandstone at five locations in the basin. Fracture characterization involved construction of detailed fracture network maps of outcrops that provided information on the fracture orientations, lengths, and spatial distribution. The fracture network maps clearly demonstrate that regional fractures are a unidirectional set of fractures that are perpendicular to bedding and have varying length and spacing. The spatial distribution of regional fractures is controlled by bed thickness, with fewer and longer fractures per unit area as bed thickness increases. The fracture data was combined with matrix permeability data to compute an anisotropic horizontal permeability tensor (magnitude and direction) corresponding to an equivalent reservoir system in the subsurface. This analysis shows that the maximum and minimum horizontal permeability is controlled by fracture intensity and decreases with increasing bed thickness. The relationship between bed thickness and the calculated fluid-flow properties was used in a reservoir simulation to predict gas production from vertical, hydraulically-fractured wells and horizontal wells of different lengths in analogous naturally fractured gas reservoirs. Simulation results show that horizontal wells drilled perpendicular to the maximum permeability direction can maintain a high target production rate over a longer time and have higher cumulative production than vertical wells. Longer horizontal wells are required for the same cumulative production with decreasing bed thickness.
Practical Considerations in the Analysis of Gas-Condensate Well Tests
Authors: Raghavan Rajagopal , Chu Wei-Chun , Jones Jack R. 
Published: December 2007

ABSTRACT
Several pressure buildup tests are analyzed with a view to evaluate the potential of the ideas given in the literature. A broad range of tests is examined to demonstrate the characteristics of responses in wells producing below the dew point. Methods to obtain quantitative information that is consistent for different tests are outlined.
Invasion-Based Method For Estimating Permeability From Logs
Authors: Semmelbeck M. E. , Dewan J. T. , Holditch S. A. 
Published: December 2007

Summary
We have developed a new method of estimating permeability from logs. Our method, called PermLog, is mechanistic rather than empirical and does not require extensive (and expensive) core analysis for calibration. PermLog is based on modeling filtrate invasion from the time a zone is penetrated until it is logged. This method provides reasonably good estimates of permeability in moderate permeability formations. Similar methods applied to time-lapse logging have been presented by Tobola and Holditch1 and Yao and Holditch.2 Our method has been improved over these earlier works in two significant ways. First, our method is applied to the prediction of new generation array induction logs and docs not require multiple "time-lapse" logging runs. The development here is applied to the Schlumberger AIT log but our method is extensible to any tool which can provide a resistivity profile of the reservoir surrounding the wellbore. Second, our model includes an experimentally-verified model for predicting mudcake thickness and permeability during static and dynamic filtration conditions.3,4
PermLog is an important step in tying the static or volumetric petrophysical data normally associated with log analysis to the fluid flow petrophysical information required for reservoir performance prediction. Reservoir engineers, petrophysicists, geologists and geophysicists are challenged to bring their specialties to bear on the problem of creating a reservoir model which can be used to optimize the value of oil and gas reservoirs. Layered and otherwise complex models arc more often applied to interpret well tests and production data to reflect our increased understanding of the importance realistic models have in predicting and optimizing reservoir performance.5,6 Acquiring sufficient data to satisfy these analysis methods is often too time consuming and expensive. PermLog, in conjunction with new generation logging tools, provides a much-needed source of information on the distribution of permeability within reservoirs.
This paper presents a description of the PermLog model, the underlying assumptions and the data requirements necessary to apply this technology. We also present comparisons between PermLog estimates and core measurements of permeability. The permeability estimates agree quite well with core data and the trends of permeability within an interval match up very well with the trends from cores.
Through Casing Resistivity Measurements and their Interpretation for Hydrocarbon Saturations
Authors: Vail W. B. , Momii S. T. , Dewan J. T. 
Published: December 2007

Abstract
Through casing resistivity logs obtained at three different wells are reviewed including the logs from a blind test. The physics necessary to interpret the data is presented in brief form and future corrections to data are discussed. Anticipated applications for the technology are described.
A Multiarray Induction Tool Optimized for Efficient Wellsite Operation
Authors: Barber T. , Orban A. , Hazen G. , Long T. , Schlein R. , Alderman S. , Tabanou J. , Seydoux J. 
Published: December 2007

Abstract
A new multiarray induction tool has been developed as part of the Platform Express,* a suite of tools intended to significantly improve wellsite efficiency. The tool measures formation conductivity with eight arrays ranging in length from 6 in. to 6 ft. Previously published methods1 are used to provide logs with 90% vertical resolutions of 1, 2 and 4 ft, each with depths of investigations of 10, 20, 30, 60 and 90 in. Integral to the tool is a sensor that measures the mud resistivity to provide accurate borehole corrections for the induction logs. The total length of the instrument package is 16 ft.
One problem encountered in multiarray induction tools is stick-slip motion of the tool in the borehole. To solve this problem an accelerometer included in the high-efficiency toolstring is used to provide real-time depth correction for nonuniform tool motion for all the tools in the string. In addition, this guarantees that the high-resolution logs are on depth with each other.
A special effort has been made to extend multiarray induction technology into more difficult logging conditions. A new algorithm that provides improved logs in very rugose boreholes and salty conductive mud has been developed and applied to the log processing of this tool. Additional features include correction to the resistivity logs for dip or deviation up to 60 degrees and more accurate estimates of Rt in the presence of annulus. The effectiveness of these algorithms has been demonstrated in case studies with both computed and field logs.
Shear Sonic Interpretation in Gas-Bearing Sands
Authors: Brie A. , Pampuri F. , Marsala A. F. , Meazza O. 
Published: December 2007

Abstract
The introduction, a few years ago, of shear dipole sonic logs gave the industry the possibility to record high-quality shear and compressional slownesses in soft formations. Data sets were acquired and analyzed on Vp/Vs versus Δtc crossplots. Trends were identified in sands and shales and were matched with semi-empirical correlations based on the Gassmann formalism. These trends can be used to quality control shear logs and for quicklook lithology interpretation.
The presence of gas in soft formations makes the interpretation more complicated as it can affect the sonic slownesses significantly, in particular the compressional. On the Vp/Vs crossplot, gas-bearing formations clearly differentiate from liquid filled formations. However, quantitative interpretation of the gas effect with the Gassmann equation gives deceptive results, although this model is successfully used in geophysics interpretation at a lower frequency. We indicate that the Gassmann model itself is not at fault. The responsibility is with the pore fluids mixture law used to compute the average fluid properties. We therefore propose a new empirical mixture law that better fits laboratory measurements and field observations. Using this revised model realistic gas trends can be identified on the Vp/Vs crossplot. The model can be solved to evaluate gas volume from compressional and shear slownesses. Additionally, the effect of shaliness can be accounted for. The results agree well, in most instances, with flushed-zone saturation obtained from resistivity measurements and provide another opinion on gas volume. An additional product of the interpretation is to provide reliable values of dry-frame dynamic elastic constants of the rock for possible subsequent use in a rock mechanics evaluation.
Ultrasonic Rate Measurements in Two-Phase Bubble Flow
Authors: Kumar Manoj , Home Roland N. 
Published: December 2007

Abstract
One of the most important tools in well testing and production logging is the downhole flowmeter. Unfortunately, existing spinner and tracer tools have limited accuracy in low-rate single phase flow and multiphase flow situations. Two experimental studies investigated the use of ultrasonic methods to measure flow rates under these conditions. The experiments showed that the ultrasonic transmission method can be used for accurate measurements of low-rate single phase water flow. The ultrasonic reflection method provided reasonably accurate bubble velocities in two-phase bubble flow regime under laminar flow conditions.
Experiments using ultrasonic transmission provided higher accuracy and better sensitivity in measurement of low-rate single phase water flow than conventional methods. The one-inch square flowcell device investigated in this study used the trans-mission properties of ultrasonic waves to measure the volumet-ric rate in single phase water flow. The flow cell was installed in a vertical flow loop. Water also passed through a section where the weight of water was recorded accurately against time, thus giving another rate measurement for cross-checking purposes. The device-measured flow rates were compared with actual rates obtained by the weight measurement. The device was accurate down to a flow rate of 1.0 gallon/min, which is the slowest flow rate achievable in this loop. Such a low flow rate would normally be difficult ta measure using a conventional spinner tool.
Experiments using ultrasonic reflection examined how accurately an experimental flow tool measured bubble velocity in a two-phase bubble flow regime. Measurements were made in a graduated, transparent pipe with an inside diameter of 5.50 inches. The tool diameter is 3.25 inches. Gas and oil were bubbled through a stagnant column of water, and bubble velocities were measured. To cross-check the accuracy of tool measurements, bubble motion was also recorded using a video camera. The video frame had a clock, with a resolution of one hundredth of a second, providing time information. Tool-measured bubble velocities were compared with actual velocities determined by a frame-by-frame playback of video data. The tool readings were linearly related to the actual velocities in the range from 0.38 ft/sec to 1.30 ft/sec, although the velocities registered by the tool were consistently in error. This velocity information, in combination with the void fraction data, will provide the dispersed phase volumetric flow rate. The result is significant because, in contrast to the currently employed spinner and tracer tools, this technique can provide us with flow rates for individual phases in a two-phase bubble flow situation.
Hydrate Plug Decomposition: Measurements and Modeling
Authors: Yousif M. H. , Dunayevsky V. A. 
Published: December 2007

Abstract
Depressurization (venting) is almost the only option available to remove hydrate blockages from subsea natural gas or gas condensate pipelines. This process is normally applied with little or no accurate information about the plug location, size or composition.
Hydrate decomposition by depressurization is a heat and mass transfer dependent process. Quantifying this dependency is necessary to perform an optimum plug removal scheme.
In this paper, a moving boundary mathematical model is developed to predict the decomposition rate of a hydrate plug under various depressurization scenarios. The model was validated experimentally by measuring the rate of decomposition of hydrate plugs in a 2 inch internal diameter, 38.5 inch long pipe. The motion of the hydrate plug/gas interface is tracked by 16 pairs of infrared light transmitters and receivers diametrically positioned across the pipe.
Improved Completion Designs In The Hugoton Field Utilizing Multiple Gamma Emitting Tracers
Authors: Hecker M. T. , Houston M. E. , Dumas J. D. 
Published: December 2007

Abstract
Multiple gamma emitting tracers and post fracture spectral gamma ray logs were used to optimize production and improve the completion designs of 150 gas wells in the southwest Kansas region of the Hugoton Field. The information from the tracers and logs has revealed unstimulated pay zones and has been the impetus for completion modifications, yielding substantial gains in production. Through the use of limited stress barriers and permeability variations, perforation schemes have been successfully modified to improve fracture containment and proppant placement over the 200 ft Chase Group intervals. Previously these intervals were treated with multiple individual zone treatments.
Sequential Decision Analysis and Risk Analysis for Antarctic Offshore Petroleum Development
Authors: Belke D. 
Published: December 2007

ABSTRACT
Integration of geological, engineering, environmental and economic parameters of the Ross Sea, Antarctica led to the development of a quantitative assessment of potential petroleum development in this region. A decision analysis model of 90 outcomes (excluding ‘no’ decisions) indicated that the best alternative is a 400,000 Bopd production scenario. This is based on reduction of capital investment of US$7.6 billion (base case) by US$2.2 billion and producing an equal volume as in the base case (400,000 Bopd). A risk analysis model, based on cumulative probabilities, indicated that a US$ 15 increase in the price of oil has more impact on Antarctic petroleum development than a combined 75% decline in capital and operating costs.
A New Generation of Gas Hydrate Inhibitors
Authors: Kelland M. A. , Svartaas T. M. , Dybvik L. 
Published: December 2007

Abstract
New, cost-effective, and environmentally acceptable hydrate inhibitors that allow multiphase fluids to be transported untreated over long distances have been under increasing investigation by the oil and gas industry.
Replacing traditional hydrate inhibitors such as methanol and glycols with a new generation of hydrate inhibitors can lead to very substantial cost savings, not only for the reduced cost of the new inhibitor but also in the transportation costs and the size of the injection, pumping and storage facilities. Thus it is possible to redesign production facilities on a smaller scale. Such a change-over in hydrate inhibitor technology may also be an environmental requirement in the near future.
We will present an overview of patent and other literature on new hydrate inhibitors, including specific chemicals that have been investigated. Our own results on some of these published chemicals will be given and their applicability compared. We will also present data on new inhibitors developed at RF, as well as improved methods of evaluating their activity. A discussion of the relative merits of the two main types of new hydrate inhibitor, "kinetic inhibitors" and "anti-agglomerators", will be given.
New Dual Completion Method Eliminates Bottom Water Coning
Authors: Swisher M. D. , Wojtanowicz A. K. 
Published: December 2007

Abstract
This paper discusses the design, implementation, and results of a new completion method to eliminate bottom water coning. This method uses a dual completion in the same zone to produce water-free oil at higher rates than conventional completions. This is accomplished by producing water from perforations below the oil-water contact, at the same time that oil is being produced from perforations at the top of the sand. The method is currently being used in the Nebo Hemphill Field in North Louisiana. Mathematical models are used to assist in the design of this completion. With this modeling, the perforation spacing is determined, along with an estimate of the water production needed to prevent coning. The first well to use this new completion method has been on production for over a year. This paper documents the production rates, and economic success of the test well using this completion method.