bluuebunny/crossref_metadata_2025_split huggingface dataset:
Applying Modern 3D Modeling Technology for a Large Gas-Condensate Field in the Pricaspian Basin
Authors: Dmitrievsky S. A. , Bolotnik D. N. , Posvansky D. V. , Sarkisov G. G. , Schepkina N. E. , Yufin P. A. , Zaitcev I. U. 
Published: December 2007

Abstract
This paper will discuss modeling and compositional simulation of a large gas-condensate field in the Russian part of the Precaspian basin.
The naturally fractured limestone reservoir is highly heterogeneous with complex geology and having high initial pressure. The field was modeled using different reservoir modeling software packages : STORM, TIGRESS and ECLIPSE
The behavior or reservoir was modeled with 3D simulation grid, having corner point geometry. TIGRESS and ECLIPSE compositional models with dual porosity options where used
A lack of geological and laboratory data was complicating the modeling task. Reservoir geometry was obtained only from well observations, using mapping algorithms, implemented in TIGRESS software Dual porosity sigma values was obtained from well test data, using ECLIPSE WELLTEST and TIGRESS pressure analysis software and were history matched. Only total porosity values from petrophysics observations were available in this project At first the total porosity distribution was obtained at fine 3D grid, using STORM stochastic modeling technique and upscaling procedures.
Fractured matrix porosity was calculated from total porosity, using simple constant multipliers, which were then treated as history matching parameters. Permeability distribution was obtained from a little amount of core data and porosity – permeability correlation, using STORM petrophysic properties modeling facilities. Then permeability data was corrected, to be consistent with well tests interpretation results.
Three phase study was initialized, using equilibration algorithms, implemented by TIGRESS and ECLIPSE software
The flow dependent skin factor options for calculation well inflow performance was used to take in account non – Darcy flow to the wells, having high pressure dropdown.
3D visualization tools implemented in RESVIEW, TIGRESS, ECLIPSE software allowed us to view and better analyze our input data and results.
Modem 3D modeling technologies allowed us to achieve a better description of the large and complicated reservoir, giving more reliable predictions of the field production performance
Applied Uncertainty Analysis Using Stochastic Modelling
Authors: Sandsdalen C. , Barbieri M. , Tyler K. , Aasen J.O. 
Published: December 2007

Abstract
At the appraisal phase of an offshore field development, there are limited amount of hard data for reservoir description. For that reason significant uncertainty exists not only in the variability of the observed petrophysics and facies data (heterogeneity uncertainty) but also in the representativeness of the observed data (model parameter uncertainty).
The aim of this study is to quantify the effect of these uncertainties on the dynamic behaviour of the reservoir and provide input for the overall uncertainty analysis. These uncertainties are important at this field development stage, contributing to decisions being made with respect to gas contracts, facility design and commercial evaluation.
It is difficult to incorporate the model parameter uncertainty by simply generating a certain number of realisations out of one global set of model parameters - i.e. a standard stochastic modelling approach. Thus, different parameter distributions were utilised as input to different heterogeneity models provided by the disciplines involved (sedimentology, petrology, petrophysics and geology). In order to ensure equi-probability of the realisations generated, a higher hierarchical model with two individual levels of uncertainty was used.
The problem arising with a hierarchical model is the large number of possible model parameter combinations. Hence, the Latin Hypercube technique was used for experimental design when planning for realisations. 99 realisations of the reservoir plumbing have been generated including facies and petrophysics modelling. However, because of the complexity of the fluid system and the need for compositional reservoir simulation very few of the realisations could be evaluated with the full field simulation model. The realisations were therefore ranked on element models using front-tracking and simplified black oil models.
The results of this analysis were applied in the overall uncertainty analysis. In addition, the results contributed significantly to the understanding of the reservoir and its potential dynamic behaviour.
Introduction
Reservoir simulation is an indispensable tool in modern reservoir management. However, large uncertainties are known to exist in the production profiles thus calculated. One reason is that heterogeneities are generally poorly represented, due to lack of knowledge of the spatial distribution of the architectural elements in the reservoir. Specially in offshore reservoirs, the large distances between wells result in geological models which rarely represent the heterogeneities influencing the fluid flow. In recent years, a large effort has been dedicated to representing more correctly the geological features of the reservoir and the associated uncertainty. However, to date, little has been done in the modelling to correctly handle uncertainty of the input parameters which is critical to the outcomes of the geological architecture.
A Production Logging Measurement of Distributed Local Phase Holdup
Authors: Halford F. R. , MacKay S. , Barnett S. , Petler J. S. 
Published: December 2007

Abstract
This paper describes early UKCS experience of a new production logging sensor, the Digital Entry and Fluid Imager, or DEFT* tool.
Deviated and horizontal wells can cause complex flow regimes to arise that render interpretation of conventional production logging sensors difficult or sometimes impossible.
The DEFT tool is a new type of production logging tool which facilitates the understanding of the nature of wellbore flow and improves confidence in interpretation. The tool makes four independant measurements of the phase holdup, distributed in differring quadrants of the pipe cross section.
Results to date show that the DEFT tool gives a direct count of the dispersed phase bubbles. Each probe can give an indication of the flow type, the absolute velocity of the dispersed phase, and the bubble flow direction. As the four measurements are distributed at different locations within the pipe cross section, an image of pipe flow may be interpreted.
Early results also show how the DEFT tool can be used to define the location of oil entries and to pin-point circulatory flow.
The paper briefly describes the tool principles. Interpretation is illustrated with example logs made during its field introduction.
Underground Disposal of Acid Gas in Alberta, Canada: Regulatory Concerns and Case Histories
Authors: Longworth H. L. , Dunn G. C. , Semchuck M. 
Published: December 2007

Abstract
Over the past couple of years oil and gas operators in Alberta have been faced with an increasing challenge to reduce atmospheric emissions. One of these emission sources comes from oil and gas pools that contain uneconomic quantities of hydrogen sulphide and carbon dioxide (acid gas). Disposal of this acid gas to underground formations is sometimes a cost effective alternative to sulphur recovery and it also can reduce the public concern resulting from sour gas production and flaring
In Alberta, the Oil and Gas Conservation Act requires that operators apply for and obtain approval from the Alberta Energy and Utilities Board (EUB) to dispose of the acid gas. Before approving any scheme, the EUB reviews the application in order to satisfy several primary issues: maximizing conservation of hydrocarbon resources, minimizing environmental impact, promoting public safety, and ensuring that the equity interests of mineral rights owners are protected. To adequately address these matters, the EUB requires that applicants submit information regarding surface facilities, disposal well configurations, and reservoir factors. This paper discusses the information required and describes the process that should be followed by operators who wish to obtain EUB approval for underground disposal of acid gas In addition, this paper discusses the performance of some of the acid gas disposal schemes currently operating in Alberta.
MB Solution for High Pressure Gas Reservoirs
Authors: Elsharkawy Adel M. 
Published: December 2007

ABSTRACT
Accurate estimation of the initial gas in-place for high-pressure gas reservoirs is quite often difficult because of the effect of formation compressibility and the uncertain presence of water influx from small, associated aquifer or adjacent shales.
This paper presents a material balance solution for estimating the initial gas in-place and predicting the prevailing production mechanism for high-pressure gas reservoirs. The material balance solution incorporates water influx from aquifer, water influx from shale, formation expansion, connate water expansion, and formation of condensate. Application of the proposed solution to four case histories of high-pressure gas reservoirs shows that this solution would successfully estimate the IGIP after production of 15% of the initial gas in-place and predict the prevailing reservoir production mechanism. In comparison with the available methods, the proposed solution requires no prior assumptions about the formation compressibility, aquifer size, or volume of adjacent shales.
Multi Model Simulation Study for Strongly Faulted Gas Condensate Reservoir Using Fault Block Modelling
Authors: Ursin Jann-Rune , Mæland Leidulf 
Published: December 2007

Abstract
Optimization of reservoir performance is strongly related to feasible evaluation of reservoir uncertainty. In modern reservoir engineering, a substantial amount of effort is allocated to maintenance and upgrading of what is believed to be the current best realization model of the reservoir, where reservoir uncertainty is demonstrated through parameter variation. This technique is frequently applied even though the nature and extent of uncertainty associated to reservoir characterization, strongly suggests a multiple model approach, i.e. visualization of reservoir uncertainty through realization of alternative models. Awareness of this problem is particular important in the case of strongly faulted gas- and condensate reservoirs.
The model described in this paper is designed for production from gas or gas condensate fields, where modelling of highly faulted and compartmentalized reservoirs is severely impeded by the nature and extent of known and undetected faults and, in particular, their effectiveness as flow barriers. The model redefines individual fault block traps in terms of block volume and cross-flow probability to adjacent blocks, where geological uncertainties are carried through in the model by error propagation techniques. Three different realizations of reservoir models are created; one representing the most likely (average) reservoir while two others represent the extreme alternatives, reflecting the reservoir uncertainties. The fault block evaluation is treated as input to material balance calculation, where reservoir production is assumed to take place from individual block volumes.
The reservoir model is easy to modify by varying block volumes and/or cross-flow probabilities, according to improved knowledge about the reservoir or simply as a sensitivity test of the degree of communication across fault barriers. The model also estimates the total well drainage coverage and the sequence of blocks from where wells should start production. The model may also certify the research area of interest, where improved information about the reservoir has the greatest impact on improved reservoir performance.
Sorption Irreversibilities and Mixture Compositional Behavior During Enhanced Coal Bed Methane Recovery Processes
Authors: Chaback Joseph J. , Morgan Don , Yee Dan 
Published: December 2007

Abstract
Enhanced coalbed methane (ECBM) recovery processes rely on the sorption of a stripping or displacing gas to recover the sorbed methane. Both the adsorption and desorption of methane and the injected gases are important to the success of the process. Oxygen, which can chemisorb to coal, is expected to show different adsorption than desorption behavior. However, adsorption and desorption isotherms for mixtures of physisorbed gases such as nitrogen and methane appear similar in form to those for oxygen. Moreover, results from a field ECBM recovery project also suggest that in the mixed state physisorbed gases may show different behavior during desorption than during adsorption. Because reservoir simulators typically use a reversible equilibrium sorption model such as the Langmuir isotherm, the presence of hysteresis due to sorption irreversibilities could affect the reliability of the simulations.
Constant composition expansion and constant volume depletion sorption results were analyzed. This analysis demonstrates that although mixtures of physisorbed ECBM recovery gases (no oxygen) become enriched in the more strongly held component during desorption, the process is one of reversible equilibrium sorption and isotherm models such as the extended Langmuir isotherm effectively capture this adsorption/desorption equilibrium. No additional changes to the simulator are needed because of this compositional effect. However, for oxygen-bearing gases modification of the Langmuir isotherm will be needed to quantitatively represent adsorption/desorption behavior during an ECBM recovery process.
Case History of a Unique Gas Injection Scheme and its Simulation Using Material Balance Based Simulator
Authors: Behbahani H. S. -Z. , Kharrat R. , Vossoughi S. 
Published: December 2007

Abstract
A gas injection for the purpose of pressure maintenance was initiated in a field located in south of Iran in 1984. It is the largest gas injection project in Iran and possibly in the world without the use of compressors. The field was discovered in 1968. It consists of two non-communicating formations one on top of the other namely Asmari and Bangastan group. The Asmari reservoir contains oil and the Bangastan reservoir contains dry gas with little amount of condensate at much higher pressure. Gas is produced from one well completed in Bangastan reservoir and injected into an injection well completed in Asmari reservoir by a direct pipeline.
History matching was performed over 18 years of production of the Asmari field. Long term prediction of the reservoir performance was obtained for 42 years above the initial 18 years of history matching. Prediction was evaluated under different scenarios namely: 1) natural depletion, 2) pressure maintenance, and 3) repressurizing the reservoir close to its initial pressure.
This paper will present the actual reservoir data for both formations over eighteen years of their operation. In addition, history matching and future performance of the reservoir predicted by a simple simulator based on material balance concept will be presented. It is encouraging to observe a satisfactory match of the reservoir performance and to gam insight into its future performance without resorting to a much more sophisticated and much more expensive simulators.
Application of PermLog - A New Log-Based Permeability Estimation Method
Authors: Semmelbeck M. E. , Diyashev I. R. 
Published: December 2007

Abstract
This paper presents error analysis and applications of a new method for estimating permeability from logs. This method is called PermLog and its development is documented by Semmelbeck et at1. We present an example application of PermLog and show how it can be used with pressure transient testing to characterize complex, low to moderate permeability gas reservoirs. We also present the results of a detailed error analysis in which we determine the expected accuracy of the PermLog permeability estimates. We show confidence intervals expected from PermLog based on assumed accuracy of parameters used in the PermLog analysis.
Well tests in complex multilayered reservoirs can be analyzed with more realistic reservoir models when layer permeability estimates are provided by the PermLog analysis. Monte-Carlo error analysis indicates that at least 80% of permeability estimates from PermLog will be within a factor of 3 of the true in-situ gas permeability when the permeability is in the range of 0.01 to 10 md.
The permeability estimates fine-tuned by matching pressure transient behavior will lead to better performance forecasts and optimization of stimulation treatments and well spacing.
Discriminant Analysis as a Technique for Exploitation of Petroleum Reservoirs
Authors: Schrider Leo A. , Byrd Jack 
Published: December 2007

Abstract
Discriminant analysis, a statistical technique, was used to classify oil wells into productivity groups based upon data obtained productivity groups based upon data obtained from geophysical well logs. A calibration run conducted in the northern area of the East Canton oilfield verified that valid forecasts can be obtained by the procedure. Of 20 wells studied, four appeared to have a greater potential than that indicated by actual potential than that indicated by actual production figures. A similar study of the production figures. A similar study of the southern area of the East Canton reservoir also proved discriminant analysis to be effective for predicting productivity, although different variables were significant than those for the north reservoir. Discriminant analysis was indicated to be adequate and potentially helpful in arriving at decisions potentially helpful in arriving at decisions concerning well completion.

Introduction
Located in northeastern Ohio, the East Canton oilfield is one of the largest ever discovered in the Appalachian basin. The field now comprises over 60,000 acres with more than 1,000 oil wells. Fig. 1 shows the field and illustrates a proposed additional drilling area—one of more than 500 similar locations for new wells in the area. Upwards of 12,000,000 barrels of premium Pennsylvania Grade crude oil have been obtained from the field; current production is about 11,000 barrels per day.
Exploiting the East Canton reservoir presents many problems to the petroleum presents many problems to the petroleum engineer, not the least of which is deciding to complete a well. Log data and field experience in offsetting wells can be helpful but evaluating oil wells for porosity and hydrocarbon saturation on the basis of log analysis is especially difficult. Few of the wells have been plugged as "noncommercial" immediately following drilling, but about 20 percent of them could have been plugged percent of them could have been plugged because they will not return drilling and completion costs.
Discriminant analysis, which has been shown to be useful in oil and gas exploration and other areas of endeavor, was investigated by the Bureau of Mines as a method of predicting oil well production from the East predicting oil well production from the East Canton field. Current oil well production data and log data serve as input to the discriminant function, and the model is then used to classify new wells into high, medium, and low production as a function of log-determined reservoir properties. Rate of return from a new well can then be estimated, and a decision can be made concerning completion of the well. A unique feature of the concept is that the statistical prediction technique adapts itself to the reservoir.
First Assessment of Effects of Air-Gun Seismic Shooting on Marine Resources in the Central Adriatic Sea
Authors: La Bella G. , Cannata S. , Froglia C. , Modica A. , Ratti S. , Rivas G. 
Published: December 2007

Abstract
A series of investigations were carried out to test the effects of air-gun seismic shooting on main fishery resources of the Adriatic Sea during summer 1995.
The energy source used for the trial was formed by one air-gun array made up by two sub-arrays consisting in 8 air-guns each developing a total volume of c.a. 2500 i3 at 2000 psi with an amplitude of 60 bar/m. The interval between two was of 25 s The intensity was of 210 dB re 1 mPa-m/Hz.
Acoustical and spectral analysis were performed simultaneously in the surveyed areas to correlate fishery and behavior observ ations with sound pattern of the energization.
Main results were: Analysis of trawl catch data evidenced no significant changes before and after the air-gun seismic profiling.Echosurvey relative estimate of pelagic biomass, performed simultaneously to trawling operations, failed to evidence any significant change in the pelagic biomas.Small differences were observed in the trammel net catch composition, but one single set of pre-post fishing operations could be done in the study period.Similar density estimate were obtained from dredge surveys performed by an hydraulic dredger before and after air-gun seismic profiling over a clam bed in 14 md.Video recording of captive fish, kept into cages moored on the sea bottom at 12 m depth, evidenced a behavioral response to the approach of the sound source; but no lethal event was recorded on captive sea-bass immediately after the seismic shooting.Biochemical and histological analysis were performed to verify if it is to be related to the captive condition or is somewhat consequent to the air-gun energization.
These results confirm that no relevant effects are induced on fishery resources by seismic air-gun shooting.
Duri Indonesia Air Emission Inventory and Dispersion Modeling Study
Authors: Soetjiptono T. E. , Nugraha S. , VanDerZanden D. F. , Petersen L. P. , Verstuyft A. W. , Schievelbein V. H. , Rabideau C. G. , Gilmer L. K. , Comey K. R. 
Published: December 2007

Abstract
The Caltex Pacific Indonesia production field located in Duri, Indonesia, is the world's largest steam flood. Because of the large scale of these operations, there is an interest in understanding the emissions into the atmosphere from the various sources in the field as well as the possible impact on the air quality resulting from these emissions. To be proactive and to fulfill this need, a study was done to inventory emissions from the facilities in the field and to use air dispersion models to estimate impacts on the air quality using the inventory results. This paper will discuss methods and procedures used in the study to quantify the emissions from the following sources in the Duri field: process vents, production impoundments and wastewater canals, Toads, fugitive emissions, storage tanks, and combustion sources. Emissions of the following compounds were addressed in the study: nonmethane hydrocarbons (NMHC) and aromatic hydrocarbons (BTEX), hydrogen sulfide, nitrogen oxides, sulfur oxides, paniculate matter (PM), and carbon monoxide. Because of the diverse nature of the sources in the field, a wide range of emission estimating procedures were used including direct measurement methods, empirical methods based on mass transfer principles, and standard emission factors or procedures available from the United States Environmental Protection Agency (U.S. EPA). To quantify and track the emissions data generated, a computerized emissions inventory was developed. This paper will also discuss the dispersion modeling methods that were used to estimate the ground level concentrations in the surrounding areas using the data developed in the emission inventory. These discussions are based upon the results of a preliminary study which is limited to a portion of the Duri production field.