bluuebunny/crossref_metadata_2025_split huggingface dataset:
StarWars Laser Technology Applied to Drilling and Completing Gas Wells
Authors: Graves R. M. , O'Brien D. G. 
Published: December 2007

Abstract
This paper describes results of the first phase of a Gas Research Institute (GRI) funded research program. The overall purpose of this research is to advance a fundamental change in the method currently used to drill and complete natural gas wells applying the U.S. Defense Department's StarWars laser technology. Results of tests conducted at the U.S. Air Force and the U.S. Army's high power laser research facilities are presented.
Initial testing on reservoir rocks conducted with the Mid Infrared Advanced Chemical Laser (MIRACL) at the U.S. Army's High Energy Laser Systems Test Facility at White Sands, New Mexico, showed the potential for laser drilling. The laser beam drilled at a speed that indicates penetration could be increased by more than 100 times current rates.
Planned testing for the next phase of this research is to use the Chemical Oxygen-Iodine Laser (COIL) high powered laser invented in 1977 by the U.S. Air Force Research Laboratory in Albuquerque, New Mexico, for air-to-air defense. COIL has gained notoriety as an airborne laser tactical weapon capable of tracking and destroying missiles.
An annotated bibliography was developed for the GRI that comprehensively reviews published laser-rock interaction, current drilling research, and technical data related to laser applications in non-reservoir rocks.1 Developing commercial applications of StarWars laser technologies has commenced not only in the U.S., but also in Russia and the former Soviet Union.
Wellbore Stability: A New Conceptual Approach Based on Energy
Authors: Santos Helio , Diek Adel , Roegiers Jean-Claude 
Published: December 2007

Abstract
The conservation of energy principle is applied to analyze wellbore stability. A conceptual model and simple method to quantify the energy associated with the main events during drilling are proposed here. However, evaluation of the consequences in terms of damage to the rock requires specially designed tests to determine the response of the rock in terms of energy. This approach can explain the failure mechanisms usually observed in laboratory tests and most of the problems faced in the field. In view of this new approach, adequate solutions to effectively alleviate current instability problems are discussed. Successful field cases are described, demonstrating the validity of the suggested failure mechanisms.
P. 805
Modeling Relative Permeability Effects in Gas-Condensate Reservoirs
Authors: Pope G.A. , Wu W. , Narayanaswamy G. , Delshad M. , Sharma M. , Wang P. 
Published: December 2007

Abstract
Many gas condensate wells show a significant decrease in productivity once the pressure falls below the dew point pressure. This significantly decreases the productivity of very high rate gas wells in many of the world's largest hydrocarbon reservoirs. A widely accepted cause of this decrease in productivity index (PI) is the decrease in gas relative permeability due to build up of condensate in the near weIlbore region. Predictions of well inflow performance require accurate models for the gas relative permeability as a function of interfacial tension (IFT) between the gas and condensate phases (actually it should be trapping number rather than IFT). Since these relative permeabilities depend on fluid composition and pressure as well as condensate and water saturations, a model is essential for both interpretation of lab data and for predictive field simulations. The key to such a gas condensate relative permeability model is the dependence of the critical condensate saturation on the capillary number or its generalization called the trapping number. We have made careful comparisons of such data with a capillary trapping model and have found that we can match these data with a simple two-parameter model. We then developed a general scheme for computing the gas and condensate relative permeabilities as a function of the capillary trapping model and with only data at low trapping number (high IFT) as input and have found good agreement with the experimental data in the literature. We then used this model and typical parameters for gas condensates in a compositional simulation study of a single well to better understand the PI behavior of the well and the significance of the condensate buildup.
P. 643
How to Include the Capillary Number in Gas Condensate Relative Permeability Functions?
Authors: Blom S.M.P. , Hagoort J. 
Published: December 2007

Abstract
The important role of near-miscible relative permeability functions in the formation of a retrograde condensate zone around the well bore is well established. The functions depend on the ratio of viscous to capillary forces on a pore scale, denoted by the capillary number. A large number of methods have been proposed for including the capillary number in the gas condensate relative permeability functions.
We have reviewed and analyzed fifteen different methods. These can be divided into two classes:using Corey functions in which the Corey coefficients are interpolated between immiscible and miscible limits, andinterpolation between integral immiscible and miscible relative permeability curves.
In both methods the interpolation is weighted by capillary number dependent functions. From the reviewed methods we have distilled three different weighting functions that are most suitable. We have calibrated the correlations to four experimental data sets. As the capillary number we have used.
The results show that the weighting function proposed by Whitson and Fevang is the most convenient; this function covers the entire range of capillary numbers, and is able to reproduce the most important aspects of the dependence of relative permeability on the capillary number with a limited number of parameters. The function can be used for the interpolation of Corey coefficients as well as of integral relative permeability curves.
P. 661
Compositional Grading in the Ghawar Khuff Reservoirs
Authors: Temeng K.O. , Al-Sadeg M.J. , Al-Mulhim W.A. 
Published: December 2007

Abstract
The paper presents the results of a study to investigate the variation of gas composition and key PVT properties with depth in the Khuff carbonate reservoirs of the Ghawar field in Saudi Arabia. The study was performed as part of a larger effort to characterize the reservoir fluids for compositional simulation and development planning. Laboratory PVT reports on over twenty appraisal wells were used as a basis for the study.
It was found that both condensate content and hydrocarbon compositions decreased with depth and/or temperature while acid gas composition increase with depth. The composition of hydrogen sulfide varied from zero, at a threshold depth and temperature, to over five mole percent at greater depths. The observed variations of composition with depth were contrary to what would be expected from gravity-chemical equilibrium considerations.
We propose that the dominant process for compositional grading in the Khuff is the generation of hydrogen sulfide by thermo-chemical reduction of sulfate. This process is believed to occur at temperatures above a threshold value (about 270 0F for the Ghawar Khuff), and utilizes hydrocarbons as one group of reactants. Thus, as is shown in the paper, hydrogen sulfide composition increases with depth at the expense of hydrocarbons in a way that upsets the effect of gravity- chemical equilibrium.
P. 685
Targeting of New Wells Through an Integrated Characterisation of the Basement Reservoir in Zeit Bay Field
Authors: Kamal Mohamed , Ismail F. , Fattah Kh. A. , Khairy M. , Sayouh M.H. 
Published: December 2007

Abstract
The Zeit Bay field consists of sedimentary reservoir units partially overlying a tilted block of fractured basement reservoir. The field has a complex combination drive mechanisms including a secondary scheme of gas re-injection into the original gas cap. One of the major problems was to define the fracture pattern of the reservoir. The main objective of this paper is to present a method of integrating multidisciplinary data to determine and characterise the fracture pattern along the basement rock. A relationship between the fracture pattern and producing zones identified from the production log interpretation was established. Better definition of the fracture pattern improves the well trajectory in order to intersect more fractures for optimum sweep. An extensive fracture analysis was performed using fracview data from FMS (Formation Micro Scanner) in four wells. The obtained data were insufficient for the fracture characterisation across the field. A relationship between fracview data and conventional log data was derived. This relationship was applied to predict fracture porosity in the 22 remaining wells (without FMS). The prediction of cut off parameters (effective and fracture porosity) was improved by detailed cornparative analysis of logs, well tests, and production data. Geological analysis of the basement reservoir were performed and integrated with the analysis of basement surface outcrops at Gebel El Zeit, which exhibited well-defined fracture and joint network to the main Gulf of Suez trend. Maps of reservoir properties were generated and compared to the trends observed on the production data maps. The understanding of the reservoir using this integrated approach successfully helped to target new wells in the basement reservoir.
P. 699
Fieldwide Integrated Waterflood Development of a Complex Paralic Clastic Reservoir, Upper Burgan Formation, North Kuwait
Authors: Abdullah F. , Conway P.I. , Wethington W.B. , Morrison N.H. , Al Saig T. , Nemaflallah M. , Al Eidan A. , Al Qabandi S. 
Published: December 2007

Abstract
The Upper Burgan reservoir is a major productive interval in both the Raudhafain and Sabiriyah fields, located in Northern Kuwait. A fivefold increase in production is planned from this reservoir through the implementation of a fleIdwide watefflood development plan.
Dynamic reservoir performance data has been combined with sedimentological studies and 3D geological modelling to evaluate the dynamic complexity of the reservoir during the depletion phase. Due to limited aquifer support, a frill field waterflood development plan is to be implemented, with seawater injection scheduled to commence in 1999. The evaluation and understanding of key dynamic reservoir parameters such as productivity, injectivity and connectivity have been shown to be of critical importance in the planning of the waterflood project.
Although waterflood development will initially commence with a peripheral waterflood scheme on Raudhatain, it is expected that the ultimate development will constitute a patterntlood of both reservoirs, in common with analogue complex paralic clastic systems. The Raudhatain and Sabiriyah waterflood development plan therefore places much emphasis on flexibility and cost optimisation. Integration of this development with that of the larger, shallower Mauddud carbonate reservoir has been identified by alignment of the associated waterflood grids such that each well location may be an injection or offlake point for both reservoirs. Grid alignment provides maximum flexibility to each reservoir, accelerates drilling in the Upper Burgan, and reduces ultimate drilling expenditure by as much as 80 wells. In essence, the Upper Burgan reservoir is developed for the incremental cost of a dual wellhead, packer and additional tubing string.
P. 727
Determination of Geostatistical Parameters Using Well Test Data
Authors: Gautier Yann , Noetinger Benoit 
Published: December 2007

Abstract
We have set up a general framework to obtain estimations of the geostatistical parameters (GP) such as the correlation length, lc and permeability variance, ln from well test data. Most often, in practical studies, the GP are estimated using geological and petrophysical data, but in a lot of cases, these data are too scarce to give high confidence results.
The method was tested using synthetic well-test data performed on some training images, and correct estimations of the underlying correlation length, lc and permeability variance, ln were recovered. Once the GP are estimated, other well established techniques can be used to get well-test matched reservoir images consistent with the geostatistical model. In practical applications, excellent well test data are needed, and the method should be improved using multiple well test data.
P. 669
An Assessment of Lateral Variability of Geological Parameters Using Modal and Geostatistical Analysis of Outcrop Analog
Authors: Misra Debasmita , Schatzinger Richard A. , Cil Murat , Wheeler John R. , Fite M. Jill 
Published: December 2007

Abstract
Spatial variations in petrophysical properties have been described for interwell scale outcrop analogs to subsurface reservoir facies in the marginal marine upper Almond formation near Rock Springs, Wyoming. The objective of this study was to determine interwell scale lateral trends in heterogeneity that can be translated to nearby analogous reservoirs.
More than 1,600 one-inch diameter plugs were collected for petrophysical analysis from outcropping tidal delta, tidal channel and foreshore facies. These facies comprise reservoir quality sandstones in the Greater Green River Basin east of the Rock Springs Uplift. Modal analysis of 78 thin sections provided compositional and packing parameters.
Porosity loss in outcrop and near-outcrop tidal channel sandstones was due to both compaction (COPL) and cementation (CEPL), whereas porosity loss in tidal delta and shoreface sands was dominated by compaction. For all three facies a correlation can be found between increased intergranular volume (IGV), carbonate cements and CEPL if petrographic and petrophysical properties are first sorted according to IGV. In contrast, increased IGV correlates negatively with porosity, COPL, grain contact index, compaction index, and relative amount of lithics.
Geostatistical analysis of the petrophysical data was undertaken to determine its distribution structure, characterize lateral continuity and predictability within this system. Samples from equivalent facies at different geographic locations show geostatistical continuity although they were often found to be statistically dissimilar. Results of geostatistical analysis, therefore, are representative of the internal architecture of the facies studied. Although the statistics of reservoir properties are geographically variable, the data can be used in a predictive sense because it is geostatistically consistent in terms of variance and continuity of parameters. Geostatistical trends interpreted from the variogram analysis were imposed by ordered internal facies architecture. For our data set, oscillations beyond the variogram range could be related to the distribution of bed set boundaries.
P. 683
From Well Data to 3D Models: Determination of the Critical Path in the Process of Characterization of Reservoirs
Authors: Rolando J.-P. 
Published: December 2007

Abstract
At any stage of hydrocarbon field life, well data is obviously the key parameter to build realistic 3D models of reservoir properties.
Usually, reservoir models are built based on available data although it is not necessarily the optimum data for the field to be modelled. The key heterogeneity, that drives flows in the reservoir, may not have been extensively characterized by available data.
The objective of this paper is to propose an approach that takes into account the geological heterogeneity early on during the study in order to anticipate appraisal requirements and optimize rock-type distribution in reservoir models. In fact, it consists of finding the critical path: a better characterization and a more rapid diagnosis.
The method is illustrated based on various examples. It differs depending on whether the reservoir is still in the appraisal phase or already in production. Similarly, tools and techniques to be used are different according to the type of geological heterogeneity: sandy clastic reservoirs, fractured/karstified reservoirs, mixed reservoirs (clastics and carbonates, clastics and fractures)… In each case, different types of data are needed to characterize key heterogeneity. The diagnosis made on the cases given in the examples shows that an optimum interpretation is achieved when data is representative of the sampled medium.
P. 711
3D Modeling form Seismic to Fluid Flow Simulation: A Case Study
Authors: Samson P. , Casaux J.-M. , Cavailles B. , Larribau E. , Morandini F. , Biondi P. , Calassou S. , Janodet D. , Chautru J.-M. , Legrand X. , Fainaud J.-F. 
Published: December 2007

Abstract
The benefit of a 3D Modeling chain in Exploration Production is demonstrated on a real case study. It consists in constructing a Shared Earth Model integrating data and interpretation from geophysicists, geologists and reservoir engineers. Fast and easy updating of consistent 3D information is a key aspect. The shared earth model is the integration of the following speciality models:3D Structural Model3D Sedimentary Model3D Reservoir Model
As it contains all reservoir data, it is the reference model for:–Integrating new data–Integrating analysis form structural unfolding, foward sedimentary modeling,…–Checking new or alternative interpretations–Uncertainties–. . .
This case study highlights that a consistent model can only be achieved through a full 3D interdisciplinary team work.
P. 741
Combined Magnetic Resonance Relaxation and Imaging for Quantitative Determination of Matrix and Vugular Porosity in Carbonate Cores
Authors: Borgia G.C. , Bortolotti V. , Fantazzini P. 
Published: December 2007

Abstract
A method is presented to characterize the internal structure of full-size carbonate cores by combining nuclear magnetic resonance relaxation and imaging techniques (Relaxation-Tomography, RT). In addition to usual imaging techniques, a method for obtaining images as relaxation time maps was developed. An operational definition of matrix porosity based on the RT technique is presented, which has the advantage of taking into account the pore connectivity and which therefore seems to be useful in describing the flow properties of the rock. Several internal images were obtained as H nuclei density and relaxation time maps on a set of vugular and microporous carbonate cores saturated with water. From RT maps the histograms of relaxation times of selected internal regions of interest can be obtained. Reference measurements on smaller samples were performed by means of a specialized NMR relaxometer, and the reliability of the distributions of relaxation times from RT maps was confirmed. The matrix porosity was determined by combining voxel by voxel information from porosity and relaxation time maps. This investigation was performed on some meters of cores in all. In the samples examined, all from the same outcropping reservoir, the matrix porosity averages about 30% of the total porosity, with a threshold for the matrix pore space of the order of a micron or a few microns. The results indicate this approach to be a very promising technique for obtaining, among other things, basic structural information on undisturbed full-size cores. The advantages are twofold. On one hand, this technique furnishes a cost- and time-saving method of work. On the other, there are technical advantages of specificity to the phenomena involved and also the ability to select isolated regions of interest within a core. This method can be useful when it is necessary or convenient to investigate some internal parts of the cores, without any cut or disturbance. Another promising opportunity lies in the possibility of enhancing the knowledge of petrophysical properties by avoiding the effects of the mud-invaded zone of the core.
P. 751
Integrating Static and Dynamics Surveillance Data to Characterize Naturally Fractured Reservoir: A Case study of Baka Oil Field
Authors: Zhang Yonggui , Wu Ying , Ma Xiaojuan , Chen Mingqiang 
Published: December 2007

Abstract
Waterflooding of Baka Oil Field is dominated by natural fractures. Based on core and outcrop observation and fracture identification from logging, the static geological model of fracture distribution has been set up by studying fracture geometry and basic characteristics (orientation, aperture, extent, density, porosity and permeability). The fracture mineralization features and the factors that determine the occurrence of fractures were also studied, which include the degree of folding and/or faulting, in-situ stresses, rock properties and bedding thickness, etc.
Due to small borehole-scale and difficulties to map some factors which determine open and permeable fractures, the static model may not be representative of the large-scale fracture network which will determine reservoir performance, thus dynamics production data are integrated to get a good understanding to fracture's influence. The productivity index of per meter reservoir (Jo, ton/m.MPa.m) is used to characterize natural fractures, For production well, Jo is calculated from dynamic surveillance data directly. But for every injection well, the injectivity index of per meter reservoir (Jw) is estimated from injection data firstly, then Jo is calculated from the Jo/Jw ratio, this ratio is estimated from several actual wells which were switched from production to injection. In order to make the ratio Jo/Jw convincing, further discussion that involve Krw (Sor) / Kro (Swi) was made. Finally geostatistical method was used to distribute the productivity index. The dynamic index map matches the permeability of several wells estimated from well testing very well, and a good explanation about breakthroughs is derived, but some differences from static model still exist.
P. 757
Well Log Characterization of Sediment Porosities in Gas-Hydrate-Bearing Reservoirs
Authors: Collett T.S. 
Published: December 2007

Abstract
With growing interest in natural gas hydrates, it is becoming increasingly important to be able to determine the volume of gas hydrate and included gas within natural gas hydrate accumulations. Gas volumes that may be attributed to gas hydrates are dependent on a number of reservoir parameters, one of the most difficult reservoir parameters to determine is porosity. Well logs often serve as a source of porosity data; however, well-log calculations within gas-hydrate-bearing intervals are subject to error. The well-logging devices that show the greatest promise of yielding gas hydrate reservoir porosities are the gamma-gamma density and neutron porosity logs. Well log response modeling has revealed that under most conditions, the bulk-density of a water-bearing sedimentary section is almost identical to the bulk-density of a gas-hydrate-bearing sedimentary section as measured by a gamma-gamma density logging tool. At relatively high porosities (O&gt;40%) and gas-hydrate saturations (Sh&gt;50%), however, the downhole log derived bulk-density porosities need to be corrected for the presence of gas hydrate. A neutron well-log response computer simulator, SNUPAR, has been used to calculate nuclear transport and capture parameters for various gas-hydrate-bearing reservoirs. The calculated thermal neutron capture cross section of various hypothetical gas-hydrate-bearing reservoirs indicates that methane hydrate has little effect on neutron porosity measurements within "normal" reservoir conditions (O&lt;40%) and low gas-hydrate saturations (Sh&lt;50%). Within this study, density porosity and neutron porosity nomographs have been developed with which it is possible to correct for the effect of high gas-hydrate saturations on the log derived porosities. In the field verification phase of this study, downhole density and neutron porosity log data (in some cases corrected for the presence of gas hydrate) have yielded accurate porosities for gas-hydrate-bearing reservoirs on the North Slope of Alaska.
P. 765