bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrocarbon Liquid Phase Definition, Determination and Allocation in Two-Phase Hydrocarbon Reservoirs
Authors: Hamoodi A. N. , Babajan S. A. W. , Desouki A. H. , Ruffier-Meray V. , Pina A. 
Published: December 2007

Abstract
Identification of the produced hydrocarbon liquid stream, as either oil or condensate, in two-phase hydrocarbon reservoirs, gains special significance in cases where the gas cap and its associated condensate owners are different from the oil rim owners. Thus, the definition of the produced hydrocarbon liquid stream is critical in determining the allocation of the produced liquid phase and accounting for the volumes of oil and condensate produced to satisfy marketing constraints. In this paper we will discuss classification procedures of the produced hydrocarbon liquid stream, laboratory sampling and analysis, and compositional modeling demonstrated for a saturated oil reservoir with a large gas cap and a critical fluid reservoir.
Field Testing and Study of Horizontal Water Injectors in Increasing Ultimate Recovery from a Reservoir in Thamama Formation in a Peripheral Water Injection Scheme in a Giant Carbonate Reservoir, United Arab Emirates
Authors: Cunningham A. Bryce , Chaliha P. R. 
Published: December 2007

Abstract
Development trials of peripheral horizontal injectors were performed in an attempt to establish waterflood sweep within the low permeability lower half of a Thamama reservoir. This paper describes the performance of the horizontal injectors, as well as a time lapse formation tester interference test between a horizontal injector and open hole observation well, spaced 100 meter apart. The test was designed to measure the distance it takes water from the horizontal injector to break through into the high permeability upper half of the reservoir.
Interpretation of the results show that water from horizontal injectors moves vertically out of zone within 100 meters of the injection point, and is not contained within the lower half of the reservoir. Full field simulation after history matching the interference test results shows small increase in vertical and areal sweep efficiency resulting from utilization of horizontal injectors. Radioactive tracer injected into a horizontal injector in the lower part of the reservoir migrated upward into the upper part and traveled up dip 1km to an observation well within 3 years, traveling more than 3 feet per day.
While use of horizontal producers has been identified as the primary method for increasing recovery from the lower part of this Thamama reservoir, the benefits of horizontal injectors over vertical injectors is small. Horizontal injectors can only be justified when costs of adding a horizontal tail to a newly drilled injector is equally small. High recompletion costs of converting existing peripheral vertical injectors to horizontal injectors through sidetracking is not justifiable, or economic.
Fluid Characterisation for Gas Injection Study using Equilibrium Contact Mixing
Authors: Takahashi Koh , Fevang Øivind , Whitson Curtis H. 
Published: December 2007

Abstract
This paper describes the development of an equation of state (EOS) for a gas injection simulation study of a compositionally-grading near-critical oil reservoir. As the number of initial oil sample was limited and no gas-cap gas compositional data was available, the equilibrium contact mixing (ECM) test was used to (a) help tune the EOS to nearcritical phase equilibrium existing at the near-critical gas-oil contact, and (b) to estimate the initial gas-cap PVT properties. Available standard depletion type PVT data, multi-contact swelling test data, slim tube test data and ECM data were used in the development of the full-fluid "detailed" EOS using 16 components. Characterisation of the C7+ fraction together with regression of EOS parameters was carried out to tune the fluid model to match all available measured PVT data. Isothermal compositional gradient calculations were performed for all available samples and then a sample was selected to best represent the most important measured properties such as saturation pressure, saturated density and the compositional gradients in the reservoir. Equilibrium contact mixing data provide key gas-cap gas properties and vapour/liquid phase equilibria data for developing the EOS, also important for studying near-miscible gas injection processes.
Log-Derived Permeability in a Heterogeneous Carbonate Reservoir of Middle East, Abu Dhabi, Using Artificial Neural Network
Authors: Badarinadh V. , Suryanarayana K. , Youssef Fahd Zaki , Sahouh Khalid , Valle Antonio 
Published: December 2007

Abstract
Estimation of permeability in carbonates has been a challenge for many years. Well logs, particularly high-resolution logs, are influenced by rock properties. Therefore, when there is limited core coverage and scarce high-resolution log data, permeability estimation using the standard suite of logs (resistivity, density, neutron, caliper, gamma ray) is crucial for populating and constraining a 3D geological permeability model.
Two new traces, the deep and micro resistivity activity traces, are derived from the corresponding resistivity logs. The activity traces are not affected by fluid effects and, thus, preserve better the formation characteristics. Permeability estimation using an artificial neural network approach is made through a two-step process. In the first step, probabilities of log-derived rock types are estimated from a trained neural network using the micro and deep resistivity activity traces, and the standard suite of logs as input. In the second step, a separately trained neural network uses rock type probabilities from step 1, along with a suite of logs to predict permeability.
Two examples are provided to illustrate the validity of the method in predicting permeability in a heterogeneous carbonate reservoir located in Abu Dhabi, UAE. This reservoir exhibits permeability ranging from half a milli-Darcy to more than 20 Darcies. The first example represents a blind test where the estimated permeability shows good agreement with core permeability data. The second example demonstrates the predictive capability of the method in a non-cored well that is located in the vicinity of cored wells. The estimation technique is robust and was found valuable to supplement core data in the construction of geo-cellular permeability models.
Static and Dynamic Characterization of Fracture Pattern in the Upper Jurassic Reservoirs of an Offshore Abu Dhabi Field: From Well Data to Full Field Modeling
Authors: Gauthier B. D. M. , Auzias V. , Garcia M. , Chiapello E. 
Published: December 2007

Abstract
In the oil bearing reservoirs of a mature field in the offshore Abu Dhabi, the understanding of the fracture network is essential with growing gas and water productions. Fracture characterization and modeling at the full field scale is the key to match the production profile and to optimize infill drilling.
The interpretation of fracture data from image logs and cores allows defining accurately the fracture pattern in terms of orientation, typology, density and relation with lithology and faulting. Two main fracture sets are chronologically observed: (i) NW-SE fractures are generally mineralized and clustered around faults of similar orientations; (ii) NE-SW fractures are generally open, homogeneously distributed with their density controlled by the lithology and a few portion located in swarms.
The calibration of fracture data with PLT's in horizontal drains suggests that: (i) the main flow comes from the matrix in porous layers; (ii) in areas without mineralized fractures, wells can be connected to water, either through matrix (permeable layers) or through open NE-SW fractures, particularly in zones of large curvature where a higher fracture density is expected; (iii)in areas with mineralized fractures, water in permeable layers is channelized and tight layers can be vertically connected to more permeable layers by open fractures whereas the lateral flow can be hampered.
Full field fracture modeling is done through an innovative geostatistical approach. First, discriminant analysis is used to derive, from geological attributes that are known to be physically related to fracturing, a (geological) component best correlated to well fracture data. Second, sequential indicator simulation generates equiprobable fracture density maps. Third, optimization of infill drilling is made through risk analysis.
The pertinence of this approach for the optimization of well planning is validated against recently drilled wells. Matching the production profile is made more difficult however by the different opening times of production wells and by their complex completions.
"New Insights From Old Data": Identification of Rock Types and Permeability Prediction Within a Heterogeneous Carbonate Reservoir Using Diplog and Openhole Log Data
Authors: Aplin Graham F. , Dawans Jean-Michel L. , Sapru Ajay K. 
Published: December 2007

Abstract
Diplog and openhole log data has been used to predict reservoir rock type and permeability distribution within a heterogeneous Thamama Group reservoir from a field in the UAE. Porosities within the reservoir are fairly constant, but permeabilities vary by several orders of magnitude for a given porosity, reflecting variations in primary depositional facies and to a lesser extent diagenesis. The reservoir is characterised by common thin vuggy bioclastic-rich facies that form high permeability streaks and tight cemented intervals that are below the resolution of standard openhole logs. The higher resolution of the diplog tool allows the distribution of these thin units to be established.
The diplog data has been processed using the same techniques applied to modern image logs and a series of false colour pseudo-images generated. A diplog facies scheme was established based on the diplog pseudo-images, diplog microresistivity curve response, microresistivity curve activity, and openhole log response, which were calibrated using core. The diplog facies are grouped into a series of diplog rock types (DRT) based on their petrophysical properties and open hole log characteristics. These DRT can be directly related to core-based petrophysically defined reservoir rock types. Each DRT is assigned a permeability range based on statistical analysis of cored wells and then used to provide an estimate of permeability distribution and heterogeneity within uncored wells. Comparison of the diplog rock types with conventional core analysis and miniperm results from a series of ‘blind’ tests indicates that there is a good relationship between DRT and permeability, which shows a broad agreement with the detailed rock typing undertaken on core.
This study demonstrates the value of revisiting old data, and that where diplog data is calibrated with core data, meaningful geological interpretations can be made and provide a valuable input to reservoir characterisation in heterogeneous reservoirs.
Experimental Determination of Elastic Anisotropy and Biot's Constant in a Saudi Arabian Reservoir Sandstone
Authors: Azeemuddin M. , Khan K. , Khan M. N. , Abdulraheem A. , Rahim Minerals, Z. , Al-Qahtani M. Y. 
Published: December 2007

Abstract
Rock mechanical triaxial and hydrostatic tests were conducted on 1.5-inch diameter sandstone samples obtained from four wells. A total of 23 different depth intervals were tested, at pressures representing the in-situ reservoir conditions. Static elastic moduli (Young's modulus and Poisson's ratio) and static Biot's constant were determined from the results of the triaxial tests. Dynamic elastic constants of selected rock samples were determined from ultrasonic compressional and shear wave transmission data obtained under hydrostatic stress conditions through vertical, horizontal and 45-degree-oriented samples. Porosity and permeability measurements were also made on corresponding sister samples.
Wave velocities and the computed dynamic moduli indicated the existence of stress-induced elastic anisotropy, which was found to decrease with increasing confining pressure. Biot's constant values in planes parallel and perpendicular to the bedding were found to be nearly the same, indicating that the anisotropy in the wave velocities and dynamic elastic moduli does not translate directly into anisotropy in the Biot's constant. However, the Biot's constant in both planes decreased significantly with hydrostatic stress, indicating a stress-dependency.
The static Biot's constant obtained from triaxial tests also decreased with increase in axial stress, demonstrating a significant axial stress-dependency as well. The results were found to be in general agreement with the literature.
A Case History 3D OBC Seismic Data Acquisition Over a Giant Oil-Field Offshore Abu Dhabi
Authors: Lilley G. , Belaid K. , Hagiwara H. , Najia W. , Ebed A. , Usher L. 
Published: December 2007

Abstract
Fifteen hundred square kilometers of the 3D OBC Seismic Survey was acquired, over an 18-month period in 2000 and 2001, as a joint Venture between ADNOC, ADMA-OPCO and ZADCO. The seismic acquisition contractor was Petroleum Geo-Services (PGS).
This paper concentrates on some of the Operational, Quality & HSE aspects and the many challenges faced in acquiring such a highly specified orthogonal OBC survey (in excess of 300 fold) over a very active field which is extremely densely populated with infrastructure and partly located over very shallow water.
The field has hundreds of well head towers (jackets), huge super complexes, satellite platforms and many hundreds of kilometers of criss-crossing, untrenched oil, gas and water pipe-lines. Areas of dense coral pinnacles and other field debris exist. Water depths less than 5m were measured but even these depths were effectively reduced in many areas by the presence of the hazards.
Fault and Fracture Characterization Using 3D Interval Pressure Transient Tests
Authors: Zeybek M. , Kuchuk F. J. , Hafez H. 
Published: December 2007

Abstract
Permeability is one of the most important parameters that affects almost all phases of reservoir management and well performance. It is considered to be the most basic formation property and a tensor (directional dependence). As stated well by Weber1 in 1986: "Reservoir heterogeneity is among the major reasons why enhanced oil recovery is so difficult. Projects undertaken without detail reservoir evaluation often end in failures related to unexpected baffles to flow, permeability heterogeneity, or wrong appreciation of the residual oil distribution." Fractures and faults can behave as barriers, baffles, or open channels to fluid flow in the reservoir and often cause early water breakthrough, gas channeling, etc. that are costly.
In this paper, we use 3D interval pressure transient tests to estimate horizontal and vertical permeabilities and to delineate of fracture and fault conductivities. 3D interval pressure transient tests are conducted using the wireline conveyed dual-inflatable-packer module with multiple observation probes that can be set along the wellbore a number of times as the number of fracture and fault zones require. The dual-packer, with one meter open interval is set against the borehole wall to hydraulically isolate the tested section from the rest of the wellbore. In this set up, the dual-packer open interval encircles fractured and/or faulted zones. The formation fluid is produced through the isolated packer interval for more than a few hours, after which a pressure buildup test takes place. For the interval tests, the observation probes are usually mounted above and/or below the packer module. These probes measure pressure changes due production from the open interval at different locations in the formation.
For the interpretation of each interval test, first we use the well-known flow regime identification methods of pressure transient testing. After the flow regime identification and analysis, we use a computationally efficient optimization algorithm that allows simultaneous nonlinear parameter estimation of the unknown parameters (horizontal and vertical permeabilities and fracture and fault conductivities) from 3D transient pressure measurements that are spatially distributed. For this nonlinear estimation or history matching, a detailed reservoir model is constructed by incorporating to all geological and well openhole log data, particularly resistivity images that are crucial for identifying, testing, and modeling faults and fractures. During the minimization process, the reservoir model and its parameters are updated as all pressure measurements are matched with the model behavior. This process is continued until a satisfactory match is obtained for all 3D transient pressure tests.
Two examples (one synthetic and one actual field data) are presented to demonstrate the application of the methodology.
3-D Image Processing Techniques Applied to Carbonate Reservoirs and Structures
Authors: Massaferro Jose Luis , Bourne Ruth , Jauffred Jean Claude 
Published: December 2007

Abstract
Conventional 3-D seismic mapping is not an ideal predictive method when attempting to characterise carbonate reservoirs due mainly to the complexity and heterogeneity of carbonate systems. In carbonates, the combined effect of variations in depositional facies and diagenetic alterations plays a key role in controlling variations in sonic velocities and thus in acoustic impedance. As seismic facies are delineated by acoustic impedance contrasts, the depositional facies may be rather poorly defined for various carbonates environments (e.g. shallow-water platform carbonates). Accurate 3-D imaging of seismic facies and geometries is critical to construct a realistic, seismically constrained reservoir model 3D image-processing techniques of stacked and migrated data incorporate all three dimensions, which when combined help to identify/highlight events of significance in the data. The result is an attribute cube or volume that can be analysed and interpreted more objectively by the interpreter than the conventional horizon-based interpretation. We have applied various 3-D image-processing techniques to produce filtered seismic reflectivity data and volume attributes to better visualise and delineate seismic facies, geometries and the structure of heterogeneous carbonate reservoirs. Image filtering techniques were applied to improve signal-to-noise ratios and to suppress random noise to obtain a better reflection definition. Combined volume dip and azimuth was calculated from the seismic cubes to detect subtle stratigraphic features such as low-angle progradation units and shoal-type mounded seismic facies in the Permian Khuff and Upper Cretaceous Natih E reservoirs. Semblance volumes were used to highlight reflection terminations and helped to distinguish between stratigraphic and structural features. Texture mapping was applied to 3-D attribute-generated volumes to extract different seismic facies and properties, which can be related to potential good reservoir zones in the Malampaya field. 3D visualisation tools were used to image both horizons and faults of a complex inverted structure of a deep Upper Cretaceous lacustrine carbonate reservoir in the Yacoraite Fm. Argentina. Seismic facies and geometries interpreted from the attribute analyses, combined with interpretation of the original seismic and core/log data, allowed us to construct robust structural and depositional models of carbonate environments that were used as input for static reservoir models.
3D Visualisation for Seismic Processing
Authors: Ellis David 
Published: December 2007

Summary
Seismic data can now be interpreted in great detail. Interpreters employ highly sophisticated systems that facilitate visualisation and interaction with 3D datasets. In contrast processors do not routinely analyse seismic data using the same tools as the interpreter. This is an unhealthy state of affairs – processors may be unaware of features in the data that are significant in terms of exploration or development; interpreters may identify problems in datasets that were invisible to processors.
3D visualisation and interpretation technology offers the opportunity to make a step change to key tasks performed in seismic data processing, for example first-break picking and velocity analysis. Potentially processors could benefit from the same orders of magnitude increase in productivity and attention to detail as interpreters have enjoyed over the last two decades.
Reservoir Management of a Giant Lower Burgan Reservoir in North Kuwait – Reservoir Monitoring and Production Enhancement by Innovative Tracking of Bypassed Oil and Time-Lapsed Data Integration
Authors: Chetri Hom B. , Khan Ali Nasar , Al-Ajmi Moudi F. , Srivastava Sanjeev , Al-Anzi Ealian , Al-Hajeri Mubarak 
Published: December 2007

Abstract
Lower Burgan reservoir is a giant multi layered reservoir in Sabiriyah field of North Kuwait operating under active bottom water drive as well as edge water drive. The reservoir is on production since 1960s and has so far produced about 63% of the original reserves. The effective reservoir management by innovative tracking of water movement, identifying segments with bypassed oil, opportunistic well workovers, prudent selection of infill well targets and continuous reservoir monitoring have made it possible to sustain the reservoir production rate near to the projected plateau and carry it forward for next 4-5 years.
The lower Burgan reservoir comprises predominantly channelised facies, which impact a high degree of heterogeneity to the reservoir. The massive M sand produces through a vertical sweep of aquifer whereas the interbedded L sand experiences largely lateral edge water sweep. The key of the reservoir/production management from this reservoir has been to monitor the water encroachment pattern and track the bypassed oil. The primary tool for tracking water movement & bypassed oil has been thermal neutron decay logs (Schlumberger TDT and Western Atlas PDK logs). These logs have provided excellent data for mapping water movement in lower burgan reservoir due to the high formation salinities and generally high porosities. The data was holistically analyzed in conjunction with time lapsed PLT and well test data. The information on identification of pressure regimes and vertical connectivity available from RFT data from recent penetrations added further confidence to the interpreted results.
A prudent strategy to acquire static bottom hole pressure measurements and PBU tests was developed so as to have the layer wise characterization and optimize the perforation planning. The event based well tests in key wells periodically led to deliverability optimization. The fluid characterization for each flow unit helped to refine the assessment of well performance vis-à-vis the completion. Innovative approach to estimate the sweep/ recovery efficiency and residual oil saturation by analytical methods proved useful to fine-tune the ranges of expectations.
Simulation models were made in 1980s and mid 1995 which are under revision at present. The model is likely to help the field engineers to manage this giant reservoir more effectively and efficiently on long term basis.