bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Integrated 3D-Fracture Modeling and Flow Simulation Study: A Giant Saudi Arabian Carbonate Reservoir
Authors: Al Qassab Hisham M. , Al Khalifa Mohammad A , Al-Ali Zaki , Ameen Mohammed , Phillips Robert , Hartley Lee 
Published: December 2007

Abstract
An innovative fracture modeling process has been successfully developed and utilized in a giant Saudi Arabian fracture carbonate reservoir. This modeling process constrains the discrete fractures to sets of geologic drivers describing the fracture relationships to reservoir matrix properties such as porosity, lithology and stylolites as well as to structural attributes including faults and curvature. The reservoir has very good matrix permeability, but it is enhanced significantly by faults, fractures and strataform.
The workflow starts with the construction of a stochastic discrete fracture network generated in a given simulation volume by providing the static distribution of all relevant fracture parameters from image and core logs and geologic drivers. The fracture distribution is then validated in wells with the fracture counts from image logs and cores. The fracture counts from the model were found to give a consistent magnitude with the observed fracture counts in core and image logs in more than 70% match.
The fracture network is then translated into fracture properties by incorporating geo-mechanical in-situ stress information including direction, magnitude, and vertical gradient to identify open fracture and to determine the effective fracture aperture. Due to high matrix permeability a representation of the matrix and strataform was incorporated with the fractures to produce a discrete feature model of the combined fracture/matrix system. This is essentially single medium model was used to calibrate against well-test data.
Single flow simulation was then performed for the discrete feature model on each of the cells in the model. The calculated fracture properties include fracture permeability, fracture porosity, and the transfer function (sigma) measuring the interaction between the matrix and the fracture.
The dynamic behavior of the simulated fracture permeability compared well to the Kh from pressure buildup tests. Results were very encouraging, as it appeared that in general, the fracture distribution in the reservoir had been properly described. Moreover, calibration of the fracture parameters such as permeability to match the observed dynamic behavior proved to be an effective way to achieve history match of both pressure and water cut, as was seen from simulation models using both dual porosity dual permeability and single porosity single permeability modeling techniques.
Challenges of Horizontal Drilling with Coiled Tubing in a Depleted, Hard and Abrasive Sandstone in Algeria
Authors: Leslie Charles , Shero Winston , Ortiz Richard , Weihe Axel 
Published: December 2007

Abstract
This paper discusses how the challenge to improve production from a depletedoil field in Algeria was approached using an advanced Coiled Tubing DrillingSystem. The paper covers the planning and implementation of the project anddiscusses lessons learned, results and conclusions.
Reliability Analysis Spanning Whole Well Life
Authors: Hother John A. 
Published: December 2007

Abstract
Reversionary Mode Analysis (RMA) was used to analyse the reliability of the whole life-cycle of a proposed well development, so that the risks associated with different well designs could be quantitatively compared. The technique combines engineering analysis and economic modelling in a systematic and rigorous way. For this project, we needed to extend the economic aspects, to match the level of detail used in the business case economics for this field development.
RMA is an innovative and powerful system analysis technique that has been adapted from its aerospace origins for application in oil and gas projects. The engineering aspects, founded on conventional failure mode analysis methods, were already well developed.
The process started with engineering analysis of the failure modes, determining cause, effect and probability. To ensure proper coverage of the whole life-cycle, RMA handles both activities, defined by process flow diagrams, and equipment defined by system block diagrams. To confirm the validity of the analysis, the estimated probabilities of failure were checked with alternative sources.
Then an economic model was produced, quantifying in financial terms the consequences of a whole range of different types of failure. The analysis software consolidated all the failure mode data with the economic model.
The results in ‘risk-Dollars’ highlighted the aspects that are critical to the project's viability, and provided a good basis for comparing different well options. The rigorous data structure provided the capability to ‘drill-down’ into critical aspects, to identify key causes for which mitigating measures were needed, which may occur at any stage in life-cycle.
Structure and Regional Context of Onshore Fields in Abu Dhabi, UAE
Authors: Johnson Christopher A. , Sattar Mohamed Abdul , Rosell Rafael , Al-Shekaili Fatema , Al-Zaabi Naema , Gombos Andrew 
Published: December 2007

Abstract
High quality 3-D seismic and well data allow detailed structural analysis of the major onshore fields of Abu Dhabi. Most of the large onshore fields were examined for this study. The fields are generally asymmetric anticlines with reservoir units in the Mesozoic section. All are interpreted as deepseated (probably Proterozoic) grabens and half grabens that were gently inverted to various degrees in Late Cretaceous time. The timing, distribution, and geometry of structural relief link trap formation to foreland compression during orogenesis and ophiolite obduction along the Arabian margins, particularly in Oman.
Traps are cut to varying degrees by remarkably regular sets of cross faults that grew as strain developed in more competent units during structural growth. Some traps display welldeveloped conjugate cross faults indicative of NW-SE or WNW-ESE compression. Other traps have only one set of cross faults, indicative of more oblique transpression at an angle to the underlying basement structure. On 2-D seismic data the cross faults are quite linear and often appear to cut the entire structure for distances of several kilometers. However, 3-D data reveals that the faults are actually fault zones composed of arrays of smaller en echelon faults. These observations indicate oblique offset and show that the fault zones can be interpreted as conjugate shears. Some of the faults are detached, limited stratigraphically, and their vertical offset diminishes from 10's of meters near structural culminations to zero off structure. If true for the majority of faults, this would indicate an origin related to internal strain within the fold, not a major, through-going basement shear zone. However, some faults may not terminate at the structural limbs, but instead could extend much further off structure. This, combined with possible evidence for basement involvement, would support a regional shear or wrench model. Ongoing interpretation is focused on deciding which of these models is appropriate.
The cross faults can influence fluid flow and are thus of interest from a trap segmentation and production perspective. In general, steps and relays between fault segments allow diminished fluid communication across the fault zones, but do not completely partition the reservoirs into compartments.
Analysis of Bed Height in Horizontal and Highly-Inclined Wellbores by Using Artificial Neural Networks
Authors: Ozbayoglu Evren M. , Miska Stefan Z. , Reed Troy , Takach Nicholas 
Published: December 2007

Abstract
Knowing the amount of cuttings that accumulate inside horizontal and highly-inclined wellbores is part of the information that is essential for controlling bottom-hole pressure, preventing stuck pipe, minimizing the circulation time for cleaning the wellbore, etc.
A dimensional analysis is conducted using basic drilling information such as pump rates, fluid densities and viscosity, drilling rate, and wellbore geometry. By using these drilling variables, three dimensionless groups (Reynolds Number, Froude Number and cuttings concentration at the bit) are developed for estimating the height of stationary cuttings beds deposited in horizontal and highly-inclined wellbores for a wide range of drilling fluids, including foams and compressible drilling fluids for underbalanced drilling.
A series of cuttings transport tests were conducted within the annular test section of Tulsa University's Low- Pressure/Ambient-Temperature Flow Loop. The test fluids included water, polymer muds and foam with a wide range of pump rates and rates of cuttings injection. The experimental data are used to develop two different models. The first model is a traditional least-squares fit of the dimensionless groups to the data. The result is an equation with four empirical constants. This equation calculates bed heights that are within 15% of measurements for all fluids. One of the disadvantages of this traditional approach is that different correlations are needed for different flow regimes, e.g., turbulent flow requires a correlation that is different from one for laminar flow.
The second model is an Artificial Neural Network (ANN) program that uses the same dimensionless groups but has been "trained" by using the test data. The ANN model predicts bed heights with an error of less than 10% over the entire range of measured data. One of the advantages of the ANN model is that it can accommodate data from all flow regimes and provide equally good results. It can also be more easily extended to include other effects such as drillstring rotation.
Application and Comparison of Two Models of Foamy Oil Behavior of Long Core Depletion Experiments
Authors: Bayon Y. M. , Coates R. M. , Lillico D. A. , Cordelier Ph. R. , Sawatzky R. P. 
Published: December 2007

Abstract
The behavior of gas in foamy oil is one of the key factors for the heavy-oil solution-gas-drive process. Due to the high viscosity of the oil, and the interaction between capillary pressure and viscous forces, the depressurization of live heavy oil below the bubble point causes bubbles of gas to nucleate, grow, cluster, and eventually connect into a free phase.
In this paper, two models aimed at simulating foamy oil behavior are described and compared. One model partitions the gas into three groups (solution gas, dispersed gas, and free gas), while the other distinguishes four groups (including two types of dispersed gas). In the first model, two kinetic equations for mass transfer are defined to describe how one group of gas is transformed into another, while in the second model six kinetic equations for mass transfer are proposed. Each model defines in an original way the mobility of the gas groups, which leads to different relative permeability models.
Both models were applied to two sets of long core depletion experiments with significantly different depletion rates. A comparison of the matched results from the two models is presented in this paper.
Improving Project Performance in a Heavy Oil Horizontal Well Project in the San Joaquin Valley, California
Authors: Cline Veronica J. , Basham Michael 
Published: December 2007

Abstract
The Tulare Steeply Dipping Horizontal Well Project is a multi-year project that is designed to recover oil by steamflooding the Tulare and Amnicola sands in the Cymric and McKittrick fields in the San Joaquin Valley, California utilizing horizontal producers and associated vertical steam injectors. The scope of the project includes ~79 horizontal wells, associated vertical injectors and surface facilities, using a staged-development for a multi-year drilling program. The average horizontal well produces about 100-250 BOPD in comparison to an average vertical well in the reservoir that makes approximately 30 BOPD. Throughout the early phases of the project, the multi-disciplinary team gained insight into improving the design and implementation of the project. Several improvement areas were identified to reduce drilling costs and enhance early oil production, which resulted in improved project economics.
The first stage of development drilled in 1997-98 included eleven horizontal wells. Although these wells demonstrated good productivity and the viability of applying horizontal producers in these fields, the overall economics were poor, partly due to high capital costs and a slow production response. During a low price environment, the team took an initiative to identify areas that would reduce costs and optimize operability for future development of the field with horizontal wells.
Some of the changes affecting costs identified were reducing the casing size in both the build and lateral sections of the wellbore, selecting a directional drilling contractor with extensive experience in the area and eliminating LWD. Operational and start-up changes included cyclic steam stimulation of the horizontal wells before placing them on production, maximizing lift, and the use of fiber-optic temperature surveys to understand heat distribution in and near the lateral. Another change later identified before drilling the next set of horizontal wells were to utilize 3-D well path planning tools to iterate plans in real time with the directional drilling contractor to meet geologic and anti-collision parameters. The eight well drilling program in 2000 resulted in a 30% reduction in both the drilling costs compared with the 1997-98 program. As a result of cyclic steaming, the wells averaged between 150-250 BOPD above forecast for the first six months of production. A third stage of development in early 2002 resulted in a 45% reduction in drilling costs relative to the 1997-98 programs.
An Alternative Water Supply for Heavy Oil Steam Generation Plants: Potential Sources of Brackish Water From the Cretaceous Mannville Group in the Cold Lake Region
Authors: Horne Emmett , Stephen Sun , Lee Nichols , Agatonovic Vlad 
Published: December 2007

Abstract
Heavy oil production requires large quantities of freshwater for steam generation. Currently these operations utilize surface water and shallow groundwater for supply. An alternative source of water is the brackish groundwater from basal aquifers which exist in the lower portion of the Mannville Group and below the heavy oil horizons. Hence, the term "basal aquifers" is used to describe these water bearing sediments.
Due to corrosion and precipitation concerns, source water must have acceptable salinity and Total Dissolved Solid (TDS) levels. Salinity and TDS of groundwater can be conveniently estimated from electrical logs using empirical formulae.
CHOPS in Jilin Province, China
Authors: Dusseault Maurice B. , Liang Chun Xiu , Ma Yiqiu , Gu Wu , Xu Baoci 
Published: December 2007

Abstract
Taobao Oilfield has been producing viscous oil (μ = 1850 mPa.s @ 18°C) with sand for several years from a fine-grained reservoir on the west flank of the Songliao Basin in northern Jilin Province, China. The practices used closely follow the approaches developed in Canada in the last 15 years, but production is from a much shallower depth (-160m) and from a field that is fault-controlled and possesses some dip, rather than being stratigraphically controlled. The reservoir is composed of unconsolidated sands with high porosity (~35%) and high permeability (5 Darcy), suggesting a good prospect for CHOPS. The aggregate thickness of the sands is about 15 m with a formation thickness of 28 m; individual layers are 1-6 m thick, with an average of 4 m, substantially thinner than the beds usually exploited in Canada. Over 75% of the oil in place is in layers less than 5 m thick.
The first well started production in Aug 13, 1997. At present, there are 71 wells producing oil in Block 87 and Block 92. A crude oil recirculating system from the stocktank is used to keep oil flowing down the annulus to prevent blockage of the well. Conventional production using progressing cavity pumps is still low, the best wells are only producing approximately 25-30 b/d, but production can apparently be sustained for as long as 16 months.
Taobao Oilfield initiated CHOPS in approximately 22 wells in Blocks Bai 87 and Bai 92. The sand cuts range from 0.1 to 10% by volume, which is a broad range for a single field, compared to Canadian experience. Water cut is very reasonable, from as low as 0% to as high as 52%, with an average of 5-8%.
The article will review the geology and the production history of the Taobao CHOPS project to date. Petrophysical parameters and reservoir properties will be presented and compared to typical Canadian and Venezuelan information. Case histories from existing developments are used to illustrate how technologies developed in Canada have allowed the difficult heavy oil fields to be developed. Finally, the future direction for this CHOPS project is discussed, aiming at improving the oil production rate and the oil recovery. It appears that production gains are possible through improvements in operational practices.
An Example of a Steam Drive Pilot Project Management With 3D Seismic Survey in Northeast Brazil
Authors: da Silveira Cursino Delson Fernando , Mynssen Ferreira Andre Luis , Ferreira Gomes Frederico Aguiar 
Published: December 2007

Abstract
Estreito field contains heavy oil and has been successfully cycled with steam since 1984. The first steam drive pilot was initiated in November 1998 in the standard pattern of the field.
A seismic survey to monitor the steam front was acquired six months after the pilot had begun.
This work intends to present the integration of the pilot results, the seismic survey and the numeric flow simulation as a way to manage a steam drive process.
The paper shows also the importance of 3D seismic activities to support the steam drive management in a large scale, creating possibilities of improvements and optimization.
Optimal 3-D Directional & Horizontal Wells Planning Using Genetic Algorithm
Authors: El-M Shokir E. M. , Emera M. , Eid S. M. , Waly A. A. 
Published: December 2007

Abstract
This paper introduces a new software that uses the genetic algorithm to give the optimum drilling depth of directional & horizontal wells in 3-D. A special penalty function, mutation, crossover probabilities, and a special accuracy of the stopping criterion were used to get the global minimum of the problem. The minimum drilling depth is achieved at the minimum values for kick-point, inclination, and angle build-up and drop-off rates. The minimum parameters reduce the dogleg severity, which in turn reduce the chances for operational problems like high torque and drag. The optimized design has been compared with the conventional design (based on trial and error method) and WELLDES program (based on Sequential Unconstraint minimization Technique) for a well drilled in the Gulf of Suez (application I) and with conventional design for a theoretical well (Application II). Results of the comparison have been validated by genetic algorithm software. The optimization model reduced the total drilling length of the two applications. This was achieved while all other operational parameters were kept within the limiting constraints and casing setting depths were taken into consideration. In contrast, WELLDES program and conventional design have some variables within their constraint limits and the casing setting depths are outside their consideration.
Heavy Oil Rheology as a Function of Asphaltene and Resin Content and Temperature
Authors: Argillier J-F. , Coustet C. , Hénaut I. 
Published: December 2007

Abstract
Because of very important reserves that are of the same order of magnitude than conventional oils, heavy oils represent a strategic source of hydrocarbons. The major difficulty for producing and transporting these crudes comes from their very high viscosities. The success of exploitation of these petroleum products requires new treatments to improve their transport. Such a target implies to better understand the relationship between the composition of heavy oils, in particular in terms of asphaltenes and resins content and their flow properties. Influence of asphaltenes content in the crude has been particularly studied in our lab : the experimental work revealed the existence of a critical concentration C* above which the asphaltenes particles overlapp. This structural change dramatically increases the viscosity and intensifies the elastic character of heavy crude oils. A further series of experiments has focused on the influence of resins: they show that in dilute regime (C&lt;C*), resins increase the viscosity of the crude and in concentrated regime (C&gt;C*), which corresponds to the case of a heavy oil, they lower the asphaltenes effect on viscosity. Experiments were first carried out with asphaltenes and nonylphenol as a model of resins and followed by experimental work on real crude that confirmed the trends. To understand the rheological behavior of a heavy crude oil in relation with its internal structure, asphaltenes and resins have to be simultaneously considered. From this study we conclude that the origin of the high viscosities of heavy oils comes from to the entanglement of solvated asphaltene particles stabilized by resin molecules. A strong influence of temperature on the rheology is also revealed by high activation energy measurements. This thermal dependent rheological behavior shows that the internal organization of the heavy crude oil is partly based on thermal dependent physical bonds. Using the reversibility of these physical links, we should be able to modify the structure of heavy crude oils to facilitate their transport.
Scalability of the Deterministic and Bayesian Approaches to Production Data Integration into Field-Scale Reservoir Models
Authors: Vega Leonardo , Rojas Danny , Datta-Gupta Akhil 
Published: December 2007

Abstract
Current techniques for production data integration into reservoir models can be broadly grouped into two categories: deterministic and Bayesian. The deterministic approach relies on imposing parameter smoothness constraints using spatial derivatives to ensure large-scale changes consistent with the low resolution of the production data. The Bayesian approach is based on prior estimates of model statistics such as parameter covariance and data errors and attempts to generate posterior models consistent with the static and dynamic data. Both approaches have been successful for field-scale applications although the computational costs associated with the two methods can vary widely. This is particularly the case for the Bayesian approach that utilizes a prior covariance matrix that can be large and full. To date, no systematic study has been carried out to examine the scaling properties and relative merits of the methods.
The purpose of this paper is twofold. First, we systematically investigate the scaling of the computational costs for the deterministic and the Bayesian approaches for realistic field-scale applications. Our results indicate that the deterministic approach exhibits a linear increase in the CPU time with model size compared to a quadratic increase for the Bayesian approach. Second, we propose a fast and robust adaptation of the Bayesian formulation that preserves the statistical foundation of the Bayesian method and at the same time has a scaling property similar to that of the deterministic approach. This can lead to orders of magnitude savings in computation time for model sizes greater than 100,000 grid blocks. We demonstrate the power and utility of our proposed method using synthetic examples and a field example from the Goldsmith field, a carbonate reservoir in west Texas.