bluuebunny/crossref_metadata_2025_split huggingface dataset:
REAL-TIME DOWNHOLE DRILLING PROCESS DATA COMPLEMENT SURFACE DATA IN DRILLING OPTIMIZATION
Authors: Robnett E. W. , Heisig G. , McGinley P. J. , Macpherson J. D. 
Published: December 2007

Abstract
In directional drilling, MWD technology is applied to transmit directional and petrophysical data from downhole. In combination with modern directional drilling tools such as rotary steerable systems, MWD technology has enabled the drilling of complex 3D well profiles precisely placed in the reservoir. However, even on these high-tech wells the drilling process itself is still controlled mainly using traditional surface acquired data such as hook load, ROP, RPM etc.
The transmission and utilization of downhole drilling process data in addition to the surface logging data offer a not yet fully explored potential for drilling process optimization, since modern data acquisition technology close to the bit can provide not only more accurate data but also important additional parameters not available at the surface. Examples of value-adding downhole drilling process data are annulus pressure, weight-on-bit, drillstring bending, RPM, bit torque and dynamics diagnostics. Additional drilling process information on drilling hydraulics or drillstring friction can be obtained by feeding drilling engineering algorithms with downhole and surface acquired data.
The paper provides an overview of the available downhole drilling process data and demonstrates with numerous case studies the value that these parameters add. Furthermore, the paper discusses factors constraining the use of the technology and gives an outlook on future developments in drilling process optimization utilizing real-time downhole data.
Simultaneous Stimulations and/or Packing in Multiple Zones. Effective Solutions.
Authors: Romero Jorge L. , Pizzarelli Sergio , Mancini Jimmy 
Published: December 2007

Abstract
This paper describes 12 history cases of the successful applications of Alternate Path (shunt tube) Technology in wells in Bachaquero Lago, Tía Juana Lago and Lagomedio fields, in Lake Maracaibo.
The use of divergent tubes combined with packoff in these wells, allowed to complete two zones in a single trip (stimulation or packing in the superior zone and packing in the inferior zone), reducing the number of pipe trips in each well and therefore, reducing the operational risks and drilling costs. This type of completion will also allow independent isolation in anyone of the zones in the event of watering problems, allowing selective production.
In all the cases, successful gravel packing were achieved as well as 45% saving in drilling time, compared with conventional completion. In all the cases productivity was higher than the initial estimate, without formation sand production, confirming the success of the application.
This technology provides a reliable and profitable alternative for the completion of two or three simultaneous zones.
Using Computational Fluid Dynamics (CFD) Simulation to Model Fluid Motion in Process Vessels on Fixed and Floating Platforms
Authors: Frankiewicz Ted , Lee Chang-Ming 
Published: December 2007

Abstract
Computational Fluid Dynamics (CFD) is a mathematical tool capable of simulating a wide range of fluid flows. Integrated CFD software has been applied to study the flows in two- and three-phase oilfield separators. The influence of inlet nozzle configuration, flow distributors, perforated plates, and outlet nozzles have been studied.
Of particular value has been the ability to simulate wave induced sloshing in vessels mounted on floating platforms. The design and placement of baffles to mitigate liquid sloshing was determined by using CFD to simulate fluid flows in vessels destined for service on floating platforms. The simulations accounted for the movement of the vessel based upon its actual location on the platform and identified the influence of process fluid flows on slosh motion. Where possible, laboratory testing has been used to validate CFD simulation results, leading to increased confidence in the mathematical models.
Crude Oil Emulsions: A State-of-the-Art Review
Authors: Kokal Sunil 
Published: December 2007

Abstract
Formation of emulsions during oil production is a costly problem, both in terms of chemicals used and due to production losses. This paper discusses production and operational problems related to crude oil emulsions, and present a review that will be very useful for practicing engineers.
The first part of this paper presents why emulsions form during oil production, the types of emulsions encountered, and new methods for characterizing them. Crude oil emulsions are stabilized by rigid interfacial films that form a "skin" on water droplets and prevent the droplets from coalescing. The stability of these interfacial films, and hence the stability of the emulsions, depends on a number of factors including the heavy polar material in the crude oil (asphaltenes, resins, waxes, etc), solids (clays, scales, corrosion products, etc), temperature, drop size and drop size distribution, pH, oil and brine composition. These effects on emulsion stability are reviewed.
The second part of this paper presents ways to tackle crude oil emulsions. The focus is on the destabilization of emulsions and the demulsification process. Emulsions are destabilized by increasing temperature and residence time, removal of solids, and controlling emulsifiers. The mechanisms involved in demulsification (flocculation, aggregation, sedimentation, creaming, and coalescence) are discussed in terms of the stability of the interfacial films. The methods involved in demulsification including thermal, mechanical, electrical, and chemical are also presented. Experience and economics determine which methods and to what degree each method is used for emulsion treatment.
Finally, a section on field applications is included that should be useful for the practicing engineer who deals with emulsions, either regularly or on a limited basis. Herein the field emulsion treatment program is discussed, and more importantly, methods to prevent emulsion problems are highlighted. Recommendations are made for reducing and optimizing demulsifier dosage and controlling emulsion problems.
Thermal Desorption as an Alternative to Cutting Reinjection in Niger Delta Waste Management Operations
Authors: Ntukidem James , Omonigho Raymond , Anighoro Sunny 
Published: December 2007

Abstract
Thermal Desorption Units (TDU's) are gradually supplementing cutting re-injection in Niger Delta waste management operations. Its acceptance is based on report from operators in other oil zones and not on any comprehensive study on this inconclusive waste management methodology.
This technology separates contaminants from soil. Contaminated soil is heated in a chamber where water, organic contaminants and certain metals are vaporized. Most of our wastes treated so far are pseudo-oil-based mud cuttings using the High Temperature Thermal Desorption (HTTD) units at 400 to 800 °C (752 to 1472 °F) off well site.
This paper would look at the questions environmental managers' believe are not answered by this method. It would also compare cost cut at future date and draw an analysis based on its benefits, limitations and concern over alternatives as a new form of technology as it is applicable to our geomarket.
Quantifying Tortuosities by Friction Factors in Torque and Drag Model
Authors: Gaynor Tom , Hamer Doug , Chen David C-K , Stuart Darren 
Published: December 2007

Abstract
Tortuosity occurs when a well deviates from a straight hole. The most commonly known tortuosity is the local dogleg severity variation associated with the use of steerable motors in "slide/drill/slide" drilling. However, there is a tortuosity that exists in many wells, which the authors will refer to as "micro-tortuosity" in which the hole axis is a spiral instead of a straight line. This paper presents a study of micro tortuosity using field data from the North Sea wells. The friction factors and tortuosity index are used to quantify the effect of tortuosity on the torque and drag. The results show that hole spiraling, associated with the use of conventional short-gauge bits, is a major contributor to today's friction factors used in the torque and drag model.
Exploitation Evolution of a Mature Oil Field from Campos Basin, Brazil
Authors: Ida M. , Ferreira D.M. , Malagutti S.R. , Thedy E.A. , Castro F.C.C. 
Published: December 2007

Abstract
This paper presents the successful exploitation strategy chosen for a matureoil field from Campos Basin, Brazil. The field was discovered in March 1984 and began producing in April 1985. The exploitation was carried out by stages, eachstage supported by increase in geological and production behavior knowledge obtained along the time. This strategy led the field to be one of the majorproducers of Brazil. Management aspects, such as well production plan, waterinjection and sand control are presented.

Introduction
The field is located in a water depth that varies from 300 to 700 m. Thecurrent production is 49,000 BOIP from 25 wells tied up to three floating production units.
The field produces oil from santonian cretaceous and eocene turbiditesandstones. There are minor occurences of oil in maastrichtian and turonianturbidite sandstones.
The main reservoir of the field is the santonian reservoir, that contains 95% of the OOIP. A non associated gas reservoir also occurs in an oligocenesandstone. Nowadays the field is at half life, having produced half of the recoverable oil volume.

History
The field exploitation was carried out by stages, each stage supported byincrease in geological and production behavior knowledge obtained along thetime. Due to this strategy, the limits of the reservoir have been enlargedalong the time, demanding the implementation of five exploitation projects forthe field.
The period 1984/85 corresponds to the discovery and inicial delimitation ofthe santonian reservoir, based on 2Dseismic data. In order to anticipateproduction and gather reservoir behavior information, in 1985 the wildcat wellwas tied up to a Production Floating System nearby. Three appraisal wells weredrilled and confirmed the existence of the reservoir.
In 1987, the first exploitation project was approved for the field, supported by good production behavior of the wildcat well and based on new3D-seismic data interpretation. The Project I consisted of a FloatingProduction Unit for the field, utilizing three already drilled appraisal wells, four new producers and two new water injectors plus the convertion of thewildcat well into a water injector (Figure 1).
Parallel to that, the exploration staff continued the investigation of thereservoir limits towards east. Two new appraisal wells confirmed that thereservoir extended to the eastern area, incorporating oil volume (Figure 2).One of them was put on stream afterwards, in a water depth record for thattime.
Sand Control: Sand Characterization, Failure Mechanisms, and Completion Methods
Authors: Abass H. H. , Nasr-El-Din H. A. , BaTaweel M. H. 
Published: December 2007

Abstract
Sand production has historically been a problem associated with some consolidated, poorly consolidated, and unconsolidated sand formations. The result is usually lost production due to formation sand and fines plugging gravel packs, screens, perforations, tubular, and surface flow lines or separators.
Completion methods applied to minimize sand production include: gravel packing, sand consolidation, critical production rate, oriented/selective perforation, FracPacking, or any combination of these methods. These techniques are used in consolidated, poorly consolidated, and unconsolidated sand formations. However, there are no guidelines available in the literature on how these methods are selected.
Mechanisms for sand failure include: tensile, shear, cohesive, and pore collapse. Additionally, failure due to chemical effects can occur when the cementation materials are weakened due to chemical interactions. Many mathematical models have been presented in the literature to predict sand failure, and consequently determine sand production. These models are based on different failure mechanisms and include: pressure drawdown/compressive strength, failure based on a given failure criterion such as Mohr Coulomb, cohesive strength failure, elastoplastic failure around a perforation, viscoplastic modeling, and empirical correlations. However, there are no guidelines on how these models are applied based on the characteristics of the sand formation.
Experimental studies have been presented in the literature to model sand failure. These studies include sand arching, hollow cylinder strength, triaxial and hydrostatic, and large scale testing. Laboratory testing are designed to study a given failure mechanism, and thus to predict sand production.
The objective of this paper is to categorize sand formations that potentially exhibit sand failure and sand production. Based on this characterization, an appropriate laboratory testing and mathematical modeling are recommended, and a completion method is suggested. Examples from standstone reservoirs in Saudi Arabia will be used to demonstrate certain methods used for sand control.
Experiences Learned After Production More Than 300 Million Barrels of Oil by Polymer Flooding in Daqing Oil Field
Authors: Wang Demin , Cheng Jiecheng , Wu Junzheng , Wang Gang 
Published: December 2007

Abstract
Daqing Oil Field started industrial scale polymer flooding in 1996. The production by polymer flooding since then has rapidly increased. In year 2001, the annual production by polymer flooding was more than 70 million barrels (bbl), cumulative production more than 300 million bbl and more than 3 thousand wells are on polymer flooding. In these 6 years, much experience has been learnt on large scale polymer flooding including: actual recovery in the field; major factors that influence the recovery and methods to increase the recovery; measures to obtain a uniform polymer flood front; and how to lower the costs of producing crude oil by polymer flooding.
Transient Pressure Unloading – A Model of Hydrostatic Pressure Loss in Wells after Cement Placement
Authors: Nishikawa Somei , Wojtanowicz Andrew K. 
Published: December 2007

Abstract
Hydrostatic pressure loss (unloading) after cement placement is widely considered a reason for early gas migration in wells. In the presence of high-pressure zone, the unloading leads to pressure underbalance causing gas invasion and flow in the cemented annulus.
The work, reported here, is an attempt to analyze and model pressure unloading as a propagation of pressure transient resulting from downhole fluid loss-a primary mechanism of slurry volume reduction. (Experiments, discussed here, had shown that another mechanism of volume reduction-volumetric shrinkage is not at work early enough to contribute to the pressure unloading process.)
The pressure-unloading model has been validated using data from field experiments in the instrumented wells. The theoretical results matched experimental data showing exponential trend of the downhole pressure loss. Also, the model was used in a sensitivity study to identify parameters controlling the process.
The study revealed that large annuli with high water loss would give rapid and large reduction of hydrostatic pressure in the cement column and more likely intrusion of gas. The observation implies that surface holes should be more sensitive to gas migration than deep holes and the cement slurry filtration should be minimized in surface holes. Another finding showed that compressible annular cement systems would be more tolerant to fluid loss in terms of losing hydrostatic pressure than the low-compressibility systems. The observation emphasizes the importance of annular system compressibility control.
Identifying Bypassed Reserves and Monitoring Fluids Using Carbon-Oxygen Logs in Tia Juana Field, Lake Maracaibo, Venezuela
Authors: Mendoza Erasmo , Duran William , Monsegue Alan , García Germán 
Published: December 2007

Abstract
Carbon-oxygen (C/O) tools have been used historically to evaluate wells that are candidates for recompletion, and slim tools introduced in the 1990s permitted the analysis of intervals behind the casing without having to pull the production tubing. The challenge was then to evaluate zones behind both the tubing and casing and very often behind gravel packs. This logging technique requires diligence because the tool is run through the production tubing, which contains accessories such as mandrills, sleeves, and packers that are responsible for changes in the fluid distribution in the annulus. Identification of the fluids in the formation and the well (i.e., in the tubing, in the gravel pack, or in the tubing-casing annulus) requires a full understanding of the C/O tool response in these conditions.
This technology has enabled recovery of bypassed or ignored reserves in mature areas of the Tia Juana field in Venezuela and has permitted the reconditioning of wells with low production and high water cut. It has also facilitated the workover of neighboring wells, mapping fluid contacts by way of construction of structural and stratigraphic sections. This paper briefly discusses the conditions of acquisition, interpretation, and applications of the C/O data acquired in three cases and emphasizes the impact of the workovers on production.
Application of Permeability Predictions in Profile Modification and Water Shutoff Using Genetic Algorithms
Authors: Zheng Jian , Liu Yusong , Li Jiyong , Zhang Daisen , Chen Dehong , Shao Hongyun 
Published: December 2007

Abstract
This paper deals with a new method used to describe the present permeability of reservoir theoretically and its application in profile control and water shutoff. The reservoir permeability has been changed greatly compared with the initial stage of development after long time water flooding. Generally speaking, it is very hard to obtain the current reservoir permeability data. Only the native permeability, which has great diversity with the actual reservoir conditions, can be considered in profile modification. So a lot of problems usually exist in the process program designed according to the native permeability data. It doesn't conform to the actual conditions of current reservoir. So the expected result is hardly obtained after field implementation according to project design. In such cases a good predictor is necessary, requiring more rigorous models capable of adequately handling any inherent non-linearity. Genetic algorithm is a new intelligent computing method, based on which the technology of permeability prediction is developed. The approach adopted here allowed us to integrate the theory of survival of the fittest into our geologic understanding of the reservoir to look for the permeability distribution that is closest to the actual reservoir conditions by using the three operators of selection, crossover and mutation repeatedly. Using genetic algorithm, we have established a relationship between permeability and field production datas that are available. These datas include bottom hole flowing pressure, production rate, waterflood injection rate and water cut etc of test field. This technology is suitable for well pattern or fault-block with balanced injection and production. According to the relative accurate and reliable permeability distribution, the blindness of profile modification project design can be avoided. Accordingly the implementation result can be improved greatly, and can obtain good evaluation by using this technology again after implementation.
This technology has been applied successfully in L58-2 Fault-Block of Linpan Oilfield, M12 Fault-Block of Qinghe Oilfield, M14 Fault-Block of Qinghe Oilfield and Feiyantan Oilfield before and after profile modification to predict their present permeability distributions and evaluate implementation results. The predicted results basically accorded with the performance results analyzed by field technicians, which had led to an enhanced reservoir characterization and decreased reservoir heterogeneity. This benefits both daily operations and reservoir stimulation efforts. This technology will be popularized in Gudao, Gudong Oil Field. With further development and improvement, it will play more and more important role in profile modification, water shutoff and enhanced oil recovery in heterogeneous reservoir.
Laboratory Testing of Long Term Fracture Permeability in Shales
Authors: Cuisiat Fabrice , Grande Lars , Høeg Kaare 
Published: December 2007

Abstract
The results from laboratory and theoretical work pertaining to the permeability of fractures in shale are presented. The main objective of the work is to improve existing models for hydraulic fractures in basin simulators.
A simple theoretical model is proposed to quantify the effect of creep on the permeability of fractures in shales. The model assumes that the aperture of the fracture changes due to creep of the intact shale material at contact points (asperities). The interaction between contact points is not taken into account. The time dependent deformation of the asperities is based on a model published in the literature for the behaviour of clays, and which is calibrated on cap rock materials tested at NGI. The permeability of the fracture is calculated directly from the aperture changes, assuming that the flow along the fracture can be represented as flow between parallel plates. The results from the model show that the effect of creep on the fracture aperture and permeability is not negligible, although closure of the fracture due to creep is only attained after extremely long times.
Some preliminary results obtained with new laboratory equipment suitable to investigate the long term permeability and hydraulic aperture of fractures in shale are presented. Fractured samples from typical North Sea cap shale are subjected to constant effective normal stress. Flow through the fracture and change of fracture aperture are measured continuously with time. The results show that the fracture behaviour is highly sensitive to its degree of "matedness". The measured significant variation in permeability during creep does not seem compatible with the measured small reduction in fracture aperture. The preliminary test results demonstrate the experimental difficulties in obtaining reliable fracture permeability (conductivity) with time.
Dependence of Drilling Specific Energy on Bottom-Hole Pressure in Shales
Authors: Detournay Emmanuel , Tan Chee P. 
Published: December 2007

Abstract
Cutting experiments were carried out to quantify the dependence of the specific energy e (the energy required to cut a unit volume of rock) on the bottom-hole pressure pm and on the pore pressure po in shales. The experiments were conducted with an instrumented cutting device specially designed to operate inside a triaxial cell. With this set-up, four longitudinal grooves could be cut simultaneously on epoxy-coated shale plugs, under confining pressure and initial pore pressure (which is different from confining pressure). The results of about 20 cutting experiments performed on Mancos and Pierre I shales and on Johnstone, an artificial shale, for various combinations of confining pressure (up to 50 MPa) and initial pore pressure are reported in this paper. This preliminary experimental investigation supports the theoretical findings that the specific energy s depends only on pm, and not on the "differential" pressure pm- po in shales under conditions when the rock is shear-dilatant. In such cases, e can indeed be expressed as ε = εo +mpm, where εo denotes the specific energy under atmospheric conditions and m is a coefficient which is a function of the cutter backrake angle θ and the internal friction angle φ of the shale.