bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unsteady and Pseudo-steady State Characterization of Matrix and Fracture Systems for Multiple Size Blocks with the Use of Empirical Correlations
Authors: Morales-German Gabriela , Rangel-German Edgar , Samaniego-Verduzco Fernando , Cinco-Ley Heber 
Published: December 2010

Abstract
This paper presents solutions to the pressure diffusivity equation for fractured porous media including multiple block sizes with a uniform distribution, for both unsteady and pseudo-steady states by means of dimensionless variables, the Laplace transform, and the Stehfest algorithm.
The general solution was validated through the classic Warren & Root single-sized block distribution and pseudo-steady state model.
It is common that in transient well test analysis, generalized plots of the models’ solutions are used. In this paper plots in time domain: " pwD vs. tD" and " tD [d(pwD)/dtD] vs. tD," as well as in Laplace domain: " spwD¯ vs. 1/s " and " s[d(spwD¯)/ds] vs. 1/s" are presented, showing the influence of the parameters that more strongly influence the behavior of the solutions, such as the matrix storativity ratio (ωm), fracture storativity ratio (ωf), maximum interporosity flow coefficient (λmax), and minimum interporosity flow coefficient (λmin).
As is known, the derivative pressure curve is more sensitive to the variation of these parameters, providing very valuable information about the reservoir. Thus, various plots including the derivative of dimensionless pressure in both time and Laplace domains, such as tD [d (pwD)/dtD]min and s[d(spwD¯)/ds]min, and their behavior with respect to reservoir parameters were also analyzed. From these plots, empirical and easy-to-evaluate correlations were obtained. Using these correlations, it is possible to calculate initial values for the parameters that characterize fractured reservoirs:ωm0, ωf0, λmax 0, λmin 0, hmax 0, and hmin 0. These initial values are very close to the real ones; therefore, ωm, ωf, λmax, λmin, hmax, and hmin are rapidly found.
Using Intelligence to Improve Efficiency in Remote-Oilfield Operations: Case Histories
Authors: Tirado R. , Haapanen B. , MacLeod J. 
Published: December 2010

Abstract
Unfortunately, most of today's oil and gas fields are not located in our backyard, or in easily accessible locations for that matter. The "easy oil," as many call it, is long gone so now we are forced to explore new frontiers, from ultradeepwater areas, to the Arctic Circle, deserts, or deep inside tropical jungles. These remote and inhospitable environments present a series of logistical challenges to oilfield operators. Accessing these areas, establishing the necessary infrastructure, and mobilizing personnel and equipment required to operate an oil field can be costly, risky, and time-consuming.
On the other hand, in today's modern business world, technology is employed on a daily basis to overcome geographical boundaries or obstacles and make us more efficient. Thanks to telecommuting, millions of workers do not have to drive to the office: the office comes to them. Thanks to collaboration through virtual teams, individuals do not need to work in the same physical space nor meet face to face to be able to accomplish tasks; which saves millions of dollars in cost and time associated with business travel.
This paper presents a series of case histories demonstrating how intelligent completion and production systems can be used to apply the same telecommuting and virtual team concepts to solve some of the logistical challenges faced in today's remote oilfield operations. An outline of general considerations and recommendations is also proposed as a guide for individuals planning to implement these technologies.
Effect of Liquid-Liquid Extraction Process by Using a Paraffinic Solvent in the Removal of Acidity in Colombian Heavy Crude Oil
Authors: Picón H. Héctor J. , Quiroga B. Haydee , Caballero D. Eivarth F. , Castro G. Jesus A. , Poveda M. Diana M. , Gutiérrez P. Jenny R. 
Published: December 2010

Abstract
Processing heavy and acid crudes involves failure risks associated to sulfidation and naphthenic corrosion in refinery equipments (Troncoso, E., 2009). In addition, acid crudes show a tendency to cause fouling in transportation pipelines and processing production facilities.
In Colombia, the increasing rates in heavy oil production have driven the development of technologies to remove contaminants like sulfur, metals and acids.
This work present the results obtained in laboratory test for the precipitation of asphalthene aggregateds applied to three different Colombian crude oils. This method includes mixing the crude with a paraffinic solvent, and following decantation and separation by gravity using a vacuum filtration technique. The acid content in the Asphalthene Aggregate fraction (AAF), and the Aggregate Free Fraction (AFF) was quantified using KOH titration method ASTM D664.
Three different solvent-crude ratios were evaluated in this study (3:1, 5:1, 7:1) and the results shown an acidity content reduction found was an average of 11%, a reduction of sulfur content, and increase of gravity API in 7 points. Additionally a decrease in asphalthene content in the treated crude (nC7 insolubles) was found in all scenarios.
A methodology to simulate Liquid Liquid Extraction process (LLEX) of acid and heavy crudes by tuning the binary interaction parameters of solvent-asphaltene pairs of pseudocomponents with experimental data is used here. The model predicts the process behavior under similar conditions than experimental test, and this allow to expand this study in a theoretical basis, reducing the cost in test and laboratory analysis.
LWD Bimodal Acoustic Tool Delivers Full Range of Sonic-Wave Arrivals
Authors: Llorente Carlos , Pineda Giser , de la Fuente Joel , Contreras Javier 
Published: December 2010

Abstract
The recent development of an LWD BAT™ Bimodal Acoustic Tool has shown that compressional, shear, and Stoneley arrivals can be captured by these tools while drilling. Mexico's national oil company recently drilled a deep water exploratory well to a planned depth of 4,752 m. A full suite of LWD tools was run by a major service company, followed later by an evaluation with wireline tools owing to the importance of this deepwater exploratory well.
The relevance of these runs was that the LWD tools provided the full set of curves normally generated by the wireline tools, including shear and Stoneley arrivals. A comparison of both technologies was performed, which showed that BAT tools can provide equal or better data, hole-quality dependant, than the wireline tools because the freshly-acquired logs from the LWD tools are not affected by borehole washouts, tool standoff, or fluid invasion.
Comparison logs were put together using the LWD BAT data versus logs from the competitor's latest generation wireline sonic tool. Evidence shows that both tools provided excellent data, with a slight advantage in quality for the LWD logs, as evidence of soaking and invasion had an adverse effect on transit-time arrivals on the wireline curves. This comparison proves the concept that sonic logging while drilling can deliver the same quality, or better, providing DT compressional, DT shear, and DT Stoneley arrivals under drilling conditions.
Real-Time Drilling Optimization in Sihil Field With Remote Operation Center
Authors: Loo Enrique , Arango Fidel , Millan Angel 
Published: December 2010

Abstract
Sihil field, one of the most challenging drilling environments in Mexico, is a block located 54 miles from Ciudad del Carmen in the Continental Shelf of the Gulf of Mexico and is part of a deep portion of Cantarell field in Campeche Bay.
Sihil is a structural hydrocarbon trap with a failed anticline and hydrocarbon occurrence controlled by faulting distribution, diagenesis, and dissolution phenomena in the field. Hydrocarbons produced include oil with an API classification ranging from 22 to 30.
Directional drilling challenges in this field include total lost circulation (Akal Block Cretaceous formation and Sihil Block Eocene) and drilling through rock with a high-strength compressibility (35-40 kpsi average). The risk is high for a differentially- stuck bottomhole assembly (BHA), borehole instability, and pack-off conditions, resulting in considerable non-productive time (NPT), loss of geological targets, and higher costs.
Initial exploratory wells required an average of 12 months to drill to TD, with many geological incidents, lost BHAs, and well construction issues. By applying drilling optimization technologies in real time with the Remote Operation Centre in Ciudad del Carmen, a major service company has helped reduce drilling time and the number of incidents.
Ten of the 12 wells in which optimization technologies were applied showed improved service delivery, less NPT, and greater drilling efficiency.
The Sihil 3 and Sihil 8 wells are the two best examples of what can be achieved, with each well setting drilling records (108 days for Sihil 3 and 84 days for Sihil 8) and reducing the original drilling program by 22 and 63 days, respectively, for significant cost savings to the operator.
The Value of Flexibility to Expand Production Capacity for Oil Projects: Is it Really Important in Practice?
Authors: Costa Lima G. A. , Gaspar Ravagnani A. T. , Sampaio Pinto M. A. , Schiozer D. J. 
Published: December 2010

Abstract
The selection of the best oil production strategy consists of finding the optimal number of wells and their locations, well flow-rates, well opening schedule, platform production size, water treatment capacity, etc to maximize NPV, RF, among others. But, there is always uncertainty in the determinants of these variables and also there will be risk. An increase in oil price may change the optimal number of wells. Similarly, with an oil price decrease, it may be necessary to shut-in some wells. The problem becomes more complicated because the production strategy must be defined at the early stage of the development. Then, management may find it suitable to pay for some flexibility that could be useful in the future and improve the project profitability. These flexibilities have two benefits. First, they reduce the risk of the NPV of the project. Second, they add value to the entire project. To estimate the value of flexibility in the management of an oil project towards profit maximization, we consider an offshore oil field with 28 °API and 98 million cubic meters of OOIP. Because oil price fluctuates, management finds suitable to start production with 16 wells and a platform with liquid production capacity of 17,700 cubic meters per day. This platform has extra-capacity that can be used in case management needs an increase in oil production, which, is strongly dependent on oil price. This extra-capacity adds value to the project since it allows management, the option to increase production in case of an increase in oil price. To evaluate this flexibility, NPV method is not the right tool, but real options models. We analyze the possibility to exercise the flexibility to increase production by drilling more wells in years 1, 2 or 3 after the opening of 16th well. In this study, we conclude that the value of the flexibility to expand production is not very high. This is unexpected, since in most cases in literature, the value of flexibility is above 25% of the static NPV. The reason, in this case, is due to the high investment in drilling wells and the low impact on the production curve.
Methodology for Cementing Low-Fracture-Gradient Gas Wells: Application in Cashiriari Field, Block 88
Authors: Santisteban M. A. , Mendoza J. R. , Barrett S. , Cassanelli J. P. 
Published: December 2010

Abstract
The Camisea project is one of the most important hydrocarbon production projects in Peru. Its importance for the growth of the Nation is becoming even greater as internal consumption of gas and liquids increase.
To date, the Camisea Project has successfully completed the first three development stages. The first two stages were in the San Martin and Pagoreni fields. However, the third stage in Cashiari field was the one that brought the greatest technical challenges. The Cashiriari Field required the application of the very best technologies available in the industry to successfully drill and complete the 12 wells (2 re-entries, 8 new producing wells and 2 cuttings re-injection wells).
The Exploratory wells drilled several years previous experienced severe circulation losses in the producing horizons. This condition made cementing jobs extremely difficult using conventional methods and technology, which proved to be the wrong choice during the exploratory stage. Nonetheless, a good cementing job was paramount in these sections in order not to compromise deeper reservoirs drilling.
The Cashiari Field is a group of condensate gas reservoirs with low fracture gradients, high reservoir pressures (due the gas columns), and somewhat high permeability with the added complexity of natural fractures. These factors combine to make cementing without circulation losses and obtaining good zone isolation a major challenge.
This paper explains in detail Cashiriari field problems. It then details considerations applied to cement successfully. The methodology includes the optimization of pre-flushes, the use of ultra-light, light weight, and standard weight slurries, along with designs to prevent gas migration. All this metholody is backed with laboratory results. Finally, cement evaluation logs are showed summarizing results obtained.
Sand-Control Project for the First Receiving Lateral Well (U-Well) in the World
Authors: Pedroso Carlos Alberto , Borges Carlos A. , Paixão Luiz C. 
Published: December 2010

Abstract
In order to drain some very distant reservoirs from a small fixed platform in Campos Basin, called PCP-1, a horizontal well with wet completion was projected. In spite of the forecasted high productivity well, this project was considered economically unviable due to the need of frequent interventions with an expensive semisubmersible rig, for maintenance of the ESP. On the other hand the structure available in that small platform does not allow the drilling of a long dry completion well to drain these distant reservoirs. The surprising and ingenious solution proposed by the Well Engineering was the construction of a satellite well, using the resources of a semisubmersible rig, intercepting a dry completion well, located in PCP-1 Platform. This project received the denomination of "Receiving Lateral Well" which patent was already granted.
As the target sandstones are unconsolidated, an efficient sand control method is mandatory to protect the ESP. An additional challenge is that the well will cross the sandstones horizontally, due to the well geometry necessary to achieve the interception.
Usually, the operator's first option would be an OHHGP. This solution however became unviable due to the reasons: i- after drilling the two reservoirs, both extremely depleted, an extensive reactive shale, almost 1200m long, should be horizontally drilled, with problems of well stability in the shales and loss and/or differential pressure stucking in the reservoir. ii- the well should drain two different reservoirs, with an Oil/Water contact located in the lower reservoir: selectivity, therefore, is highly desirable.
The sand control method chosen to drain these two reservoirs was four "stacked" horizontal frac pack. As the operator does not have experience to frac-pack in these conditions, an extensive analysis was made trying to maximize the possibility of success of this complex well, what includes: analysis of the well azimuth relatively to the fracture propagation direction, the perforation strategy, the sand control design, the choice of the best group of tools (through a design competition), etc..
The present work aims to shortly describe the complete project for the receiving lateral well construction and deeply depict this very challenging sand control project.
First Campos Basin Raw-Water-Injection Well: Sand Control and Stimulation
Authors: Pedroso Carlos Alberto , Denadai Nilson José , Duarte Eduardo Lopes 
Published: December 2010

Abstract
As part of the production sustainability project for the Albacora Field, in Campos Basin, Brazil, it has been planned to inject raw water (RWI) above the fracture pressure (IAFP). The main drive for choosing RWI was the big difficulty to properly treat the injection water in the very busy Albacora platforms.
The injection target reservoirs are unconsolidated, demanding a robust sand control method. The operator's first choice would be an OHHGP with premium screens. However, due to extremely aggressive amount of dissolved oxygen, the RWI demands a very special metallurgy. The manufacturing and acquisition process of mesh premium screen or wire wrapped screens, in this special metallurgy are extremely expensive and can last many years. Besides that, these kinds of screens are prone to crevice corrosion.
To cope with this new challenging scenario, an innovative lower completion was planned and executed:
use of a 4,5″ alloy 625 sloted liner, run in an 8,5″ hole; maximizing the slot opening to 400 micrometers, in order to minimize the plugging process and the corrosion by the non treated sea water and to maximize the liner mechanical resistance; use of 3 ABTs (2 ECPs and 1 swelling packer) to protect the production casing.
Also, due to the low fracture gradient, combined with an unfavorable mechanical configuration, it was necessary to reduce the risk of partial packing:
use of the Rat Hole Zero conception, with the pioneer application of a retractable casing shoe in the 9 5/8″ production casing; use of light proppant (alpha wave) combined with ultralight proppant (beta wave).
Besides that, due to the inexistence of inverted seals to provide the divergence for the conventional mud cake removal through an acid treatment, the option was:
the mud cake removal using a pre-cursor formic acid.
The desired injectivity index was not obtained and the contingency was applied:
backflow, followed by the bullheading of foamed 15% HCl (it was the first application of this stimulation method in a Campos Basin OHHGP well).
The final result, in spite of this great amount of technological innovations, were wells that fulfill all the reservoir engineering requirements.
Assessment of ultrasonographic morphometric measurements of digital flexor tendons and ligaments of the palmar metacarpal region in Icelandic Horses
Authors: Boehart Sara , Arndt Gisela , Rindermann Georg , Gmachl Maria , Carstanjen Bianca 
Published: December 2010

Abstract
Objective—To obtain morphometric values for the superficial digital flexor tendon, deep digital flexor tendon, accessory ligament of the deep digital flexor muscle, and suspensory ligament in the palmar metacarpal region of Icelandic Horses.
Animals—50 nonlame Icelandic Horses in training.
Procedures—Horses included 2 stallions, 30 geldings, and 18 mares from 4 to 20 years of age with a body mass index from 149.1 to 250.11 kg/m2. Transverse ultrasonographic images were obtained with an 8- to 10-MHz linear transducer and a standoff pad. In both forelimbs, the cross-sectional area, circumference, dorsopalmar width, and lateromedial width were measured 3 times at 5 regions of interest (ROIs).
Results—The coefficient of variation for all measurements of each ROI was < 5%. Comparisons were performed among and within structures and for each variable at all ROIs. Comparisons among horses revealed homogeneity because no significant influences of age, sex, height at the withers, or body mass index were found. Additionally, a characteristic skin condition interfering with ultrasonographic examination was observed.
Conclusions and Clinical Relevance—The morphometric values of the structures examined were consistent with those reported for other breeds, although some differences were observed.
Molecular characterization of the L1 gene of papillomaviruses in epithelial lesions of cats and comparative analysis with corresponding gene sequences of human and feline papillomaviruses
Authors: Anis Eman A. , O'Neill Sarah H. , Newkirk Kim M. , Brahmbhatt Rupal A. , Abd-Eldaim Mohamed , Frank Linda A. , Kania Stephen A. 
Published: December 2010

Abstract
Objective—To characterize the L1 gene of papillomaviruses detected in epithelial lesions of cats and to determine the relationship between those L1 gene nucleotide sequences and known L1 gene sequences of human and feline papillomaviruses.
Sample Population—10 tissue samples of epithelial lesions from 8 cats.
Procedures—DNA was extracted from tissue samples. Primers were designed to amplify the L1 gene of papillomaviruses. Amplicons of DNA were sequenced; nucleotide sequences were compared with known L1 gene nucleotide sequences of papillomaviruses and used for phylogenetic analysis.
Results—Tissue samples were obtained from lesions (diagnosed as dysplasia [n = 1], squamous cell carcinoma in situ [3], or squamous cell carcinoma [6]) of the skin (9) and oral mucosa [1]. Two amplicons had 99% homology with the L1 gene nucleotide sequence of human papillomavirus type 38b subtype FA125. Another amplicon had 84% homology with the L1 gene nucleotide sequence of human papillomavirus type 80 and was considered to be a new type of papillomavirus. Phylogenetic tree analysis revealed that these 3 papillomaviruses were grouped into 2 clades that were not similar to the clades of Felis domesticus papillomavirus type 1 or F domesticus papillomavirus type 2 (FdPV2). The remaining 7 amplicons had 98% to 100% homology with the L1 gene nucleotide sequence of FdPV2. Phylogenetic tree analysis revealed that those 7 papillomaviruses were grouped nto a single clade with FdPV2.
Conclusions and Clinical Relevance—Results support the likelihood of transmission of papillomaviruses between humans and cats.
Effect of heparin administration on urine protein excretion during the developmental stage of experimentally induced laminitis in horses
Authors: Uberti Benjamin , Pressler Barrak M. , Alkabes Stéphane B. , Chang Ching-Yun , Moore George E. , Lescun Timothy B. , Sojka Janice E. 
Published: December 2010

Abstract
Objective—To investigate the effects of heparin administration on urine protein excretion during the developmental stages of experimentally induced laminitis in horses.
Animals—13 horses.
Procedures—Horses received unfractionated heparin (80 U/kg, SC, q 8 h; n = 7) or no treatment (control group; 6) beginning 3 days prior to induction of laminitis. All horses were given 3 oligofructose loading doses (1 g/kg each) at 24-hour intervals and a laminitis induction dose (10 g of oligofructose/kg) 24 hours following the final loading dose (designated as 0 hours) via nasogastric tube. Serum glucose and insulin concentrations were measured before administration of the first loading dose (baseline) and at 0 and 24 hours; urine protein-to-creatinine (UP:C) ratio was determined at 0 hours and every 4 hours thereafter. Lameness was evaluated every 6 hours, and horses were euthanized when Obel grade 2 ameness was observed.
Results—Mean ± SD time until euthanasia did not differ significantly between the heparin-treated (28.9 ± 6.5 hours) and control (29.0 ± 6.9 hours) horses. The UP:C ratio was significantly increased from baseline at 20 to 28 hours after induction of laminitis (ie, 4 ± 4 hours before lameness was evident) in control horses but did not change significantly from baseline in heparin-treated horses. Serum glucose or insulin concentration did not change significantly from baseline in either group.
Conclusions and Clinical Relevance—Urine protein excretion increased during the developmental stages of carbohydrate-induced laminitis in horses; administration of heparin prevented that increase, but did not delay onset or decrease severity of lameness.