bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heavy-Oil Waterflooding: Back to the Future
Authors: Alvarez J. M. , Sawatzky R. P. , Moreno R.. 
Published: September 2014

Abstract
Waterflooding of conventional oil fields has been going on since the dawn of oil and gas production. In the 1940s and '50s, researchers in the oil community undertook a successful effort to understand the mechanisms underlying waterflooding, in order to improve its application. One of their findings was that as the mobility ratio increases the breakthrough time decreases exponentially. Furthermore, at high mobility ratios (&gt; 500), the recovery factor does not increase much after breakthrough even after further water injection. Despite this conventional wisdom about waterflooding, it is gaining popularity around the world as a potential technology for recovering heavy oil. For example, in western Canada heavy oil reservoirs with a dead oil viscosity of up to 2,000 mPa.s have been targeted for waterfloods. Some surprising results, which appear to be at odds with conventional theory, include: extended periods of oil production at very high water cuts; and, much higher recovery factors than could be predicted from conventional theory. Mechanisms that have been proposed include: pressure support; unstable displacement and creation of water channels; water imbibition from those channels; viscous drag; emulsification; solution gas drive; apparent swelling of the oil; increasing gas saturations in the water channel causing a reduction in the water relative permeability; and, fracturing. Unfortunately, the speculation about the potential mechanisms involved in heavy oil waterflooding has not yet coalesced into a more tangible understanding of the role of each mechanism and the interplay between them. The relative importance of the mechanisms involved in heavy oil waterflooding, and the capability to enhance them at different stages in the operational life cycle of the waterflooding process, may provide a key to improving the recovery factors in heavy oil reservoirs that are being exploited by waterflooding. This paper will discuss the effort required to examine the mechanisms involved in heavy oil waterflooding, from an experimental perspective. It will address the different laboratory scales that can be employed to investigate these mechanisms, from the pore scale via micro-models to the semi-field scale using large experimental cells. Pathways incorporating these mechanisms in numerical models will be also discussed.
Novel Spotting Fluid to Handle Problems Associated With Differential Stuck Pipe in Heavy-Crude-Oil Reservoirs
Authors: Toro Carlos , Mesa Sebastian , Vergel Alfonso , Villalobos Mario , Orozco Diego , Charry German 
Published: September 2014

Abstract
Stuck pipe caused by differential sticking in horizontal wells is a problem that can result in the loss of tools in the hole, non-productive time (NPT), side tracks and even total loss of the well, with the consequence of significant cost increase for wellbore construction.
A differential pressure that pushes a drill string into the filter cake of a permeable formation causes differential sticking. It is typically remediated by pumping spotting fluids that are designed to break down the filter cake and reduce the bond between the filter cake and the pipe.
When drilling heavy crude oil reservoirs, conventional spotting fluids often fail to free the stuck pipe, because the filter cake is covered with heavy crude oil, which prevents the spotting pills from achieving good diffusion through the filter cake.
Additionally, these conventional spotting pills contain solids that cannot be easily removed from the production section when the well begins production.
Eventually, the solids would damage to the formations of interest. For this reason, a viable alternative was evaluated that could effectivety remove differential stuck pipe, and minimize potential formation damage.
To achieve this objective, a spotting fluid was formulated with a surfactant package that produces very low interfacial tension, enables high oil-cleaning capacity and easily removes heavy crude oil. This formulation is a solid-free fluid, formulated without acid. The mechanism to eliminate the bond between the pipe and filter cake is a diffusion process and solubilization of the heavy crude oil into the microemulsion, leaving the filter cake very porous, achieving quick release of the stuck pipe string. The fluid is mixed at the rig, using conventional equipment, and pumped downhole using standars rig pumps.
This paper discusses the use and operational procedures for application of this novel spotting fluid for cases of differential sticking occurring while drilling heavy crude oil reservoirs. Currently, the new spotting fluid has been applied in eight wells, with successful release of differential sticking in the reservoir zones during drilling of horizontal sections.
A Successful Gravel-Packing Technique in Vertical and Deviated Wells with Enlarged Open Hole in Cased Completions: A Case Study, Rubiales and Quifa Fields
Authors: Florez A.. , Osorio M.. 
Published: September 2014

Abstract
Rubiales and Quifa fields are the major oilfield in Colombia; two heavy oil reservoirs (API in the range 11.3° to 14.4°) with unconsolidated sandstone formation with high permeability, however, there is low productivity in vertical and deviated wells, caused by formation damage from drilling fluids, and cased gravel packing completion.
These two formation damages have been mitigated by applying a successful gravel packing technique in both vertical and deviated wells. On June 30, 2014, the oil production rate was 186 thousand BOPD, of which 14.5 thousand BOPD (7%) came from 162 vertical and deviated wells with the successful gravel packing technique.
The successful gravel packing technique consists on first running a standard cemented 7 inches casing and then cutting the casing in the production zone and enlarge the open hole section from 8.5 inches to 13 or 16 inches diameter to remove cement bond overpassing the washout. Finally, the enlarged open hole section is gravel packed with mesh 20-40.
The completion technology purpose is to increase the well productivity, isolating high water saturation intervals on both top and bottom of the oil zone, reducing the skin damage.
Before 2007, 30 wells were completed with conventional cased hole gravel packing. Most of these wells were damaged having to be frequently stimulated with organic treatment; 14 of these wells have been re-completed using gravel packing technique. The results show an increase in the productivity index from 2 to 5 times, compared to conventional completion and showing a maximum increase in total fluid rate from 600 BFPD to 3000 BFPD.
Finally, some examples are presented comparing gravel packing using this technique and the cased hole completion method. Operation procedures, advantages, limitations, and production results are presented in individual well performance comparisons. The successful application of this technology has contributed to increase oil production in Rubiales and Quifa fields development and it has also been extended to others analogues fields.
Analytical Prediction Model of Sand Production Integrating Geomechanics for Open Hole and Cased – Perforated Wells
Authors: Araujo E. F , Alzate-Espinosa G. A , Arbeláez-Londoño A.. , Peña Clavijo S.. , Cardona Ramirez A.. , Naranjo Agudelo A.. 
Published: September 2014

Abstract
Sand production treatment, control and mitigation generate high costs for the petroleum industry. Therefore, this is considered a critical problem and requires a continuous monitoring and special management. A sand production study is fundamental in field development and will help to eliminate or mitigate the related problems. This way, an analytical geomechanical sand production model is proposed to design the best field sand free production plan and to select the type of sand control measures and sand management techniques. The model needs as input data, the reservoir characteristicsn and a mechanical earth model derived from well logs that includes the stress state regime. It also requires the well direction, azimuth and completion information in order to evaluate the well characteristics. In this model an onset sand production condition is calculated looking for the borehole pressure that makes the maximum effective tangential compressive stress equal or higher than the rock strength (failure criteria), which is usually known as critical borehole pressure (CBHP). The results are presented on two kinds of graphs: the CBHP versus depth graph that allows determining the sand production free interval and the CBHP versus reservoir pressure graph that helps to design different well production plans for optimizing the recovered volume avoiding sand production. Results must be calibrated and verified with data field to simulate the real reservoir behavior. Briefly, for a specific well path it is possible to propose the operating CBHP as a function of the reservoir depletion and well completion (open or cased hole), also for a new well, it is possible to design the best well direction and the completion type, in addition to the operating CBHP to minimize sand production.
Assessment of Thermal Recovery: Steam Assisted Gravity Drainage (SAGD) to Improve Recovery Efficiency in the Heavy-Oil Fields of the Peruvian Jungle
Authors: Chun Nestor Antonio 
Published: September 2014

Abstract
The decline of medium and light oil production of most of the fields in Peru in the last years, the increase of the domestic demand, the rising of oil prices and the recent discoveries of large heavy oil resources in the Marañon Basin, makes the suitable scenario to economically develop such heavy oil reservoirs. The technical recoverable volumes estimated for heavy oil fields in Peru (with API degree of 12 or even less) represent a significant energy resource for the country. Reasons for applying SAGD process to improve recovery factor in these fields.
Cold production technologies in heavy oil fields with API degree of 12 or even less, yielded low recovery factors (no more than 15%). The fluid property that most affects the productivity and recovery of heavy crude oil is viscosity; therefore, it is expected that thermal process like SAGD would increase the recovery efficiency of heavy oil fields by adding heat.
An screening criteria matrix was prepared based on worldwide analogous projects, which includes the fluid and rock properties to apply in Heavy Oil Fields of the Peruvian Jungle; then, a conceptual local-grid refined simulation model was built to evaluate production performance and estimate a recovery factor for the zone. The SAGD process was compared in performance to conventional cold production methods of the region (deviated and horizontal wells with ESP pumps).
As a result, a matrix with recovery factors of SAGD process is provided; which with an average recovery factor of 25% looks very promising for a feasibility study.
With the success of SAGD process in analogous heavy oil fields around the world, this study aims to bridge the gap that Peru has in Thermal Recovery and EOR processes, with Screening matrix and Reservoir Simulation of SAGD process to apply a pilot program, increasing the national production.
Unlocking the Potential of a Mature Heavy Oil Field Using Innovative Well Placement Technology: A Case Study from Offshore China
Authors: Nie Chaomin , Jia Yong , Hu Yong , Bie Xuwei , Yang Liuhe , Zhai Gang , Su Jinchang , Wang Fei , Kok Jeffrey , Xu Chonghui , Gao Zhujun , Li Shuzhong , Wu Kai , Yu Xiaoning , Xu Tianyun 
Published: September 2014

AbstractThe Qing Huang Dao oilfield, located in the Bohai Bay has been in production for more than 10 years. To achieve production targets, many directional wells and horizontal wells were initially drilled with conventional tools and measurements. However, at the end of 2012, as the oilfield matures, the field's average water cut had reached a high of 86.4%.Following a multidisciplinary study on bypassed oil distribution in this field, a new horizontal well drilling program was launched in 2012. The study team highlighted challenges in identifying the oil water contact (OWC) while placing the trajectory within a very small target window close to the roof that the program needs to be overcome. Off a detailed technology review, advance azimuthal LWD, with the ability to map the distance to the multiple boundaries such as the OWC, the top and bottom of the reservoir structure in the remaining oil column, was selected as the fit-for-purpose application and to enhanced reservoir understanding. In combination, rotary steerable drilling system (RSS) was selected to improve drilling efficiency and deliver smooth trajectory control.This new approach using innovative azimuthal LWD technology implementation proved value in its utility by achieving the ultimate objective of drilling productive horizontal wells in QHD oilfield. The application reduced drilling cost, avoided unnecessary trajectory adjustments and kept the lateral trajectory within a very small target window of 1m to 1.5m close to the reservoir cap. Production from these horizontal wells surpassed production by 31% with only 4% water cut. The integrated solution of innovative LWD, well placement and RSS optimized this mature oilfiled development. The authors believe this approach and techniques could effectively address other similar mature oilfields development.
Differential Cased-Hole Shear Anisotropy DCHSA Methodology as a Calibration and Evaluation Tool of Hydraulic Fracture Height in Colombian Fields
Authors: Santamaria Jose Camilo , Velez Edgar , Bahamon Jorge 
Published: September 2014

AbstractDue to specific reservoir features such as high skin levels and poor petrophysical properties, a common activity applied in order to reduce skin levels, and increase well productivity index, is hydraulic fracturing operation; this formation stimulation activity, use generation of preferential channels of high conductivity, in order to improve these reservoir features.Mechanical properties play a relevant role, during a successful fracturing job, planning and execution. Geomechanical parameters are valuable information, in order to select the most convenient intervals, to perform the fracturing job, and estimate the theoretical fracturing height results. Additional tools are essential in order to evaluate hydraulic fracture effectiveness; these tools will provide important information, related to fracture height, containment and complexity.This paper presents the application of differential cased hole shear anisotropy (DCHSA) methodology, in Chichimene and Castilla Colombian fields, where hydraulic fracture height was determined, based on acoustic logs information. By determining hydraulic fracture height, mechanical barriers can be identified, in some cases these barriers can be acting containing the fracture growth, and planning of following fracture jobs, can be optimized along field. Using differential cased hole shear anisotropy (DCHSA) methodology, a better understanding of post stimulation production results can be obtained, this information helps to reach better calibration of existing geomechanical model, and fracture design can be optimized, in order to improve fracturing planning, for better well production and field development optimization.
Investigation of Orifice Type Flow-Control Device Properties on the SAGD Process Using Coupled Wellbore Reservoir Modeling
Authors: Noroozi Mehdi , Melo Marco , Singbeil R.P.(Pete). P.(Pete) , Neil Blair 
Published: September 2014

AbstractIn order to optimize production of a SAGD process many strategies have been adopted. These strategies may include; a Dual-Tubing completion which contains short and long tubing strings to inject steam in to the reservoir, Proportional-Integral-Derivative (PID) to control steam injection, flow control devices (FCDs), and others. In all these methods; operators try to maximize ultimate recovery by increasing thermal communication between well pairs, enhancing steam conformance, and improving oil displacement efficiency. Currently flow control devices (FCDs) are widely used in thermal operations. This tool can be installed on both production and injection wells in a SAGD well pair. The FCD tool in an injection well is also known as a steam splitter, which gives the operator the opportunity to target sections of the wellbore to receive steam. In a production well, FCDs are used to develop a uniform inflow along the horizontal section of the wellbore. This helps in managing the interface between the injection and production wells to maximize the productivity. The effects of orifice type FCD properties on a SAGD process have not yet been investigated. These properties include port (orifice) size and port quantities. Locations of FCDs in both injector and producer are another important parameter that needs to be addressed and optimized in a SAGD operation. This paper investigates the impact of each of these FCDs properties along with the location of FCDs on a SAGD process through coupled wellbore-reservoir modeling. In addition; a detailed study is carried out to present a workflow for the FCD optimization that can help engineers to design FCDs in both injector and producer in a SAGD well pair.
Treatment of Water in Heavy Crude Oil Emulsions with Innovative Microemulsion Fluids
Authors: Pietrangeli Gianna , Quintero Lirio , Jones Thomas , Darugar Q.. 
Published: September 2014

Abstract
In-situ formation of water-in-oil emulsions in crude oil is one of the severe problems encountered during the production phase of oil wells. These in-situ emulsions produce crude oil viscosities that are much higher than the viscosities of native crude oil. It is well known that these problems are frequently found in heavy and extra-heavy crude oils, because these oils have significant amounts of carboxylates and naphthenates, which are polar molecules that are excellent stabilizers of water-in-crude oil emulsions.
These in-situ emulsions form in the reservoir and in the near-wellbore regions. However, when the crude oil is produced to surface, they may also develop at various downstream locations such as at wellheads, pipelines, separation plants, and even at the refinery before processing. The major factors that determine the formation of in-situ emulsions are the crude oil/produced water ratio, properties and composition of the crude oil and connate water, and some reservoir properties such as temperature. Demulsifiers are traditionally used to prevent the formation of in-situ emulsions. These treatments are generally effective. In situations where the demulsifier chemistry cannot change the curvature of the oil/water interface, the emulsification problem persists, with inherent consequences such as loss of production, high-pressure drops in flow lines and increased operational costs.
A solution to treat these troublesome emulsions is to use microemulsion fluids technology. Microemulsion fluids typically have very low oil/water interfacial tension and can alter the interfacial curvature of the emulsion, producing coalescence and increasing water droplet size until the emulsion separates into water and crude oil.
This paper discusses the evaluation of microemulsion fluids as a treatment for emulsified heavy crude oil samples from oil fields. The evaluation includes crude oil characterization, interfacial tension, microscopy evaluation, fluids compatibility tests and treatment of the emulsion in an HPHT filtration cell.
Radiographic assessment of lower third molar eruption in different anteroposterior skeletal patterns and age-related groups
Authors: Jakovljevic Aleksandar , Lazic Emira , Soldatovic Ivan , Nedeljkovic Nenad , Andric Miroslav 
Published: September 2014

ABSTRACT

Objective:
To analyze radiographic predictors for lower third molar eruption among subjects with different anteroposterior skeletal relations and of different age groups.

Materials and Methods:
In total, 300 lower third molars were recorded on diagnostic digital orthopantomograms (DPTs) and lateral cephalograms (LCs). The radiographs were grouped according to sagittal intermaxillary angle (ANB), subject age, and level of lower third molar eruption. The DPT was used to analyze retromolar space, mesiodistal crown width, space/width ratio, third and second molar angulation (α, γ), third molar inclination (β), and gonion angle. The LC was used to determine ANB, angles of maxillar and mandibular prognathism (SNA, SNB), mandibular plane angle (SN/MP), and mandibular lengths. A logistic regression model was created using the statistically significant predictors.

Results:
The logistic regression analysis revealed a statistically significant impact of β angle and distance between gonion and gnathion (Go-Gn) on the level of lower third molar eruption (P &lt; .001 and P &lt; .015, respectively). The retromolar space was significantly increased in the adult subgroup for all skeletal classes. The lower third molar impaction rate was significantly higher in the adult subgroup with the Class II (62.3%) compared with Class III subjects (31.7%; P &lt; .013).

Conclusion:
The most favorable values of linear and angular predictors of mandibular third molar eruption were measured in Class III subjects. For valid estimation of mandibular third molar eruption, certain linear and angular measures (β angle, Go-Gn), as well as the size of the retromolar space, need to be considered.
Fuzzy ranking based non-dominated sorting genetic algorithm-II for network overload alleviation
Authors: Pandiarajan K. , Babulal C.K. 
Published: September 2014

Abstract
This paper presents an effective method of network overload management in power systems. The three competing objectives 1) generation cost 2) transmission line overload and 3) real power loss are optimized to provide pareto-optimal solutions. A fuzzy ranking based non-dominated sorting genetic algorithm-II (NSGA-II) is used to solve this complex nonlinear optimization problem. The minimization of competing objectives is done by generation rescheduling. Fuzzy ranking method is employed to extract the best compromise solution out of the available non-dominated solutions depending upon its highest rank. N-1 contingency analysis is carried out to identify the most severe lines and those lines are selected for outage. The effectiveness of the proposed approach is demonstrated for different contingency cases in IEEE 30 and IEEE 118 bus systems with smooth cost functions and their results are compared with other single objective evolutionary algorithms like Particle swarm optimization (PSO) and Differential evolution (DE). Simulation results show the effectiveness of the proposed approach to generate well distributed pareto-optimal non-dominated solutions of multi-objective problem
Novel ultrasonic distance measuring system based on correlation method
Authors: Gądek K. , Jaraczewski M. 
Published: September 2014

Abstract
This paper presents an innovative method for measuring the time delay of ultrasonic waves. Pulse methods used in the previous studies was characterized by latency. The method of phase correlation, presented in this article is free from this disadvantages. Due to the phase encoding with the use of Walsh functions the presented method allows to obtain better precision than previous methods. The algorithm to measure delay of the reflected wave with the use of microprocessor ARM Cortex M4 linked to a PC has been worked out and tested. This method uses the signal from the ultrasonic probe to precisely determine the time delay, caused by the propagation in medium, possible. In order to verify the effectiveness of the method a part of the measuring system was implemented in LabVIEW. The presented method proved to be effective, as it is shown in presented simulation results