bluuebunny/crossref_metadata_2025 huggingface dataset:
Gas Migration Modeling to Prevent Sustained Casing Pressure and Casing Vent Flow
Authors: Vu Manh-Huyen , Bois Axel-Pierre , Badalamenti Anthony
Published: January 2018

One of the main objectives of primary cementing is to provide zonal isolation by preventing the percolation of gas through a cemented annulus, which could result in channels in the cement sheath. Gas channeling, once established, has proven to be extremely difficult and costly to repair.

The most current theory used to explain gas migration is the early gelation of the cement slurry, which leads to a decrease of hydrostatic pressure within the cement annulus. Over the years, various models have been developed, most of them revolve around the concepts of static gel strength (SGS), critical static gel strength, (CSGS), and transition time. Unfortunately, these approaches have failed to accurately predict gas migration. One of the main reasons for this failure is that these approaches are based on fluid-mechanics theories, and do not take into account the cement phase changes during hydration (fluid to solid) besides their effects on the SGS. Additionally, most models do not take into account the true mechanisms at the origin of gas percolation: Matrix, chimney, and micro-annulus.

This paper presents the use of a new gas migration model that eliminates these drawbacks, in order to investigate the effect of the cement composition on the cement sheath integrity. This model considers two different stages in the life of the cement sheath (fluid-type and porous-solid type), and is characterized by constitutive laws, which are integrated over the length of the cement column by time to determine if gas migration will occur and what are the mechanisms according to which it would occur. The simulations demonstrate the crucial role that the cement composition has on the state of stresses and pore pressure in the cement sheath, on the opening and closure of micro-annuli and on the vertical displacements of cement sheath during cement early ages. They highlight that an analysis of cement sheath integrity during hydration requires checking a combination of different mechanisms during the life of cement from fluid-type to porous-solid type.
Optimizing Well Integrity in Intelligent Oil Fields
Authors: Khreibeh Hanaa Abou , Shamsi Saoud Al , Vasallo Edilberto , Farag Fadi , Lunt Ged , Bhardwaj Jiten
Published: January 2018

As operators move towards intelligent wells and fields, data management systems need to be adapted to support the transformation. With technology advancements and a growing network of sensors that enable faster and higher frequency data gathering, there is a need to sustainably scale data management systems to the level required to handle higher volumes of data and faster processing response. The most comprehensive systems, however, are those that support efficient decision making.

A Middle Eastern operator embarked on a project to enhance the existing well integrity data management system to add new capabilities and extend the system to other fields in the Arabian Gulf. The updated well integrity management standards were also incorporated to reflect the operator's latest business principles.

The system was further integrated with a geographical information system and well integrity business workflows were developed. The system automatically monitors data and sends notifications on abnormal well conditions. This is being supported by a single repository of all necessary data, historical inspection, pressure trends and well intervention histories.

Through continuous monitoring of operating conditions by the system and automatic task assignment when conditions indicate the rise of well problems, engineers can work more proactively and manage a growing number of assets. Automated monitoring relieves engineers from the efforts previously exerted on manual processes and allows them to focus on the engineering analysis. Having a single repository with historical inspection, safety critical equipment test data, full pressure trends and well intervention histories, provides a wealth of information from which to make informed decisions.

A benefit of having such methodology, from a management viewpoint, is that there is a common approach to well integrity indicators and key performance indicators for all assets. This allows benchmarking from field to field so that a consistent decision making approach can be made and resources of different types properly focused on those places where the challenges and demands are higher. In a period where the industry has gone through some substantial rationalization, the fact that staff can be assigned to different assets through the use of a common system with which they are familiar helps them to quickly understand, analyze and tackle well problems.

This paper examines the application of intelligent software analytics and a robust system to optimize resources and enhance efficiency and performance. By collecting a wider range of data with increased frequency and applying intelligent software analytics, the operator has been able to greatly improve the asset management coverage, thus improving efficiency and performance; satisfying regulatory requirements and achieving production targets.
ATP Bioluminescence Assay for Onsite Microbial Assessment in Drilling Rig Operations
Authors: Hernandez Susana Amaya , Zhu Xiangyang , Al-Humaid Ghassan A. , Al-Attallah Fahd S. , Al-Humam Abdulmohsen A.
Published: January 2018

Deep drilling often requires the use of circulating fluids to facilitate the drilling process, carrying cuttings and rock fragments to the surface. In this practice, microbial contamination and extensive growth of bacteria in the drilling fluids impact drilling operation and reservoir integrity. An onsite and rapid microbial assessment technique is required to provide an early warning of microbial activities in drilling fluids, and manage microbial risks through proper countermeasures.

Bioluminescence method is a rapid testing technique for quantification of living cells based on the measurement of adenosine-5'-triphosphate (ATP) found in the sample. ATP test has been widely used in food and pharmaceutical industries; however, its application in the oil and gas industry has been hindered by many interference substances present in typical oil industry samples. In this study, we have validated an ATP-based bioluminescence test for its linearity and repeatability in various types of samples from drilling rig operations (make-up water, drilling mud, and cement mix fluid). The results from ATP test showed an excellent linear relationship with the microbial numbers in the samples determined by plate count method. The study proved ATP bioluminescence technique as a reliable method for onsite determination of microbial contamination in drilling operations, obtaining results in minutes, rather than days or weeks with traditional methods.

The action levels based on ATP measurements were recommended for drilling engineers to assess microbial risks in drilling fluids. The implementation of this onsite microbial monitoring technique in the field will facilitate real-time detection and immediate mitigation countermeasures for microbial control in drilling fluids, reducing risks such as loss of rheological properties of drilling fluids from biodegradation, H2S production during drilling downtime and deep in the formation, biomass plugging in the formation, and microbial corrosion. This is the first study of the use of ATP-based test to assess microbial contamination in drilling rig operations.
Self Healing Durable Cement; Development, Lab Testing, and Field Execution
Authors: Al-Yami A. S. , Alqam M. H. , Riefky A. , Shafqat A. U.
Published: January 2018

Pressure and temperature changes during the life of the well (drilling/production) cause some Casing-Casing annulus (CCA) pressure leaks in the annulus between 13 3/8" and 9 5/8" casings, and 13 3/8" and 18 5/8" casings thereby indicating that the well barriers failed to isolate all the zones and subsequently resulting in the migration of the fluid to the surface. Such failures in wellbore isolation prevent us from taking full potential of ourhigh performance wells.

Under most failure conditions, tensile strength of a cement has a greater impact on its failure as compared to the cement's compressive strength. Consequently, increasing tensile strength of a cement is higher priority than increasing its relative compressive strength. This can be achieved by using additives such as latex, polyvinyl alcohol or fibers or simply by increasing cement flexibility. The objective of this paper is to discuss the development, testing and field execution of a new type of cement, Self-Healing Durable Cement to mitigate such failures due to pressure or temperature cycling.

This new cement was developed utilizing novel components that results in a cement with a reduced Young's Modulus. Lower Young's Modulus makes the cement more elastic in order to resist pressure and temperature cycling, absorb applied stresses and prevent cement cracks. The developed Self-Healing Durable Cement also provides an additional benefit of mechanical properties enhancement as the included additive exhibits swelling and sealing capacity when contacted by hydrocarbon fluids. In the event cracks form in the cement, this will be a path for the fluid to trigger the swelling and self-healing mechanism.

The paper includes detailed testing data for thickening time, rheology, free water, settling at different ranges of densities. An additional test was also included to evaluate the durability of the system with time. Mechanical properties testing was performed for cement samples after 10, 20 and 30 days curing at representative targeted field conditions. Single stage triaxial tests were performed on dry cement core plugs to measure static and dynamic properties through ultrasonic and shear velocities. These properties were determined at confining pressures and included the Young's modulus, the Poisson's Ratio, and Peak Strength.

Offset wells cemented with conventional formulations have shown CCA pressure with slight oil flows. The developed Self-Healing Durable Cement was applied for 13 3/8" casing covering oil bearing zones. The deployments were declared successful since negative testing and temperature and pressure cycling did not result in any CCA. Ultimately, good cementing performance is always measured by having zero psi casing/casing annulus pressure.
Integrated Off-Bottom Cemented Inflow Control Device System Design Toward Well Delivery Optimization
Authors: Madan Mohammed A. , Khamseen Mazen Bu , Suherdiana Hedy , Abdulmohsen Ahmad Al
Published: January 2018

Off-bottom cementing (OBC) operations are unique to Saudi Arabia and also represents one of the most challenging types of drilling and workover operations, when deployed in combination with inflow control devices (ICDs) across horizontal sections. In a conventional ICD system, an inner string with packer setting tools is required for setting open hole packers, and to have 100% circulation at the bottom of the completion, to wash down any tight spots. As a consequence, this introduces additional issues such as health, safety and environment, logistics and additional rig time. The inner string also increases the ICD completion string weight, while deploying the system in the horizontal section, creating more drag and increasing the risk of getting stuck.

The multitasking valve (MTV) feature in the upgraded ICDs offers safe, simple and cost-effective deployment operations. The MTV allows the system to be deployed without the need for an inner string. This will positively impact the deployment by simplifying the complexity in the rig operation while achieving 100% circulation at the shoe. Besides, all the hydraulically activated equipment, such as the liner hanger packer, open hole mechanical packers, etc., can be pressurized and set simultaneously. Furthermore, the ICD completion will weigh less in the horizontal section, resulting in less friction and drag to reach total depth (TD). The MTV feature provides an opportunity to deploy the ICD system and the OBC liner system together in one trip. This paper will discuss the first deployment of a combined ICD system with an OBC system for a workover operation, in a historical oil well producer in the Kingdom of Saudi Arabia. The merged system was successfully deployed to depth, then cemented off-bottom, saving approximately 40 hours of rig operation time.
Pillar Fracturing Technique Application in the Algerian Desert for Well Production Enhancement
Authors: Forno Luca Dal , Allal Mohammed A. , Gheraissa Mohammed , Kateb Mahmoud , Mohammed Omar
Published: January 2018

Rhourde Attar field in the northwestern Algerian desert is exploited from the Lower Devonian sandstone. This formation is composed of sandy and silty-sandy intervals with thin, shaly intercalations. The reservoir is characterized by very porous sands (20 to 25%), which also show relatively low permeability (1 to 15 md). Deposition of chamosite minerals reduced permeability, without reducing primary porous volume. This paper proposes a pillar fracturing technique designed to overcome formation constraints and enhance production.

Beyond the moderate petrophysical properties related to rock diagenetic history, the reservoir is suffering from a gradual depletion trend, limiting the oil production rate and driving the bottomhole operating condition below the bubble point. It was proposed that placing a highly conductive fracture stimulation treatment could possibly help overcome these constraints. An oil producer well of the field was selected for the first application of a pillar fracturing technique combined with a resin to consolidate the created channels within the fracture.

The pillar fracturing technique allows conductivity maximization through the placement of open channels within the stabilized proppant pillars. This unique fracture geometry is achieved by pulsing clean fracturing fluid stages alternated with slurry stages that carry the propping agent. The proppant pillars are then stabilized with the addition of a specifically designed resin to coat the proppant as it was being pumped throughout the entire fracturing process. Proper candidate selection, accurate fracture modeling, and employment of proven pumping equipment are crucial elements for achieving a successful and safe intervention. The implementation of this stimulation technique provided positive results both in terms of operational execution and final well performance.

Additionally, this technique mitigates the risk of undesired screenout by reducing the proppant volume compared to a conventional job. Moreover, the initial production of the well revealed a significant improvement while the long-term performance showed a stabilized trend. Based on these outcomes, the use of this technique could face a fast increase within the Algerian market, considering also possible refracturing interventions on older wells.
Development and First Application of Monobore Openhole Expandable Clad in the Tarim Oilfield
Authors: Guo H. J. , Xu B. G. , Yin H. W. , Liu Z. T. , Lv M. J. , Wang J. L.
Published: January 2018

The application of the first open-hole expandable liner in Tarim Basin has demonstrated the value of the numerical models developed to assess the effects of the required large expansion ratio, particularly on connection sealability. This paper discussed the modeling, the assessment of the highly expanded thread form, lab testing to confirm its performance, and the field application.

The expandable casing was required to span 127 m of open-four hole to prevent the closure of a section of mobile mudstone. The 10 ¾ in. in originally planned across the interval could not be run due to the tight hole, and the expandable was successful in allowing the well to continue below the mudstone in an 8 ½ in. hole. The concern was the effect of the large expansion ratio on the sealability of the connector. ABAQUS was utilized to build a model which was then calibrated with ten groups of expansion tests with a variable diameter cone. Tests included both internal and external pressure loads.

Expansion ratios of 20.2% were achieved in the lab without tube failure or thread leakage at the loads expected in the Tarim Basin application. The casing was successfully installed and expanded in June 2016, and drilling continued to the planned total depth. The success of the modeling in lab and field applications creates confidence that the model itself can be used to develop designs for other loading conditions in other applications with minimal full-scale lab testing. While there is an additional opportunity in the Tarim Oilfield, confidence in a generalized model will encourage engineers to assess other opportunities.

The ability to predict expansion stresses and sealability are also seen as the first step for the operator in the development of a monobore system that provides full pass-through and a casing-to-casing seal that can be deployed economically in the low-cost Tarim Basin operations.
Smart Loss Circulation Materials for Drilling Highly Fractured Zones
Authors: Mansour A. Khaled , Taleghani A. Dahi
Published: January 2018

Lost circulation materials (LCMs) have played an essential part when trying to decrease the heavy financial costs resulting from mud loss and non-productive time. However, the LCMs used in the field today still have drawbacks such as failure to work in a high pressure - high temperature environment, damage to production zones, inability to seal big fractures and plugging the drilling tools. In this paper, we introduce a new smart lost circulation material made out of anionic shape memory polymers and it does not have the disadvantages that the LCMs experience in the field today. The smart LCMs has the ability to be programmed to change in shape, bridge and expand when stimulated by a specific temperature. A fully coupled simulation is developed to test the sealing efficiency of the newly introduced smart LCMs. Various particle size distributions and fracture sizes were used to further understand the properties of the smart LCM. The proposed smart LCM shows efficacious sealing of fractures and could be the next smart solution for lost circulation.
A Novel 8000m Rig and its Application for Ultra-Deep Well Drilling in Submountain Region
Authors: Chen Peng , Fang Taian , Zhou Zhixiong , Wang Junjie , Yuan Xubo
Published: January 2018

A new type of the 8000m drilling rig ZJ80/5850 has been researched, manufactured and successfully applied for ultra-deep well drilling in the submountain region of China's Tarim oilfield. The new kind of rig was developed to deal with the problems of load incapacity of drilling with the 7000m rig and high cost of drilling with the 9000m rig in ultra-deep well drilling.

Deep or ultra-deep well drilling operations in the piedmont area were predominated by the 7000m rigs. In order to tackle the situation of ultra-deep well drilling in the piedmont zone in Tarim oilfield, primary technical parameters of the rig had been enhanced with maximum hook load capacity 5,850kN, 52MPa high pressure rig pumps were equipped, compacted strands high tension wirelines were first used, derrick structure of the rig was optimized, and high strength material was selected for the main structure. Thereby a perfect general technical scenario of rig and associated techniques were formed.

The Tarim basin in northwestern China featured complex geological conditions and deep buried reservoirs. The potential risk of the 7000m rig safety as drilling around 8,000m ultra-deep wells emerged and the rig accident occurred as the big-size casing was deeply set due to the bare weight of the casing exceeding the load capacity of 4,500kN. Drilling efficiency has significantly been enhanced after 22 rigs of the type 8000m rig were applied for ultra-deep well drilling in the Tarim oilfield in less than three years. The 8000m rig has become prevailing equipment for drilling operations in the submountain region of Tarim. The procurement cost of roughly USD2.5bln was cut down per set of the 8000m rig as compared to that of the 9000m rig. The daily drilling rate per rig was saved by 20%-30%. Total amount of USD36.8bln for integral cost of drilling was saved per rig per year.

The optimization of the 8000m rig parameters and advanced associated technologies have filled in the gaps of China's rig standards and perfected the standard series of China's rigs. R&D of the new type 8000m rig was a result of market demand and satisfied by clients for the exploration and production of ultra-deep buried reservoirs.
Successful Implementation of Multi-Modal, Self-Assembling, Self-Degradable and Environmentally Friendly Solids Particulates as Diverter in Acid Stimulation Treatments in Carbonate Reservoirs
Authors: Malik Ataur R. , Asiri Mohammed A. , Ogundare Tolulope M. , Khalifa Mohamed
Published: January 2018

This paper focuses on the evaluation of novel diversion technology based on self-degradable solids particulates that were applied in the complex carbonate reservoirs. The well performance results were compared in this paper between wells stimulated with novel and conventional diversion technologies as part of the evaluation.

The continued dependence on fossil hydrocarbons and the need to increase oil and gas production present solider challenges to more effectively stimulate marginal reservoirs with cost effective and improved technologies. In carbonate reservoirs, this challenge to maximize production comes from the increase in the stimulated reservoir volume. Diversion techniques in acid stimulation treatment in carbonate reservoir plays a major role in improving the stimulated reservoir volume. A typical acid stimulation design includes the diverter stages in between acid stages with the objective of both temporarily plugging the stimulated intervals and directing the treatment fluids to other untreated intervals and enhancing far-field diversion. It is necessary that these diverting materials are completely degradable and non-damaging to the reservoir.

High temperature, high stress, pressure depletion, sour environment, and heterogeneity make certain carbonate reservoirs very complex and several diversion techniques have been tested in complex carbonate reservoirs over the last decade. In fact, enhancement in diversion technique for carbonate reservoirs is continuously being explored by the local well stimulation network team. Because of extreme reservoir complexities and heterogeneities in multifaceted carbonate reservoirs, it is critical to select an appropriate diversion technique along with optimum acid blends to redirect stimulation fluids from treated intervals to untreated intervals. The post-stimulation high resolution temperature logs and productivity index analysis indicated that wells stimulated with a novel diversion technology exhibited enhanced production due to its ability to produce more uniform distribution of acid along the net pay intervals.

The novel diversion technology consists of multi-modal, self-assembling, self-removing, and environmentally friendly particles, presented in dry solid form to provide quicker and stronger redirection of fluid-flow paths by using the particle-bridging technique and sealing-off the width near the fracture's tip. More effective stimulation is achieved by branching fractures from subsequent stages as a result of far-field diversion.
Scaling and Completion Fluid PH Effect on Sandstone Formation Damage
Authors: Hamzaoui Bilel , Moajil Abdullah M.
Published: January 2018

The effectiveness of completion fluids prior to the actual cost and risk of implementation is critical to evaluate. High salinity/ high pH brine can cause formation damage to sandstone formation following well completion operations. The magnitude of damage depended on the fluid/fluid and fluid/rock proprerties.

This work demonstrates the experimental results to evaluate the effect of completion fluid pH on sandstone minerals and the compatibility with the formation water.

Solids and core plugs analysis were conducted using XRD. ICP analysis of three completion fluid samples was performed to determine its elemental composition. Fluid/rock interactions assessment were conducted using zeta potential analysis.

Scaling of calcium sulfate andsalt self-precipitation occurred when high pH completion fluid was mixed with formation water. Zeta potential results showed that sand stone minerals were less stables at high pH.
Date Pit-Based Additive as Density Reducing Agent in Underbalanced Drilling
Authors: Adewole Jimoh K. , Najimu Musa O. , Adewunmi Ahmad A.
Published: January 2018

A new drilling fluid additive has been developed for application as density reducing agent. The additive can be used for preparing lightweight drilling fluid formulation for use in underbalanced drilling. The preliminary results obtained from the performance analysis revealed that the date pit - based additive possesses some potential to be used as a density and formation fluid flow control agents in water-based drilling fluid. The addition of 5ml (ca 1.40 vol%) of the additive to bentonite drilling fluid formation decreased the density of the fluid by 21%. The effect of the additive on other drilling fluid properties such as fluid loss and filter cake thickness were also evaluated.
Fiber Glass Casing Design, Planning and Installation Experience in Observation Wells
Authors: Al-Oqab Mohammad , Kaushik Preyankar , Ahmad Abuzar Tanweer , Kumar Subodh
Published: January 2018

Monitoring and continuous reservoir evaluation is very important aspect of a well-planned Waterflood program. Valuable well and reservoir information needs to be obtained during the course of waterflood operation, which helps in determining oil recovery and decide on the future strategy of the Waterflood program. Keeping this in view, KOC decided to drill some observation wells completed with cemented fiberglass casing for monitoring the flood performance in sandstone and carbonate reservoirs in two different fields. The use of fiberglass casing facilitates the application of some deep induction logging tools for measuring the changes in formation properties behind the casing. Vital information such as oil saturation change during waterflood operation, vertical sweep efficiency and arrival time of different fluid fronts can be determined from these log surveys in fiberglass casing.

Cemented fiberglass casing and liners were used over the years globally mainly for observation wells and in some cases for highly corrosive injection wells. However, the use of fiberglass tubulars as casing or liner needs careful planning for its safe deployment and longer life. The casing policy, depth, drilling mud weight and logging requirement mainly dictates the selection of a particular size and thickness of fiberglass casing. Special cementing program needs to be formulated due to its lesser strength properties (collapse, burst & axial rating) compared to normal steel casing. They can be run either as complete fiberglass casing/liner or as combination string with steel casing depending on the zone of interest and purpose of deployment.

KOC has successfully deployed 9-5/8" size fiberglass casing as combination string with steel casing in more than 20 vertical/deviated observation wells. The depth of deployment ranges from 4500 ft. in sandstone formation to around 8000 ft. in carbonate formation. Additional care was taken while preparing/ planning the cementation to prevent failure of the fiberglass casing while cementing across deeper formations.

This paper describes in detail the design and planning of the observation well completed with fiberglass casing. Different scenarios leading to selection of particular size of fiberglass casing supported by StressCheck application and cementing technique are presented. Some special consideration related to cementing and running in equipment, which needs careful attention. The paper with the deployment cases will be a quick guide to engineers.
Evolution of Drilling Dynamics Measurement Systems
Authors: Akimov O. , Hohl A. , Oueslati H. , Reckmann H.
Published: January 2018

Continuous development of drilling technology has enabled the oil and gas industry to drill deeper and more complex well paths. Drilling dynamics measurements have been the dominant contributor to rate of penetration maximization, overall drilling optimization and downhole assembly reliability assurance for more than three decades.

A consequence of today's complex downhole assemblies and well paths are higher downhole forces and vibrations. These conditions require more quality drilling dynamics information than before for safe and efficient drilling. Driven by this demand, new developments in downhole and surface equipment have made available larger amounts of drilling dynamics data with higher sample rates. In parallel, development of reliable high-speed telemetry allows the high-resolution drilling dynamics data to be utilized on surface to deliver answers while drilling. These developments were made possible due to the recent advent of high-performance downhole-capable electronic technologies, as well as the availability of increased computation power for signal processing at the rig site.

This paper describes improvements in the drilling dynamics measurement systems to overcome the challenges imposed by deeper and more complex wells. Gathering, processing and transmitting drilling dynamics data at high rates introduces challenges due to tighter downhole sensor requirements, the required digital signal processing power, amount of available memory, electronics temperature tolerances and telemetry requirements. Optimized hardware design, signal processing and enhanced telemetry sequences and methods are answers to these challenges, to ensure the adequate performance of drilling dynamics measurement systems. These improvements allow a fast response to new drilling conditions, the adjustment of drilling parameters to changes in formation, and a rapid evaluation of drilling performance. This enables field personnel to make decisions focused on drilling optimization, and these case histories are added to advance drilling optimization best practices.

The drilling dynamics measurement system described in this paper has been successfully run in challenging fields in the North Sea and Middle East. Compared with offset runs, the system has significantly increased data quality and sample rate and provided, in addition to industry-standard-measurements, unique measurements for the identification and mitigation of high-frequency torsional oscillations. Examples of the improved capability and operational performance are provided.

This paper also highlights changes necessary to further improve drilling dynamics measurement systems for evolving real-time drilling optimization needs.
Step Change in Wellbore Positioning Accuracy
Authors: ElGizawy Mahmoud , Aklestad Darren , Lowdon Ross
Published: January 2018

A survey program is designed for every well drilled to meet the well objective of penetrating the target reservoir and to avoid colliding with other offset wells. The selection of the wellbore survey tools within the survey program are limited to the current accuracy available to the industry. A newly developed wellbore survey technique has proven to have superior accuracy compared to the current standard measurement-while-drilling (MWD) surveys with in-field referencing and multi-station analysis (MSA).

In almost every drilling bottom hole assembly (BHA), there is an MWD survey tool to survey the wellbore while drilling. Accuracy of the MWD surveys has been improved over the years by correcting potential error sources such as misalignment of the survey package from the borehole, drillstring magnetic interference, limited global geomagnetic reference, and gravity model accuracy. This new positioning technique takes the accuracy of MWD surveys to the next level by combining surveys from two independent survey packages. The second survey package is installed inside the rotary steerable system (RSS). Surveys from both packages are retrieved while drilling.

Results have been obtained from multiple runs worldwide, enabling comparisons between the new technique and standard MWD surveys from both an enhanced accuracy and true wellbore placement point of view. A proposed error model is based on both the theoretical improvements in accuracy and the empirical proof from the data analyzed. The improved accuracy while drilling assures higher confidence that the well placement will maximize reservoir production and avoid collision with nearby offset wells.

In reservoir sections, the wellbore survey accuracy limits the lateral spacing, and this constrains the reservoir production. In top and intermediate sections, wellbore survey accuracy limits the well plan, and this affects how close the well can be drilled in proximity to other offset wells. This directly impacts the complexity of the directional work and the cost per drilled foot. The new technique unlocks the potential to significantly improve the wellbore positioning accuracy.
First Multilateral Well Worldwide with an Intelligent Completion System and Openhole Acid Stimulation
Authors: Hart Sofiri , Saggaf Hatem
Published: January 2018

The Middle East has long been a pioneer in innovation in drilling and completion technologies for multilateral wells. It was here that the first1 multilateral tool (MLT) on coiled tubing was used to access and stimulate each openhole lateral in a trilateral well. Over the years, several2-4 applications of this and similar technologies have been made. In each instance, a conventional upper completion system was installed.

In a multilateral well with a conventional upper completion and an openhole lower completion, there is no independent flow control from each lateral. Because of this, production is not optimized to account for differences in the production rate or reservoir quality of each lateral. For a well with an upper intelligent completion system (ICS), independent control of flow from each lateral is possible through the use of surface controlled flow control valves (FCVs). This feature addresses the shortcomings of the conventional upper completion mentioned earlier.

The challenge in performing an acid stimulation of each openhole lateral in a well with an ICS is the inability to access any of the laterals after the ICS has been installed. Current technologies do not afford this option and designs in the pipeline do not have field proven applications.

This paper chronicles a novel attempt at acid stimulating each openhole lateral of a trilateral well in a carbonate reservoir. It includes the installation of the ICS in the same well. The challenges, results, learnings and future courses of action are documented in what should provide a template for continuous improvement.
FGF-21 as a Potential Biomarker for Mitochondrial Diseases
Authors: Scholle Leila Motlagh , Lehmann Diana , Deschauer Marcus , Kraya Torsten , Zierz Stephan
Published: January 2018

The diagnosis of mitochondrial diseases is still challenging due to clinical and genetical
heterogeneity. The development of advanced technologies including Whole-Exome-
Sequencing (WES) and Whole-Genome-Sequencing (WGS) has led to improvements in genetic
diagnosis. However, a reliable biomarker in serum could enhance and ease the diagnosis
and indeed reduce the need for muscle biopsy. Several studies suggest Fibroblast growth factor
21 (FGF-21) as a biomarker for diagnosis in mitochondrial disorders. It is known, that in
patients with mitochondrial disorders, the expression of FGF-21 gets elevated in an effort to
counteract the underlying metabolic deficiency. The growth and differentiation factor 15
(GDF-15) has been described as a potential biomarker for mitochondrial diseases, too. In the
present review, a literature research, using PubMed database about the reliability of FGF-21
as a biomarker for mitochondrial disorders and its comparison with GDF-15 has been performed.
Nociceptin /Orphanin FQ Peptide (NOP) Receptor Modulators: An Update in Structure-Activity Relationships
Authors: Mustazza Carlo , Pieretti Stefano , Marzoli Francesca
Published: January 2018

Nociceptin /Orphanin FQ Peptide” receptor (NOPr) is a G-protein-coupled receptor
with the nociceptin/orphanin FQ peptide (N/OFQ) as endogenous agonist. It is expressed
in the nervous system as well as in some non-neural tissues. Its activation has
pronociceptive effect at the supraspinal level, whereas at the spinal level it produces nociceptive
effects at low doses and antinociceptive effects at higher doses. NOPr is also involved
in mood and blood pressure regulation, immunoregulation, airway constriction,
feeding, urination, bowel motility, learning and memory. Selective NOPr agonists have
been tested clinically as anxiolytics and antitussives, and the antagonists as analgesics, antidepressants
and in the treatment of alcohol addiction. Two NOPr radioligands have also
been tested in humans as neuroimaging agents. Furthermore, the partial agonist peptide
SER100 and N/OFQ have been used in clinical trials, respectively for congestive heart
failure and overactive bladder. The evidence of interactions between NOP and μ-opioid
receptor (MOPr) receptors has been exploited in the use of mixed NOPr/MOPr modulators
as analgesics and in the treatment of drug addiction. These drugs are devoid of typical
opioid liabilities. In this review, we outline the latest advances in the structure-activity relationships
(SAR) of NOPr agonists and antagonists, with emphasis on affinity, activity,
selectivity and pharmacokinetic features.
Beyond the "Lock and Key" Paradigm: Targeting Lipid Rafts to Induce the Selective Apoptosis of Cancer Cells
Authors: Alves Anna Carolina Schneider , Dias Reinaldo Antonio , Kagami Luciano Porto , das Neves Gustavo Machado , Torres Fernando Cidade , Eifler-Lima Vera Lucia , Carvalho Ivone , de Miranda Silva Carolina , Kawano Daniel Fabio
Published: January 2018

For more than 40 years, the fluid mosaic model of cellular membranes has
supported our vision of an inert lipid bilayer containing membrane protein receptors that
are randomly hit by extracellular molecules to trigger intracellular signaling events. However,
the notion that compartmentalized cholesterol- and sphingomyelin-rich membrane
microdomains (known as lipid rafts) spatially arrange receptors and effectors to promote
kinetically favorable interactions necessary for the signal transduction sounds much more
realistic. Despite their assumed importance for the dynamics of ligand-receptor interactions,
lipid rafts and biomembranes as a whole remain less explored than the other classes
of biomolecules because of the higher variability and complexity of their membrane
phases, which rarely provide the detailed atomic-level structural data in X-ray crystallography
assays necessary for molecular modeling studies. The fact that some alkylphospholipids
(e.g. edelfosine: 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine) selectively
induce the apoptotic death of cancer cells by recruiting Fas death receptors and the
downstream signaling molecules into clusters of lipid rafts suggests these potential drug
targets deserve a more in-depth investigation. Herein, we review the structure of lipid
rafts, their role in apoptotic signaling pathways and their potential role as drug targets for
the treatment of cancer.
Multi-Target Directed Drugs as a Modern Approach for Drug Design Towards Alzheimer’s Disease: An Update
Authors: de Freitas Silva Matheus , Dias Kris Simone Tranches , Gontijo Vanessa Silva , Ortiz Cindy Juliet Cristancho , Viegas Jr. Claudio
Published: January 2018

Alzheimer’s disease (AD) is a progressive multifactorial neurodegenerative disorder.
Currently, no effective treatment is available and this is due to multiple factors involved
in pathophysiology and severity of AD. A recent approach for the rational design of new drug
candidates, also called multitarget-directed ligands (MTDL) strategy, has been used to develop
a variety of hybrid compounds capable to act simultaneously in diverse biological targets.
The discovery of drug candidates capable of targeting multiple factors involved in AD
pathogenesis would greatly facilitate in improving therapeutic strategies. This review is a
complement to another review article, recently published by our group, which covered the
previous period of 2005-2012, and highlights recent advances and examples of the exploitation
of MTDLs approach in the rational design of novel drug candidate prototypes for the
treatment of AD.
Proprotein Convertase Subtilisin/kexin type 9 Inhibition in Cardiovascular Prevention
Authors: Ali Ali , Costanzo Pierluigi , Hoye Angela
Published: January 2018

Elevated levels of Low Density Lipoprotein cholesterol (LDL-C) are directly associated with increased
risk for atherosclerotic cardiovascular and cerebrovascular events. Statins have been used to control serum LDLC
and this has translated into reduction in cardiovascular and cerebrovascular events. However, despite high dose
statin therapy, LDL-C control may remain inadequate in some patients, particularly those with familial hypercholesterolemia.
A new therapeutic approach has emerged in recent years with proprotein convertase subtilisin/kexin
type 9 (PCSK9) inhibitors.

In this review, we describe the development and the use of this new class of drugs.
Amyloid-β Inhibits PDGFβ Receptor Activation and Prevents PDGF-BBInduced Neuroprotection
Authors: Liu Hui , Saffi Golam T. , Vasefi Maryam S. , Choi Youngjik , Kruk Jeff S. , Ahmed Nawaz , Gondora Nyasha , Mielke John , Leonenko Zoya , Beazely Michael A.
Published: January 2018

Background:

PDGFβ receptors and their ligand, PDGF-BB, are upregulated in vivo after neuronal
insults such as ischemia. When applied exogenously, PDGF-BB is neuroprotective against excitotoxicity
and HIV proteins.

Objective:

Given this growth factor's neuroprotective ability, we sought to determine if PDGF-BB would
be neuroprotective against amyloid-β (1-42), one of the pathological agents associated with Alzheimer's
disease (AD).

Methods and Results:

In both primary hippocampal neurons and the human-derived neuroblastoma cell
line, SH-SY5Y, amyloid-β treatment for 24 h decreased surviving cell number in a concentrationdependent
manner. Pretreatment with PDGF-BB failed to provide any neuroprotection against amyloid-β
in primary neurons and only very limited protective effects in SH-SY5Y cells. In addition to its neuroprotective
action, PDGF promotes cell growth and division in several systems, and the application of PDGFBB
alone to serum-starved SH-SY5Y cells resulted in an increase in cell number. Amyloid-β attenuated
the mitogenic effects of PDGF-BB, inhibited PDGF-BB-induced PDGFβ receptor phosphorylation, and
attenuated the ability of PDGF-BB to protect neurons against NMDA-induced excitotoxicity. Despite the
ability of amyloid-β to inhibit PDGFβ receptor activation, immunoprecipitation experiments failed to
detect a physical interaction between amyloid-β and PDGF-BB or the PDGFβ receptor. However, G
protein-coupled receptor transactivation of the PDGFβ receptor (an exclusively intracellular signaling
pathway) remained unaffected by the presence of amyloid-β.

Conclusions:

As the PDGF system is upregulated upon neuronal damage, the ability of amyloid-β to
inhibit this endogenous neuroprotective system should be further investigated in the context of AD
pathophysiology.
Cetuximab and the Head and Neck Squamous Cell Cancer
Authors: Concu Riccardo , Cordeiro M. Natalia D.S.
Published: January 2018

The Head and Neck Squamous Cell Cancer (HNSCC) is the most common type of head and
neck cancer (more than 90%), and all over the world more than a half million people have been developing
this cancer in the last years. This type of cancer is usually marked by a poor prognosis with a really
significant morbidity and mortality. Cetuximab received early favor as an exciting and promising new
therapy with relatively mild side effect, and due to this, received authorization in 2004 from the European
Medicines Agency (EMA) and in 2006 from the Food and Drug Association (FDA) for the treatment
of patients with squamous cell cancer of the head and neck in combination with radiation therapy
for locally advanced disease. In this work we will review the application and the efficacy of the Cetuximab
in the treatment of the HNSCC.
Aurora Kinase Inhibitors in Head and Neck Cancer
Authors: Qi Guangying , Liu Jing , Mi Sisi , Tsunematsu Takaaki , Jin Shengjian , Shao Wenhua , Liu Tian , Ishimaru Naozumi , Tang Bo , Kudo Yasusei
Published: January 2018

Aurora kinases are a group of serine/threonine kinases responsible for the regulation of mitosis.
In recent years, with the increase in Aurora kinase-related research, the important role of Aurora
kinases in tumorigenesis has been gradually recognized. Aurora kinases have been regarded as a new
target for cancer therapy, resulting in the development of Aurora kinase inhibitors. The study and application
of these small-molecule inhibitors, especially in combination with chemotherapy drugs, represent
a new direction in cancer treatment. This paper reviews studies on Aurora kinases from recent
years, including studies of their biological function, their relationship with tumor progression, and
their inhibitors.
Traumatic Dental Injuries Resulting from Sports Activities; Immediate Treatment and Five Years Follow-Up: An Observational Study
Authors: Spinas Enrico , Mameli Antonello , Giannetti Luca
Published: January 2018

Background:

Traumatic dental injuries (TDIs) represent 18-30% of all oral pathologies and a considerable number of these are sports related. It is very important to treat sports-related injuries and prevent complications. However, very few studies investigate the most expedient therapeutic strategies for the treatment of dental trauma correlated to sports.

Objective:

The aim of this work was to focus on the average recovery time for different lesions, to assess adequate times for each athlete, to identify any association with complications and to investigate whether or not the use of mouth-guards interfered with a full recovery to normal health.

Methods:

This study involved a group of 30 athletes (15 male and 15 female) who had dental injuries of varying severity.

For the purposes of data collection, two classifications were taken into account: a classification for hard tissue trauma and another for periodontal lesions. The athletes were subdivided in “type of lesion’ groups”.They were then treated depending on their individual lesions and followed up for 5 years. A statistical analysis was carried out to study the association between recovery time, lesion types and occurrence of complications.

Results:

The time for recovery was different for each type of lesion and ranged from 3-5 days (only uncomplicated fractures) to 14 days (all hard-periodontal tissue traumas). The total number of recorded pulp complications amounted to 6 cases. Among 30 athletes, 20 had begun and maintained, during the five-year follow-up period, the habit of using mouth-guards when practicing their sport activities.

Conclusions:

Recovery time and the severity of lesions are statistically associated: the more serious the injury, the more time an athlete needs to recover and return to competitive sports events. Furthermore, recovery time and precautionary measures (mouth-guards) did not influence the onset of complications. The subjects’ habit of wearing a mouth guard continued even after the end of the therapy and follow-up periods.