bluuebunny/crossref_metadata_2025 huggingface dataset:
Importance of selenium homeostasis in chronic and end-stage kidney diseases
Authors: Kiss István
Published: October 2013

Selenium is an essential trace element for the human body with a significant antioxidant effect. Selenium deficiency and excess are both detrimental for proper functioning of the human body. The possible association between selenium deficiency and acute or chronic renal disease, along with their complications has been less intensively investigated, however, there are firm data showing that selenium deficiency and renal failure increase the risk of both coronary artery disease and total mortality. Further studies revealed that selenium deficiency increases the risk of death due to infection in patients treated with hemodialysis through dysfunction of the immune system. However, there are no data whether the imbalance of selenium metabolism, especially selenium deficiency, could cause chronic kidney disease or renal failure. As far as results of selenium measurements, there is convincing evidence that protein loss and renal replacement treatment reduce serum selenium levels. Despite some contradictory results obtained from various studies regarding selenium deficiency in chronic kidney diseases, it seems that selenium supplementation may be beneficial in many patients with severe or end-stage kidney disease including those treated with dialysis. Orv. Hetil., 154 (41), 1641–1647.
Structural and Functional Properties of Iron (II, III)-Doped ZnO Monodisperse Nanoparticles Synthesized by Polyol Method
Authors: Collantes Yesusa , Perales-Perez Oscar
Published: October 2013

In this work, bare and (Fe3+ and Fe2+)-doped ZnO nanoparticles (NPs) have been synthesized in a polyol medium at 180oC. The synthesis in polyol allows a precise control of doping under size-controlled conditions. The Fe concentration varied in the 0-2 at. % range. As-synthesized samples were characterized by X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR), Photoluminescence (PL) spectroscopy and Vibrational Sample Magnetometry (VSM). XRD measurements confirmed the formation of well crystallized wurtzite ZnO with absence of secondary phases in bare and doped samples; the average crystallite size was estimated at 8.4 ± 0.3 nm for bare ZnO NPs. Systematic shifts in the main diffraction peaks due to the incorporation of the dopant species were observed in the Fe3+ and Fe2+ doped-ZnO samples. FT-IR analyses evidenced the presence of organic moieties on the surface of the nanoparticles that are associated to the functional groups of polyol by-products; these adsorbed species could explain the observed stability of the NPs when suspended in water. PL measurements (excitation wavelength 345 nm) reveled that a tuning in the emission bands of ZnO NPs can be achieved through doping. VSM measurements evidenced a weak but noticeable ferromagnetic response at room temperature (RT) in doped samples.
Effect of Adding Zn in Cd1-XZnXS Thin Films Prepared by an Ammonia-Free Chemical Bath Deposition Process
Authors: Carreón-Moncada Iyali , González Luis A. , Pech-Canul Martin I. , Ramírez-Bon Rafael
Published: October 2013

The present investigation work shows the results of Cd1-XZnXS thin films (where X= 0.04, 0.08, 0.12, 0.16 and 0.2), obtained by total ammonia-free chemical bath processes. The reaction solutions were prepared with precursors of metallic salts as CdCl2 and ZnCl2 and replacing the ammonia with trisodic citrate (C6H5O7Na3) as complexing agent. The reaction solutions were stabilized with KOH to get alkaline solutions. As result of adding Zn, the as deposited films showed changes in their morphological, structural and optical properties. Moreover, additional changes were obtained when thermal treatments to 400°C under N2 environment were applied to the as deposited films. The agglomerates at the surface of the annealed films showed larger grain sizes compared to that of the as deposited films. Due to preferential orientation of the hexagonal wurtzite-type structure in the films, changes in the intensity in the (002), (100) and (101) peaks from x-ray diffraction analysis were observed. Finally, a reduction on the maximum energy band gap from 2.65 to 2.59 eV was obtained as effect of the annealing treatment to the films.
Ultrafast Optical Measurements of Acoustic Phonon Attenuation in Amorphous and Nanocrystalline Silicon
Authors: Andrade Joseph A. , Rachmilowitz Bryan E. , Daly Brian C. , Norris Theodore B. , Yan B. , Yang J. , Guha S.
Published: October 2013

We have measured the attenuation of longitudinal acoustic waves in a series of amorphous and nanocrystalline silicon films using picosecond ultrasonics. We determined the attenuation of amorphous Si to be lower than what is predicted by theories based on anharmonic interactions of the ultrasound wave with localized phonons or extended resonant modes. We determined the attenuation of nanocrystalline Si to be nearly one order of magnitude higher than amorphous Si.
Expanding the Drilling Envelope to New Horizons in Saudi Aramco Shaybah Operations
Authors: Saleh Rami , Verma Chandresh , Osman Ahmed , Kuncahyo Dony , Elgali Yasir , Mikati Nadim
Published: October 2013

The Shaybah oil field is a major oil-producing field for Saudi Aramco. The field has been extensively developed by exploiting horizontal drilling technology for the last two decades. A typical Shaybah well is a shallow extended reach drilling (ERD), fork-type multilateral, targeting the oil reservoirs in the Shu'aiba formation. Because of low reservoir permeability, drilling maximum reservoir contact (MRC) wells has been a needed practice in Shaybah field.

In a quest to maximize reservoir contact in the Shu'aiba formation, Saudi Aramco has adopted strategies to increase both the lateral section lengths and the number of laterals via ERD and deep openhole sidetracks. The main challenges that are faced drilling extended reach laterals and performing deep sidetracks are severe drilling dynamics experienced by downhole drilling equipment; causing considerable nonproductive time (NPT), and drill string strength and buckling limitations; preventing weight transfer to conventional steerable systems.

In SHYB-A, Saudi Aramco implemented new drilling technologies and procedures to manage the adverse drilling dynamics challenges, maximizing reservoir contact to new field records and extending the drilling envelope to record laterals and new horizons.
Communication protocol management tool between Rigs in "CAT-A" wells and the successful story to deliver sour gas project
Authors: Elsaify Abdelfattah
Published: October 2013

This paper is going to present Communication Protocol Management Tool between Rigs in "CAT-A" Wells and the Successful Story to Deliver Sour Gas Project and using Simultaneous Operations Management Tool based on a new concept and the respective qualification program run in the Field.

CAT-A; CATEGORY-A is the high risky wells, gas wells, and exploration wells has high content of H2S and CO2 We should think about Communication Protocol in SIMOPS terms of "Sharing Information Maximizes Our Personnel Safety". With this stated, a plan can be created by following a process outlined as: Communication Protocol - Study the project, Identify possible SIMOPS, Meet with all Parties Involved, Organize a Plan, and Share the plan/Information. This practice should begin at project inception and is repeated throughout the entire process until completion. Thus making the SIMOPS plan dynamic and causes communication between all parties.

This Communication Protocol I in SIMOPS plan will be applicable from spud in Rigs operation and all persons likely to be working within the Emergency Planning Zone (EPZ) during the drilling of the H2S bearing formations must be made aware of this plan and establish a means of communication with Field Control room prior to entering the zone.

Based on this approach, we implemented a Communication Protocol in SIMOPS plan in one of Sour Gas Field where the Rigs needed to operate inside the emergency planning Zone (EPZ) of the third one of other project. This is one of the biggest challenges in Sour Gas Field project due to high risk encountered with high exposure of H2S up to 26% PPM and 10% CO2 in one of High Gas Reservoir Field. There were numerous challenges in terms of the harsh sour gas environment.

The implementation of this particular Communication Protocol in Simultaneous Operations was very successful, several large scale exercise were made to verify the effectiveness of the process and an evacuation of the EPZ was done before entering the H2S successfully, this project and the other Rigs within the EPZ area completed the drilling and production testing operation objectives without incident and successfully with no harm.
Next-Generation, Right-Angle-Setting Composition for Eliminating Total Lost Circulation
Authors: Savari Sharath , Whitfill Donald L. , Scorsone Jason T.
Published: October 2013

The total loss of fluid during drilling continues to plague the oil and gas industry. For many reasons, the various technologies that have attempted to combat this severe issue have been unsuccessful. In Middle East drilling operations, carbonate and limestone formations pose difficult geological conditions, such as naturally occurring fractures and vugular and/or cavernous zones. These troublesome zones are the primary reason for additional costs, including increased drilling non-productive time. The lack of an efficient, controllable solution has led operators to implement complicated and potentially risky drilling practices to access the targeted depths of many wells in the area.

A Right-Angle-Setting Composition (RAS-Co) has been developed to provide the industry an efficient solution for plugging and isolating specific problematic zones. The RAS-Co is engineered to remain at a low fluid viscosity (18–30 cP) during placement and quickly react to bottomhole temperature in a consistent and controllable manner. The instant transition in viscosity from a thin fluid to a rigid composite lets the technology be mixed at the rig site, pumped through any drillstring configuration, and spotted/placed in any suspected loss zone—thereby eliminating further fluid losses. The innovative RAS-Co can be applied in two different versions. The dual-pill version can be used in zones up to 400°F (~204°C) wherever water-based fluids are being used. This version is deployed like a standard ‘gunk squeeze’ application. The time-delayed single pill version can be used where both non-aqueous and water-based fluids are being used at up to almost 300°F. It can tolerate up to 50% contamination with water or drilling fluids, and will not invade the formation. Both versions can be removed with acid. The chemical formula of RAS-Co is customized to offer a versatile, yet controllable solution that is effective for stopping even the most severe lost circulation events.

Key advancements made during the developmental stage (laboratory data) are presented, as well as several successful field applications of the engineered, fluid composition.
One Page Program (OP2): New systematic drilling program work flow for time and effort optimization, A successful Trial in ADCO-
Authors: Al Menhali Adnan Mohammed , Sulaiman Ali , Al Shamsi Juma , Bin Shamlan Abdulla , Abu Aishah Abdel Nasser , Kuyken Chris
Published: October 2013

One Page Program (OP2) is a creative approach to save environment and time. Using the best available process and practices in our daily activities is one of our aims and core values towards the HSE in ADCO. Therefore, as a valuable step and part of our commitment, we have minimized consumption of papers by initiating OP2. Implementing (OP2) upgrades the responsibilities of Drilling engineer to be in charge of other supportive operations such as; HSE, mud properties, cement slurry properties, direction drilling severities and reservoir rock and fluid properties and its characterization. OP2 eliminates the repetitive work which has direct effect on time saving and maintaining the quality of the program.

ADCO's Business Plan demands high number of wells to be delivered in development Fields for better reservoir sweeping efficiency such as; Infill drilling, injector's patterns and maintenance work-over operations in the end of each year. Also lately, for improving Drilling Division system organization, a life cycle engineer concept has been introduced; where two drilling engineers work back to back and each one is responsible for planning, well engineering and operations execution for every alternate well. Therefore drilling engineer has to maximize his effort and utilize his time efficiently in order to produce multiple drilling programs with excellent quality at the same time.

The (OP2) idea evolved and thought to be useful for the standard wells which have 90 % contribution to the business plan.

This paper will take you through the process and steps in how it was evolved. Also the challenges faced between the field asset teams in formatting & generating the OP2. In addition to that the approval process and signature flow of OP2.
3D Displacement Simulator Realistically Predicts Free Fall during Cementing
Authors: Chiney Abhinandan , Yerubandi Krishna Babu
Published: October 2013

Understanding equivalent circulating density (ECD)/downhole pressure is important for a successful cement job design and execution. One of the critical parameters to control ECD is the pumping rate, which, in turn, controls the wellbore fluid rates. But, in some cases, specifically when pumping heavier fluids, the well might go into a scenario called "free fall." During free fall, the fluid in the wellbore loses physical contact with wellhead/pump and flows on its own under the influence of gravity, making control of ECD difficult from the surface. For a well under free fall, the dynamics of wellbore rate depend not only on the densities but also on the movement of the wellbore fluids. Traditionally, job design simulators assumed flat fluid interfaces, thereby compromising on the accuracy of wellbore rate estimation. A more accurate estimation of the fluid movement/flow patterns would help operators better predict the pressures.

In the present work, a free-fall algorithm is implemented to complement a three-dimensional (3D) displacement simulator. The displacement simulator solves momentum balances, continuity equations, and scalar convection-diffusion equations on top of a 3D grid to provide fluid flow profiles in three dimensions. The simulator is capable of simulating intermixing of fluids and the resultant frictional pressure drops. This paper presents, for a model wellbore configuration, the differences in free-fall estimation and the resultant differences in ECD estimation between a traditional hydrostatic job design simulator and a 3D simulator. Traditional hydraulics is observed to be conservative for estimating wellbore rates compared to the 3D simulator during free fall, which can result in predicting lower than actual ECDs.
Advanced Bottomhole Assembly Design and Motor Technology Extends Reach and Optimizes Well Placement in Challenging Middle East Wells
Authors: Dabyah Ali Al , Toutoungy Fadi , Aldawood Jahad , Al-Madan Mohammad , Hudaithi Mohammad Al
Published: October 2013

Poor drilling performance can lead to increased costs when enhanced drilling performance and extended reach are the main goals for oil operators. Service companies, using the latest technology, can achieve these objectives.

A rotary steerable system (RSS) with advanced motor technology provides significant performance improvements. In addition to the improved drilling performance, the advanced system enables extended reach drilling to wells that were previously beyond the limits of a project.

This paper presents the advances in motorized RSS technology and bottom-hole assembly (BHA) design considerations that provide increased drilling performance, thereby enabling faster well delivery and extended drilling. In addition, the authors examine ongoing initiatives aimed at reducing drilling risk (vibration and torque) and optimizing well placement.

The motorized RSS technology has been used in many applications, including open hole side tracking, whipstock drill-off, cement plug side tracking and horizontal section drilling. In most instances, the technology demonstrated the capacity to deliver better penetration rates and directional control that outperformed conventional directional drilling systems. Using a motorized RSS BHA to drill-off the whipstock saved rig time by eliminating one trip in each offshore oil lateral. In addition, the nearly 25.6% improved rate of penetration (ROP) was one of the main impacts for using the motorized RSS BHAs in an onshore oil field.

The paper describes the experiences from two case studies in the Middle East. The extremely long, extended drilling of a horizontal section of an offshore field, and the successful targeting of a thin reservoir while exceeding ROP targets in an onshore field.
Automated Downhole Vibration Damping
Authors: Hutchinson Mark
Published: October 2013

Automated downhole rotary steering devices that were developed in the 1990's for directional control were initially d eployed on extended reach wells. They are currently more widely applied to improve both drilling performance and wellbore quality. Automated surface control systems have also been developed for safer pipe-handling, downhole pressure control and for mitigating stick-slip when induced by cumulative friction along the drill string. A novel self-adapting downhole drilling tool can now autonomously detect and suppress excessive downhole shock and vibration levels by adjusting the stiffness of its damping fluid which in turn instantaneously changes the vibration characteristics of the bottom-hole-assembly.

The downhole drilling environment is continuously and unpredictably changing as the drill string gets longer and as stabilizers navigate around micro-doglegs or past geological strata where the borehole has enlarged and no longer provides stabilization. Whenever the driller (or an automated control system) makes changes to the surface drilling parameters this also changes the downhole vibration characteristics. Each blade of the bit can additionally induce torsional shocks as it alternately cuts softer and then harder rock at a lithological transition in an inclined borehole when the formation on the upper side of the wellbore circumference is harder or softer than that on its lower side.

In order to respond to a frequently changing environment, vibration sensors in a shock-sub send data to its autonomous control system with an intelligent algorithm that iteratively adjusts the stiffness of a magneto-rheological damping fluid in response to the severity of the various modes of downhole vibrations. In this way the novel self-adapting shock-sub seeks out the optimal dynamic stiffness of the drilling assembly for each change in the downhole drilling environment.

This paper presents insights as to the nature of downhole vibrations encountered when drilling in the Middle East, describes the intelligent self-adapting shock-absorber, examines some of the characteristics of a magneto-rheological damping fluid and explains how the intelligent shock-absorber can be configured for various drilling scenarios.
First Fully Sulfide Stress Cracking Resistant Drill Pipe System for Critical Sour Drilling
Authors: Jellison M. , El-Rayes K. , Al-Khanferi N.
Published: October 2013

As the severity of sour drilling applications has increased the need for drill stem materials resistant to Sulfide Stress Cracking (SSC) has accelerated. This is especially true in the Middle East with some of the most severe H2S environments in the world. Sour service drillpipe, built with SSC resistant tubes and tool joints, has been available for some time. The friction welds joining the tubes and tool joints were not SSC resistant. This has been acceptable for many sour applications since the weld is not the high stress area of the drillpipe and because the operator has some control over the environment through the drilling fluid properties and additives. As more severe H2S environments were identified for exploration, it became apparent that a fully SSC resistant drillpipe system including the friction welds was necessary. This paper presents the successful development of SSC resistant friction welds for critical sour applications. It describes the engineering and manufacturing philosophy, laboratory testing procedures and results and applications for the SSC resistant drillpipe. Since NACE MR-0175 does not cover friction welds the engineering team developed unique and innovative criteria and testing procedures. A new patent pending four point bending test procedure and fixture were develop that employed unpolished samples that represent the surface finish of the product in service, unlike polished samples typically used in NACE TM-0177 testing. This paper provides background information on the evolution of sour service drillpipe and reviews case histories where sour service drillpipe has been successfully used including the new pipe with SSC resistant friction welds. A preview of some vital planning considerations for an upcoming world-class ERD well in Saudi Arabia with high H2S concentrations is also included. The paper can benefit drilling engineers involved in critical sour drilling operations in the Middle East and other world regions.
Remote Operations Centers and Re-engineering Work Processes: Retaining Competent Personnel in an Extremely Competitive Marketplace
Authors: Saeverhagen E. , Kellas R. , Bouillouta F.
Published: October 2013

During the last 5 to 6 years, the utilization of real-time operations centers has gradually expanded to comprise a wide range of remote services traditionally handled at the rigsite. Some oil and gas operators have reduced the footprint for new and mature fields, which has driven the need to re-engineer the traditional work processes carried out at the rigsite. Another driver is the reduced availability of competent personnel. Over time, several functions have changed and merged into one common operation. In addition, multiple functions have been relocated from the rigsite to centrally located operations centers where the "digital part" of the jobs is now performed. Field personnel have undertaken in-depth cross training to perform new, more hands-on functions, and senior personnel have undertaken key functions in the real-time operations centers. The new remote operations approach, transforming several traditional rigsite positions, requires changes in the individual's thought and skill set. Oil and service companies, therefore, are developing and adopting new remote operations strategies for the workforce to meet the ever-increasing demand for efficiency and automation. The underlying challenge is the availability of younger competent personnel in an industry that will soon experience a workforce demographic age gap, as the aging workforce retires over the next decade. The remote operations initiative enables retention of highly competent senior personnel in the operations centers, providing knowledge transfer, cross-discipline training and efficient and effective operational advice to the workforce in the field as well as to the client.

The paper presents the evolution of remote operations over a decade with examples and effects, and discusses how remote operations centers, driven by new digital technologies and work processes, will influence the industry in the future.
Fully Rotating PDC Cutter Gaining Momentum: Conquering Frictional Heat in Hard/Abrasive Formations Improves Footage Totals
Authors: Zhang Youhe , Burhan Yuri , Chen Chen , Tammineni Sandeep , Durairajan Bala
Published: October 2013

A fixed PDC element creates an inherent limitation because only a small portion of the cutter contacts formation and as the cutter wears/chips drilling efficiency declines. It is well documented that wear flats generate a high degree of frictional heat which breaks the diamond bond. To solve the issue an R&D initiative was launched to investigate different methods to enable a PDC shearing element to rotate while drilling to increase overall cutting efficiency and bit life. Engineers investigated different retention methods to create the optimal driving force and allow full cutter rotation.

The assemblies were modeled using an FEA based engineering system and then tested in the laboratory to evaluate function and strength. Experiments confirmed the new rolling cutter (RC) was able to shear an extended section of rock with a consistent force level (lbs). A traditional fixed-cutter assembly required steadily increased force to drive the cutter the same distance. Examination of the rolling cutter's dull condition clearly indicated significantly improved durability and cutting efficiency.

The recent introduction of a new rolling cutter PDC bit that utilizes the entire 360° of diamond edge has delivered positive results in field trials. Initial testing was targeted at the highly abrasive Granite Wash formation in Western Oklahoma/Texas Panhandle where cutter wear is the predominant failure mechanism. A six-bladed prototype PDC bit, with three rolling cutters positioned in the shoulder area was run on PDM and increased total footage capabilities compared to conventional PDC.

The next prototypes were equipped with a smaller, yet more robust generation-3 retaining device. Starting in Q4 2012, the total RC count/bit was progressively increased on five/six bladed designs from 3, 5, 7, 10 and then 12. The 13mm designs are consistently exceeding footage totals compared to offsets in central USA, North Dakota and Canada. In central USA, which contains the largest data set (13 RC runs) the rolling cutter has increased average footage totals by 34.4% compared to offsets drilled with standard PDC from various manufacturers. Case studies will document performance improvement in these challenging drilling environments. The authors will discuss plans to develop a rolling cutter bit to extend lateral run length in an abrasive Middle East formation.
South Oman Well Engineering: Where Creativity Runs Deep
Authors: Hammour Abdel-Moneim Abdel-Fattah , Al-Battashi Yousuf
Published: October 2013

Creativity and innovation in well delivery are key drivers for overcoming the challenges arising from fields' maturation and the need to maximize the recovery factor via new technology and unconventional ways of problem solving. In spite of steady performance improvements and many broken drilling records achieved, through many years of drilling operations, the South Oman Well Engineering Team (UWS) are continually looking for areas of further improvement and going beyond the previous field records by applying different techniques such as in-depth wells' detailed design, Global Well Delivery Process, Provocative Concepts, Lean, "Out of Box Thinking Approach"etc.,.

Recently; the team has successfully optimized the casing design for one of the most common oil producer well types simply by tapering the bottommost 40 m of the 9 5/8-in. production casing to 7" casing size complete with 7". casing floats. This eliminate the dedicated trip to drill out the 9 5/8-in. float equipment with an 8-1/2" drilling assembly, as the reservoir section is designed to be drilled with 6-1/8" bit and cased with 4-1/2". WWS (Wire-warped screens) including EZIP (Open Hole Swellable Packer). With in excess of 20 of these well designs per year a saving of USD 15,000 on consumables and 8 hours of rig time are realized per well completed. The potential saving is USD 300,000 over the course of the year.

Lean principles have been deployed in the most standard horizontal well type where the team has taken advantage of the programmed 6 hours waiting for wellbore acid soak to lay down the excess drill pipes and prepare the completion tubing in stands. This job, conducted some ±120 times per year represents a saving of USD10,000 per well. The potential saving is USD 1.2 Million over the course of the year

Shallow gas drilling practice has been challenged and updated. The surface hole in South Oman is characterized by medium to hard rock (limestone interbeded by gypsum with little strikes of shale and Anhydrite) of 14 kpa/m fracture gradient. Total losss of drilling fluid in these shallow formations is always seen at around ±420 m depth (UER formation). Traditionally a divertor system is used instead of a BOP when it is thought that the surface formations have insufficient strength for a kick to be shut in with the BOP without breaking down or cratering the surface formations.

The two conditions mentioned above makes the the risk of rig cratering unlikely therefore the use of 13-3/8" Diverter system has been phased out and replaced by 13-3/8" BOP system for the whole well operation. This has saved Diveter system rental cost and installation time. This job is being repeated ±40 times per year saving USD 25,000 per job, a yearly saving some USD 1Million per year.
The Importance of Acceptable Electrical Power Quality to the Drilling Industry Worldwide
Authors: Evans Ian C , Al Khaimah Ras
Published: October 2013

Electrical power quality is routinely taken for granted by oil and drilling industries worldwide despite the fact that the quality of electrical power is fundamental to the safety and operational integrity of drilling rigs and oil production platforms worldwide, without exception. US$100m's are lost each year, direct and indirectly, due to poor quality of power.

Currently some offshore safety authorities are considering the imposition of strict limits on harmonic voltage distortion in their jurisdiction. Harmonic voltage distortion may become a regulatory issue in the future.

This paper examines the salient harmonic and power quality issues onboard drilling rigs with full SCR drilling packages, as well the more recent hybrid (mixed SCR and VFD drives) and full VFD (variable frequency drive) drilling packages.

With SCR drives the main problems are harmonic voltage distortion, line notching and voltage spikes which destroys capacitors inside equipment. Low generator power factor is also often an operational problem.

For VFDs, harmonic voltage distortion is also a problem but increasingly so is excessive common mode voltage caused by VFD operation which disrupts susceptible electronic equipment.

The paper will offer advice on proven solutions for common power quality problems and introduce a remote/local power quality monitoring system which can be easily retrofitted to existing rigs and platforms.
Formation Damage Evaluation of Drill-in Fluid Lubricant Products for Optimized Production in Low-Permeability Gas Reservoir
Authors: Osode Peter , Otaibi Msalli , Bataweel Mohammed , Ammari Saleh , Himes Ron
Published: October 2013

Conventional lubricant products composed of different surfactant materials are required in water-based mud for drilling highly deviated and horizontal pay zone sections due to their lubricity associated with torque reduction and better penetration rate. Drill-in fluid (DIF) filtrate-induced formation damage in low-permeability gas reservoirs as a result of water blockage and reduced relative permeability to gas can be significant in view of the high capillary pressure associated with small pore throats. Formation damage risk assessment of the drilling lubricants utilization was therefore considered critical for a low-permeability gas reservoir development project.

Lubricant product evaluation experiments were designed to provide the production impairment potential measurements using Berea and Unayzah sandstone cores with a laboratory formulated DIF and base brine containing 3–4% lubricant by volume and to confirm fluid compatibility with divalent salt (CaCl2) brine. Fluid compatibility and emulsion risk was investigated using mineral oil as the representative formation hydrocarbon fluid. Core flood and dynamic filtration tests were carried out at an estimated bottom-hole temperature of 250 °F and pressure of 1,000 psi for the high-temperature reservoirs while the compatibility tests were carried out at room temperature. Filter cake removal tests were also performed by using high pressure, high-temperature filter press equipment and synthetic disks to determine filter cake removal efficiency with acid brine breaker fluid.

The obtained results from the laboratory study were integrated to evaluate and rank the lubricants based on their assessed formation damage risk. The test results showed that both lubricant return permeability and compatibility tests were important in selecting the best performance lubricant.

This paper discusses the experimental analysis of the formation damage potential of 12 commercially available water-based mud (WBM) lubricants. It also provides an insight into the formation damage (FD) impact of the drilling fluid lubricants on gas reservoir deliverability.
Precise Gain and Loss Detection Using a Transient Hydraulic Model of the Return Flow to the Pit
Authors: Cayeux Eric , Daireaux Benoît
Published: October 2013

Abnormal variations of pit volume are a prime indicator of mud losses and formation fluid influxes. However the detection of gain and loss at the pit level can be difficult because of the transient behavior of several components in the hydraulic loop. For instance, during circulation the compressibility of the drilling fluid changes the total volume of mud needed to fill the well compared to static conditions. Similarly, changes of the drilling fluid temperature modify the volume of mud due to its thermal expansion. Furthermore, the transport and separation of cuttings also influences volume variations in the pit. Finally, the retention capacity of some of the mud transport and treatment equipment (e.g., return flow-line, shakers, sand-trap, degasser, transfer pit) has a direct impact on the active pit level. All of these effects are transient and can cause substantial variations of the active pit volume that may be interpreted as gain or loss while they actually have natural origins.

Most of these effects are well known and are dealt with in a pragmatic way by using finger printing between the current pit volume variation and a reference pattern obtained in similar drilling conditions. Nevertheless, the finger printing method has its limitations when the current drilling condition variation does not have an obvious reference pattern. In addition, it necessitates a selection of the reference pattern by an operator and therefore is rather difficult to automate.

This paper describes in detail a transient hydraulic model of the downhole and surface equipment effects on the pit volume variations. Several use cases are also described including early kick detection with small margins during pump shutdown and detection of tiny gains during draw-down tests used in an MPD (Managed Pressure Drilling) operation.
Minimizing Phase Trapping Damage Using Malaysian Diesel Oil
Authors: Lashari Arshad A. , Shuker Muhannad T. , Bahrami Hassan , Memon Khalil R. , Memon Faisal H. , Kumar Sandeep
Published: October 2013

The low permeability and tight gas reservoirs are problematic throughout of their development (drilling, completion, stimulation and production) around the wellbore. However, they required advanced improvement techniques to achieve flow gas at optimum rates.

Phase Trapping or retention of fluids is a form of mechanical formation damage mechanism, which is caused by fluid invasion into formation, and also when liquid leak-off into formation during fracturing stimulation near the wellbore. Low permeability and tight gas reservoir are sensitive to water invasion damage results create water blocking and phase trapping damage due to high critical water saturation, relative permeability effects, capillary pressure and Interfacial tension between produced fluid and wellbore fluid. Proper evaluation of damage and its factors which influenced its severity is essential for prevention and optimizing well productivity.

Thus, this study is presenting both laboratory experiments and simulation to evaluate phase trapping damage. In which, the core flooding was performed to evaluate permeability damage by using Malaysian diesel-oil drilling fluid in comparison with water based drilling fluid. Further, interfacial tension was tested between produced gas and wellbore fluids at different temperature and pressure conditions. The effect of interfacial tension on phase trapping damage was observed and validate with the result of core flooding experiments where the affect of water injection and diesel-oil injection on core permeability was studied and shown. Reservoir Simulation approach was also used to study the effect of relative permeability curves on phase trapping damage and its impact on well productivity. The result highlights the benefits of using Malaysian diesel-oil in drilling and fracturing the low permeability and tight gas reservoirs in meaning of 30% increment in well productivity compared with water based fluid.
Strategies for Improving Sweep Efficiency and Waterflood Recovery in a Complex Reservoir in the Greater Burgan Field; Learning from a Pilot Water Injection Project and Evaluation Using Sector Model Simulation
Authors: Rajan S.. , Al-Naqi M.. , Ameen A. A. , Al-Hashash H. H. , Madhavan S.. , Al-Qattan A.. , Al-Enizi N.. , Al-Qattan M. N. , Brooks A. D. , Beer A..
Published: October 2013

The Greater Burgan Field, operated by Kuwait Oil Company (KOC), is the largest clastic and overall the second largest oilfield in the world. First discovered in 1938, with production from 1946, production to date has relied on primary recovery methods. In recent years secondary and enhanced recovery techniques have been investigated with water flood now at an advanced state of implementation. The first such water flood project is in the Upper Cretaceous (Cenomanian) Wara Formation, one of the main producing reservoirs within the Greater Burgan complex where production has been accompanied by falling reservoir pressure.

The Wara Formation comprises multiple sandstone units deposited in a fluvial-tidal coastal system. The reservoir exhibits a considerable degree of permeability heterogeneity, which poses significant challenges to the implementation of waterflood. The highly complex nature of the reservoir necessitate for implementation of suitable strategies from an early stage of waterflood to ensure better volumetric sweep and ultimate recovery. Several initiatives/studies, including sector model simulation, were undertaken to formulate strategies and evaluate the waterflood performance in this multilayered reservoir.

This paper summarizes results of the studies and strategies: Issues related to vertical sweep and lessons from pilot study.Strategies for improving vertical sweep.Evaluation of strategies by using sector model simulation to improve recovery.Well completionstrategies and candidate selection criteria.
Understanding True Unconventional Reservoir Properties Using Nanoscale Technology
Authors: Hu Dandan , Yang Vincent , Li Gang , Chen Cheng , Matzar Luis
Published: October 2013

Research on shale using focused ion beam/scanning electron microscopy (FIB/SEM) technology has become commercially important. However, the traditional method used in the industry tends to misinterpret reservoir properties. With the improved method discussed in this paper, results are free of perspective distortion and shading effects, and it is possible to preserve the true pore throat shape and three-dimensional (3D) volume information. Accurate pore throat information assures the most reliable calculation of porosity and permeability and benefits the prediction of shale gas/oil recovery. Furthermore, this work is not limited to shale gas/oil studies—other tight gas systems can also be investigated using this method. The same technology can also be applied to coal beds to study cleats' patterns and impurities (clays and sulfides) in coal samples.
"Chlorine Dioxide for the Treatment of Microbiological Growth and Elimination of Under Deposit Corrosion in Refinery and Oilfield Source Water Systems"
Authors: Barron Keiron
Published: October 2013

The control of microbiological fouling in industrial cooling water for ‘open-recirculating’ and ‘once-through’ systems is important for reducing corrosion as well as increasing process efficiency and equipment longevity. Microbial biofilms insulate well and cause significant loss of heat transfer efficiency. In addition, they promote ‘under-deposit corrosion’ by multiple microbial induced corrosion (MIC) mechanisms. Furthermore, in ‘once-through’ seawater-cooled water systems where there is potential for colonization by various species, mussels create additional problems.

Historically, microbiological growth is controlled through a continuous chlorine feed, either as gaseous chlorine or sodium hypochlorite form. Gaseous chlorine has been largely eliminated because of safety concerns involving handling. Sodium hypochlorite is frequently used, but has significant problems involving storage, onsite generation and its usage in high concentrations leading to corrosion. In addition, recent environmental regulations limit the amount of these oxidants and their reaction by-products, such as tri-halomethanes, which can be discharged into waterways.

Chlorine dioxide an alternative that is a highly effective and safe microbiological control program. It is superior in offers a performance to all other chemistries with none of the environmental disadvantages. It is capable of maintaining excellent control of microbiological growth in cooling water systems and hence removing potential for MIC. This paper discusses how chlorine dioxide is generated, highlights its effectiveness against microbiological bacteria and presents the results of applications under various operating conditions, including those encountered in the Middle East.

The author recognizes SPE copyright
Digital Oilfield Technologies Enhance Production in ESP Wells
Authors: Al-Mutawa S. A. , Saleem E.. , Anthony E.. , Moricca G.. , Kain J.. , Saputelli L..
Published: October 2013

Two common challenges to sustain production in North Kuwait (NK) include (1) management of artificial lift equipment run life and (2) reduction of production decline through pressure maintenance by water injection. Standard electric submersible pump (ESP) management guidelines promote practices to protect ESP run life while sacrificing well production rates. However, using operating rates that are not always safe can permit optimum reservoir recovery. Better management of well production targets is required to maintain safe ESP operation ranges while pushing the limits to increase production.

A methodology has been developed to continuously optimize the well production potential without surpassing its safe operating envelope, keeping pump intake pressure (PIP) above the bubble point, ensuring optimum delivery at the surface, and minimizing pump downtime. This workflow was developed to assist the engineers in expediting data analysis and interpretation.

This paper describes the developed production optimization methodology, which enables short- and long-term production enhancement while honoring reservoir, ESP, and surface constraints. The process involves historical and real-time data collection and production test interpretation. From this analysis, the best estimations of short- and long-term well production potentials are identified, and the correspondent action plans are determined.

The developed workflow and the result of such an iterative production optimization process are illustrated. To date, as a result of this effort, an average of 8% in production gains has been certified in a number of wells in Sabriyah, NK.
Laparoscopic insemination of sheep in Republic of Serbia
Authors: Milovanovic A. , Maksimovic N. , Barna T. , Lazarevic M. , Delic N.
Published: October 2013

This paper describes a procedure of laparoscopic insemination (LAI) performed
in 42 Ile de France ewes with deep-frozen rams? semen. Frozen semen doses was
imported from France, originating from two rams (A and B), and used
intermittently in three LAI cycles on different females. The ewes were
examined ultrasonographically for pregnancy, two months following
insemination and data of lambing were recorded at the end. Total achieved
lambing rate was 61.90% (26/42) and total number of lambs was 49 (prolificacy
1.88; 1.16 lambs per sheep included in LAI protocol). Three labs from 2 ewes
were stillborn and one dyed at 10th day after lambing. Lambing rates for rams
A and B were 53.85% (14/26) and 75.00% (12/16), respectively. Introduction of
laparoscopic insemination of sheep with imported deep-frozen semen of top
quality rams, gaining technical experience and achieving conception rate over
65% could make this technique acceptable in improving genetic potential of
top quality sheep flocks.
Influence of agro-ecological conditions and foliar fertilization on yield and yield components of buckwheat in conventional and organic cropping system
Authors: Popovic V. , Sikora V. , Glamoclija Dj. , Ikanovic J. , Filipovic V. , Tabakovic M. , Simic D.
Published: October 2013

Forgotten or neglected arable land plants, such as buckwheat, are becoming
increasingly important in crop production. Grain and one seed nuts are in the
usage for humans and domestic animals diet. On the fields of the Institute of
Field and Vegetable Crops, Backi Petrovac, researches were conducted in terms
of conventional (2010-2012) and organic cropping systems, 2012. Analysis of
the average yields showed that Novosadska buckwheat variety achieved a
statistically significantly higher yield in 2010th (2,996 kg ha-1) compared
to the 2011th and 2012th (p <0.01). The year showed statistical significance
based on the analysis of variance. The average yields of Novosadska buckwheat
variety, the variant with foliar fertilization in the conventional cropping
system, were significantly higher compared with the control. The average
yields amounted 1.395 kg ha-1 and were higher by 214 kg ha-1, or 18.12%
compared to the control. The average plants height was 144 cm. 1000 grain
weight was on the average of 23.72 g for the entire experiment. Average
yields in the organic cropping system were higher in variants with foliar
fertilization (1322 kg ha-1) by 7% compared to the control and plants were
higher by 7.28%. Plants were higher in the organic system of cultivation by
13 cm, or 9% compared with plants grown in conventional cropping system,
while the yields fell for 73 kg ha-1, respectively by 5.52%. Foliar
fertilizers proved to be a possible method for yield, 1000 grain weight and
plant height increasing in conventional and organic cropping systems.
Agro-ecological conditions and morphoproductive properties of spelt wheat
Authors: Jankovic S. , Ikanovic J. , Popovic V. , Rakic S. , Kuzevski J.
Published: October 2013

Experiments were conducted during 2011-2012, at three localities in Serbia
(Valjevo, Nova Varos and Nova Pazova). The seed of spelt wheat cultivar
Nirvana was used, having been selected at the Institute of Field and
Vegetable Crops in Novi Sad. The objective of the research was to assess the
effect of agro-ecological conditions on morphological and productive
properties of spelt wheat grown on different types of soils. The effect of
the locality was significantly expressed in all tested morphological
properties of spelt wheat (plant height, number of spikelets, number of
grains per spikelet), while meteorological conditions (year) affected spike
length and grain mass per spike significantly. The average grain yield from
all three localities was 3.20 t ha-1. A considerably higher yield was
achieved on chernozem, locality Nova Pazova (3.89 t ha-1). The comparison of
the grain yields from Valjevo (eutric cambisol) and Nova Varos (grey forest
soil) did not show any significant differences.