bluuebunny/crossref_metadata_2025_split huggingface dataset:
Validation of a Centrifuge Permeameter for Investigation of Transient Infiltration and Drainage Flow Processes in Unsaturated Soils
Authors: Parks Jean M. , Stewart Melissa A. , McCartney John S. 
Published: October 2011

Abstract
This paper focuses on the validation of a centrifuge permeameter and testing methodology developed to investigate transient water flow processes in unsaturated soils. The centrifuge permeameter is capable of controlling the boundary conditions for infiltration and drainage and contains instrumentation to measure profiles of the volumetric water content and matric suction with height in a soil layer during centrifugation. Evaluations of the measured matric suction and volumetric water content profiles from a series of infiltration and drainage tests performed on a fine sand at centrifuge acceleration levels ranging from 20 to 50 times earth gravity indicate that the established equations for calculating the hydraulic conductivity of unsaturated soil at steady-state conditions might not be appropriate, except at higher centrifuge accelerations. The transient profiles were also analyzed using a form of the instantaneous profile method in which the centrifuge acceleration was incorporated into the hydraulic gradient. Although the calculated soil water retention curve and hydraulic conductivity function data show some scatter, the hysteretic behavior of the soil during wetting and drying could be assessed.
Strength and Stiffness Characteristics of Unsaturated Hydrophobic Granular Media
Authors: Byun Yong-Hoon , Khoa Tran M. , Sup Yun Tae , Lee Jong-Sub 
Published: October 2011

Abstract
The nonwetting nature of hydrophobic soils, which results from wildfires or organic substances, may influence the shear strength and stiffness of granular soils. Since surficial soils are often unsaturated, their shear strength and stiffness are also affected by the magnitude of negative pore-water pressure. The goal of this study is to investigate the dominant factors affecting the strength and stiffness of hydrophilic and hydrophobic soils. Hydrophobic granular media were synthesized by a silanization technique with glass beads (D50 = 0.25 mm) to a degree of saturation of S = 0, 5, and 10 %. The prepared specimens were sheared using a direct shear device at various normal stresses. The shear waves were continuously monitored by bender elements. The experimental results showed that hydrophobic specimens had a lower shear strength than hydrophilic specimens due to lower friction, even though the hydrophobic specimen was under a denser packing condition. The shear stiffness was constant at small strains in the specimen composed of hydrophobic particles. However, as a result of the higher friction, the stiffness at small strains in the specimen composed of hydrophilic particles increased as the horizontal displacement increased. The results demonstrate that capillary force, interparticle friction, and packing density are important contributing factors to the shear strength and stiffness in hydrophobic soils.
Technical Innovations and Important Guidelines for Demanding Drilling Applications
Authors: Jellison Michael , Chandler R. Brett , Sanclemente Leianne 
Published: October 2011

Abstract
Critical wells exceed the capabilities of S-135 drill strings. Drilling teams are evaluating advanced technologies to expand the drilling envelope. The paper details the development of ultra-high strength UD-165 drill pipe, provides comparisons with S-135, Al and Ti drill pipe and provides field trials summaries. New developments are necessary to drill and complete deeper and longer-reach wells. Rotary shoulder connections offer significant advantages when coupled with high-pressure seal technology for completion pipe and intervention risers. The paper provides details on critical applications that benefited from new connection technology.
With water depths over 10,000 ft, well depths exceeding 34,000 ft, and extended-reach targets over 35,000 ft, operators are setting larger diameter and heavier casing. These casing strings require landing strings with setting capacities approaching 2.5-million pounds that extend the limits of tubular manufacturing and handling capabilities. The paper describes the technology advancements required to develop and implement an ultra-high capacity landing string system. A 6-5/8 in. drill pipe based riser system for offshore completion and intervention work has been successfully used for several years. The primary advantage of the drill pipe based system relates to the rotary shoulder connections (RSC). RSC makeup and breakout quickly, are rugged, and are superior at resisting galling and handling damage compared to casing connections that are often used for risers. The use of these intervention risers in sour gas areas has been prevented because there were no fully Sulfide Stress Cracking resistant tubular systems with RSC. This paper presents the successful result to develop and qualify an SSC resistant friction weld for intervention risers. Industry advancement has led to an increasing trend of drill stem downhole friction heating failures. The paper includes characteristics of these failures with case histories and prevention methods.
Mitigating Loss Circulation And Differential Sticking Problems Using Silicon Nanoparticles
Authors: Javeri Saket M. , Haindade Zishaan W. , Jere Chaitanya B. 
Published: October 2011

Abstract
The most frequently encountered problems while drilling an oil or natural gas well are lost circulation; the uncontrolled flow of drilling fluids into a downhole formation and differential sticking; condition whereby the drill string cannot be moved along the axis of the wellbore. These problems in turn augment the non-productive time (NPT) causing substantial financial loss. These harms occur generally in the vicinity of porous & permeable zones. The proposed method incorporates using Silicon nanoparticles in drilling mud composition to decrease the mud cake thickness.
The advantage of Silicon nanoparticles is that, there is formation of more continuous and integrated mud cake. Hence, by having an integrated (having low permeability and low porosity) mud cake, there is less volume of filtrate entering the formation and therefore mud cake thickness is less than in normal cases. The consistent particle size distribution provides better compaction medium with constrained flow of liquid from the drilling fluid. Furthermore, a thinner mud cake reduces the probability of stuck pipe. The addition of Silicon nanoparticles does not have much effect on the drilling fluid viscosity and other properties.
Silicon nanoparticles have thermal stability upto 2500 degree Fahrenheit. Moreover, the use of Silicon nanoparticles does not have side effects on the environment. These nanoparticles are generally immediately available in the required volumes. These require simple application techniques, consequently providing an appropriate solution to problems like stuck pipe and loss circulation while drilling.
This technique will provide novel insight in the reduction of problems faced while drilling (both vertical and deviated) wells and help in countering those problems in a more efficient and environment friendly manner.
Performance Step Change: New 16" TCI Design Solves Multiple Middle East Carbonate Drilling Challenges
Authors: Al-Baghli Waleed , Al-Khaldy Ali , Al-Mutawa Faisal , Saradhi Vijay , Maliekkal Harish , Fayed Mustafa , Ghoneim Osama 
Published: October 2011

Abstract
Drilling the 16" hole section through mostly carbonates in southern Kuwait presents several distinctive challenges. Interbedded formations with vastly different compressive strengths that vary between 5-30 Kpsi and a significant amount of blind drilling can result in twist-off and lost-in-hole situations. The most common tungsten carbide insert (TCI) rollercone bit failures mechanisms are impact induced cutting structure damage, hydraulic inefficiency issues and bearing failure caused by high weight-on-bit (WOB) through the hard Dammam to Ahmadi carbonate sections.
To solve the challenges the operator's drilling team, working in conjunction with the bit supplier, launched a performance improvement initiative. The carbonate application was analyzed using finite element analysis (FEA) based dynamic simulation program to fully understand how to stabilize the bit in different downhole conditions and improve hydraulic efficiency. Based on the computer analysis and field run data, engineers conceived a new stable bit design. The technology platform includes improved hydraulics and a specialized cutter structure configuration with tougher insert carbide grades to mitigate impact damage. A high-aspect ratio seal employs two dynamic sealing surfaces (ID, OD) that reduces frictional heat and minimizes wear to improve bearing reliability.
The new rollercone bit was run with an optimized drilling plan with outstanding results establishing a performance step change in southern Kuwait's carbonate applications. The bit recently set a new 16" world cumulative TCI footage record of 12,656ft drilling three wells shoe to total depth (TD) and 531ft of a fourth well. The bit amassed a total 446 hours of on-bottom drilling time turning 2.4 million revolutions without a seal failure. The bit saved the operator 4.5 days of rig time plus bit spend. The new technology has enabled the operator to drill long footage intervals or multiple wells using a single bit with good penetration rates (ROP). The authors will discuss the formation challenges, application analysis and resulting performance improvement.
Two Years of Progress: Field Driven Rollercone Design Iterations Cut Conglomerate Formation Drilling Costs by 40% in Oman
Authors: Al-Farei Ibrahim Abdullah , Al-Sukaiti Abdullah Humaid , Al-Lawati Ali , Portwood Gary , Krishnamurthy Ram , Gatell Josh 
Published: October 2011

Abstract
The predominant drilling challenge in Oman's southern fields is efficiently penetrating the thick conglomerate sediments. The sedimentary section is encountered at depths ranging between 2500–3400m and is approximately 700–900m thick. The hard conglomerate sections have UCS values that range between 12–30 kpsi. The formations’ rounded clasts, pebbles, and/or boulders are deposited in a fine grained matrix and make rollercone (RC) drilling difficult. The major dulling issue is early gauge row cutting structure degradation that requires multiple bits/trips to complete the 12 ¼" hole section.
Over the last two years, a series of iterative design changes and subsequent field tests have led to optimized tungsten carbide insert (TCI) geometry and strategic placement of 100% diamond enhanced heal row inserts. A new-type of insert and layout geometry has also enhanced shirttail protection. The ever improving TCI design has significantly extended cutting structure life and improved borehole quality. New carbide grades, tougher inner row inserts and an advanced twin elastomer sealing system that protects the bearing have all extended bit life in high WOB conditions.
The field derived design iteration process has consistently improved performance over the last 12 years. In 1999 a typical rollercone used in Oman's conglomerate fields had a life expectancy of 10–20 hours. Currently, the operator can expect a rollercone bit to provide sustained ROP for 110–120 hours drilling in these same fields. The improved bit and motor technology has optimized drilling the build sections and dramatically reduced cost/ft by an average of 40% over the past two years. This paper will examine the bit development/design, parameter selection and the science that led to a significant increase in conglomerate drilling efficiency. Finally, the authors will outline new durability and ROP benchmarks and discuss reduced rig-time and resulting cost savings.
New Robust "High Torque" Casing Connection Reduces Risk and Cost
Authors: Sam G. , Szlachta M. , Schaffer M. , Winkler P. 
Published: October 2011

Abstract
Because of the fact of increasing complexity of well paths (higher deviations, longer horizontal sections), the demand of reasonably priced casingconnections with high capability of torque transmission is rising. On the one hand it would be useful to have the option to turn the casing-string during running in hole, in case it could not be lowered by its own weight, on the other hand the quality of the cement bond should be improved with rotating during cementing. The on the market available flush type connections, are normally high priced and have additional technical disadvantages like difficult handling and low connection efficiency and therefore seem not to be the right choice for marginal field exploration.
The paper shows the connection development and first practical use of a casing-string of the size 4½-in. 13.5 lb/ft of the grade L-80-1, with a torque capacity of 11,000 Nm and additional significant overtorque capacity. The connection efficiency is 100% and the connection is still compatible to standard API Buttress accessories like reamer shoe or landing collar.
Described is the development from the prototype to the serial connection type and its first field trial. Explained are the differences to the API Buttress thread and the performance tests this connection was subjected too. Torque-turn diagrams recorded during make-ups, which were carried out in the mill and in the field, are presented and discussed. Special attention is given to proper connect to API Buttress connections (reamer shoe, liner hanger packer, landing collar).
In the end an outlook about future possible applications and benefits for the oil industry is given. The connection fulfills the features: High robustness, reasonable cost-performance ratio and API Buttress compatibility and can also be used for casing drilling whereas special enhanced tightness due to gas was not a development goal.
A Holistic Approach to Drilling Parameters and Drill Bit Design Optimization Improves Rate of Penetration by 37%, Hassi Messaoud OMfield-Algeria
Authors: Doudou S. , Chafai R. , Benyoucef L. , Sekat L. B. , Zerari D. , Dhina O. 
Published: October 2011

Abstract
Drilling challenges in the Hassi Messaoud (HMD) oilfield have proven to be equal to the magnitude of its production. Historically, wells drilled in this field were vertical, moderate borehole diameters having a long 12 ¼"section. In order to increase production and to gain a better understanding of the reservoir, Sonatrach Drilling engineering moved to moderately deviated large diameter boreholes, delivering 1000 meters of drain in the reservoir.
Instead of the conventional 12 1/4’’ vertical section, 1800 meters was drilled in 16’’ diameter. This section consists of abrasive sands, inter-bedded evaporate/carbonate and sand/claystone formations prone to instability and collapse. In addition, there is a 30 meter band of extremely hard dolomite. Rock strengths vary widely from 5 Kpsi to 30Kpsi.
Since early 2000, Sonatrach and National Oilwell Varco (NOV) have been working as a team to rise to the challenges presented by the larger hole size. Most significantly drilling vibrations, slow penetration rates, increased trips to TD, severe bit and BHA damage and NPT due to stuck pipe while pulling out-of-hole.
This article describes first, the process by which significant performance improvement was achieved as a result of combining innovative bit design techniques and technologies, BHA optimization, optimization of parameters through BHA dynamics modelling, and formation Rock Strength Analysis.
Secondly, the article discusses optimized techniques introduced to enhance performance for the 16’’ section on rigs that have been recently equipped with VFD - AC top drives and properly deal with torque limitation issues.
This enabled Sonatrach to repeatedly set ROP drilling records as well as consistently making section TD in a single run. The net result was a 37% improvement in rate of penetration1.
Rapid Rig Design – A Cost Effective Innovative Design For Field Development
Authors: Peytchev Peter , Crighton Alan , Upadhyay Abhishek , Doodraj Sunil , Malik Sumit D. , Abraham Arun , Meempat Balu Govind 
Published: October 2011

Abstract
During the exploration and appraisal phase in the RJ-ON-90/1 block, operated by Cairn Energy India in the Thar Desert of Rajasthan, India, the company discovered numerous oil fields in the Barmer Basin spread over a huge area. The emphasis was to develop these fields with significant savings in both land and infrastructure costs while minimizing environmental impacts. A compact rig design coupled with a multi-well pad concept was the chosen solution.
The paper presents use of an innovative onshore pad drilling system which was implemented via a custom built Rapid Rig technology that allows fast, efficient drilling operations on multi-slot pads to enhance the success of the extensive drilling campaign for these oilfields.
The rigs are highly mobile, skid mounted, electrically driven 1,000HP "Super singles". They were custom built in Houston for Cairn to deploy in Rajasthan for the drilling of more than 350 development wells. The Rapid Rig's small footprint and self deploying design allows for ease of transport and faster onsite rig-up. These rigs are the first of their kind with wheels attached to the base structure. Unlike conventional rigs, these purpose-built rigs move easily and quickly (4hrs) between pad slots without rigging down, which in turn cuts well construction time and delivers greater efficiency at reduced costs. The fully automated rig floor coupled with an innovative pipe handling system reduces crew size and accident exposure (zero pipe handling LTI's) while providing a more comfortable and efficient work environment, leading to a substantial reduction in well construction time (1,2001,500m wells are drilled in 7 to 9 days).
The paper will explain detailed aspects of the custom made Rapid Rig design and its implementation including the pad drilling concept. It will also demonstrate how this significantly improved the well delivery, contributing to substantial cost and well construction savings without compromising HSE standards.
Control of Severe Loss and Kick Situations - A Case History of West Kuwait Wells DF-15 and MN-159
Authors: Al-Saleh A. M. , Al-Khaldy M. D. , Shehab A. A. , Altekar P. K. , Al Mulla D. A. , McKinnell D. C. 
Published: October 2011

Abstract
Kuwait has been drilling and producing from the deep, sour Jurassic reservoirs in the West Kuwait area during the past 25 years. The wells, which are mainly vertical, penetrate heavily fractured, highly pressured reservoirs and produce high quality light oil. New wells are planned to be added with more complex deviated and horizontal well profiles, in an attempt to intersect multiple fractures and fracture swarms.
Selective production has contributed to the depletion of certain reservoir intervals, which in addition to the pressure reversals in the lower reservoirs and their fractured nature presents increased complications and challenges to the drilling of these wells. The difficulty of drilling such depleted / fractured formations has presented the operator with new and complex challenges, especially in deviated and horizontal wellbores. These include partial / total losses, gas kicks, and mechanical / differential sticking, resulting in some instances in having to sidetrack the wellbore.
A case history of two recent West Kuwait directional wells, DF-15 and MN-159, is presented to explain the nature of the problems that have been encountered and the solutions that were successfully developed to handle them. The challenges of drilling in these environments were analyzed, with practices and materials being developed and adapted to enable drilling to continue through these troublesome zones. The new solutions and methodologies provide a basis for future optimization in subsequent wells.
Study on Pressure Measuring and Formation Evaluation Methods while Underbalanced Drilling
Authors: Li Gao , Meng Yingfeng , Chen Yijian , Zhu Kuanliang , Xu Xiaofeng 
Published: October 2011

Abstract
There are several instruments with which wellbore fluid pressure and flow parameters can be measured during underbalanced drilling(UBD). However, the real-time formation pressure test while drilling is yet a great challenge. Therefore, a much more precise pressure control drilling is not easy to be achieved. In this paper, technological methods and procedures are developed to obtain not only wellbore fluid pressure but also formation pressure while underbalanced drilling. Based on real-time pressure and fluids measuring during underbalanced drilling, methods to evaluate formation parameters such as permeability, porous media types and potential productivity are also developed. First, the pressure-while-drilling (PWD) methods, wellbore pressure calculation models and wellbore pressure rapid adjustment procedures are applied to get much more precise wellbore pressure profile and formation pressure while underbalanced drilling. Next, a surface real-time detection system is developed to detect the flux and fluid compositions while underbalanced drilling. Third, interpretation methods to evaluate formation parameters such as permeability, porous media types and potential productivity are also developed. These methods has been applied in three underbalanced drilling wells, one is a horizontal well and the others are vertical wells, which proved their significance at the first stage and reveal its potential in precise pressure control and formation parameters evaluation while underbalanced drilling.
Behaviour, the Final Frontier- A Proven Approach to Changing Organizational Behaviour
Authors: Cram Robert S , Sime Julie-Ann 
Published: October 2011

Abstract
A wise person once said "If you always do what you always did, you'll always get what you always got". Never was it more true than in the field of safety. More of the same approaches to safety will give organisations exactly the same outcomes. That is why many complain their safety performance appears to be stuck on a plateau. Despite all of their efforts over months and in many cases years, they are not seeing any discernible improvements.
To get down the final slope towards a zero accident culture requires major changes in how companies and people approach safety in the workplace. To most managers, already besieged by deadlines, cost controls, staffing issues in an ageing workforce, national and international legislation, the idea of modifying corporate culture at the same time is perhaps a step too far.
A complete change is essential if the ultimate goal is to be achieved. Society is demanding that organisations and the management of these organisations are held accountable for their safety performance. Charges of corporate manslaughter are no longer theoretical penalties, they are a fact of life.
This paper discusses what is required of management to change safety behaviours and presents the results of a behavioural safety initiative which delivered tangible improvements in overall safety performance.