bluuebunny/crossref_metadata_2025 huggingface dataset:
A Fair and Competitive Drilling and Workover Services Assignment Process
Authors: Amer Mustafa , Ilya Ibrahim , Ali Abdullah , Amir Ali , Muhaisen Abdullah
Published: August 2016

An essential element for business success is to secure the best quality services from external providers at the lowest possible cost, which is a challenge not only for operating companies but also for service providers. This challenge is becoming more important for D&WO business, which is a major services consumer. NOCs strive to create a competitive and fair environment to encourage long-term business partnerships with service providers through a transparent process to assign more than 13 D&WO services.

A new process put into practice in the last 2 years, objectively evaluates service providers based on measurable criteria that include the pricing schema, historical performance, HSE compliance, and nationalization compliance of all providers against their contractual obligations. To assure the integrity of the process, an application was developed to fully automate the process, starting with the collection of data from its original sources to evaluate the service providers, through the electronic approval of the final assignment by management.

The application, Automated Services Assignment System (ASAS), provides different functionalities that allow seamless integration of different data sources like performance data from drilling rig morning reports and rig activity scheduling from a corporate database. It evaluates and ranks service providers automatically and provides an automated workflow for approving the services assignment based on a hybrid business model (standard process, service packaging, or lump sum turnkey), and allowing the adoption of additional business requirements during the execution phase through automated change request functionality.

The process and the application enabled D&WO organizations to respond to dynamic changes in their business by running as many scenarios as needed to identify the best business approach, with potential cost savings up to 15 percent (initial rough estimate). Effective management of the process delivers time savings up to 40 percent, compared to the manual process.

Implementing multidimensional evaluation criteria strengthens the credibility and integrity of the process compared to evaluations done based upon single criterion, such as cost or performance. In addition, this automated system combines three different business models seamlessly; capitalizes on corporate official records for drilling operations, HSE, and rig schedule; and enforces comprehensive business rules.
Achieving Zonal Isolation Objectives in Carbon Dioxide Rich Gas Production Environment in South East Asia
Authors: Chikara T. , Salehpour A. , Azwar C.
Published: August 2016

Constructing wells in reservoirs with high concentrations of carbon dioxide (CO2) is a challenge in itself. In South East Asia region drilling campaign in a high-CO2 reservoir was made even more difficult because of high well deviation, long production sections, a narrow drilling window, and loss of circulation. Prior attempts to develop the field established that this reservoir would not be easily exploited. One complicating factor was that the reservoir has multiple stacked layers of sand up to 8 zones in each well, These zones have different pressure regimes that are spread out in the reservoir section of average 3,000 meters per well. Effective mud removal is essential to achieve zonal isolation in these wells because mud left behind the cement will likely result in communication between the zones. In order to realize the long-term production plans for these offshore wells, the operator needed a fit-for-purpose cementing solution.

The operator was able to successfully overcome the aforementioned challenges and successfully cement seven wells using a system that incorporate blast furnace slag (BFS). The wells were drilled with a jackup rig in a water depth of 90 m [274 ft]. A cement evaluation log and the absence of sustained casing pressure confirm that there have been no zonal isolation concerns since the first well started producing in November 2013. The BFS system has proven to be cost effective and has the added advantage of being compatible with the existing cementing equipment without any special modifications.
Effective Calculation Model of Drilling Fluids Density and ESD for HTHP Well While Drilling
Authors: Zhou H. , Niu X. , Fan H. , Wang G.
Published: August 2016

Drilling wells for oil/gas has been increasingly challenging with the companies moving towards difficult environments, such as in Tarim basin of China, some reservoirs buried so deeply (>7,000m) that we experience high temperature and pressure. The problems faced in these locations range from very narrow margin between pore (or collapse) and fracture pressure. The density of drilling fluid is often affected by HTHP, the careful research on the drilling fluids density at HTHP is very important for precisely predicting ESD as well as controlling the downhole pressure. A utility calculation model of drilling fluids density and ESD was proposed, which can predict the HTHP density and ESD.

Firstly, a new utility artificial neural network HTHP drilling fluid density prediction model was established based on the traditional BP neural network and PSO (Particle Swarm Optimization) optimization method. Then PSO-BP neural network HTHP drilling fluid density prediction model was proposed, in which the influence of drilling fluid component (oil phase, water phase volume fraction) was taken into account. Available experimental measurements of water-based and oil-based drilling fluids at pressure ranging from 0-96MPa and temperatures up to 183°C were used to develop and the PSO-BP network model and then the network weights, threshold parameters. Through this model the high-precision HTHP drilling fluids density can be obtained easily with the knowledge of the drilling fluids component data (oil phase and water phase volume fractions) and its density at standard conditions(0MPa, 20°C) based on the basic principle of PSO-BP network. Moreover, an new comprehensive ESD calculation model of HTHP well was established, which is applicable for all common type drilling fluids and through we can obtained the ESD profile of the well easily.

The prediction of this model has been compared with an extensive set of data from literature, the comparisons of different fluids density in HTHP show very good agreement, the prediction accuracy was improved, and in which the maximum average absolute error of predictions is less than 0.005sg. Finally, the proposed model has been applied for HTHP drilling fluids density and ESD prediction in several wells of the Tarim basin in China, the results show that the proposed model can exactly provide the HTHP drilling fluids density and ESD profile.

This study proposed an utility calculation of HTHP drilling fluids density and ESD profile while drilling, based on the new PSO-BP neural network, the optimal network weights, threshold parameters of was obtained, through which the high-precision drilling fluids density and ESD can be obtained easily. Moreover, the model has been verified and applied for field monitoring. Therefore, this model can be applied to provide more accurate predictions of HTHP drilling fluids density and ESD while drilling.
Optimizing Offshore Infill Drilling: Application of Conductor Sharing and Casing Drilling Techniques
Authors: Terimo Jumasri , Zaman Hazim Kamarul , Pallath George , Cherchawankul Teerasak , Costeno Hugo , Djohor Mohamed , Mokhti Ridzuan , Gonzalez Luis D.
Published: August 2016

This paper describes the application of casing drilling technique for the top hole section in conductor sharing wells in a brown field, offshore Malaysia. Its objective is to describe the integration of the casing drilling technique and the conductor sharing design when used in conjunction. It is intended to share the challenges faced during the design and execution phases of the project, the solutions analyzed and applied; as well as the outcome and learnings.

In this case study, the conductor sharing design makes it possible to maximize the well capacity of the offshore drilling platforms by accommodating multiple wells per drilling slot. The casing drilling technique is implemented to manage drilling risks related to wellbore stability, losses and shallow gas. The feasibility for combining the two technologies is evaluated during the planning stage by reviewing the documented previous industry experience of the two technologies, combined or separate; while local knowledge is analyzed to ensure all drilling factors are considered.

Solutions to challenges such as wells interface inside the shared conductor, directional control, losses, cement design and placement techniques, well control, operational procedures and time and cost efficiency are analyzed. The execution results are analyzed by comparing design estimations and assumptions with field data and actual results. These data is translated then into recommendations and lessons learnt. The conclusions of this case study are presented as a set of design work, drilling practices and risk analyses processes and their results that can be replicated or considered in future wells design where conductor sharing and casing drilling are to be implemented together.

While several individual studies of particular conductor sharing wells configurations, casing drilling and well construction techniques are available, the present work discusses one of the few applications to date where conductor sharing and directional casing drilling technologies are combined to address specific offshore challenges. The team considers of paramount importance that the knowledge obtained on this very specific combination of two technologies is documented and shared within industry professionals to provide reference for future applications.
Time-Based Drilling Dynamics Modeling Provided BHA Solutions to Motor Development
Authors: Shi Jibin , Shen Yuelin , Zheng Guishui , Xu Gang
Published: August 2016

In several shale plays in North America (for example, the Eagle Ford), a common trajectory for 8.5-in or 8.75-in section consists of vertical, curve, and lateral sections. When running conventional positive displacement motors (PDMs), these sections are drilled in several trips. A new motor was developed to drill the vertical, curve, and lateral in a single run, eliminating trips and reducing drilling times. This new motor has a short bit-to-bend distance with higher dogleg severity (DLS) capability at lower bend angle settings. New high torque transmission and driveshaft were designed to pair with specially developed high torque power sections to achieve improved performance and tool life. When developing the new motor, a question arose about stabilizer placement because it greatly impacts wellbore quality, directional tendency, and toolface control. Traditional methods such as laboratory testing and static analysis were not able to provide sufficient insight; therefore time-based drilling dynamics analysis was used to design the optimal BHA for this new motor.

The time-based drilling dynamics simulation considers the effect of cutting structures and the transient dynamics of the drillstring. The cutting element and rock interaction was considered, enabling 3D bottom hole geometry to be calculated based on rock removal. Extended length of drilling can be mimicked and the wellbore surface quality and directional tendency can be evaluated. An optimal BHA was selected for this application based on simulation results.

The new short bit-to-bend motor and the proposed BHA design were tested in several basins in US land. In South Texas, the first three runs all reached total depth (TD) with high rate of penetration, showing excellent reliability and significantly improved performance. The only concern was that the toolface angle was not easily controllable when it kicked off near the Austin Chalk Formation. A simulation scenario was designed to mimic the motor drilling in such a transitional formation. Results revealed that sudden toolface angle change occurs when there is a sudden change in rock type and strength. The BHA was optimized accordingly based on the learnings from the study. The improved BHA was tested in the five following field runs and showed a step change in toolface control. Based on the successful field test runs, this short bit-to-bend motor was commercialized in March 2014.

Time-based drilling dynamic simulation provided a novel and unique solution to directional drilling using PDMs, delivering insights not achievable using traditional methods. The BHA design using such technique is one of the keys to successful motor development.
A New High-Temperature Shear-Tolerant Supramolecular Viscoelastic Fracturing Fluid
Authors: Jiang Qihui , Jiang Guancheng , Wang Chunlei , Zhu Qi , Yang Lili , Wang Le , Zhang Xianmin , Liu Chong
Published: August 2016

The properties of novel supramolecular complex fracturing fluid are discussed in this paper. Based on the supramolecular polymer thickener (SMPT), the thickening system forms a gel with viscoelastic surfactant (VES) wormlike micelles through experimental design. The resultant gel contains very efficient cross-links between the wormlike micelles and polymer chains that can be advantages in elastic and viscous properties of the fluid.

The fracturing fluid contains nearly twentieth of conventional surfactant fracturing fluid. Both VES and SMPT synergistically enhance the shear-tolerant property in high-temperature much more than the single. The electron microscopy photos of the solution microstructure and rheological results reveal the suitable ratio of SMPT and VES forms a supramolecular network honeycomb structure, which is built by strong hyper-branched compound structures through noncovalent interactions. Meanwhile, the physical model can legitimately expound the gelation mechanism of the supramolecular viscoelastic gel. Moreover, proppant suspension behavior, gel breaking test and the permeability damage rate of core matrix were studied.

Laboratory data showed that the viscosity of new fluid could be maintained above 50 cp with the formation of 0.8%SMPT and 0.5%VES. The steady shear viscosity test has been conducted for 2 hours at 150 °C and 170s−1. Shear restoration experiment proved the new supramolecular viscoelastic fluid was in high viscosity at low shear rate and a strong reversible shear thinning behavior. The dynamic rheological properties showed high viscoelasticity, while elastic modulus was higher than loss moduli at an oscillation frequency 0.01Hz. The result of sand sedimentation experiment with 20% sand ratio was well. The supramolecular viscoelastic fluid was completely broken and gel breaking liquid was transparent with no water insoluble residue. The permeability damage rate of core matrix caused by this fracturing fluid was 20% less than guar fluid.

The supramolecular viscoelastic fluid presents in this paper could be a total or partial alternative to VES and guar for hydraulic fracturing whose price is subjected to harvest areas. Results show that the new supramolecular viscoelastic fluid is an effective fracturing fluid satisfies high temperature tight gas reservoir.
The Application of Robotic Drilling Systems in Extreme Environments
Authors: Watt Martin , Rafati Roozbeh , Hamidi Hossein
Published: August 2016

The oil and gas industry has always relied on the use of cutting edge technology right from its inception however, as years have progressed, oil and gas reserves around the world have become harder than ever to extract. The problem lies where unlike conventional drilling, the industry is beginning to explore extreme environments, where oil and gas reserves are plentiful, but in regions so inhospitable that humans cannot conduct and operate the drilling process on-site. A solution to this is to make use of autonomous robotic drilling systems.

The use of robotics in any industry presents a way of completing tasks that could be deemed too challenging or risky for humans to attempt in an accurate, safe and economically-sound manner. With these clear advantages of robotics in mind, it makes sense that oil operators and service companies around the world should choose to research more into how robotics can be utilised in advancing the industry and making the extraction of oil and gas in extreme environments safe and efficient in order to prevent any major incidents from occurring.

Robotic drilling systems have been identified as the key in ensuring drilling operations can be conducted in extreme environments in a safe and environmentally friendly manner. Robotic drilling systems have several key benefits compared to conventional drilling methods such as allowing for greater efficiency, improved HSE statistics, cheaper to operate and are capable of operating autonomously in inhospitable conditions.

It is paramount that if drilling is to commence in extreme environments, that it is done with caution and care with regards to the environment and safety of personnel. This paper found that robotic drilling systems, if researched and developed further, could hold the key to being able to explore extreme frontiers in a safe and efficient manner, which will allow for preservation of delicate environments whilst ensuring the worldwide energy demand can be met for years to come.
Collaborative BHA Design Optimization Modeling Leads to a Successful Run in a Challenging Formation
Authors: Noviasta Bonar , Awaliyah Siti , Hasudungan Boyke D.
Published: August 2016

An oil and gas operator in Indonesia had a second exploration well (L-2) in the L field located in Seram Island of eastern Indonesia. This field is known for its extremely harsh drilling environment. One of the challenging parts is the overpressured carbonate formation, which was planned to be drilled in the 8½-in section with 17-lbm/galUS water-base mud (WBM) mud density.

Based on the experience in the previous well (L-1) and looking at the challenges that could potentially happen in L-2, good prejob planning is required to improve the drilling performance. A collaborative modeling job was performed—involving well trajectory design, BHA design optimization, hydraulics modeling, and torque and drag modeling—which utilized static simulation as well as drillstring vibrations modeling utilizing finite element analysis (FEA) dynamic simulation. This collaborative modeling greatly improved the bit and bottom hole assembly (BHA) selection capability by eliminating the uncertainty. Additionally, the dynamics simulation was also capable of generating a stable drilling parameters roadmap as a guideline for the driller and directional driller onsite. Several drill bits and BHA options were modeled and simulated under different drilling conditions to determine the most stable configuration. The result shows that the combination of point-the-bit rotary steerable system (RSS) and a seven-blade, 16-mm-cutter bit is the optimal BHA in the 8½-in section to drill through the hard and overpressured carbonate interval within a certain stable drilling parameters window.

The result was satisfactory where the bit-BHA-parameters combination successfully delivered the service for drilling the 2,780-ft interval in 12 fewer days than the expected drilling time (as per AFE with motor BHA), drilling 18 days faster than the previous 8½-in section in L-1 well, and reduced the number of BHA runs by 50%. Such performance was translated into 18 days spread cost saving (USD 2,673,000) for the operator as compared with the previous well, and 12 days cost saving (USD 1,782,000) as compared with AFE days.
Drilling Competency Model, A Case Study of an Upstream Oil & Gas Company
Authors: Al-Daihani Eisa Hadi , Al-Otaibi Marzouk , Valdivieso Juan Pablo , Nandi Arun Kumar
Published: August 2016

The advancements in drilling technology have led to rapid and sustained improvements in drilling operations. This gradual development of tools and techniques has resulted in time savings and safety improvements. The number of directional and horizontal wells is growing every year and many of these are being drilled in more challenging oilfield environments such as deep gas fields, carbonate reservoirs and high pressure-high temperature zones. There is also an increasing demand for precision directional and horizontal drilling in mature oil fields. Such advancement of technology and tools require an appropriate approach of developing the available technical manpower with related drilling competencies. Therefore, a competency based model becomes essential for National Oil Companies (NOCs) to develop their technical manpower to keep pace with the technology development.

Effective competency development is a combination of awareness, knowledge, skills and attitude that must be demonstrated to meet the performance standards required for their jobs. The paper emphasizes the need for a customized competency model for a drilling engineer in order to meet the major challenges as mentioned above. The Drilling Competencies in an Upstream National Oil Company needs to be categorized in three main disciplines which are Drilling Engineering, Drilling Operations and Drilling Techno Commercial. Therefore, exposure to these core competencies is essential for an effective drilling engineer. A case study of an Upstream Oil & Gas Company has been illustrated in this regard.

The implementation of the Drilling competency model will result in improved job satisfaction, better talent management and employee retention. Such approach of competency modeling of different job families in upstream NOCs will empower them to achieve their goal with admirable clarity, better hydrocarbon discovery index cum increase in production and field management expertise. The proposed Drilling Competency Model can serve as a guide for other National Oil Companies in their endeavor to achieve excellence.
GeoSteering in Complex Channel Sand Architecture, a Reality Now with High Definition Deep Directional Multi Boundary Detecting Technology: Case Study From Greater Burgan Field, Kuwait
Authors: Hussain Bahman , Gazi Naz H. , Al-Sabea Salem , Al-Zankawi Omran , Ali Farida , Aqeel Anfal M. , Keot Chandan Jyoti , Juyal Mukul , Wenang Martine
Published: August 2016

The primary reservoirs in the Greater Burgan Field in Kuwait is the Lower Cretaceous Burgan Sands. Burgan sands are divided into five major units which consist of stacked, massive fluvial channels and some units mostly consist of delta distributary channels and bays in a tidal delta setting grading to shallow marine. These are discontinuous both laterally and vertically. Channel sand geometry in geosteering perspective often sums up to discontinuous patches of sand lenses at differing stratigraphic levels. Maximizing net pay in a channel sand reservoir is known to be a very challenging task for the geosteering domain. Navigating a drainhole through such geometry requires precision geosteering technologies that can map multiple reservoir boundaries with high accuracy enabling precise forward designing wellbore trajectory with respect to the dynamic reservoir geometry. Deep directional distance to boundary "DTB" technology revolutionized the whole concept of geosteering in this regard by enabling proactive geosteering for the first time in industry. Introduced in 2005, it features the capability of detecting reservoir boundaries up to 15ft around the wellbore and achieved great success all over the world through proactive geosteering in thin reservoir layers and maximizing the percentage reservoir contact. However, this technology is limited to mapping only 2 layers, above and below the tool, up to a distance of 15ft around wellbore. It cannot detect a third layer beyond the two layers surrounding it.

High definition deep directional multi boundary detecting technology is a noble advancement on the first generation Distance to Boundary technology. With significantly improved signal to noise ratio, supported by a robust and new multilayer stochastic inversion algorithm that incorporates a whole gamut of measurements, principally from 3 firing frequencies (100kHz, 400kHz and 2Mhz), this technology extends its capability by mapping multiple boundaries up to 20ft around the wellbore.

This paper examines a case study from the Greater Burgan Field, Kuwait where the extended capability of this technology has yielded exemplary results in navigating wellbores through very complex channel sand geometry with very sharp local dip changes and varying thicknesses. Extreme geosteering is finally made possible with this fit-for-purpose technology in complex subsurface environments, lowering construction risk while maximizing net pay for each well drilled.
Field Tests of Drill Bits With Enhanced Hydraulic Design
Authors: Moslemi Ali , Cunningham Jason , Wang Alan , Garcia Alexis
Published: August 2016

This paper aims to report the field test results of several drill bits with enhanced hydraulic design features including optimum nozzle orientation and blade height as well as new patent-pending flow guide. These drill bits were developed based on numerous experimental and numerical tests. Computational Fluid Dynamics (CFD) was used to model the effect of various design features on bit hydraulics and then they were tested in Pressurized Drilling Lab (PDL). After the encouraging results of the experimental bits, several bits with enhanced hydraulic design were manufactured and sent to the filed for the final tests. The drilled formations were mostly soft to medium hard and ranged from shale to limestone. In most of reported cases, these bits outperformed the competition bits with Rate of Penetration (ROP) improvement ranging from 24% to 108% resulting in cost and time savings for operating companies.
Integrating Software for Improved Well Planning
Authors: Ponsonby M. C. , Andersen O. J. , Mathisen P.
Published: August 2016

Each company has its own method of capturing data during the Drilling and Well Construction process, and these methods will vary from simple spreadsheets to more complex systems that captures the live data and stores it. Each company will also have a method of capturing the lessons learned, usually in the form or an End of Well Report or wash up meeting with all of the service companies. Turning this data into useful information and thence to knowledge is at the moment a difficult problem

This transition process had been brought about by combining two specialist pieces of software. The first has the ability to take in date from all sorts of sources ranging from spread sheets via daily reporting systems to historical log data or real time data stream, mud logs etc. and then to present that data in a form that is useful to the drilling engineer in designing a well. The software also allows storage of experiences, both positive and negative, and links them to wells, rigs, specific types of equipment or operations.

This central store of data and the ability to transition it into useful information gives the engineer designing a well the ability to identify the risks and also the spread of times taken for various operations.

The second piece of software uses probabilistic calculations and the ability to place branches into the process that take into account the risks identified using the data storage software. Once a risk is identified then the mitigation steps are identified: how it will be addressed, what is needed and when.

All this information is taken into account when calculating the time and cost, giving a spread from Technical Limit through to Worst Case. More importantly all of the steps, and assumptions are stored in one place rather than the traditional multiple spreadsheets that generate the "Excel Hell" scenario.

By following a simple process with only two pieces of software the accuracy of well costing and scheduling can be increased additionally the understanding and mitigation of risk improves and lessons learned are no longer lost as personnel move within the company or the industry.
First Implementation of a Resilient and Self-Sealing Cementing System to Optimise Long-Term Zonal Isolation in Challenging Offshore Wells - Review of 3 Case Histories in Malaysia
Authors: Brandl A. , Alegria A. E. , Ismail M. , Dean G. , Mohd Mahaiyudin A. R.
Published: August 2016

Three consecutively drilled, highly deviated, high-temperature offshore wells in Malaysia with multiple thin payzones and planned close perforation distances required the use of a self-sealing cementing technology with optimized mechanical properties to minimize the risk of unwanted fluid communication that would necessitate immediate abandonment. This paper reviews the successful implementation of the corresponding cementing system starting from its development, through the jobs' planning phases, to the operational executions and evaluation with results. A pre-job study was executed to design a suitable cementing system, including thorough lab tests, CFD simulations for optimized fluid displacement efficiencies, and cement sheath stress modelling to optimize the cement mechanical properties. A novel HPHT multi-function test cell (MFTC) was used to measure in-situ ability of fractured cement specimens to seal hydrocarbon flows under the given simulated downhole conditions. Yard tests were conducted to ensure quality and field applicability of the engineered cementing system.

With the help of the simulations and lab tests, the mud-spacer-cement fluid trains could be optimized for fluid friction and density hierarchies during each 7-in. liner cementing job for effective synthetic oil-based mud removal and cement slurry placement covering the desired >1,000 m annular length in highly deviated wells with low frac gradients at temperatures up to 300 °F. Combining the self-sealing additive with a mineral fiber in the tested cement designs significantly reduced the Young's modulus of the set cement while the tensile strength and the Poisson's ratio improved, resulting in a higher resilience of the cement sheath to survive the anticipated downhole stresses from the completion program. The crack-and-seal tests demonstrated the cement system could repeatedly seal cracks or micro-annuli up to at least 0.15 mm (0.006-in.) due to the swelling of the self-sealing additive in the presence of a hydrocarbon flow at differential pressures below 1,000 psi and temperatures up to at least 300 °F. The expansion of the set cement was also optimized to enhance the bond to formation and pipe. The evaluation of the pre-job planning, job execution as per program, post-job simulated pressure matches, positive ultrasonic cement logging results, and the fact that no issues have been observed during or after the job indicated well-isolated intervals. The novel cementing concept combines several advanced design features (self-sealing in the presence of hydrocarbons, expansion, resilient mechanical properties) that improve long-term zonal isolation in critical well scenarios.
Common Incident Reporting and Tracking Platform
Authors: Ponsonby M. C. , Andersen O. J. , Mathisen P.
Published: August 2016

The objectives was to investigate the present systems used for QHSE reporting and suggest how these may be combined in to an industry standard that is independent of the size and specific area of our industry. The system would allow tracking and comparison of incidents across companies and reduce the element of humane error.

The process involved researching the systems used in different industries such as IT and Car manufacturing and the systems used in the Oil and Gas industries. For the Oil and Gas industries the focus was on the Norwegian Continental Shelf and included Operating and Service companies as well as Government agencies.

The research confirmed the theory that there was a huge amount of variation between all of the companies on how their process worked. An additional finding was the amount of variation internally in some of the larger companies. This variation makes any collaboration between companies or Government agencies to track trends or follow up on the incidents extremely difficult. Historical lessons cannot be utilised across different companies or geographical regions resulting in the same incidents occurring as the learnings have been lost due to movement of personnel (especially important in the current industry climate) or the difficulty of finding the information.

Our conclusion is the development of a system that allows learning, not only from within our own industry but also from other industries. The system allows learnings to migrate from other industries and within our own industry gives a simple process for recalling, sharing, and collaborating on the incidents not only for safety but also for quality.
A Unique ICD's Advance Completions Design Solution with Single Well Dynamic Modeling
Authors: Goh G. , Tan T. , Zhang L. M.
Published: August 2016

Inflow control devices (ICD) completion is a downhole flow control solution that is designed to balance influx contributions across wellbore horizontal section, to delay water breakthrough or coning hot-spots and to increase ultimate cumulative oil recovery. This paper illustrates a novel and successful systematic workflow to implement this technology in order to effectively manage the marginal green reservoir uncertainties while achieving field development requirements. In general, this production-upsides justification and design process started from an early stage full field ICD completion feasibility study; followed by single well pre-drill ICD design through dynamic simulation as preparation for real time drilling operation support. Subsequently, ICD nozzle-configuration optimization and packer placement design fine-tuning were performed before run in hole during real time operation. The final optimized design for ICD and tracer tally can then be proposed for on-site execution. The key enabler of this process is a novel and time-efficient single well dynamic simulation method, which is compiling the dynamic time-lapse production responds with various ICD nozzle and packer design optimisation workflow. The sensitivities of various design scenarios were applied as a working range to guide on-site ICD installation.

This paper highlight the design and optimization workflow from the perspective of dynamic modeling against the conventional nodal-based or single time-step production scenario simulation carried out. In illustrating the more ‘down-to-earth’ production upside results when time-lapse impact are considered, single well dynamic modeling can provide a more realistic real-time design especially in marginal oilfield application and critical decision-making during real-time. Against the typical over-optimistic production upsides analysis result portrayed by conventional single time-step production scenario simulation, some actual design cases as conservatively predicted by dynamic modeling single well will be demonstrated to influence decision-making when ICD's upsides is marginal . This crucial differentiation in due dilligence upside analysis will guide towards most optimal ICD's configuration RIH or reciprocally applying standalone screen (SAS) instead against the ICD's RIH minimal production benefits against its cost value. The results showed that the uncertainties and production repercussion that are affecting the decision of either running ICD's or SAS during real-time ICD's modeling updates are handled more inclusively and objectively with time-lapse based dynamic prediction.
Application Focused Drill Bit Engineering Delivers Consistent Improvement in Efficient Drilling Performance
Authors: Agawani Waleed , Al-Ajmi Abdulla M. , Taha Mohamed , Gohain Ashish , Omar Marwa , Al-Haj Hussain Ali , Abdelhamid Atef
Published: August 2016

Balancing aggressiveness, stability and durability bit behaviours is the principal engineering challenge when designing an application-specific PDC bit. The application this paper addresses is a directionally drilled interbedded abrasive formation that generates dysfunctional drilling torque. This paper demonstrates the engineering process of designing a bit that balances the three major bit behaviours, thereby optimizing drilling efficiency to meet the goals of successfully drilling the required interval while improving rates of penetration.

West Kuwait's 12.25" section primarily involves interbedded abrasive sandstone and hard shale sublayers that induce torque fluctuations. The combined result is impact and abrasion wear on cutters causing mid-run reduction in rates of penetration, prematurely terminating the run. The section involves a J-type directional profile drilled using an adjustable-bend mud motor or a rotary steerable system. It starts off drilling vertically till the kick off point followed by building up to the tangent section and holding angle to section end. The high torque and vibrations faced in this application make steering difficult for any directional drive type; further compounding the challenge to achieve higher rates of penetration.

Building a solution to match the application involved:

Reviewing bit dulls and studying locations of extensive wear on the bit body Comparing current design performance against success metrics in the target application Bit design requirements for specific rotary steerable systems and mud motors to build a universal design that works with all major drive types Consideration of different torsional stability technologies and their appropriateness for our application Field trials across different drive types

The engineering process concluded with a seven bladed PDC bit with aggressive cutting structure that successfully completes the interval while improving rates of penetration by over 50%. Trials were implemented across several wells involving the major drive types to verify the new design's effectiveness versus previous designs. Most trials proved the bit was more efficient in directing mechanical specific energy into the formation rather than squandering drilling energy on damaging vibrations. This resulted in rates of penetration higher than the field average through better bit stability and smoother steerability on all directional drive types used in the application.

This paper highlights the engineering process and the technology invested in developing a PDC bit for drilling directional runs through mixed abrasive and impact prone formations.
Study of Acrylic Acid-co-Polyethylene Glycol Allyl Ether as Cement Retarder Over a Broad Temperature Range
Authors: Brandl Andreas
Published: August 2016

In adjusting the correct thickening time of a cement slurry for reliable placement into a wellbore at given bottomhole circulation temperature (BHCT), an engineer must select a suitable retarder with optimum dosage and compatibility for the cementing system. The BHCT for each drilled section of a wellbore can vary, in extreme cases, from below freezing temperatures to 500 °F or even higher. In this case, each of several cementing jobs in a well might require a different retarder, which has drawbacks for logistics, operations, and laboratory testing. Therefore it would be advantageous to identify one cement retarder that is effective over a broad temperature range.

The performance of acrylic acid-co-polyethylene glycol allyl ether (AA-co-PEGAE) as a retarder was evaluated in API cement slurries for various loadings, temperatures, and densities. A model of the working mechanism of AA-co-PEGAE as a cement retarder is proposed. Cement testing procedures, lab test results, logistical and operational aspects, and case histories from East Texas and the Gulf of Mexico are presented and discussed.

The study demonstrates that AA-co-PEGAE is applicable as retarder in API cement slurries from ambient temperatures to at least 550 °F without negatively affecting fluid loss, free fluid control, right-angle setting, or hard set of cement. Slight deviations in AA-co-PEGAE dosages did not cause tremendous changes in thickening times, and the retarder response was fairly predictable. The response of AA-co-PEGAE was even found to be linear and insensitive to BHCT up to 200 °F. Chelating of calcium ions seems to be the primary retardation mechanism of AA-co-PEGAE in cement slurries.

The findings serve to improve understanding the mode of action of cement retarders with the goal to optimize slurry designs and admixture compatibility. The robust and predictable characteristics of AA-co-PEGAE over a broad temperature range contribute to more reliable and safe placement of cement slurries.
Study on Corrosion Mechanism of Sour Gas to Cement Stone
Authors: Zeng Yijin , Zhou Shiming
Published: August 2016

Many researchers have conducted study on mechanism of single phase of CO2 or H2S corrosion to cement stone, but the corrosion mechanism of CO2/H2S mixture to cement is seldom involved. The fact is that most of sour gas fields contain CO2/H2S mixture, for example, Puguang gas reservoir in China contains H2S and CO2 as high as 15% and 8% by volume. In this paper, test methods are established under bottomhole condition of Puguang gas reservoir, changes of compressive strength and permeability of corroded cement stone samples by H2S/CO2 mixture are evaluated to study corrosion mechanism of CO2/H2S mixture to cement stone.

Slurry is prepared according to API Spec10B and poured into test mold and cured in HTHP cell for 24 hours. The half of set samples are removed from molds and numbered and putted into the corroding chamber and cured for 21 days, then seal the chamber and inject CO2/H2S mixture and apply heat and pressure according to required temperature and CO2/H2S partial pressure. The rest are cured in HTHP cell as comparative samples. The temperature and pressure in the chamber keep constant during the test.

Compressive strength and permeability cement stone samples were tested to probe the changes before and after corrosion. Microstructure and corroded products of samples were observed by SEM and XRD to investigate changes before and after corrosion.

Result shows the corroded products of CO2/H2S mixture to cement are similar to those by single-component H2S or CO2 gas, except that the amount of expansive crystal produced by H2S is reduced. Combination of H2S and CO2 accelerates the corrosion progress, the recession of strengthen and permeability is more serious than that of single H2S or CO2, but CO2 dominates the whole corrosion process after the long duration. Fly ash and Clay have benefits to resist corrosion of combination of H2S and CO2.

The CO2/H2S mixture will bring serious corrosion on cement ring in wet environments, and damage its' seal ability. The higher the temperature, the more severe of the recession of strengthen and permeability, which presents a complete opposite rule with corrosion by H2S or CO2. The composition of cement slurry is the predominant factor affecting cement corrosion resistance. The introduction of Latex and Fly ash and clay into system will reduce the alkalinity in the cement slurry system and improves the corrosion resistance. The hydration products are crystallized after corrosion under combination of H2S and CO2, and loose arrangement of those crystals is the reason of strength decline and permeability rise.
Application of High Density Non-Aqueous Fluid Technology in the Efficient Development and Production of Super-Deep Complicated Formations in the Tian Mountain Front Block
Authors: Da Yin , Long Li , Xianguang Xu , Jianhua Wang , Lei Li , Rongchao Cheng , Shuang Li , Haijun Yang
Published: August 2016

The Tian Mountain Front Block in North Border of Tarim Basin is very complicated, such as ultra-thick composite gypsum-salt formation, high pressured brine layer, ultra-high temperature hydrocarbon zone, fragmented formation widely distributed in this Block, and narrow mud density window, so abnormal high pressure formations and high collapse stress formations are widely distributed in the Tian Mountain Front Block, which brings enormous challenge to drilling engineering.

Traditionally the oil-gas wells in this area are drilled using high-density water-based drilling fluids (WBM), however, significant non-productive time (NPT) and low rate of penetration (ROP) are easily encountered in dealing with borehole instability, stuck pipe, high pressured brine influx and downhole losses in the process of drilling the gypsum-salt formations or fractured pay zones. To meet the need of drilling operation in the Tian Mountain Front Block, a kind of high-temperature high-density non-aqueous fluids (NAF) is used in drilling engineering. So far, NAF system has been recommended to run for 56 wells in this Block, achieving quite good results.

Ultra-high density NAF system (>2.50 g/cm3) as well as corresponding well killing fluid (up to 2.85 g/cm3) has been developed, and successfully applied to drill through the gypsum-salt formations of six wells in KES 9 Block, and wellbore stability as well as regular hole diameter could be achieved.

This paper presents a study on the successful application of NAF in the Tian Mountain Front Block, and evaluates the potential technical benefits that this NAF technology might provide to petroleum development and production.
Work-to-family spillover: Gender differences in Hungary
Authors: Radó Márta , Nagy Beáta , Király Gábor
Published: August 2016

It is crucial to understand the role that labor market positions might play in creating gender differences in work–life balance. One theoretical approach to understanding this relationship is the spillover theory. The spillover theory argues that an individual’s life domains are integrated; meaning that well-being can be transmitted between life domains. Based on data collected in Hungary in 2014, this paper shows that work-to-family spillover does not affect both  genders the same way. The effect of work on family life tends to be more negative for women than for men. Two explanations have been formulated in order to understand this gender inequality. According to the findings of the analysis, gender is conditionally independent of spillover if financial status and flexibility of work are also incorporated into the analysis. This means that the relative disadvantage for women in terms of spillover can be attributed to their lower financial status and their relatively low access to flexible jobs. In other words, the gender inequalities in work-to-family spillover are deeply affected by individual labor market positions. The observation of the labor market’s effect on work–life balance is especially important in Hungary since Hungary has one of the least flexible labor arrangements in Europe. A marginal log-linear model, which is a method for categorical multivariate analysis, has been applied in this analysis.
Effective removal of lead (II) ions by dead calcareous skeletons: sorption performance and influencing factors
Authors: Lim Ai Phing , Zulkeflee Zufarzaana , Aris Ahmad Zaharin
Published: August 2016

Dead calcareous skeletons (CSs) as low-cost adsorbents were studied to remove lead ions (Pb (II)) in an aqueous solution. Factors influencing the efficiency of CSs were evaluated by adsorbent size, contact time, initial concentration, dosage concentration and pH. The optimum CS size for removal of Pb (II) was 710 μm at an equilibrium time of 720 min. The best dosage of CS was 10 g/L for a 99% removal efficiency without pH adjustment. Pb (II) ions were effectively removed in the initial pH of the metal solution. CS was able to remove a high concentration (100 mg/L) of Pb (II) at a removal efficiency of 99.92% and at an adsorption capacity of 13.06 mg/g. Our results demonstrated the potential of CS as a metal adsorbent in the aqueous phase with a high-removal efficiency and distinct physical characteristics.