bluuebunny/crossref_metadata_2025_split huggingface dataset:
Peninsular Malaysia Coiled-Tubing Drilling Case Study: Atypical Approach to an Unconventional Drilling Technique
Authors: Abdul Rahman A. A. , Hamzah N. E. , Razak M. S. , Ahmad Fauzi N. , Jenie J. R. , Hariry H. E. , Chaari Y. 
Published: July 2012

Abstract
Peninsular Malaysia has a number of fields where reserves are not economical to be further exploited using conventional drilling methods. With the increase in oil prices over the last few decades, an operator decided to embark on a new drilling technique of using acoiled-tubing drilling (CTD) unit to successfully access a bypassed reservoir.
One of the candidates chosen for the project was Well D in which the completion includes 3½-in. tubing in 7-in. production casing. The challenge in this well was to place the whipstock through the cased tubing before drilling operations could be performed because there was no through-tubing (3½-in.) whipstock design for 7-in. casing available on the market. The placement of the whipstock was crucial due to the existence of a shale zone uphole through which it was to be drilled thatwould createa borehole stability issue. The other reasons taken into considerations were to avoid dual-casing exit and the potential associated complications as well as to provide a uniform wellbore to create adequate annular velocity for cuttings transportation to the surface. The team proposed an atypical solution to assist whipstock setting by plugging the entire 7-in. production casing column until the end of tubingwith cement.Once the cement was hardened and tested, a directional drilling assembly with a 2.8-in. speed mill was used to mill a pilot hole through the cement plug, boring along the high side of the casing. Next, a caliper log was run on slickline to confirm hole diameter, and a whipstock wasthen runinto the pilot hole and set with it facing toward the casing. These operations were successfully performed by a rig-less CTD package.The milling assembly was run smoothly and the sidetrack window was effectively cut prior to drilling the target sand.
The successful case study presented summarizes in detail the technique used to mill such a wellbore, the challenges presented, and considerations madein designing the job, which proved to becorrect and accurate on the first attempt.
The Influence of Wellbore Stability on the Feasibility of Extended Reach Drilling Wells: A Case Study from Offshore Vietnam
Authors: Gui Feng , Khaksar Abbas , Gilmore Todd 
Published: July 2012

Abstract
Wellbore stability is important for successful horizontal and extended reach drilling (ERD) wells. Hole instability problems associated with ERD wells can sometimes change the original development plan because of complications and unforeseen operational and geomechanical issues.
This paper presents a case study from offshore Vietnam, where historically, no significant wellbore stability problems had been reported for vertical and low-angled wells. There were plans to develop the field by drilling highly deviated and ERD wells from one platform. However, instability problems and significant non-productive time from frequent pack-offs, tight holes and stuck liners were encountered while drilling one of the designed wells. The hole was sidetracked three times and finally drilled at a lower angle than originally planned.
Geomechanical analysis using core, well log, drilling data and experiences were used to build a field scale geomechanical model characterizing the in situ stress, pore pressure and rock mechanical properties in both the overburden and reservoir sections. Stress-induced borehole failure observed in image logs from an offset well and diagnostic analysis of failure mechanisms from cavings recovered from the problematic well provided significant insights into the likely nature of instability problems in the ERD well. Hole instability problems were attributed to the failure of weak bedding planes and anisotropic rock strength in the shales interbedded with sandstones. To control the weak bedding and anisotropic failure, stronger mud weights were needed than were in the original plan. The required mud weight for maintaining stability varies depending on wellbore trajectory and bedding characteristics. The usagee of high mud weights is unfavorable because of possible formation damage that could occur and the risk of fracturing the reservoir (because of lower fracture gradient). Consequently, the original ERD plan had to be revised and new optimum well trajectories designed that took into account any drilling issues, in addition to completion and productivity requirements.
The First Real Time Reservoir Characterization, Well Placement and RSS Applications in Shale Gas Horizontal Well Play in Central China - A Case Study
Authors: Xing Liang , Sheng Lou ji , Qiang Zhang Yong , Hui Zhang Jie , Lei Zhang , Ju Song , Parlindungan M. H. , Habib Rana Khalid , Yu Dai Guo , Bisain Amarjit Singh 
Published: July 2012

Abstract
A shale gas play operator in Central China has commenced horizontal well drilling development. Upon completion of multiple vertical pilot or evaluation wells, the shale gas target reservoir zones have been identified and are to be developed with horizontal wells. Due to the difficulties and risks associated with acquiring wireline measurements in horizontal sections, Logging While Drilling (LWD) measurements along with Rotary Steerable Drilling Systems (RSS) are used to provide real time formation evaluation, allow the well to be placed optimally within the target reservoir, reduce drilling risks, improve rate of penetration and help optimize completion design.
An integrated LWD tool and RSS was run for the first time in a horizontal shale gas well. The LWD tool delivers elemental spectroscopy, formation sigma and sourceless neutron along with the conventional triple-combo measurements of gamma ray, density, thermal neutron and resistivity. The system provided:
Improved lithology determination and enhanced formation grain density evaluation from elemental capture spectroscopy. This led to improved porosity determination and completion design Optimized lateral placement in the best quality sub-layer with near-bit GR and density images The ability to avoid drilling hazards through real-time monitoring of the drilling parameters available from the LWD tool Greatly improved ROP through the improved drilling capabilities of the RSS. This minimized the time that the formation was exposed to drilling fluids before measurements were acquired. These measurements provided the information required for the success of the first horizontal drilling in a shale gas play.
This paper will detail the use of LWD measurements and a RSS drilling system for an integrated shale gas solution providing comprehensive petrophysical evaluation, accurate well placement, and drilling efficiency optimization for the first horizontal well drilled in a shale gas play in Central China.
Integrated Drilling and Evaluation Solution to Improve Malaysia Deepwater Exploration Drilling Efficiency and to Mitigate Potential Drilling Hazard
Authors: Hamzah Rosli , M’Bareck Khalil Mohamed , Wei Kitty Chan , Sisson Keith , Ming Lim Kien , Loong Ng Kwai 
Published: July 2012

Abstract
PETRONAS Carigali, as one of the major deepwater operators in Malaysia worked closely with the service providers to develop a series of procedures that ensures the success of two planned wells in the perspective of improving drilling efficiency and minimizing potential drilling hazard. These procedures included employing advanced technology in bottom hole assembly (BHA) design for drilling systems as well as the acquisition and monitoring of both real-time formation logging information and downhole drilling dynamics measurements.
This paper starts with sharing the result of drilling efficiency improvement comparing Jet-In and Drill-Ahead BHA using Mud Motor versus Rotary Steerable System (RSS). Secondly, we demonstrate the applications of downhole multiple-sensor- dynamics measurements which enable drilling optimization in real-time. Lastly, the utilization of formation pressure measurement while drilling to monitor and optimize the mud weight system in real-time for drilling efficiency enhancement as well as potential drilling hazard mitigation.
The RSS Jet-In and Drill-Ahead BHA achieved 83% improvement in Rate Of Penetration compared to the Mud Motor BHA. It also improved the well vertically from +/‒3° to less than 1°. The downhole drilling dynamics tool helped the driller to optimize the drilling process especially in the harsh drilling interval and confirmed the premature failure of the Hole Enlargement Device. The real-time data acquired from the formation pressure measurement sub helped the drilling team to make prompt decision on the mud program. The mud weight was reduced from 9.6 lb/gal to 9.2 lb/gal, which avoided fracturing the formation and reduced the operational cost.
Managing Shallow Gas Drilling Risk with Casing Drilling Technology in Brown Field Re-Development Campaigns
Authors: Costeno Hugo , Roed Haakon , Erivwo Ochuko , Usun Ngau Christie , Harris Andrew 
Published: July 2012

Abstract
Casing Drilling was introduced to optimize the drilling of the top hole section in the Phase 1 wells of the mature Samarang Field re-development campaign. Lost circulation and stuck casing incidents in the surface section had been observed in previous campaigns, and Casing Drilling was identified as a solution to mitigate these problems.
Company procedures require that a pilot hole be drilled on the first hole section out of the conductor on the first well drilled during a platform revisit, for shallow gas mitigation. Although the risk of shallow gas was considered low in the Samarang field, the requirement applied to the first well to be drilled in the campaign. In the absence of a conclusive shallow seismic survey, other analyses to evaluate the likelihood of shallow gas were used, and Casing Drilling provided a different approach to mitigating the risk of shallow gas blowout.
This paper discusses the benefits of Casing Drilling in Samarang, with special focus on its application as mitigation for a reduced risk of shallow gas blowout. It reviews the modeling and risk analysis conducted to justify and obtain the waiver required to drill without drilling the conventional pilot hole. It also discusses the lessons learned from the execution.
The implementation of Casing Drilling in mitigating the shallow gas drilling risk, among other benefits, was a significant milestone in the project. The drilling operations became more efficient based on the substitution of the pilot hole on the first well of the re-development campaign. This has opened the opportunity for potentially valuable savings in the next phase of the project (with seven platform revisits) and other similar brown fields revisit campaigns.
Mechanism and Characteristics of Horizontal Wellbore Cleanout by Rotating Jets
Authors: Song Xianzhi , Li Gensheng , Huang Zhongwei , Zhang Laibin , Tian Shouceng , Cui Liu 
Published: July 2012

Abstract
Horizontal wellbore cleanout by rotating jets has been developed rapidly in the past decade. However there are few investigations on mechanism and characteristics of the high pressure water jet impacting and annular helical flow, which are two primary powers to break up the consolidated bed, lift and suspend particles, and increase the wellbore cleanout efficiency. To realize the characteristic of helical flow, the pathilines of rotating high pressure jets and annular velocity distributions were investigated firstly in this paper. The results indicated that the motive power to form the annular helical flow is the non-uniform cross flow generated by partial lateral jets which impact on the wall at an angle, while other jets provide the fluid sources. Further, base on the particle trajectory model and liquid-solid mixture model, the motions of particle, the annular distribution of sand velocity and concentration in annular helical flow were carried out. The pathlines of sand were spiral curves around the drill pipe in the annular helical flow, which can enhance the sand moving ability and increase the horizontal wellbore cleanout efficiency finally. The influences of flow rate, particle size, nozzle assemblies on the annular helical flow strength and sand transportation efficiency were analyzed comprehensively. Finally, the downhole tool was designed according the theoretical results and has been tested in hundreds wells in China. The test showed that it can greatly improve the oil and gas well production and reduce the operating duration. This paper is beneficial to investigate characteristic of sand sweeping by annular helical flow and optimize the tool structure, operation parameters.
Optimization of Casing Drilling Performance Using PAYZONE Simulator and Historical Well Data
Authors: Mahmoud R. , Kelessidis V. C. , Karimi M. , Sankar V. 
Published: July 2012

Abstract
Assessment of drilling performance during Casing Drilling and optimization of the process has been achieved using an existing computer simulator, which has not been tested before in Casing Drilling applications while its value has been proven in conventional drilling. The simulator allows prediction of ROP using standard drilling data of WOB, RPM, flow rate, and formation parameters. Use of simulator post drilling allows fine tuning it to match drilling performance so that future jobs in the same field could be more optimally designed.
Different lithologies along the wellbore were defined in terms the rock type, strength, and abrasivity from drilling data collected while Casing Drilling of a 2000 ft well in Haynesville shale, where ROP was high in the upper part but fairly low in the lower part. Rock strength data normally is not given and estimation was made from databases for similar rocks while they could be estimated from sonic data if available.
Running the simulator allows for re-drilling the well utilizing all basic data and trying to match the real drilling time curve and the measured ROP. Good matching was achieved for the drilling depth-time and also ROP values were matched well over the whole depth interval. Using the simulated model, WOB and RPM were optimized to increase the ROP at the lower part of the well. The results proved that the simulator can simulate Casing Drilling effectively as it has proved its value for conventional drilling.
This work shows that the simulator can help the driller to use historical data of Casing Drilling and then by applying different scenarios, e.g. increasing WOB or RPM and he can apply them while drilling a new well to obtain higher ROP. Using the simulation results, optimal drilling parameters can thus be found for drilling future wells in similar geologic environments.
New Technique: Hydra-jet Fracturing for Effectiveness of Multi-zone Acid Fracturing on an Ultra Deep Horizontal Well and Case Study
Authors: Li G. , Sheng M. , Tian S. , Huang Z. , Li Y. , Yuan X. 
Published: July 2012

Abstract
The placement of multiple fractures in deep horizontal wells is more difficult than that in shallow formations due to HTHP conditions. This paper presents the latest advances in hydra-jet acid fracturing for solving problems in the process of deep well acid fracturing. Basic researches and application evaluations were conducted to overcome down-hole conditions. Special schedule was designed delicately to lower the cracking pressure. The jet velocity was increased more than 800ft/sec to enhance the penetration efficiency. Acid pad fluid also was jetted to the target point for 15 minutes to erode carbonate rock, which leads to lower the rock strength. An explanation how to execute process has been included in details. The different procedures of treatment in shallow and deep reservoir were also discussed.
A novel hydra-jet acid fracturing job was performed with great success on two horizontal wells in an ultra deep carbonate reservoir in China. Seven separated acid fractures were placed along horizontal section from 19,816.3∼21,056.4ft in one well and a large total acid volume of 21,824.5ft3. After acid fracturing, the well produced naturally high rate of 251∼314STB/D. The other well is completed with un-cemented liners and the deepest treatment was applied at the TVD of 20,999.1ft. Four separated fractures were achieved along the 656.17ft lateral section. The pump pressure was controlled in the scope of predicted value (Below 10,000psi).
The main finding is that the hydra-jet acid fracturing has two mechanisms. The first is the hydraulic dynamic sealing effect and the second is the reduction of the time of acid-rock reaction to extend the effective distance. An addition, hydra-jet acid fracturing method proved the effectiveness of delivering acid fractures in the ultra deep horizontal wells.
The Research of Seabed Rescue Equipment and Method of Uncontrolled Blowout in Offshore Drilling
Authors: Ren Meipeng , Li Xiangfang , Shi Fuquan , Ma Long , Xu Darong 
Published: July 2012

Abstract
Presently, rescue equipment and method for uncontrolled blowout in offshore drilling are very rare, of which the consequences were very serious. With analysis of mechanics of materials based on shut-in water hammer pressure and wellhead pressure while rescuing, and fluid mechanics of uncontrolled blowout based CFD, a rescue equipment for uncontrolled blowout in offshore drilling has been invented, and proposing a rescue method. There are several emergency scenario have been made. Take the "deep horizon oil rig" in the gulf of Mexico for example, the flow field properties around this equipment could be calculated by software to prove the reliability of it. The equipment is a conceptual invention which could be designed in different types according to the size and strength of original wellhead. This equipment has a function of rescuing and oil collecting, it could prevent well blowout and collect leaped oil as well.
Enhance Service Capacity and Boost Development Return
Authors: Li Guoshun , Wang Peng , Li Ji , Jia Pingjun , Liu Meiquan 
Published: July 2012

Abstract
In order to meet the demand for energy in economic development, CNPC has initiated the "three-enhancement" project (enhancing speed, enhancing efficiency, enhancing qualification,) to enhance drilling capacity. In recent 3 years, the cycle for well construction in major drilling speed enhancement blocks has been shortened by more than 50%. The single well yield enhancement project has been carried out with large- scale application of horizontal well, underbalanced drilling and staged fracturing technologies, so that the numbers of annually drilled horizontal wells and staged fractured wells have exceeded 1000 and 500 respectively, and number of underbalanced wells reaches 350. The yield of horizontal wells is 3 times of vertical wells, realizing efficient development of low quality reservoir.
The paper presents our thought for drilling speed enhancement, including the integrated application of mature technologies and such critical equipment as vertical drilling, fine-managed pressure drilling (FMPD) and geosteering tools developed for overcoming bottleneck difficulties. The paper also introduces our experiences in terms of development of tight gas, shale gas, CBM etc and other oil and gas reservoirs with integrated application of horizontal well, underbalanced drilling and staged fracturing technologies.
Oribatid mites (Acari, Oribatida) of bushy patches in steppe vegetation of cape Tarkhankut in Crimea (Ukraine)
Authors: Seniczak Stanisław , Kaczmarek Sławomir , Seniczak Anna 
Published: July 2012

Oribatid mites (Acari, Oribatida) of bushy patches in steppe vegetation of cape Tarkhankut in Crimea (Ukraine)
The density, species number, and age structure of oribatid mites were investigated in bushy patches (elm, hawthorn, hawthorn with rose) in steppe vegetation of cape Tarkhankut (Crimea). In these patches, the density of mites in shrub litter, herbs and moss was higher, but species number was similar like in open steppe vegetation. Hawthorn increased the density distinctly more than hawthorn with rose or bushy elms. In bushy patches, the samples of moss were richer in mites than samples of shrub litter alone or with herbs. Among oribatid mites, Chamobates c.f. spinosus and Trhypochthonius tectorum were most abundant, but relatively abundant and common were also Tectocepheus velatus, Oribatula sp. 1, Achipteria nitens, and Brachychthonius berlesei. In oribatid mite communities, adults dominated, but the age structure of populations greatly depended on vegetation type.
Arthropods in the nests of the Common Kestrel (Falco tinnunculus)
Authors: Kaľavský Martin , Fenďa Peter , Holecová Milada 
Published: July 2012

Arthropods in the nests of the Common Kestrel (Falco tinnunculus)
In 2008 we analyzed nest material from 25 nests of the Common Kestrel nesting in the residential and rural areas of Bratislava. 4486 arthropod individuals were determined, belonging to the orders Coleoptera, Mesostigmata, Prostigmata, Astigmata, Oribatida, Diptera and Siphonaptera. The arthropod fauna in the nests of the Common Kestrel can be classified into 4 groups: mites, dipteran larvae, adult beetles and dipterans. Three families of avian ectoparasites were present, comprising 26% of the total arthropod abundance. The remaining 74% of arthropod abundance in the nests comprised coprophagous and nidicolous species.