bluuebunny/crossref_metadata_2025_split huggingface dataset:
Research and Application of Automatic Vertical Drilling System
Authors: Ai Caiyun , Han Zhongyi , Mu Zongjie , Xia Zuo , Tian Hai , Xian He 
Published: July 2012

Abstract
During drilling, how to drill a wellbore vertically is a common technique issue. Though there are some anti-deviation and well straightening methods at present in drilling fields, most of them have their disadvantages, such as decreasing the weight on bit (WOB) and the rate of penetration (ROP). These drilling methods can't achieve the aim of deviation control and fast drilling economically and effectively in high dip, fractured, fault zones, and other abnormal formations.
Automatic Vertical Drilling System (AVDS) is a Mechanical-Electrical-Hydraulic integrated drilling tool, and it is also an intelligent drilling system. As an advanced technology, the AVDS is a great breakthrough in deviation control and fast drilling. According to the result of theoretical analysis and oilfield applications, the AVDS can not only increase the weight on bit and improve the rate of penetration greatly, but also can guarantee improved well bore quality. And perfect borehole quality is an important premise of subsequent operation while drilling.
By the results of the experiments, the indexes of the AVDS have met the design requirements and achieved vertical and fast drilling aim in high dip formations. The paper aims to introduce the characteristics, operating principles and matching technologies of the AVDS.
Practices on Enhancing Drilling Rate of Kenkiyak Subsalt Oilfield in Kazakhstan
Authors: Hu Ertai , Jiang Hongbo , Pan Qifeng 
Published: July 2012

Abstract
Kenkiyak sub-salt oilfield is situated in kenkiyak tectonic belt located at east edge of Caspian Sea basin in the western Kazakhstan. Challenges associated with expense and drilling efficiency in the oilfield are:
Salt creeping and deformation Hole deviation control in the thick salt layer Poor drillability of the interval from approximate 3000m to the 311.1mm section TD and of the whole of the 215.9mm section Bit optimization both in 311.1mm section and 215.9mm section Mud properties control when drilling with turbodrill in 215.9mm section
These challenges make the drilling environment very problematic. The relationship between rock mechanics parameters and log data were studied on cores cut from a well in kenkiyak oilfield. Then models for calculating rock mechanics parameters along depth using log data as input were built. Unconfined compressive strength and angle of internal friction of the wells were evaluated. Based on these parameters, the proper bit types and requirements of bit design for each section were recommended.
On the basis of detailed assessment of the formation characterization, operational parameters, bit performance and bottom hole assembly, we introduced vertical drilling system to drill the thick salt layer in 311.1mm section and impregnated diamond bit /turbodrill combination to drill 215.9mm section.
These advanced technologies have reduced the time taken to drill the 311.1mm section and 215.9mm section by an average of 13 days and 12 days respectively. This has resulted in an average cost saving of $450,000USD in time and materials in the 311.1mm section and 215.9mm section.
The Successful Application of a New-style Managed Pressure Drilling MPD Equipment and Technology in Well Penglai 9 of Sichuan & Chongqing District
Authors: Liu Wei , Shi Lin , Zhou Yingcao , Fang Shiliang 
Published: July 2012

Abstract
Managed pressure drilling (MPD) equipment is a crucial equipment to effectively solve the drilling problems of narrow pressure margin between the pore (or collapse) and fracture pressures, such as well kick, well loss, well collapse and well struck. A new-style MPD equipment is developed to accurately control the pressure in annular and effectively solve the various complex problems caused by the narrow pressure window. The MPD equipment comprises manifold system, backpump system and auto-control center, which can provides additional flowrate and back pressure to compensate for the reduction of bottom hole pressure while making a connection, reduction in rig pump rate, change in mud weight or drill pipe movement and so on. And in order to do MPD equipment development and technology research, a new MPD laboratory and simulation system have also been established which can simulate the various drilling conditions in the MPD operation, including run in hole, pull out of hole, trip, start mud pump, stop mud pump and so on.
After many experiments, the new-style MPD equipment was improved gradually, and then moved to Sichuan oilfield in Sichuan & Chongqing district of China to do the functional experiments, including equipment performance, near-balanced MPD application and a new MPD application of under-balanced drilling. Especially, the MPD technology of underbalanced drilling is different from the conventional MPD technology because the controlled bottom-hole pressure is lower than pore pressure of formation and the gas can be allowed to come out from formation at a controlled rate.
The test results prove that the MPD equipment can control the bottom-hole pressure in an exact range and the managed pressure technology of underbalanced drilling is feasible. We trust that the new-style MPD equipment and technology will be more successful in the oil or gas well with narrow pressure margin in the future.
Comprehensive & Associated Drilling Technology for Ultra-deep Well Jida 4
Authors: Yu Zhucheng , Wang Weiguo , An Chaoming , Lv Xiaoping , Zhang Zhenyou , Ai Guicheng 
Published: July 2012

Abstract
Jida 4 is an overseas ultra-deep prospecting well completed by CNPC for important scientific research, with design depth of 6350m and completion depth of 6596m. Three formation pressures and drillability profiles of rocks are established by investigation to achieve optimized and fast drilling technology, including optimization of well bore structure, bit and drilling tool combination and improvement of drilling parameters; the developed salt-resistant and high-temperature resistant ultra-high density saturated salt water drilling fluid system may ensure indoor experimental density of 2.55g/cm1, temperature of 180°C, the highest in-situ density of 2.44g/cm3 and temperature of 163°C and safely drill 450m interval of KKC layer, so as to achieve hole cleaning and downhole safety; research and application of ultra-high density salt-resistant and high-temperature resistant slurry system and spacer fluid system may ensure slurry density of 2.48g/cm3 and spacer fluid density of 2.5g/cm3, so as to achieve safe cementing of deep well.
Research and Development of Contactless Power Coupling System in Rotary Steering Tool
Authors: Ai Weiping , Zhang Lei , Deng Le 
Published: July 2012

Abstract
This paper proposes a downhole contactless power coupling system characterized by high efficiency, low noise, compact size, vibration-resistance and easy-to-maintenance. The system includes a power transformer with detachable structure. High-frequency soft switch techniques are used for power inverting circuit. In addition, resonant point of inverting circuit can be locked automatically through regulating of switch frequency in accordance with closeness to zero of phase difference between output voltage and current of inverting circuit. In this way, deviations in resonant points induced by environmental temperatures can be eliminated. Test results show that electrical energy transmission efficiency of the prototype can be maintained well above 70%. With high reliability, the system can be used to replace conductive slip ring to achieve electrical energy transmission from rotary drill pipe to guide sleeve. Application of the system may facilitate miniaturization of drilling tools. Compared with conventional drilling tools, the power coupling rotary steering tool may effectively reduce drilling cost, enhance ROP, reduce sticking and promote borehole quality. Consequently, it is significant for horizontal drilling.
Application of Smart Packer Technology in Underbalanced Completion
Authors: Chen Chao , Lei Yu , Liu Deji , Yin Yuchuan , Wang Tao , Li Xiaohui 
Published: July 2012

Abstract
Smart packer is a kind of intelligent chemical colloid which can be used in underbalanced completion. Smart packer is pumped into wellbore before gelatinization; once gelatinized, oil and gas plugging and strings penetration can be achieved. When completion operation finished, dispergation and liquefaction of smart packer can be realized.
Smart packer bears remarkable superiorities: firstly, it is cost-saving, compared with imported mechanical devices, the cost of smart packer is 1800000 Yuan lower, and its cost is only one third of that of domestic tools. Secondly, the application of smart packer is very flexible; as long as smart packer is used during the process of underbalanced drilling when there is showing of oil and gas, the investment risk of drilling will be reduced. Thirdly, compared with conventional equipment, smart packer has a much wider range of running depth. Fourthly, once failed, there is room of technical remedy and the operation can be done once again.
Presently, smart packer technology has been applied to field application. Among the applied wells, there are oil and gas wells, vertical and horizontal wells. The types of underbalanced completion including hanger screen pipe completion and open hole completion. The deepest working depth of smart packer is 3000m, the maximum formation pressure coefficient of applied wells is 1.33.
Smart packer technology has firstly been applied to Well Ya940, the production of single well is 2 to 3 times of the average production of adjacent wells; not only the underbalanced completion has been achieved, but also a heavy oil reservoir with a reserves of 10500000 tons has been discovered for the first time.
Research on a New Method to Evaluate the Hydrostatic Pressure of Cement Slurries
Authors: Haijin Zhu , Guangming Lv , Aiping Liu , Chengbin Xie , Shaohui An 
Published: July 2012

Abstract
Aimed at the oil industry short of a method to evaluate the hydrostatic pressure of cement slurries, by establishing the method of measuring cement slurries’ static gel strength (SGS) and pressure difference (PD), a method to evaluate the hydrostatic pressure of cement slurries was researched. In this paper, the hydrostatic pressure of two basic cement slurries was studied respectively by cement pressure drop test model (PDTM) and static gel strength analyzer (SGSA). The differences of these test results obtained were discussed and explained with effective stress principle, and later the result with SGSA was found more accurate. Based on previous research, a method to evaluate the hydrostatic pressure of cement slurries was established. By establishing the method of measuring cement SGS to gain the development of the annular column hydrostatic pressure, a new method to evaluate the gas migration for cement slurries was developed, and an industry standard on anti-gas migration additives was formed.
The laboratory tests were presented with good repeatability and operability, and could be used to test the alteration of cement hydrostatic pressure.
This method proposed in the paper was part of basic research result of cementing, and could do some work for the study of gas migration of cementing technology.
Fishbone Well Drilling and Completion Technology in Ultra-Thin Reservoir
Authors: Xing Guangyu , Guo Fuxiang , Song Cheng , Sun Yongcai , Yu Jing , Wang Guangxin 
Published: July 2012

Abstract
The mathematical models for the number of branches of the thin layer fish bones well, the branch borehole length, branch angle and distance between the branch borehole system optimization model have been established. Some key issues such as safe separation between the main borehole and the branch borehole, Interlayer wall construction method of the unconsolidated strata, drilling string and completion string trip-in have been solved. A suit of technology such as open hole sidetracking technology, Interlayer wall construction method of the unconsolidated strata and drilling string and completion string trip-in technology have been formed.
Through integrated application of geological-oriented drilling, composite drilling, trajectory control, open hole sidetracking technique and other supporting technologies, have completed two wells on-site testing. Technical problems such as go across the ultra-thin oil layer, branched hole three dimensional Pressurize and evaluation of drilling tool throughput capacity have been solved successfully. We achieved in drilling branch in 1.5 m thickness of the reservoir. It is currently the thinnest oil drilling fishbone wells.
The early production of the two test fish bone wells has reached 10 times to the conterminous well, stable output is 3.5 times, Its effect is significant.
Fishbone well Technology put the Single path horizontal section plane extends to more than one horizontal wellbore. Achieved more expose reservoir and increased the well production, providing an effective approach for economic development of low permeability, low abundance and thin low-yielding oil field reservoir.
Horizontal Drilling and Cementing Technology of The Gas Storage in LiaoHe Oil Region
Authors: Zhongwei Zhu , Sheng Wu , Yin Yang 
Published: July 2012

Abstract
According to the requirements of Group Corporation, a gas storage will be built in LiaoHe oilfield. There are two technical challenges for converting underground gas storage in complex fault-block reservoir: First, eastern rift basin forms a complex broken structure with reservoir deposited by complex continental rivers, therefore, it is very difficult to build the stock; Second, The gas storage well cementing technology in LiaoHe oil region is not perfect. In the face of these challenges, the measures include collaborating with construction side to complete gas storage evaluation design and operation technology, collaborating with professional oil companies, using horizontal wells, branching wells drilling and completion technology to complete gas storage drilling.
Gas storage drilling problems are that cementing quality should meet the gas storage's need for 50 years’ high-intensity injection and that there are difficulties in ensuring the integrity of the wellbore and the perfection of the gas sealing. Guantao and the upper Stratum in LiaoHe oil region is easy to leak and collapse, therefore, there is a greater well control risk.
Research for above problems contains excellent and fast drilling technology in two steps, long horizontal section of horizontal well, cementing techniques in long sealing segment and low layer.
In order to fully promote the application of gas storage well drilling and completion technology and improve overall economic efficiency, three gas storage wells have been completed in LiaoHe oil region in 2010 (one plugged well, two information wells). To meet the construction needs of gas storage wells in LiaoHe oil region, a set of relatively mature gas storage well supporting technology is formed to comprehensively improve drilling speed of gas storage wells through the research of gas storage horizontal well drilling and completion technology
Application of Multi-Branch Horizontal Well Technology in CBM Drilling
Authors: Naizhong Duan , Zhimin Gong , Helin Wang , Zengshun Wang , Lixin Lv , Qingquan Huang , Zhihui Xu 
Published: July 2012

Abstract
Application of multi-branch horizontal well technology in CBM drilling is of high technical contents, with great construction difficulties. This paper, by presenting drilling practices of BHDC (Bohai Drilling Engineering Company Limited, a CNPC company) at 10 wells including ZP02-1H and ZHP4H, makes discussion and analysis on technologies of wellbore path control, well connection, geo-steering, open-hole sidetracking, aerating, etc.
A New Model of Bit Whirl
Authors: Kovalyshen Yevhen 
Published: July 2012

Abstract
A simple analytical model of bit whirl is presented. In contrast to the previous works, which consider BHA mass imbalance to model bit whirl, the model here takes into account the history-dependent boundary conditions at the bit-rock interface. Within this model, the geometry of the bit is characterized by three dimensionless parameters. The results have shown that, depending on the value of these parameters, the system can be stable or undergo forward or backward whirl. As a result, the model has potential application as a tool that assists bit design.
Field Application of an Analytical Model for Estimating the Downhole Temperatures due to Wellbore Friction
Authors: Kumar Aniket , Singh Ajay Pratap , Samuel Robello 
Published: July 2012

Abstract
Wellbore friction has led to an increase in the temperature of the drilling fluid downhole as well as heating of the drillpipe and the bottomhole assembly. Severe downhole heating can lead to potential well-control safety issues and result in costly remedial efforts. An estimation of the increase in temperature of the drilling fluid downhole as a result of this wellbore friction will certainly help in taking measures to prevent such dire circumstances and will lead to an improved drilling plan.
This study uses a simple analytical model to analyze the heat generated from borehole friction and then predict the downhole temperatures at any depth in the well during a drilling operation. The torque acting on the drillstring as a result of contact forces has been used to model the heat generated from friction, and a steady-state heat transfer solution has been presented. The model also incorporates the heat generated downhole owing to frictional pressure losses along the drillstring as well as across the bit.
Practical field cases, including a horizontal well, have been presented in the paper to validate the model. Downhole temperatures of the drilling fluid have been calculated along the well profile using the model and then compared with the field data measured using MWD tools. The zones having the maximum increase in temperatures can be identified based on the temperature profile generated during the drilling operation. The impact of drilling parameters on temperatures has also been analyzed and can be used effectively to maintain a better check on undesired temperatures.
This simple analytical model can be suitably applied to field cases based on the well profile and can be effectively used to predict the maximum temperatures to be encountered downhole while drilling ahead as planned. An accurate estimation of maximum temperatures will help us prevent severe downhole friction heating in the future.
Study on the Well Control Safety During Formation High-Sulfur Gas Invasion
Authors: Dou Liangbin , Li Gensheng , Shen Zhonghou , Song Xianzhi , Chi Huanpeng , Du Tao 
Published: July 2012

Abstract
With the deepening of oil & gas reservoirs exploration and development, an increasing number of sour-gas reservoirs especially those with high content of H2S are developed in the world. Phase transition of high-sulfur gas or H2S will be easy to occur near the wellhead, and bottom-hole pressure reduces drastically, which possibly leads to serious blowout. Considering the special physical properties of high-sulfur gas and its possible phase transition in the wellbore, a mathematical model for wellbore flow and heat transfer during formation high sulfur gas invasion was established. The heat transfer and pressure were coupling calculated along with high-sulfur gas physical properties parameters, and a solution method of the model was proposed. The wellbore pressure and properties of gases with different content of H2S rising process along the wellbore were analyzed. The reason of high-sulfur gas easy to result in the problem of well control was presented. The paper exhibited the results of the bottom-hole pressure and depth of phase transition varying with different influx rate, injection rate, choke pressure and land surface temperature, and the reasons of wellbore pressure and phase transition influenced by these operating parameters were discussed respectively. The study is of certain significance for improving the safety of acidic oil & gas reservoirs exploration and development.
Through Tubing Technique Provides Solution to Gravel Pack Deeper Layer in Existing Gravel Packed Well
Authors: Rivero C. Maria Elba , Sepulveda Willem , Zaini Muhamad Zaki , Magna Bela Sunanda , Tusimin Fuziana Bt. 
Published: July 2012

Abstract
This paper is intended to describe the design and execution of the first through-tubing gravel pack (TTGP) performed in 2-7/8" tubing in an offshore field in Malaysia, the challenges faced as well as the lessons learned.
Petronas Carigali in Alliance with Schlumberger is currently operating this 25 years old brownfield. Most of its wells were drilled and completed in the mid 1980's and integrity issues are appearing more frequently. The production challenges encountered today range from maintaining stable and profitable rates as well as maximizing reserves and productivity. This must be achieved optimizing operating expenditures and finding solutions that minimize and reduce capital investments.
After close monitoring of production rates it was identified that the well in study was badly underperforming and after some surveys tubing integrity issues were detected in several sections of the production string. This well became a workover candidate and included in the work program and budget for intervention. During the stages of detailed design, an additional opportunity to develop a deeper layer was identified and added to the scope of the workover. Due to the low degree of consolidation of the shallow reservoir sands, this new layer required installation of sand control means.
The TTGP method was selected to access the oil of this prospective sand. This technique allows placement of a gravel pack below existing sandface completions at lower cost compared to a conventional workover intervention.
This paper details the solutions to the challenges faced as a consequence of existing well geometry, integrity and location of the new promising sand.
Despite of the technical and logistic challenges the job was performed below AFE and within technical limit estimates and with a packing factor above design. The TTGP is a low cost solution for sand control in wells with existing completion and behind casing opportunities. The presented well case has served as basis of design for two more wells on the same field and on another well on a neighboring field.