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Collaborating Authors
Yang, Guang
Optimal Design Method of Oscillator Installation Position in Sliding Drilling
Shi, Xiaolei (MOE Key Laboratory of Petroleum Engineering, China University of Petroleum) | Huang, Wenjun (MOE Key Laboratory of Petroleum Engineering, China University of Petroleum) | Gao, Deli (MOE Key Laboratory of Petroleum Engineering, China University of Petroleum) | Yang, Guang (CNPC Engineering Technology Research Institute Co. LTD) | Wang, Wenzhi (CNPC Engineering Technology Research Institute Co. LTD)
ABSTRACT: In the process of sliding drilling, installing oscillators on drill strings can decrease axial friction and increase wellbore extension effectively in sliding drilling. Traditionally, the positions of oscillators are most determined by drilling experience, which constraints the drag reduction efficiency of oscillators. To overcome this shortcoming, a new optimization design method of oscillator installation position is presented. Firstly, the initial position of the drill bit is determined according to the well structure data, drilling parameters and drilling time. Then, the drill string in the borehole is divided into key nodes according to the joint position. Based on the data of screw induced torque, the action length of screw induced torque is calculated, and the action length of static friction zone is determined. Next, based on the initial conditions and boundary conditions, establishes a dynamic model of drill string by considering the friction nonlinearity and uses finite difference method to solve it, the friction distribution of drill pipe is analyzed, and the friction of key nodes in each distribution area is calculated. Finally, the initial position of the drill bit and the action length of the static friction zone are re-determined, and the friction of key nodes is accumulated. By analogy, the maximum accumulated friction in the static friction area is determined. Based on the oscillatorโs propagation distance model and the minimum drag reduction efficiency, the recommended best installation position is calculated, and sensitivity analysis is carried out to evaluate the drag reduction effects of various parameters. The results show that, compared with the calculation results of determining the installation position of oscillator by drilling experience in the past, the model in this paper has a more significant effect on reducing friction and the installation position is more reasonable. The fluctuation of the displacement of drill string and the hook load are more obvious when the oscillators are installed in the preferred position, and the effect of reducing the average friction is significant, which is more conducive to the transfer of axial force. When other parameters are constant, using the recommended positions of oscillators or increasing the number of oscillators can not only beneficial to the transmission of axial force, and can reduce the average friction of the drill string, but also improve the drag reduction efficiency of the drill string, increasing the rate of penetration and increasing the borehole extension distance. The research results are of significant guiding significance for optimal design and safety control of drag reduction oscillators in sliding drilling.
- Asia > China (1.00)
- North America > United States (0.93)
- Research Report > New Finding (0.34)
- Research Report > Experimental Study (0.34)
Experimental Study on the Effects of Wave and Current Interaction on Vertical Motions of a Cylindrical FPSO
Deng, Shi (Offshore Oil Engineering Co. Ltd) | Cai, Yuanlang (Offshore Oil Engineering Co. Ltd) | Yang, Xiaolong (Offshore Oil Engineering Co. Ltd) | Song, Zhengrong (Offshore Oil Engineering Co. Ltd) | Yang, Guang (Offshore Oil Engineering Co. Ltd)
ABSTRACT Cylindrical floating production storage offloading (CFPSO) is an alternative for oil filed development drawn many attentions recently due to its low construction and transportation cost, especially for the mid-water-depth. However, for its circular water plane, the hydrodynamic features of a CFPSO are quite different from the conventional offshore ship-type floating structures, especially in the coupled wave and current load condition. A scaling model test has been conducted with regular, bichromatic waves and current to study this phenomenon. It is observed that the out-plane motions (including heave and roll/pitch) amplitude in the coupled load condition is a little larger than those observed from the pure wave cases. A quasi-lock-in phenomenon and nonnegligible mean displacement in heave is observed in the coupled load case, and vortex-induced force is supposed as the reason for the phenomenon. Moreover, large frequency components, far away from the eigenfrequency cannot be neglected in the coupled load case (bichromatic) compared with that in the pure wave case. Findings in this paper provide a basic reference for the initial strength and fatigue design of the CFPSO considering coupled wave and current effects. INTRODUCTION For the high-cost efficiency requirement of the oil field exploitation, the cylindrical floating production storage and offloading (CFPSO) unit had drawn more attentions in recent years for its low construction cost. Similar as the conventional ship-type FPSO, this new concept is normally moored in the open sea, as shown in Fig. 1. It sometimes works in a strong coupled load condition (combined wave and current), especially in South China sea. Previous scholars normally focused on the mooring system of the CFPSO, and the difference frequency wave loads, since the natural frequency of the surge or sway are well within the content in the spectra of the slowing vary wave loads (Afriana, 2011; Vidic-Perunovic et al., 2017; Wang et al., 2016). They studied in-plane motions (such as surge and sway) of the structure in different sea state and loading conditions.
- Research Report > New Finding (0.64)
- Research Report > Experimental Study (0.50)
A Construction Method of Complex Fractures in Marine Carbonate Reservoir
Wang, Wenzhi (CNPC Engineering Technology R&D Company Limited) | Yang, Guang (CNPC Engineering Technology R&D Company Limited) | Cui, Meng (CNPC Engineering Technology R&D Company Limited) | Wang, Haige (CNPC Engineering Technology R&D Company Limited) | Zhou, Zhou (China University of Petroleum Beijing) | Kao, Jiawei (Sinopec Research Institute of Petroleum Engineering) | Liu, Yuqing (CNOOC Research Institute, Beijing) | Wang, Lian (China University of Petroleum Beijing)
In the development process, it is necessary to connect hydraulic fractures and as many karst cavities as possible, which are the main geological components of oil and gas storage. However, the systematic theoretical of how to build complex fractures in fractured-vuggy carbonate reservoirs is scarce. Facing this situation, this paper presents a method that can improve the accuracy of fracturing effect prediction and optimize fracturing process design parameters so as toachieve the purpose of increasing production. It studies the factors that could affect that connection. It is found that the density of natural fractures and cavitiesin the reservoir is the main factor affecting the fracture propagation shape. Meanwhile, the liquid containing cavitiesin the reservoir will attract or repel the fractures. Furthermore, natural fractures will cause the migration of fracture propagation path and hydraulic fractures are easy to continue to expand along the direction of large natural fractures. This methodology could be used in future studies for the marine fracture-vuggy carbonate formation. In addition, the research conclusion could be used to design and evaluate hydraulic fracturing operation.
- Asia > China (1.00)
- North America (0.68)
- Geology > Rock Type > Sedimentary Rock (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > Asia Government > China Government (0.46)
- Well Completion > Hydraulic Fracturing (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Naturally-fractured reservoirs (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Carbonate reservoirs (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
Production Optimisation by Retrofitting Autonomous Inflow Control Devices into an ICD Well in a Oil Reservoir Offshore China
Gao, Xiaofei (CNOOC china Ltd) | Dai, Ling (CNOOC china Ltd) | Liu, Jia (CNOOC china Ltd) | Zou, Xinbo (CNOOC china Ltd) | Xu, LiQian (CNOOC china Ltd) | Yang, Guang (CNOOC china Ltd) | Moradi, Mojtaba (Tendeka BV) | Konopczynski, Michael (Tendeka Inc) | Hua, Jingheng (Tendeka China)
Abstract In the 2018 intervention campaign, CNOOC aimed to improve production by retrofitting a horizontal well offshore of China. Water mobility in the reservoir was at least 20 times higher than oil mobility and a strong aquifer was located below the well. The well was drilled along a heterogeneous formation with varying properties resulting in an uneven reservoir influx toward the wellbore. Although the well was already completed with passive ICDs, oil production from the well started suffering severely from an early water breakthrough in a couple of weeks after starting production. It was recognized that the challenges could be mitigated by deploying Autonomous Inflow Control Devices (AICDs) which can control the reservoir fluid influx toward the wellbore and therefore optimise the well performance. An AICD is an active flow control device that delivers a variable flow restriction in response to the properties of a fluid and the rate of flow passing through. An integrated workflow comprising history matching and performance evaluation of the existing completion and sensitivity analyses was adopted to determine the best retrofit completion for the well. A well with a horizontal length of 300m was drilled in a thin formation with the oil column averaging 15ft. The optimum retrofit completion was to install a 2 3/8โณ inner string consisting of AICD subs, swellable packers inside the existing ICD completion. The well was segmented in three compartments and a tailored AICD completion based on log data from the well was designed to properly restrict the production of water. The string was then connected to a redesigned ESP pump lifting the fluids to the surface. Through teamwork between the companies, the well was successfully re-completed with RCP AICD completions. Over a 9-month period of production, the well performance has been optimised with AICD devices. The AICDs significantly reduced the water cut (WC) of the well from 97% to 87% helping produce 200% more oil compared to production prior to re-completion. This application not only saved the cost of treating extra water but also added value by producing more oil. It also facilitated the connection of another well to the production system due to the enhanced capacity of the system which was then producing a lower volume of liquid. This well is an example that demonstrates the possibility of retrofitting AICDs in existing screens successfully. AICD completions ensured a balanced contribution from all reservoir sections and limited water production significantly. The lessons learnt from pre and post-installation studies will be discussed throughout. The AICD completions enabled the operator to implement an optimum reservoir drainage strategy that uses downhole control that can be manipulated autonomously based on well dynamic conditions to produce more oil.
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.47)
- Geology > Geological Subdiscipline > Economic Geology > Petroleum Geology (0.40)
Fines Migration Behavior During Cyclic Injection and Production of Underground Gas Storage Wells
Chen, Mingjun (Southwest Petroleum University) | Shao, Jiaxin (Cornell University) | You, Lijun (Southwest Petroleum University) | Kang, Yili (Southwest Petroleum University) | Meng, Seng (Southwest Petroleum University) | Yang, Guang (Southwest Petroleum University)
Abstract Different injection and production pressure modes for underground gas storage have great differences on the permeability of formation rocks. In this paper, core flow experiments are designed and carried out to simulate the real pressure gradient of the injection and production in underground gas storage, and these experiments are carried out under in-situ stress conditions. The permeability and turbidity of core outlet were monitored during the experiment. The experimental results show that under different injection-production pressure modes, the permeability changes and the turbidity at the core outlet changes. It was observed by scanning electron microscope that there were fines on the fracture wall after the experiment. Analysis shows that fine migration is the main reason for the change of permeability under different injection-production pressure modes.
- Research Report > Experimental Study (0.48)
- Research Report > New Finding (0.34)
A New Method to Detect Influx and Loss During Drilling Based on Machine Learning
Shi, Xiaoyan (CNPC Engineering Technology R&D Co. Ltd) | Zhou, Yingcao (CNPC Engineering Technology R&D Co. Ltd) | Zhao, Qing (CNPC Engineering Technology R&D Co. Ltd) | Jiang, Hongwei (CNPC Engineering Technology R&D Co. Ltd) | Zhao, Liping (CNPC Engineering Technology R&D Co. Ltd) | Liu, Yong (Petro China Tarim Oilfield Company) | Yang, Guang (CNPC Engineering Technology R&D Co. Ltd)
Abstract Influx and loss are the two most common downhole complexities. They not only cause the reservoir damage, increase the exploration cost, reduce the drilling efficiency; but also induce major malignancy. Therefore accurate and early detection of influx and loss during drilling is of great significance. Traditional influx and loss detection methods have the shortcoming of monitoring time lagging and high costs. As the rapid development of artificial intelligence techniques, researchers start to detect influx and loss using artificial intelligence method. This work adopted two machine learning algorithms(Random forests and Support vector machine) according to their characteristics to detect influx and loss during drilling in real-time. The detection methods includes four steps: 1) Generating raw influx/loss raw data set by combining real-time drilling data and drilling history data; 2) Pre-processing raw data set to obtain training data set; 3) Training classification model of random forests and SVM by training data set and algorithms; 4) Predicting influx/loss by the trained model according to the new real-time data. The case study shows that influx and loss can be detected accurately in early stage by both random forests method and SVM method after proper pre-processing the raw data and optimizing algorithm parameters. The detection accuracy of the sample data from four wells exceeds 90%. This work demonstrate a new way to detect influx and loss by utilizing huge drilling data and machine-learning algorithms, and the detection results are satisfying.
Study and Pilot Test of Activator Flooding for Heavy Oil
Zhang, Jian (State Key Laboratory of Offshore Oil Exploitation, CNOOC Research Institute Co., Ltd.) | Wang, Shanshan (State Key Laboratory of Offshore Oil Exploitation, CNOOC Research Institute Co., Ltd.) | Zhu, Yuejun (State Key Laboratory of Offshore Oil Exploitation, CNOOC Research Institute Co., Ltd.) | Yang, Guang (State Key Laboratory of Offshore Oil Exploitation, CNOOC Research Institute Co., Ltd.) | Kang, Xiaodong (State Key Laboratory of Offshore Oil Exploitation, CNOOC Research Institute Co., Ltd.) | Wang, Xudong (State Key Laboratory of Offshore Oil Exploitation, CNOOC Research Institute Co., Ltd.) | Zhao, Wensen (State Key Laboratory of Offshore Oil Exploitation, CNOOC Research Institute Co., Ltd.)
Abstract To effectively develop heavy oil with apparent viscosity above 150 mPaยทs in-situ, a heavy oil activator was designed and applied in the field, which can efficiently increase the viscosity of aqueous phase and the mobility of oil phase. The wettability, interfacial properties and the microscopic dispersion of oil with activator were measured using the contact angle meter and laser scanning confocal microscopy. Experimental results showed that the contact angle between activator and heavy oil was 34.67ยฐ and the oil-water interfacial tension could be reduced to 0.1 mN/m by adding activator. Furthermore, it was clearly observed that the crude oil was uniformly dispersed into small drops. For the hybrid system consisting of 660 mPa's crude oil and 1000 mg/L activator with a mixed ratio of 1:1 by volume, the flowing time measured by kinematic viscometers was reduced to 8 s compared with 340 s of single oil system. By adopting the activator flooding, laboratory experimental studies showed the recovery of heavy oil could be enhanced by 14.3% on the basis of water flooding. The change of oil-water front and distribution of saturation field confirmed that the activator had the ability to disperse heavy oil and improve the micro-displacement efficiency, and the contribution rate accounted for about 28% of the total recovery. This obvious effect has been successfully achieved in pilot test of both S Oilfield and D Oilfield. By applying activator huff and puff in S Oilfield for 14months, the total incremental oil reached 44,952 bbl tons. And using activator of 800 mg/L to exploit heavy oil with viscosity of 1170 mPaยทs in-situ at 35 ยฐC. After 3 years of injection, the cumulative incremental oil of D oilfield was larger than 120,000 bbl, which means that each ton of activator can ramp up production of 660 barrels oil.
Abstract Composite propeller is found to have the characteristics of weight light, hydrodynamic performance improvement and noise reduction. In order to investigate its fluid-structure hydroelastic performance, potential based boundary element method (BEM) is coupled with finite element method (FEM) for the hydrodynamic analysis of composite propeller. The calculated thrust and torque present good agreement with the experimental hydrodynamic force. A series of comparative experiments in cavitation tunnel are conducted to research hydroelastic characteristics of composite propeller compared to metal propeller, including hydrodynamic performance test, hydrodynamic decline test, cavitation inception test and cavitation observation test. The "transition point" of the open water curve is discovered, at which the attack angle's decrease balances the deformation to equal composite propeller and metal propeller. The composite propeller's cavitation inception is later and cavitation area is smaller than metal propeller. The tests above all show that the hydroelastic self-adaptive characteristic gives composite propeller better hydrodynamic and cavitation performance than metal propeller. Introduction Along with the development of propellers, composite propeller comes to be taken seriously due to its advantage of lightweight, higher efficiency, erosion or cavitation damage resistant, fatigue improvement, life cycle cost decrease and good acoustic damping characteristics. The fluid-structure interaction (FSI) hydroelastic effect is caused by the application of composite materials. The characteristics of lightweight and flexible change the hydrodynamic and structural performance, especially when anisotropic fiber ply optimized. A great deal of work begins by Young (2007, 2008) using potential-based boundary element method coupled with finite element method for the time-dependent hydroelastic analysis of cavitating propulsors and flexible composite marine propellers. The numerical method was invented to investigate moving cavity boundaries and fluctuating pressures, dynamic blade deformations and stresses(Young2008). Then the self-adaptive composite propellers occurred (Young2010). Some further research on the effects of material anisotropy and added mass on the free vibration response of rectangular cantilevered composite plates/beams was conducted (Young2013), results showed that the wet mode natural frequencies of the composite plate were 50โ70% lower than dry mode due to large added mass effects, which varied considerably with material orientation then affected the mode shapes and fluid inertial loads.
- Transportation > Marine (0.93)
- Shipbuilding (0.77)
Integrated Drilling Database Enables Automated Drilling Engineering Design
Shi, Xiaoyan (CNPC Drilling Engineering and Technology Research Institute) | Zhou, Yingcao (CNPC Drilling Engineering and Technology Research Institute) | Song, Peng (CNPC Drilling Engineering and Technology Research Institute) | Zhao, Qing (CNPC Drilling Engineering and Technology Research Institute) | Jiang, Hongwei (CNPC Drilling Engineering and Technology Research Institute) | Huo, Zongqiang (CNPC Drilling Engineering and Technology Research Institute) | Yang, Guang (CNPC Drilling Engineering and Technology Research Institute) | Zhai, Xiaoqiang (CNPC Drilling Engineering and Technology Research Institute)
Abstract As the rapid development of drilling techniques and data acquiring techniques, more and more drilling data are available. Storing, managing and effective using of these massive data are crucial to optimized drilling engineering design and strategic decision. This article is to research and design an integrated drilling database, and then further explore the innovative usage of the available drilling data. Based on the detail analysis of drilling database requirement, this article researched and designed drilling database by three phases: conceptual design, logical design and physical design. In the conceptual stage, the requirements of drilling design data, real-time drilling data and drilling construction data are extracted and analyzed, then E-R model is constructed. In the logical design stage, data tables and table relationship are designed and refined based on the E-R model. In the physical design stage, physical structure is selected for the logical data model to satisfy the application requirement. The designed drilling database is targeted data storage and management basis for drilling engineering design and craft software, real-time drilling software and drilling history management software; it conforms to drilling business process, contains comprehensive and detailed content and has high performance and refined data table structure. The construction of unified drilling database enables the efficient storage of mass drilling data and further data mining and analysis of drilling information. This work further researched the algorithms of automatic drilling engineering design, especially for automatic wellbore geometry design, based on the available data in the database. This article introduced a systematic method to design an integrated drilling database, which supports design data, real-time data and drilling management data. It also proposed an innovative way of drilling engineering design: automated drilling engineering design based on the data in the integrated drilling database and pre-installed rules.
Experimental Investigation on Global Responses of a Large Floatover Barge in Extremely Shallow Water
Xiong, Lingzhi (Shanghai Jiao Tong University) | Lu, Haining (Shanghai Jiao Tong University) | Yang, Jianming (Shanghai Jiao Tong University) | Zhang, Wei (Offshore Oil Engineering Co., Ltd, Engineering Company) | Yang, Guang (Offshore Oil Engineering Co., Ltd, Engineering Company)
Abstract Floating vessels moored in shallow water are at risk of possible bottom grounding and collision between the vessel and the subsea pipelines. Their dynamic responses are of great concern in offshore engineering. In this study, experiments were conducted to investigate the motion response of a large floatover barge moored in ultra-shallow water. White noise wave tests with five different incident angles were carried out in four different water depths. Shallow water effects were observed in the experiment. The motion characteristics of the moored barge in shallow water were also clarified in the analysis. The barge motions in the horizontal plane and the mooring line tensions increase with the decrease of the water depth, while the heave and pitch motions reduce. Results obtained from this study were provided to support the floatover installation operation.