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Analyses of mechanical conditions and affecting factors for forming micro-annuli in a casing-cement-formation system 52

Analyses of mechanical conditions and affecting factors for ...

引用

52nd U.S. rock Mechanics/Geomechanics Symposium

作者： Chen, Zhaowei dai, Caili Liao, Maolin CNPC Engineering Technology R and D Company Limited Beijing China Beijing China

Micro-annuli existing on the interface of cement-sheath might lead to the failure of wellbore integrity. Based on the solutions of the elastic and elastic-plastic deformations of a thick-walled cylinder with the internal and external pressures;meanwhile combining with the displacement continuity, a nonlinear equation set about the interfacial pressures and displacements of a casing-cement-formation system in the loading and unloading processes is established. Via solving the nonlinear equation set, the interfacial pressures and the displacements can be obtained. If the obtained interfacial pressure is larger than the bonding strength of rock, micro-annuli appear on the interface, and its size is equal to the difference of the interfacial displacement in the loading process and that in the unloading process. Numerical examples show that the micro-annuli are at an order of tens of micrometers. Moreover, as the increase of the elastic modulus of cement, the micro-annuli become broader. As a comparison, if the uniaxial compressive strength of cement increases, the micro-annuli become narrower. Therefore, to avoid the generation and development of micro-annuli, it is suggested that the cement with high uniaxial compressive strength and low elastic modulus should be used for the field practices. Copyright © 2018 ArMA, American rock Mechanics Association.

关键词： Cements

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A rapid evaluation technique of sweep efficiency for tight oil reservoir recovered with gas flooding

A rapid evaluation technique of sweep efficiency for tight o...

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SPE/AAPG/SEG Unconventional resources technology Conference 2019, UrTC 2019

作者： Mu, Lingyu Liao, Xinwei Zhao, Xiaoliang Zhang, Jingtian Zou, Jiandong Chu, Hongyang Shang, Xiongtao Beijing China CNPC Engineering Technology R and D Company Limited Beijing China

due to the special micro-pore structure and the seepage law of tight reservoirs, the research on the development of tight oil is quite different from conventional reservoirs. For the tight oil reservoirs recovered with the gas injection, the gas breakthrough is an eternal theme as a result of the preferable mobility of the gas and the strong heterogeneity of the reservoirs. It is extremely important to evaluate the sweep efficiency. Based on the stream-tube method and the non-darcy theory, this paper establishes a rapid evaluation technique of sweep efficiency considering the mechanism of the gas flooding and the seepage characteristics of the tight oil reservoir. Firstly, the relative permeability under different miscible condition are determined through the revised Coats model. Besides, the Todd-Longstaff model is adopted to describe the varying viscosities of oil and gas. Secondly, the stream-tube model of the inverted nine-spot well pattern with fracture is established. Next, the seepage equations of oil and gas in the stream-tube is constructed considering the threshold pressure and the variation of the viscosity and relative permeability. Then, the sweep efficiency is obtained by solving these equations. Furthermore, an application example for evaluating the sweep efficiency is presented and sensitivity analyses are conducted to study the effect of the viscosity, pressure difference, fracture permeability and well spacing taking the case of a real tight reservoir. Through the analyses, it can be concluded that the factors have remarkable impacts on the sweep efficiency. The threshold pressure increases the resistance and reduces the flow rate, leading to a lower sweep of the injected gas. Even worse, the excessive threshold pressure results in that the effective displacement cannot be established. The fracture greatly shortened the breakthrough time and result in early channeling of the injected gas. The sweep efficiency is improved through the increase of the

关键词： Gases

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Casing shearing failure in shale gas wells due to fault slippage caused by hydraulic fracturing-case study

Casing shearing failure in shale gas wells due to fault slip...

引用

Abu dhabi International Petroleum Exhibition and Conference 2020, AdIP 2020

作者： Liu, Kui Chen, Zhaowei Zeng, Yijin Cao, Hu Tao, Qian Wang, Zhifa Zhang, Hongbao Sinopec Research Institute of Petroleum Engineering CNPC Engineering Technology R&D Company Limited China University of Petroleum Beijing China

ISBN: (纸本)9781613997345

According to the analysis of casing deformation events and the achieved micro-seismic data in four shale gas wells, the slip of the fault is treated as the main reason for casing deformation problems in shale gas wells in Changing. Analytical model for calculating fault slippage is established based on elastic mechanics and the slippage of faults around 4 shale gas wells is calculated. The calculated results show that both the height of fault reactivation area and the angle between the maximum in-situ stress and fault have significant effect on the fault slippage. The location of the intersection point where casing goes through the reactivation area of fault can significantly affect the casing deformation. The closer the intersection point is to the center of reactivation area, the larger fault slippage and the serious casing deformation occurs. Case study in well Ning201-H1 shows that the slippage of fault at total depth 3490 of this well is 30.5mm, and the corresponding casing deformation is 10.5mm which is in agreement with field data. The casing deformation in drilling platform H19 is much more serious due to the extremely complicated faults and the large reactivation area. The maximum casing deformation reaches 35mm in well H19-5. The results of this study have significant reference value for understanding the mechanism and controlling methods for casing deformation in shale gas wells during hydraulic fracturing treatment. Copyright © 2020, Society of Petroleum Engineers

关键词： deformation

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Anomalous Behavior detection for Cloud Infrastructures via Transformer-represented Prior Knowledge 8

Anomalous Behavior Detection for Cloud Infrastructures via T...

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8th IEEE International Conference on Smart Cloud, SmartCloud 2023

作者： Zhao, Fei Chen, Mian Gao, Bo Cui, Yi Gao, reyu ding, Yan College of Petroleum Engineering China University of Petroleum Beijing China CNPC Engineering Technology R&D Company Limited Beijing China

ISBN: (纸本)9798350313505

With the rapid progression and increasing industrial relevance of cloud computing, the stability of cloud systems has become increasingly critical as they are handling a vast number of requests. To ensure this stability, the operational status of cloud servers, indicated by key performance indicators such as CPU load, network bandwidth, memory allocation, and disk I/O operations, must be continuously monitored. Any changes in these metrics could signify potential system malfunctions like network intrusion or hardware faults due to user activities. However, given the cyclical nature of the utilization metrics, which often exhibit, minute, hour, or daily patterns, merely setting thresholds may not effectively detect these anomalous behaviors. To address this, our research capitalizes on the advantages of the Transformer model, incorporating cyclical prior knowledge to extract these periodic patterns from the metrics, thereby enhancing the detection efficacy. Experimental results show that our proposed approach outperforms the Transformer model, improving the anomalous detection accuracy by 1.7%, with the comprehensive evaluation metric (F1 score) surpassing 0.88. ©2023 IEEE.

关键词： Cloud computing

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Safe and Efficient drilling technology and Practice of High risk Gas reservoirs on the right Bank of the Amu darya rive 13th

Safe and Efficient Drilling Technology and Practice of High ...

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13th International Field Exploration and development Conference, IFEdC 2023

作者： Ye, dong-Qing Wang, Gang Guo, Qi-Jun Zhong, Zhao Zhou, Tuo Li, Gan-Lu Liu, Yu-Han Liu, Chen-Chao CNPC Engingeering Technology R&D Company Limited Beijing102206 China AM River Natural Gas Company Beijing100034 China CNPC Bohai Drilling Engineering Company Limited Tianjin300452 China

ISBN: (纸本)9789819702558

The right bank of Amu darya gas field is an important oil and gas cooperation block of China ‘s overseas oil and gas business in the ‘ silk road economic belt ‘, due to the local shallow secondary high pressure gas reservoir and the target layer overlying thick salt gypsum layer, seriously affected the work area of safe and efficient drilling. Before the intervention of cnpc, 192 wells were drilled in this area, of which the engineering scrap rate was 23% and the geological scrap rate was 41%. In order to effectively solve the difficulties in the drilling operation on the right bank and improve the success rate of drilling, the drilling technology of shallow secondary high-pressure gas reservoirs and giant thick salt-gypsum gas reservoirs at home and abroad was investigated. Combined with the geological characteristics of the Amu darya gas field, the drilling engineering scheme was formulated, the advanced and complete drilling equipment was matched, and the field test and scheme optimization were carried out step by step. In view of the drilling risk caused by shallow secondary high-pressure gas reservoirs, the countermeasures of detecting the underground situation of slim hole wells, and then casing sealing after passing through dangerous formations according to the design expansion are adopted. In view of the difficulties in trajectory control of highly deviated wells in extremely thick salt-gypsum layers, the wellbore structure and wellbore trajectory design were optimized, and the directional drilling fluid for salt-gypsum layers was optimized. A series of trajectory control measures for salt-gypsum layers were proposed in combination with dynamic drilling tools and MWd technology. Finally, combined with the formation. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Trajectories

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design and Analysis of the Coaxial Magnetic Gears with Halbach PM arrays for downhole Electric drilling Tools 26

Design and Analysis of the Coaxial Magnetic Gears with Halba...

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26th International Conference on Electrical Machines and Systems, ICEMS 2023

作者： Wang, Aiguo Zhao, Xiaolong Liu, Longhui Cheng, Jin Qiao, Han Wang, Hongwei Wang, Jin Cnpc Engineering Technology R&d Company Limited Beijing China Huazhong University of Science and Technology School of Electrical and Electronic Engineering Wuhan China

ISBN: (纸本)9798350317589

This paper presents the design and analysis of a magnetic gear reducer with Halbach permanent magnet (PM) arrays developed for downhole electric drilling tools. 2d finite element simulation technology is used to investigate the performance benefits which can be obtained by the coaxial magnetic gears from applying the Halbach PM arrays. It is discovered that using the Halbach PM arrays can improve the radial magnetic field distribution of the air gap of the magnetic gears, increase the air gap flux density harmonics which is used to transfer torque and decrease air gap flux density harmonics undesired. After applying Halbach PM arrays, the output torque density increases by about 37.5%, the total losses of the magnetic gears are reduced by 34.2%, and the cogging torque is reduced by 45%, compared to the traditional design with radial magnetized PMs. © 2023 IEEE.

关键词： Torque

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Feasibility Analysis on Optimization and Expansion of Ultra-deep Well Casing Program in Fuman Oilfield 13th

Feasibility Analysis on Optimization and Expansion of Ultra-...

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13th International Field Exploration and development Conference, IFEdC 2023

作者： Chen, Xue-Feng Chen, Zhi-Xue Wen, Tao Li, Bo Zhai, Wen-Bao Wang, Zheng-Xu Jiang, Ji-Wei Guo, Xiao-Wei Liu, de-Zhi Tan, Peng CNPC Engineering Technology R&D Company Limited Beijing102206 China PetroChina Tarim Oilfield Company Xinjiang Korla841000 China

ISBN: (纸本)9789819702558

With the continuous deepening of exploration and development for Fuman oilfield, the existing casing program fails to effectively deal with downhole problems such as "overflow, leakage and collapse" caused by local high-pressure brine developed layer, leading to longer drilling time and higher drilling safety risk. Therefore, it is urgent to optimize the existing casing program according to the characteristics of geology and engineering to meet the requirements of safe drilling. For this purpose, the three types of pressure profiles in the Fuman oilfield are firstly established by using the drilling, logging, mud logging, and testing data, and the necessary setting points and risk points of geology and engineering are determined. Then, considering the level of drilling technology and the requirements of drilling and completion, the optimization and expansion scheme of casing program is formed. Finally, combined with the drilling parameters, the feasibility analysis of casing program in terms of casing string design, drilling tool strength verification, hydraulic simulation, well control risk assessment, drilling time and drilling cost is discussed. The analysis results show that the optimized casing program can effectively seal the local high-pressure brine developed layer, solve the problem of "overflow, lost circulation and collapse", reduce the downhole problems, and shorten the drilling time by 20 ~ 25 days and save 2 ~ 3 million per well. The investigates indicate that the optimization of the casing program not only effectively makes up for the shortcomings of the current casing program, reduces the drilling risk, and improves the drilling efficiency, but also provides an important reference for the drilling engineering design of the Fuman oilfield. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： risk assessment

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research and practice of full life cycle well integrity in HTHP well, tarim oilfield

Research and practice of full life cycle well integrity in H...

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International Petroleum technology Conference 2019, IPTC 2019

作者： Liu, Hongtao Cao, Lihu Xie, Junfeng Yang, Xiangtong Zeng, Nu Zhang, Xuesong Chen, Fei PetroChina Tarim Oilfield Company China CNPC Engineering Technology R and D Company Limited China

ISBN: (纸本)9781613996195

There is abundant natural gas in Kuqa foreland area of Tarim basin, the reservoir has characteristics of ultra depth(6500m-8000m), high pressure(115MPa-140MPa), high temperature(170°C-190°C) and complex corrosive medium, which bring well integrity high challenge. There are 52 production wells in the Kuqa foreland basin in 2012. The 16 wells of these production wells exist sustained casing pressure(SCP). The SCP wells caused by the tubing string failure is 61%. Since 2012, in order to build safe well barrier and achieve scientific production management, consider all important periods of drilling, well testing, well completion and production in well full life cycle. the design methods of the four main well barrier components(casing string, cement, tubing string, well head) are optimized. A set of technology for well barrier quality control, well maintenance and well production management is formed. Finally, the key technology of full life cycle well integrity for ultra depth, HPHT gas well is formed. In view of the large angle of bedding, well deviation controlled difficultly, and coexistence of high pressure saline aquifer and week bed in one open hole section which lead to serious casing wear and poor cement stone, the vertical well drilling technology, the collapse resistance casing design methods, the casing wear preventing measures, negative pressure test method and high temperature, high density cementing technology are completed. These technologies improve the safety of casing string and the quality of cement. Considering the extreme working conditions(the partial pressure of CO2 is beyond 2MPa, The content of chlorine is about 80000mg/L, acid job, 136MPa pump pressure in well head)of tubing string, material selection method, triaxial stress analysis method, quality control technology for tubing string is optimized. The failure ratio of tubing string reduced from 50% in 2013 to zero in 2017. referencing API rP 90-2 and IOS16530-2, a special calculation method f

关键词： Life cycle

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FdEM modeling on the fracture propagation behavior of hot dry rock subjected to cyclic soft fracturing 57

FDEM modeling on the fracture propagation behavior of hot dr...

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57th US rock Mechanics/Geomechanics Symposium

作者： Wu, Xiaoguang Yang, rui Li, Gensheng Huang, Pengpeng Huang, Zhongwei Liang, rui Long, Tengda State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum-Beijing China CNPC Engineering Technology R&D Company Limited China Downhole Service Company CNPC Chuanqing Drilling Engineering Company Limited China

ISBN: (纸本)9780979497582

Conventional hydraulic fracturing (HF) is an important way to develop Enhanced Geothermal Systems (EGS), but there are some problems such as high injection pressure and having trouble to create complex fracture network. To deal with those difficulties, Cyclic soft fracturing (CSF), an emerging technology, has been proposed, which adopts circulating stress waves to break down rock and forms a volumetric fracture network achieving oil and gas stimulation. In this paper, a numerical model of FdEM and a fully coupled thermal-fluid-solid solver are used to perform CSF experiments on hot dry rock (Hdr) in field scale. The influences of stress disturbance, fracture initiation and propagation and three key parameters on fracture morphology are analyzed. The research results show that CSF can indeed generate complex fracture network under parameter optimization of peak pressure and loading frequency. Compared with conventional HF, CSF forms a larger stress disturbance area and has bigger tensile stress at fracture tip, which may contribute to fracture propagation. Under large stress difference condition, with the increase of peak pressure, the fracture complexity increases first and then decreases. The results are expected to provide an insight into the stimulation mechanisms of CSF method in Hdr geothermal. © 2023 57th US rock Mechanics/Geomechanics Symposium. All rights reserved.

关键词： rocks

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Case Studies of a Novel digital Twin System for real-Time Early Identification and Warning of Pipe Stuck

Case Studies of a Novel Digital Twin System for Real-Time Ea...

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2024 International Petroleum technology Conference, IPTC 2024

作者： Zhang, Jiawei Wang, Qing Zou, Lingzhan Yu, Jingping Li, Jijun Yang, Yun Zhang, Yang Zhao, Zhixue CNPC Engineering Technology R&D Company Limited Beijing China CNPC Daqing Exploratory & Drilling Engineering Company Daqing China CNPC CCDC Drilling & Production Technology Research Institute Xi'an China Drilling Engineering Technology Research Institute of CNPC Daqing Drilling Engineering Company Daqing China

ISBN: (纸本)9781959025184

Pipe stuck serves as one of the primary downhole accidents in drilling industry with consequences ranging from minor inconvenience to severe complications. despite the variation on its cause and mechanism, this downhole accident could be prevented or avoided based on early identification of its unique symptom or data behavior, provided intervention or remediation measures are taken promptly. While conventional prediction or recognition methods, which rely on the fluctuation amplitude and curve trends of surface drilling parameters, are subject to user experience and human error, it's often the case that their timeliness cannot be guaranteed. A novel digital twin system, based on the deviation of hook load, torque and SPP (Standpipe Pressure) from theoretical modeled values and rOC (rate of Change) of these three actual parameters, is developed for real-time early identification and warning of pipe stuck while drilling. A PSrI (Pipe Stuck risk Index) ranging from 0%-100% is proposed based on rOC and deviation for comprehensive evaluation regardless of drilling state. Both T&d and wellbore hydraulics models are adopted to model the theoretical hook load, torque and SPP within preset computing cycle. rOC and deviation thresholds, corresponding to three different risk levels as low (green), medium(yellow) and high(red), were obtained by using rFA (random Forest Algorithm) based on data of historical wells with and without pipe stuck accidents. Preventive or intervention measures are generally mandatory for on-site personnels or engineers once high-risk (red) alert is identified by the system. Several case studies are outlined to exhibit that the occurrence of pipe stuck accidents could be detected typically between 30 minutes and 2 hours ahead during back-reaming and tripping operations, which proved its potential for early identification and prevention of this downhole accident in real-time drilling. Cost containment and operational efficiency could be created with sys

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