bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Fracture Behavior in the Vicinity of Interface Based on the Digital Speckle Experiment
Authors: Suling Wang , Chunlei Xing , Deshi Zhang , Chongquan Shao , jian Jiao , Kangxing Dong 
Published: October 2016

Abstract
Rock stratification develops widely in unconventional reservoirs, and it increases the non-uniform of the reservoir on vertical. The interfacial slip deformation can alter the fracture shape when it encounters the weak stratification or the natural fractures, so the rock stratification play an important role in the fracture propagation.
In this paper, the crack extension experiment about the interface is established through the three-point bending. The digital speckle measurement technology was used in order to observe the change of the strain field, near the interface layer, in the process of cracks through the interface. At the same time, based on the maximum circumferential stress criterion, an interfacial slip model has been developed, and the extended finite element method which can reveal the distribution of stress and strain on the interface has been used in the numerical realization of the model. The numerical results of the strain field agree well with those of experiments.
The experiment and numerical simulation results show that when a crack propagates the interface, the crack will break through the interface, or crack kink in the interface, or crack extend along the interface. The reason of the crack deflection, when a crack goes through the interface, is that the crack tip occurs blunt, and the crack length does not increase while the width increases. The tip blunt causes the interfacial shear strain which can turn the direction of the maximum circumferential stress. The crack deflection angle is affected extremely by the interface strength. The weaker the interface is, the greater of crack tip blunt is and the bigger the shear strain of the interface is, which cause the crack deflection angle increase. Based on the above analysis, it indicates that the blunt of crack tip in the interface is the mechanical cause of the crack to change direction extension. The weak bedding is the important factor causing the complexity of unconventional reservoir fracture morphology.
This can be used as one of the standards to evaluate the fracturing effect of unconventional reservoir.
Application of a Continuous Personal Development Methodology
Authors: Boles Jeanne 
Published: October 2016

Abstract
WOCRM is based on the Crew Resource Management (CRM) training program developed in the aviation industry in the 1980's. It is an attitudinal and behavioural training methodology; used to continuously engage the crews in repetitive, hands on and interactive exercises and simulations, providing structured feedback to develop each crew members’ non-technical skills. The training was first developed for airline cockpit crews in the 1980's and has since flourished within commercial and military aviation, mining and medical industries. A review done for Qantas by David Hainsworth, (Briefing to Qantas safety management, 2000) indicated that 96% of their LTI's root causes were behavioural in nature.
According to Edkins (2002), it follows that if we agree that the focus of CRM is to modify and reinforce effective safety Behaviour, it is reasonable then to assume that LTI's will be reduced. If LTI's are reduced, so too then is the costs associated with them, which in Oil and Gas can go into the billions and so a very good Return on Investment (ROI).
Focusing on Oil and Gas, the IOGP reports clearly indicate that Well Operations Crew Resource Management (WOCRM) training is required and that it should be incorporated into the mandatory International Well Control Forum (IWCF) and International Association of Drilling Contractors (IADC) Well Control Training. This is all well and good, however, if anything is to be learned from Dr Graham Edkins, (The state of the nation: How mature are HF/NTS programs within the Australian Airline Industry?, 2012) training alone is not enough.
From a psychological standpoint, to change or correct a Behaviour takes 66-270 days of repetition and constructive feedback. Therefore, the new Behaviour, process or procedure must be repeated for at least 3 months, to ensure that the Behaviour or procedure will in fact be applied when needed, especially in a stressful situation. This then implies the need to add coaching techniques to the methodology, which this paper will introduce.
The major benefit to Oil and Gas, is that all of the techniques mentioned herein have already been created and developed, and our Industry simply has to apply the lessons learned from those that are more advanced, to create a continuous personal development methodology to reduce Lost Time Incidents (LTI's) caused by human error, which would have a potentially massive effect on the financial loss associated with these errors, concluding that this methodology could have a very impressive Return on Investment (ROI) for companies large and small.
Separate Layer Water Injection for Offshore Directional Wells
Authors: Fuchao Sun , Deli Jia , Jiaqing Yu , Xiaohan Pei , He Liu , Lichen Zheng , Shujun BAO 
Published: October 2016

Abstract
The IOR is permanently issue for oil development. Zonal Water Injection Technology is a key technic about IOR. The zonal water injection technology faces several challenges for offshore oil field, such as numerous highly-deviated wells, complicated inter-layer contradiction, high cost, low operation efficiency, etc. High efficiency, low cost and low risk are crucial targets for offshore water-flooding. To achieve this target, CNPC developed a new offshore water injection technology featuring bridge concentric structure. It can realize multi-layer flow rate testing and adjusting efficiently and accurately with low cost and low risk. The system is composed of downhole bridge concentric regulator, downhole control instrument and surface control equipment. It can obtain multiple downhole critical parameters on line such as layer flow rate, tubing pressure, formation pressure and temperature. Also it can realize downhole flowrate dynamic adjustment automatically with no need to run and fish downhole valve. A steel cable with single core is employed for two-way data transmission. Concentric connection and adjustment between regulator and instrument is adopted to ensure successful connection for offshore deviated wells. The eccentric valve is designed as a innovation point with low leakage and low regulation torque. High-precision electromagnetic flow meter is employed to obtain layer flow rate directly to ensure test accuracy in deviated wells. Until recently, this technology has been applied in eleven wells including five in jidong offshore highly-deviated wells with maximum deviation 55 degree, maximum pressure 50MPa and maximum temperature 120 degree. The application successfully achieved the parameters of flow rate, tubing pressure, formation pressure and temperature. Besides it realized flow rate adjusting automatically. The whole process of water allocation and packer seal test were finished on line and the efficiency was significantly improved.
An Integrated Approach for Fracturing Evaluation and Optimization using Rate-transient Analysis and Dynamic Drainage Volume
Authors: Yuan Bin , Moghanloo Rouzbeh Ghanbarnezhad , Wang Kai , Zheng Da , Li Jin 
Published: October 2016

Abstract
This study presents an integrated approach to evaluate and optimize the efficiency of fracturing stimulation using early production data in Niobrara shale oil play. The proposed integrated method adopts an analytical equation of dynamic drainage volume (DDV) into the weak (integral) form of mass balance equation for long-term transient problem with moving boundaries. Multiple factors controlling the propagation of DDV and production data analysis have been considered, including: fluids and rock compressibility, stress-dependent reservoir permeability, diffusivity difference within both stimulated-reservoir volume (SRV) and unstimulated reservoirs, fracture-cluster length and spacing.
The size of DDV and associated average reservoir pressure, recovery factor (RF), and phase saturation (oil/gas/water) are calculated. The half-length of primary fractures and diffusivity within SRV are considered through a correlation; moreover, the ultimate drainage volume (used to estimate ultimate recovery, EUR) can be approximated at condition, using the proposed method.
The results suggest a better method compared to existing IPR models to characterize the well performance. Plotting the ultimate drainage volume calculated for each well as a function of fracture spacing of the same well, the wells were grouped into distinct groups in terms of performance. Next, the different characteristics of DDV obtained from previous steps are used to determine the optimal fracture spacing for the case study used here.
In practice, this method can be used by providing additional insights required to determine the optimal fracture spacing. Some of the features of the proposed method is as follows: (1) capability to ascertain DDV, associated average reservoir pressure, and thus recovery factor while accounting for compressible of fluid and rock, and multi-phase flow; 2) simplicity and efficiency: it does not require comprehensive inputs (including early production data) and yet can estimate the necessary design parameters for multistage fractured horizontal wells (MFHW).
Code of Practice for the Construction and Abandonment of Petroleum Wells in Queensland - As Mandatory Safety Requirements
Authors: Lee Peter , Porter Mika , Maggiori David 
Published: October 2016

Abstract
Objectives/Scope: In Queensland, petroleum safety legislation is enforced by the Petroleum and Gas Inspectorate. Onshore petroleum well integrity is fundamental to ensuring sustainable production, and ensuring safety outcomes and protection of aquifers during the well life cycle.
Methods, Procedures, Process: This Code of Practice has been developed to help ensure that all onshore petroleum wells are constructed and abandoned to a minimum acceptable standard resulting in long term well integrity, containment of petroleum and the protection of aquifers. This Code identifies industry standards and good oilfield practice for oil and gas well design.
Results, Observations, Conclusions: This Code addresses safety and environmental issues in the construction and abandonment (decommissioning) of petroleum wells and associated bores. This Code provides a way for petroleum tenure holders to comply with their obligations under the onshore Petroleum and Gas legislation in Queensland Australia.
Novel/Additive Information: This Code is designed to complement the petroleum operator's own internal risk assessment processes, operating standards and procedures by outlining a recommended process to ensure that: the environment and aquifer systems are protected;risk to the public and workers is managed to a level as low as reasonably practicable;regulatory and applicable Australian and international standards and requirements, as well as the petroleum tenure holder's standards, are understood and implemented where appropriate; andthe life of a petroleum well or associated bore is managed effectively through appropriate design and construction techniques and ongoing well integrity monitoring.
Field Trial Analyzing of Rodless PCP Technology: Problems, Improvements and Results
Authors: Zhongxian Hao , Peng Huang , Shijia Zhu , Lixin Zhang , Dianfeng Liu , Cai L.. 
Published: October 2016

Abstract
Currently, rod-tubing wear and suck rod failure are two serious problems in many oil fields in China. Because of the problem, in some area, the average mean-time-between-failure is only 200 days. The workover costs lots of money, not including the loss of oil production. In view of the low daily output situation of CNPC, problems have not been solved effectively until the development of the innovative ESPCP system.
A permanent magnet synchronous motor (PMSM) was developed and deployed in the bottom of the system, allowing adjusting the rotation speed between 50-500 rpm, which could satisfy the requirement of the PCP. The system included a motor protector, a cardan joint and a PCP from bottom to top.
In the initial field trial, we met many problems, such as the motor protector didn’t work suddenly, the shaft of the cardan joint broken, the system couldn’t run because of the tubing full of heavy oil. According to the specific problem, we improved the design of some components.
More than 10 systems have been deployed and the longest working life is over one year. The system saves 20% energy in average comparing with the pumping unit. It results in fewer operations and reducing the total cost of ownership. The configuration reduces the surface footprint and environmental impact of the oil field. It also reduces deployment and workover and results in fewer and safer operations.
This paper presents some problems and improvements of the system, and analyzes the advantages of the technology.
An Improved Grid Generation Approach for Discrete Fracture Network Modelling Using Line Fracture Concept for Two-Phase Flow Simulation
Authors: Wang Keke , Peng Xiaolong , Du Zhimin , Haghighi Manicher , Yu Lu 
Published: October 2016

Abstract
In traditional Discrete Fracture Network (DFN) method for fractured porous media simulation, fractures are modelled in different scales and orientations using single computational grid. However, a large number of small grids near both ends of fracture are generated, which substantially reduce the computation efficiency. In this paper, a new line fracture approach is presented to avoid generation of small grids. Combined with Multi-Point Flux Approximation (MPFA) algorithm, the simulation efficiency is highly improved without losing accuracy.
We present a modified mesh generation algorithm in which the volume of large fractures is set zero by neglecting the fracture width. The fracture aperture (very short line) is treated as single node during mesh generation using the paving method. Therefore, the number of small grids around the fracture is significantly decreased. In this paper, a quadrilateral unstructured grid system is generated using the proposed paving method. Then, by taking the median dual of quadrilateral mesh as the control volume, all fracture properties such as the aperture and permeability are accounted for as independent parameters in discrete fractures. The governing equations of DFN model are derived and solved using MPFA algorithm for oil-water two-phase flow.
A new discrete fracture network model using line fracture approach is developed. To show the efficiency and accuracy of the new model, the proposed method is applied to a case study of two separated and two crossed fractures, in the computation domain with the scale of 50 by 50 meters. Compared with the standard DFN model including the width of fractures, the computation efficiency of the new model is highly improved (by 2.5 times), due to the large reduction of grid numbers (20%). Good agreement in water and oil saturation distributions resulted from the two models validates the newly developed method.
Simulation of naturally fractured reservoirs has been a challenge for decades. Discrete fracture network modelling is a promising approach. However, without an efficient grid generation method, DFN model is not feasible and practical due to the large amount of computational time. The novelty of the present work is the improved model using line fracture approach. The new grid generation algorithm is coupled with multi-point flux approximation approach for flow simulation in fracture network system. High efficiency and accuracy of the developed method is readily applied to fractured reservoir simulation.
Sponsored by NSFC (Natural Science Fund of China - "the numerical simulation of natural fractured reservoir based on the unstructured hexahedral grid system and concurrent computation") (No. 51474179)
Field Scale Co-Optimisation of CO2 Enhanced Oil Recovery and Storage Through Swag Injection Using Laboratory Estimated Relative Permeabilities
Authors: Kamali Fatemeh , Hussain Furqan 
Published: October 2016

Abstract
Numerical simulations are widely used to investigate the performance of simultaneous water and gas (SWAG) injection in the field scale. However, they usually use two-phase water and gas relative permeability functions (kr) and one of the existing correlations (e.g., Stone, Baker) to calculate oil relative permeability in a three-phase displacement. Moreover, the same krg is used for all SWAG injections at different miscibility conditions and fraction of gas injected (FGI).
The recent experimental work has shown that gas relative permeability functions in three-phase SWAG are significantly different from the conventionally used two-phase functions. This paper presents a field scale simulation study to investigate the co-optimization of CO2 storage and EOR using experimentally estimated gas relative permeability functions.
A three-dimensional, layered reservoir model initially saturated with oil phase and connate water is used to examine different injection schemes for co-optimizing oil recovery and CO2 storage efficiency. A mixture of hexane and decane (0.65 and 0.35 mole fraction hexane and decane, respectively) is used for the oil phase. Numerical simulations are run at 70°C and three different pressures (1300, 1700 and 2100 psi) to represent immiscible, near-miscible and miscible displacements for the given fluids. A FGI of 0.5 is used for SWAG displacements run at immiscible, near-miscible and miscible displacements. Then the effect of FGI dependent relative permeability on co-optimization of CO2 storage and EOR is investigated in the near-miscible condition for FGI values equal to 0.25, 0.5, 0.75 and 1.0.
The field scale simulation results, run using experimentally estimated three-phase gas relative permeability are compared with the results when two-phase gas relative permeability is used. The numerical simulation results show that oil recovery rate is underestimated if two-phase relative permeability is used. This effect is more prominent in near-miscible and miscible displacements than immiscible. CO2 storage efficiency and therefore co-optimization function is significantly increased when estimated three-phase gas relative permeability functions are used. Therefore, the accurate description of co-optimization of CO2 storage and EOR in SWAG requires laboratory estimated three-phase relative permeability functions.
The Downhole Transmission Characteristics of Vibration Waves — An Experimental Study in the Daqing Oil Field
Authors: Jiaqing Yu , Lichen Zhen , Fuchao Sun , Zhenkun Zhu , Xiaohan Pei , He Liu 
Published: October 2016

Abstract
The downhole communication is the key technology of reservoir exploitation and downhole remote control. The vibration wave communication method provides a new way for the downhole data transmission. Using this method, control commands can be modulated and transmitted through the tubing or casing by the vibration wave. To analyzing the downhole transmission characteristics of vibration waves, a field test was implemented in the Daqing oil field. The vibration signal generator, located on the wellhead, can convert the electricity into the vibration wave by using the magnetostrictive material. The vibration wave signal is transmitted through the casing. To receive and test the signal, a signal detection device is developed. The signal detection device can be fixed on the casing firmly at any depth by a motor-activated-ram mechanism. A cable is plugged into the signal detection device, with which the detected vibration wave signals and the decoded signals can be transferred to the computer on the ground. By analyzing the received signals, the following conclusions are drawn: (1) At the depth of 900 meters, the vibration wave signal can be received and decoded correctly, which verifies the feasibility of the vibration wave downhole communication method. (2) Detection failure of vibration waves of certain frequencies occurs at specific depths. This phenomenon proves the characteristic of alternating passband and stopband in vibration wave transmission, which also validates the reliability of the multi-fundamental-frequency transmission strategy. (3) The attenuation characteristic of the vibration wave is obtained. With its low cost, convenient operation and high reliability, the vibration wave downhole communication technology can be widely used in hydraulic fracturing, water flooding and zonal production.
An Investigation on the Optimal Definition of Projects Scope, Facilities Sizing and Design Life for Truly Sustainable Deepwater Field Development: Technical Aspects and Economic Considerations
Authors: Beltrami Francesco , Gifford Andrew , Basu Shiladitya , Berardi Andre' 
Published: October 2016

Abstract
Notwithstanding the great technical changes that occurred in the offshore industry over the past decades, and the undeniable success of the subsea technologies, deepwater project sanction appears to remain rooted in traditional CAPEX minimization and NPV maximization. This paper investigates how decisions made by reservoir evaluation, and drilling and completion planning affect the design of subsea production systems and, in turn, the design of production hosts. Challenging the current approach to project framing and definition, practical alternatives are explored with a conceptual case study designed to test the ideas here presented.
Deepwater production is expected to play a significant role in meeting the future oil and gas demand of the world. To do so, new fields need to be developed in challenging environmental conditions, and existing fields will undergo brownfield modifications to sustain acceptable production levels. OPEX will reflect the increasing costs for inspection, maintenance and repair. Rethinking the requirements of deepwater field development will help to define the proper size of the subsea and surface facilities, the optimal design life and the possible need for staged developments.
A case study has been created to observe how changes in facility size, design life and development time-line (stages) result in changes to the overall subsea CAPEX and OPEX. These costs have been discussed with respect to drilling and completion costs and host facilities costs to identify possible opportunities and criticalities. Given the possibility of protracted low oil price environment, new ways of developing deepwater fields is worth considering. Greater integration of the various disciplines (subsurface, subsea, topsides, platforms, etc.) involved is also suggested in order to maximize the project objectives.
Abundant scientific literature exists on deepwater field development, but limited information appears to be available on the optimal definition of project scope, facilities sizing and design life for a deepwater project that aims to be profitable and sustainable long term. This paper is a contribution to a wider discussion that the industry needs to have on the way deepwater projects are conceived, planned and executed.