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Maria Angela Capello is an Honorary Member of SPE, thought leader, reservoir management expert, and a proponent of diversity and inclusion and talent development. She was the first woman to supervise seismic acquisition in the jungles of Venezuela. Her career has spanned three continents, with several significant achievements across technical and management disciplines. She is an SPE Distinguished Lecturer and chair of the Distinguished Service Award Committee. She was previously an associate editor of JPT, chair of the Business, Management and Leadership Committee, and serves as director at large of the Society of Exploration Geophysicists (SEG). Capello was recently knighted by the President of Italy with the “Cavaliere dell’Ordine della Stella d’Italia,” for “her contributions to the energy sector, that elevate the prestige of Italy abroad.”
This paper proposes an analytic method to solve the wave diffraction problem on the vertical cylinder with the cross-section of arbitrary shape by using conformal transformation. The derivation solution was formulated in this paper, and results were compared with those of numerical methods. The excellent agreement shows that the analytic solution is correct and applies to non-circular cross-section vertical cylinders. The proposed method provides a uniform view for the noncircular cross-section vertical cylinder in the water. The model of wave scattering by a non-circular cross-section is a general fundamental mathematical problem, not only in hydrodynamics but also in other disciplines such as acoustics, electromagnetics. The techniques to handle the governing equation and boundary conditions with the help of conformal transformation in this paper can provide a reference for other similar mathematical physics problems.
Wave loads calculation is the essential work in offshore platform design, and only a few geometry shapes can be solved analytically, such as vertical or horizontal round cylinders. With the help of conformal mapping technology, the ship's cross-section can be mapped to halfcircle to get wave loads.Non-circular section vertical cylinder's wave loads were investigated with dimensional analysis in early time. Isaacson(1978) developed a very efficient algorithm for the diffraction problem about a vertical and surface-piercing cylinder of an arbitrary section with BEM. During the 1980s-1990s, Chinese scholars tried to use conformal mapping of a rectangle section onto unit circular to get its wave potential. Zhao(1980) mapped rectangle onto unit circular and assumed the wave number remains the same value both in the physical and mapped plane. Huang(1988,1990) thought the incident wave would take the same shape in the mapped plane as in the physical plane. Only the wave number is scaled. Both Zhao and Huang show great work in their research. However, knowledge about the governing equation in the mapped plane and its features need to be further studied.
Wang, Wei (College of Shipbuilding Engineering, Harbin Engineering University ) | Ren, Zhonghao (College of Shipbuilding Engineering, Harbin Engineering University ) | Ma, Gang (College of Shipbuilding Engineering, Harbin Engineering University ) | Qiao, Dongsheng (State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology) | Qin, Yu (State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology)
With global warming, the range of sea ice and the thickness are decreased. Polar geophysical vessels need to travel to polar regions and other open seas every year. The resistance of the geophysical exploration ship in polar seas will increase due to the ice environment, and the towing operation of the geophysical exploration ship will also be affected by this condition. Therefore, it is of great significance to carry out ice load analysis and parameter sensitivity research on the geophysical exploration ship working in the ice floe environment. In this paper, the empirical formula is used to calculate the ice load on the towing cable. At the same time, the numerical curve of the ice load over time is obtained through finite element simulation. Finally, the influence of sensitivity parameters (density and thickness of ice crushing) on the towing cable is analyzed. Numerical simulation is carried out for the navigation of geophysical exploration ship in the ice breaking area to analyze the change trend of ice load under different ice breaking density and thickness.
In the Arctic human development report signed by Arctic countries, it is pointed out that the development and transportation of polar oil and gas in the future will play a decisive role in the economic development of the adjacent Arctic region and play an important supporting role in the sustainable development of the world economy and society. According to the assessment report issued by USGS, the Arctic region has 13% of the world's unproved oil reserves, and the reserves of undeveloped natural gas and coal resources account for 30% and 9% of the world's total reserves respectively (Bird et al., 2008). According to the report of the National Snow and Ice Data Center (NSIDC), the annual reduction rate of Arctic sea ice area is 3.5%. The reduction of sea ice area provides many favorable conditions for oil exploitation, so more and more ships in the ice area enter the Arctic sea area. However, the natural environment in the Arctic area is still poor, and ships are greatly affected by the ice load. Because polar geophysical exploration ship operation needs to go back and forth to polar sea area and other open sea areas every year, the floating ice environment and different ice conditions under the ice conditioning environment in polar sea area will also have a great impact on ship resistance. Resistance will affect the towing capacity of polar geophysical exploration ship operation, which has a great impact on the economy and efficiency of geophysical exploration ship. In recent years, the research on ice load is mainly focused on icebreaker and offshore platform.
Wang, Wentao (Shanghai Jiao Tong University / China Ship Scientific Research Center) | Qiu, Gengyao (China Ship Scientific Research Center) | Wang, Jianhua (Computational Marine Hydrodynamics Lab (CMHL), State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University) | Wan, Decheng (Computational Marine Hydrodynamics Lab (CMHL), State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University)
Ship bow wave breaking phenomenon is still a challenge for CFD simulation, due to unsteady mixture flow and the lack of detailed experimental validation data. As a new wave breaking study case, a scaled KRISO container ship (KCS) model of 1/52.6667 is selected. To determine the appropriate detailed wave breaking measurement case conditions for future CFD validation, experimental and computational investigations are conducted with trim and sinkage variation. The trim and sinkage have significant effects on wave breaking phenomenon. Spilling and plunging wave breaking are observed.
Wave breaking is a quite common flow phenomenon at sea for ships. The breaking waves around ship bow region can produce sprays, mixture of air – water mixture flow and will extend to the far field of ship's downstream, which will affect the performance of the hull & propulsion systems and increase the ship wake signatures.
The 3D breaking wave and the flow field due to the breaking waves are quite challenging for CFD solvers. Wilson et al. (2006) investigated the breaking waves for the high-speed transom stern ship (R/V Athena I) by using the URANS solver in CFDSHIP-IOWA. One low
Wang, Shao-dong ( National University of Defense Technology) | Du, Hui (National University of Defense Technology) | Wei, Gang (National University of Defense Technology) | Wang, Xin-long (National University of Defense Technology) | Xu, Jun-nan (National University of Defense Technology)
In order to study the influence of slope on the depression-type internal solitary wave (ISW), experiments on flow field and waveform of ISW evolving over the gentle slope are conducted by using conductivity probe array and PIV technique. Experimental results show that the flow velocity distribution induced by the shoaling ISW is consistent with its waveform under the condition without turning point, meanwhile a newborn depression ISW will be generated. For the case with turning point, the back of ISW is raised and the vertical velocity is greatly enhanced, resulting in the flow field of elevation ISW.
The internal solitary wave (ISW) is a kind of special fluctuation with the large amplitude, strong induced velocity and long propagation distance in the ocean (Leon and Marek. 2019; Jackson, 2007). During the process of propagation, the ISW can contain tremendous energy and aggravate the energy cascades in the ocean. As the ISWs pass over the topography, their waveforms, amplitudes and induced flow field will have non-regular and non-steady changes, leading to ISW structure changes, sudden strong currents and instability such as waveform distortion, inversion, breaking, and energy flux (Sarkar, et al., 2017; Lamb, 2014; Cai, et al., 2012).
Numerous remote sensing and in-situ observations demonstrate that the ISW type will be change through the turning point where the depth of the upper is equal with the bottom layer one in a density stratified water column. In other words, while shoaling across a sloping shelf from deep water to shallow part, the depression-type ISW may commence inversion to elevation-type ISW. Shroyer et al. (2009) studied the ISWs polarity reversal in New Jersey coast and founded that the symmetric waves propagating into shallow water develop an asymmetric shape. The wave front face was to be broaden while the trailing face remained steep because the leading edge accelerates, and this trend continued to develop until the front face cannot be recognized and the elevation-type wave evolved from the tail of the depression-type wave. This polarity reversal of ISW could be judged by the positive and negative vorticity field, which was consistent with the sign change of nonlinear term in KdV equation. Some oceanographers studied the polarity conversion of ISW waveforms in the South China Sea after 2002. (Orr, et al. 2003, Ramp, et al. 2004, Yang YJ, et al. 2004). Moum et al. (2003, 2007) studied the ISWs propagation characteristics in the Oregon continental shelf and showed that the wavelength would be shorter during the propagation from the deep water to the shallow water, moreover, the wave instability and breaking were analyzed and pointed out that the shear instability was the generation mechanism for turbulence. Zachariah, et al. (2005) calculated the kinetic energy, potential energy and energy flux of internal waves in the New Jersey coast by using flow field data. The research showed that the kinetic energy was equal with the potential energy approximately. Alford et al. (2010) studied the ISWs propagating westward along the continental shelf from Luzon Strait, and analyzed the wave speed, wavelength, amplitude, and energy. Martini, et al. (2013) observed the shoaling process of the internal tidal waves along the slope in the Oregon continental shelf, which included steepening, crushing and turbulent mixing. Silva et al. (2015) studied the generation and propagation of internal waves on the upstream side of a large sill of the Mascarene Ridge and pointed out the relationship between the background flow field and the generation of internal waves. Xu, et al. (2016) studied the generation and propagation of ISWs in northern South China by using the numerical simulation and satellite images, and analyzed the influence of coastline on the generation and propagation of waves. Due to the high cost of field observation and the complexity of background elements, the understanding of the influence of topography on both evolution and propagation of ISW was yet very limited.
Propellant enhancement is a method of increasing permeability through the application of a transient high pressure event to the target formation. As distinct from hydraulic fracturing, propellant enhancement does not involve the application of chemicals or water and consequently does not present the potential for legacy environmental issues. This paper compares the regulatory aspects of propellant enhancement within the states of Australia and also the differences between environmental impacts.
A series of propellant enhancements were undertaken for a suite of gas wells in the Surat Basin, Queensland. Propellant charges in the range 18-30 kg were initiated, with deflagration times in the range 500-1,000 milliseconds. The compliance regime for the transport, storage and use of propellant is established under the state’s
There are three categories of fracturing used to increase permeability: explosive fracturing; hydraulic fracturing; and propellant enhancement. Explosive fracturing applies a very high pressure transient over a period of a few microseconds and can cause local, radial fracturing but with less desired compaction; hydraulic fracturing applies a lower pressure but over a longer period and with greater surface power, resulting in fractures that can extend 200-300 m, largely in the vertical plane; and propellant enhancement, which applies a mid-range pressure over a period of 10-1,000 milliseconds, resulting in fractures extending tens of metres but with random distribution. Residuals from the deflagration process are nitrogen, hydrogen chloride, water and carbon dioxide. There are no precursors for the BTEX suite and no conditions arising that could produce BTEX.
A prime question was to determine whether propellant enhancement is captured under the term ‘hydraulic fracturing’ in states’ regulations across Australia. Propellant enhancement is a technology with very few environmental impacts. Vehicular movements to support propellant enhancement are less than five percent of those to undertake hydraulic fracturing on the same formation. There is no requirement for waste water treatment.
Cheng, Zhong (Xi'an Shiyou University and CNOOC Ener Tech-Drilling & Production Co.) | Xu, Rongqiang (CNOOC Ener Tech-Drilling &Production Co.) | Yu, Xiaolong (CNOOC Ener Tech-Drilling &Production Co.) | Hao, Zhouzheng (CNOOC Ener Tech-Drilling &Production Co.) | Ding, Xiangxiang (CNOOC Ener Tech-Drilling &Production Co.) | Li, Man (CNOOC Ener Tech-Drilling &Production Co.) | Li, Mingming (CNOOC Ener Tech-Drilling &Production Co.) | Li, Tiantai (Xi'an Shiyou University) | Gao, Jiaxuan (Xi'an Shiyou University)
Upstream Oil & Gas industry recognizes that there are significant gains to be had by the implementation of new digital technologies. For offshore exploration and development, the goal is to bring together all domains, all data, and all engineering requirements in a seamlessly interconnected solution. The industry is putting significant efforts into using instrumentation and software to optimize operations in all domains for exploration and production (E&P) to move towards the digital oil field of the future. an innovative digital solution has been designed and implemented to cover all different aspects of the well planning and engineering workflows, delivering a step change in terms of capabilities and efficiency.
As part of this transformation process, CNOOC have implemented integrated data management project of geological engineering for covering all different aspects of the well engineering workflows, delivering a step change in terms of capabilities and efficiency. The objective is to provide a continuous improvement platform to users for:
Digitalization can reduce the time spent with daily documentation and simultaneously increase the quality by removing an error prone way of work.
Technological solution enabling real-time data transmission from all rigs to CNOOC onshore headquarters and enabling real-time visualizations of the drilling data. This includes workload, number of needed rigs, daily performance, key performance indicators and even operation time forecasts based on real data.
Engineering solution to transform expert experience and accident cases into information to easily identify the areas of operational improvement allowing to implement specific measures to reduce intangible loss time (ILT) and non-productive time (NPT) which can help in reducing costs.
This project has also provided a real geological drilling environment where high frequency real-time drilling data is utilized along with low frequency daily drilling report data to provide better insights for well planning and generate ideas for improving performance and reducing risk.
This paper presents a full description of a new industry standard digital well construction solution that has the potential to transform the well operation process by providing a step change in collaboration, concurrent engineering, automation, and data analytics. Furthermore, the cloud-deployed solution challenges will be briefly discussed.
The learned lessons and gained experiences from this project construction presented here provide valuable guidance for future demands E&P and digital transformation.
We showcase an innovative campaigning and business-focused approach to reservoir monitoring of multiple fields using 4D (time-lapse) seismic. Benefits obtained in terms of cost, speed and the quality of insights gained are discussed, in comparison with a piecemeal approach. Challenges and lessons learned are described, with a view to this approach becoming more widely adopted and allowing 4D monitoring to be extended to smaller or more marginal fields.
An offshore seismic acquisition campaign was planned and successfully executed for a sequence of four 4D monitor surveys for fields located within 250 km of each other on the greater Northwest Shelf of Australia. The four monitors were acquired in H1 2020 comprising (in this order): Pluto Gas Field M2 (second monitor), Brunello Gas Field M1 (first monitor), Laverda Oil Field M1 and Cimatti Oil Field M1.
Cost savings expected from campaigning were realised, despite three cyclones during operations, with success largely attributed to detailed pre-survey planning. Also important were the choice of vessel and planning for operational flexibility. The baseline surveys were diverse and required careful planning to achieve repeatability between vintages over each field, and to optimise the acquisition sequence – minimising time required to reconfigure the streamer spreads between surveys. The Cimatti baseline survey was acquired using a dual-vessel operation; modelling, combined with now-standard steerable streamers, showed a single-vessel monitor survey was feasible. These optimisations provided cost savings incremental to the principal economy of sharing vessel mobilisation costs across the whole campaign.
Both processing and evaluation (ongoing at the time of writing) are essentially separate per field, but follow a consistent approach. Processing is carried out by more than one contractor to debottleneck this phase, with products, including intermediate quality control (QC) volumes, delivered as pre-stack depth migrations. While full evaluation of the monitor surveys to static and dynamic reservoir model updates will continue beyond 2020, key initial reservoir insights are expected to emerge within days of processing completion, with some even earlier from QC volumes. Furthermore, concurrent 4D evaluations are expected to result in fruitful exchanges of ideas and technologies between fields.
The Jurassic Plover Formation is one of two reservoirs in the Ichthys Field, North West Shelf of Australia. It consists of fluvial to shallow-marine sandstones, shales and igneous rocks. The objective of this study is to build multiple scenario-based models to optimise development planning in preparation for the upcoming production phase.
We have integrated data and interpretations of thin sections, cores, well logs and seismic data to create multiple geological concepts for the field and to identify key geological uncertainties. As the reservoir is geologically complex and many uncertainties were initially identified, it is essential to single out those uncertainties which have a significant impact on the development planning. We have established the key uncertainties and optimal model design for practical use through multi-disciplinary discussions and by running sensitivity models to check the production performance.
A rock type (RT) scheme has been devised based on detailed petrographic observations and justified in terms of sedimentology and diagenesis. Using the scheme, a wide range of permeability variations in the sandstones has been captured and modelled. Environments of deposition (EOD) are firstly interpreted at core and well-log scales, then upscaled to the model zone scale. The EOD interpretations are laterally extended using lithology (sandstone, shale and igneous rock) probability maps derived from quantitative seismic interpretation (QSI). Multiple EOD scenarios are generated to capture the possible range of reservoir distributions. Each EOD is characterised by a unique net-sand porosity and RT proportion based on the well data. These values are used to define multiple possible porosity trends and RT proportions, guided by the EOD maps. The distribution and quality of the reservoir sandstones have been identified as key uncertainties. Another key uncertainty is reservoir compartmentalisation, thought to be mainly caused by sheet-like igneous intrusions. Subtle seismic lineaments are regarded as possible indications of such igneous intrusions, and multiple compartmentalisation scenarios have been prepared based on our understanding of igneous activity across the field. Reservoir structure and water saturation are also recognised as key uncertainties. Integrating the key uncertainties, we have established a practical modelling workflow and built multiple scenario-based models to cover a sufficient range of geological uncertainty. The workflow is also adaptive for future history matching, enabling us to flexibly edit the model properties under geological constraints.
A decision tree for development planning, which defines a series of decisions for the well sequence depending on the well results, will be prepared based on the multiple scenario-based models delivered in this study. This will enable us to prepare for any potential decision-making in advance. The development planning will be continuously optimised throughout the production phase by simply selecting the scenario-based models most in line with the well results.
In hydrocarbon exploration, rock physics analysis plays a key role by connecting seismic data to rock properties. Analysis of rock physics data enables geophysicists to understand how fluid content affects the seismic response and what they should look for to improve the chance of finding hydrocarbons. In the Nong Yao oil field, the use of rock physics and AVO analysis was used to improve the hydrocarbon prediction process.
The preferred method starts with rock physics analysis of key wells. Fluid Replacement Modelling (FRM) is then performed across many wells in order to generate a predicted seismic response for different pore fluids (gas, oil and brine). The predicted AVO response is then calibrated against the actual AVO response from the seismic data from key wells in order to build a database. In the Nong Yao Field, over four hundred and fifty drilled data points from sixty-nine wells were utilized in the analysis. This database is analyzed in order to find the optimal combination of parameters for hydrocarbon prediction, which is then used to improve hydrocarbon prediction for future near-field drilling candidates.
Near-field appraisal programs in the Nong Yao oil field are driven strongly by amplitudes and AVO, as rock physics analysis has shown that sands and shale lithologies can be easily discriminated based on acoustic impedance. Fluid prediction is more difficult based on acoustic impedance alone, as other factors such as variable sand thickness and seismic data quality mean that there is significant overlap between hydrocarbon and wet sands. Rock physics analysis has shown that AVO behavior can be included to provide better separation between hydrocarbon sands and wet sands.
AVO signatures from all the data points are then analyzed using intercept vs gradient cross-plots. A background wet trend is defined with the clear observation that increasing distance from the background wet trend correlates to increasing chance of hydrocarbon fill. Data are categorized into weak, moderate and strong AVO response based upon their distance from the background wet trend and then this is used to modify the chance of success of near-field appraisal drilling targets utilizing conditional probability. This results in an increased chance of success of up to 20% in a strong AVO supported target and around 10% in a moderate AVO supported target. Targets are then quantitatively high-graded in an appraisal portfolio.