L-Band Analysis of the Effects of Oil Slicks on Sea Wave Characteristics

The purpose of this study was to investigate the characteristics of sea surface waves as they pass through oil slicks.The parameterized first-guess spectrum method(PFSM)theory-based wave retrieval algorithm was applied to 20 images of horizontal-horizontal(HH)polarization obtained using the phased-array L-band synthetic aperture radar(SAR)(PALSAR)on the Advanced Land Observing Satellite(ALOS-1).The images were collocated with simulations from the WAVEWATCH-Ⅲ(WW3)model in a 0.1°grid using the European Centre for Medium-Range Weather Forecasts(ECMWF)reanalysis(ERA-5)winds data as the forcing field.The validation of the model-simulated significant wave height(SWH)against the measurements from the Jason-2 altimeter produced a 0.66m root mean square error(RMSE)for the SWH,with a coefficient(COR)0.74.In this sense,the WW3-simulated waves were reliable for our work.A comparison between the SAR retrieval results and the WW3 simulations was performed using the dataset for the regions without oil slicks,which produced a 0.34m RMSE for the SWH,with a COR of 0.79,which is less than a the RMSE of 0.52 m and the COR of 0.70 for the regions with oil slicks.Moreover,it was found that the SAR-derived SWHs were significantly underestimated by about 0.2m in the areas with oil slicks.This difference is probably due to the underestimation of the SAR-derived wind speeds at moderate wind speeds(i.e.,at wind speeds of greater than 5ms^(-1)).An additional analysis compared the SAR-derived wave spectra with those from the WW3 model as waves passed through the oil slicks.The interesting finding is that the wave energy at short wave lengths(about 30m)is reduced by the oil slicks,causing the movement of the dominant wave spectrum to shift to longer wave lengths(about 80 m).

An oil slick spectral experiment of nearshore sea water in the East China Sea

Along with the rapid advance in global industrialization, oil spill events caused by offshore operations, trans- portation and accidents are increasing. Compared with ship surveys, monitoring oil spills through remote sensing has real-time, comprehensive, low-cost advantages, which can effectively guide cleaning and evalu- ation, and reduce the marine ecological destruction resulting from oil spills. Therefore, studying the remote sensing mechanism used to monitor marine oil spills is of great significance for ecological environmen- tal protection. This paper describes an experiment and corresponding analysis based on the above-water method, using the East China Sea coastal turbid water. The analysis shows that ＂upward short-wave＂ in ultraviolet and blue-purple bands and its displacement, along with the changing thickness, are important characteristics for distinguishing between the oil slick and the sea water, and also to differentiate oil slicks of different thicknesses. From blue to near-infrared bands, the spectrum of lube oil is flatter than that of diesel, and the diesel spectrum rises faster than the lube spectrum on the right side of the trough at 400 nm. These two features form an important basis for differentiating diesel from lube oil. These analyses will further the development of oil spill remote sensing in the East China Sea.

某slick4300磁电机排故与分析

某型号教练飞机的磁电机出现故障,点火异常,导致飞机发动机出现抖动,本文通过对此磁电机进行逐步分析、排故,最终找出故障点和故障原因,并根据此故障原因对维修工作提出相应要求。

Adsorption damage and control measures of slick-water fracturing fluid in shale reservoirs

The slick-water polymer adsorption damage and control measures in shale were examined using a shale pack model of the Ordovician Wufeng Formation–Silurian Longmaxi Formation in the Changning block of the Sichuan Basin. The adsorption law of slick water under different displacement time, concentrations, p H values and temperatures of polymer were tested by traditional displacement experiment and UV-Vis spectrophotometer. The adsorption equilibrium time was 150 min, the amount of adsorption was proportional to the concentration of the polymer, and the maximum adsorption concentration was 1 800 mg/L. With the increase of p H value, the adsorption capacity decreased gradually, the adsorption capacity increased first and then decreased with the increase of temperature, and the adsorption capacity was the largest at 45 ?C. The adsorption patterns of polymers on shale were described by scanning electron microscopy and magnetic resonance imaging. It is proved that the adsorption of polymer on shale led to the destruction of the network structure of anionic polyacrylamide molecules, and the shale adsorption conformation was characterized qualitatively. Finally, according to the adsorption law and adsorption mechanism, it is proposed to reduce the adsorption quantity of polymer on shale surface by using hydrogen bond destruction agent. The effects of hydrogen bond destruction on four kinds of strong electronegative small molecules were compared, the hydrogen bond destroyer c was the best, which lowered the adsorption capacity by 5.49 mg/g and recovered permeability to 73.2%. The research results provide a reference for the optimization of construction parameters and the improvement of slickwater liquid system.

DYNAMIC MODEL FOR OIL SLICK DISPERSION INTO A WATER COLUMN- A WINDDRIVEN WAVETANK EXPERIMENT

A dynamic experiment for oil dispersion into a water column was performed with a 21 m long, 0.5 m wide, and 1 m high wind-driven wave tank. At wind velocity between 6-12 m/s and with the oil slide kept constant (about 1 um), the rate of the oil content increase in the water column could be approximated from the difference between the dispersion rate (R) of the oil slick and the coagulation rate (R’) of the dispersed oil slick. Assuming the coagulation rate is directly proportional to the concentration of the water dispersed oil slick (i. e. R’ =KC),, the integral form of the dynamic model can be expressed as C=R*[1-exp(-K*t)]/K and parameters R and K can be regressed with a computer. The relative deviation of model results from the experimental data was mainly less than 10%. The oil slick dispersion rate (R) had exponential relationship with the wind velocity (V), and can be fitted with a formula R=A*(U+1)B.The fitted constant of the coagulation rate, K(0.8-3.0* 10-3 min-1) did not have significant

The Numerical Investigation on Oil Slick Behavior behind the Oil Boom

The dynamics of contained oil spills is investigated based on multiphase CFD (Computational Fluid Mechanics) model. The oil slick shape behind the oil boom under water current is studied. The velocity field in the oil slick is compared with the velocity field in pure water flow. The thickness of the oil slick is studied quantitatively. It is found that there is a fixed linear relationship between the oil slick relative thickness and the Froude number for different oil, different current velocity, different boom draft and different volume of oil.

Research and Application of an Environmental-Friendly Low-Damage and High Salt-Resistance Slick Water Fracturing Fluid System

The Sulige gas field is a typical low-pressure low-permeability tight sandstone gas reservoir. The reservoir has poor seepage capacity, strong heterogeneity, high mineralization of formation water and extremely scarce water resources on the site. These unfavorable factors have brought great difficulties to the on-site mining process. Now, a nano-composite green environmental protection slick water fracturing fluid system CQFR can be quickly dissolved because of the larger specific surface area, and the small molecular size makes the damage to the reservoir less than 5%, and the average drag reduction effect can reach more than 73%. It can quickly and well dissolve and maintain performance under high salinity conditions and fracturing flowback fluids. It responds well to the complex reservoir conditions on the construction site and makes the flowback fluid recyable, which greatly reduces the consumption of water resources on the construction site and effectively improves the construction efficiency and economic benefits.

深部煤层气水平井大规模极限体积压裂技术--以鄂尔多斯盆地东缘临兴区块为例

针对深煤层渗透性差、弹性模量较低、泊松比较高、塑性强、破裂压力高、裂缝扩展难度大、加砂困难等特点,提出缝网改造规模化、缝网扩展均衡化、缝网支撑有效化的压裂设计理念,形成以高排量大规模注入、高强度加砂、等孔径限流射孔、暂堵转向、一体化可变黏滑溜水、多粒径组合支撑剂为核心的深煤层水平井大规模极限体积压裂技术。将该技术应用于鄂尔多斯盆地东缘临兴区块首口深煤层多级压裂水平井先导性试验,施工排量18 m^(3)/min、加砂强度2.1 m^(3)/m、用液强度16.5 m^(3)/m,压裂后形成了复杂裂缝网络,平均缝长为205 m,储层改造体积为1987×10^(4)m^(3),最高产气量达6×10^(4)m^(3)/d,实现了深部煤层气的高效开发。

SIMULATION OF THE OIL SLICK MOVEMENT IN TIDAL WATER-WAYS

Based on particle approach and tidal flow model this article studies the behavior of the oil slick on the water surface in the Huangpu River, a tidal waterway in Shanghai. In order to track the oil slick motion, a two-dimensional oil trajectory model is used. The dynamical properties of spilled oil characterized by advection, oil spreading and turbulent diffusion are considered in the model. The simulation results consistent with the flume experimental data show that the model is applicable. Both simulation and experiment illustrate that the tidal flow has a great influence on the oil slick motion. The calculated results can be used as a reference for the response to oil spill accidents in rivers.

Determining oil slick thickness using hyperspectral remote sensing in the Bohai Sea of China

Determining oil slick thickness plays an important role in assessing oil spill volume and its environmental impacts on the ocean.In this study,we used a Hyperion image of an oil spill accident area and seawater and fresh crude oil samples collected in the Bohai Sea of China.A well-controlled laboratory experiment was designed to simulate spectral responses to different oil slick thicknesses.Spectral resampling and normalization methods were used to reduce the differences in spectral reflectances between the experimental background seawater sample and real background seawater.Fitting the analysis with laboratory experimental data results showed a linear relationship between normalized oil slick reflectance and normalized oil slick thickness[20th band(R^(2)-0.92938,n=49,pB0.01),26th band(R^(2)=0.93806,n=49,pB0.01),29th band(R^(2)=0.93288,n=49,pB0.01)].By using these statistical models,we successfully determined the normalized oil slick thickness with the Hyperion image.Our results indicate that hyperspectral remote sensing technology is an effective method to monitor oil spills on water.The spectral ranges of visible green and red light were the optimal bands for estimating oil slick thickness in case 2 water.The high,stabilized spectral reflectance of background seawater will be helpful in oil slick thickness inversion.

An alternative approach to determine critical angle of contrast reversal and surface roughness of oil slicks under sunglint

The critical angle is the angle at which the contrast of oil slicks reverse their contrasts against the surrounding oil-free seawater under sunglint.Accurate determination of the critical angle can help estimate surface roughness and refractive index of the oil slicks.Although it’s difficult to determine a certain critical angle,the potential critical angle range help to improve the estimation accuracy.In this study,the angle between the viewing direction and the direction of mirror reflection is used as an indicator for quantifying the critical angle and could be calculated from the solar/viewing geometry from observations of the Moderate Resolution Imaging Spectroradiometer(MODIS).The natural seep oil slicks in the Gulf of Mexico were first delineated using a customized segmentation approach to remove noise and apply a morphological filter.On the basis of the histograms of the brightness values of the delineated oil slicks,the potential range of the critical angle was determined,and then an optimal critical angle between oil slicks and seawater was then determined from statistical and regression analyses in this range.This critical angle corresponds to the best fitting between the modeled and observed surface roughness of seep oil slicks and seawater.

Slick Prospects

As a pillar of the country’s financial system, Chinese banks are playing a bigger role in economic revitalization and rebalancing. But challenges still lie ahead on their path of financial reform and global expansion. Bankers from home and abroad discussed these issues at the Institute of International Finance (IIF) Spring Membership Meeting held on June 10-12 in Beijing. The IIF is a leading global association of financial service firms with more than 360 members across the world. Edited excerpts of the bankers’ comments follow.

Out of a Slick Shadow

Repercussions of an oil spill in China’s coastal Dalian City have yet to be thoroughly measured and eliminated Fang Shaolan, from Huangshan City of central Anhui Province, arrived in northeast China’s coastal Dalian City on July 27 for a vacation with seven family members.Before coming to Dalian,Fang heard from media reports that the spilled oil more than a week ago had been almost cleaned up and much of the sea near Dalian hadn’t been polluted.

Slick Prospect

The retail price cut in refined oil is expected to help turn around a rapidly weakening

浅谈Slick Bore钻井系统在渤海油田的应用

SlickBore钻井系统在渤中25-1油田使用后,通过详细的数据分析,SlickBore钻井系统不仅具备常规马达导向系统的主要功能,而且该钻井系统在井眼轨迹控制方面还有着显著的优势,基本上解决了深井滑动困难、摩阻与扭矩大等问题,也满足丛式井平台优快钻井作业的需要。

The remote sensing inversion theory of offshore oil slick thickness based on a two-beam interference model

Offshore oil slicks are significant for both the monitoring of marine spill accidents and the detection of marine oil resources.The use of remote sensing technology to detect the thickness of oil slicks is a major area of research.The reflected light from oil slicks changes with the thickness of the oil.This is the theoretical basis of research on optical remote sensing of offshore oil slicks.A two-beam interference model that considers the offshore oil slick as a flat plate has been developed in this study.A quantitative remote sensing model which describes a series of processes that use oil slick thickness and reflectance as variables is established.The use of the Fresnel equation to analyze parameters in the model indicated that the key property of the quantitative relationship between the oil slick thickness and reflectance was ultimately the disappearance or extinction of the oil slick.This model has been tested and verified by data from offshore oil slick spectral response experiments.Results showed that the oil slick thickness remote sensing model can be theoretically analyzed and is efficient.The research indicated that the major cause of variations in the spectral response as a function of oil slick thickness was the different light-scattering characteristics.These characteristics can be used in remote sensing applications to identify the different types of offshore oil slicks.The theoretical interpretation of each parameter in this model led to the development of a look-up table of the model parameters which will improve the efficiency of future offshore oil slick remote sensing.

Experimental study on spectral responses of offshore oil slick

Using the seawater taken from Liaodong Bay and crude oil taken from Liaohe Oilfield,a laboratory experiment was designed to study the change of reflectance spectrum of artificial offshore oil slick with its thickness and to identify the spectrum ranges suitable for quantifying the thickness of the oil slick.During the experiment,crude oil was continuously dropped into the seawater to generate artificial oil slick with different thicknesses.After every drop of crude oil was added,reflectance spectrum of the oil slick was measured with a high resolution spectroradiometer(ASD FieldSpec Pro FR).The influence of oil slick thickness on its reflectance spectrum was explored through statistical analysis.The results show that the reflectance of oil slick changes marginally with oil slick thickness and higher than that of seawater in infrared band from 1150 to 2500 nm.This spectrum range can be practically used to distinguish oil slick from seawater.In the spectrum range from 400 to 1150 nm,the reflectance of oil slick decreases with its thickness.The negative power function is the best-fit function expressing the relationship between the reflectance and thickness.The spectral characteristics of oil slick are very distinct at 550 and 645 nm.They are the best wavelengths for monitoring the existence of offshore oil slick and estimating its thickness.

Study on the hyperspectral polarized reflection characteristics of oil slicks on sea surfaces

This study is concerned with the need for remote sensing techniques for the monitoring of oil-slick pollution on sea surfaces and the effects of oil-slick pollution on the sea.We used Daqing crude oil,Jilin crude oil,heavy oil and seawater from Dalian Bay to simulate oil-slick pollution on the sea surface and obtained multi-angle hyperspectral polarized reflectance information,from which we calculated the polarization for different kinds of crude oil,and oil-slicks of different thicknesses.By comparing the degree of polarization between oil-slicks of different thickness,and sea water,it was found that in the case of thin oil-slicks,the degree of polarization of seawater is higher than that of oil slicks with wavelengths of between 400-1000 nm.However,there was little difference at a wavelength of 785 nm.At angles of incident of 20° and 30° (the viewing angle equals the incident angle),it was easy to distinguish the changes of oil-slick thickness by the degree of polarization at 785 and 880 nm in the near-infrared band.The crude oil showed its inherent polarized characteristic as the oil-slick thickness increased to a certain degree.That is to say,the polarization of the seawater was higher than that of the oil-slick in the visible light range,but less than that in the near-infrared band.As the incident angle changed from 40° to 50°,the degree of polarization of seawater increased,and it was higher than that for the oil-sick between wavelengths of 400-1000 nm at an angle of incidence of 50°.This research on the polarized characteristics of an oil-slick on a sea surface brings new scientific techniques to the monitoring of sea-surface pollution by remote sensing.

气悬浮支撑剂技术在长庆致密气压裂中的应用

滑溜水压裂液对致密储层伤害较低,但携砂能力弱,难以实现高砂比、长距离携砂,造成支撑缝面积远低于改造缝面积。通过气悬浮支撑剂技术,对支撑剂表面进行特殊改性,使其具有吸附气泡的能力,吸附气泡后的支撑剂体积密度大幅降低,运移能力大幅增强。室内实验表明,经气悬浮剂改性的20/40目及以下粒径的支撑剂,在常温、常压、黏度为15 mPa·s的滑溜水中可100%悬浮,观察2 h无沉降。动态输砂实验表明支撑剂在裂缝中呈整体均匀铺置,高温高压条件下气泡仍能对支撑剂有效悬浮。岩心伤害实验表明,破胶液和含气悬浮剂的破胶液对岩心渗透率的伤害率接近,且均低于10%,说明气悬浮剂不会对储层带来明显的附加伤害。该气悬浮支撑剂压裂技术在长庆油田鄂尔多斯盆地东部致密砂岩气藏开展了7口井先导实验,以黏度9~15 mPa·s的滑溜水在5 m^(3)/min排量下施工,压后产量为邻井常规压裂的1.2~1.9倍。气悬浮支撑剂将对压裂液黏度的需求从40~80 mPa·s的线性胶降至10 mPa·s左右的滑溜水,大幅降低了对压裂液黏度的依赖,从而降低了储层伤害,同时增加裂缝铺置效率,有利于提高单井产量及开发效益。