Remaining oil distribution characteristics in an oil reservoir with ultra-high water-cut

An accurate mapping and understanding of remaining oil distribution is very important for water control and stabilize oil production of mature oilfields in ultra-high water-cut stage.Currently,the Tuo-21 Fault Block of the Shengtuo Oilfield has entered the stage of ultra-high water cut(97.2%).Poor adaptability of the well pattern,ineffective water injection cycle and low efficiency of engineering measures(such as workover,re-perforation and utilization of high-capacity pumps)are the significant problems in the ultra-high water-cut reservoir.In order to accurately describe the oil and water flow characteristics,relative permeability curves at high water injection multiple(injected pore volume)and a semiquantitative method is applied to perform fine reservoir simulation of the Sand group 3e7 in the Block.An accurate reservoir model is built and history matching is performed.The distribution characteristics of remaining oil in lateral and vertical directions are quantitatively simulated and analyzed.The results show that the numerical simulation considering relative permeability at high injection multiple can reflect truly the remaining oil distribution characteristics after water flooding in an ultrahigh water-cut stage.The distribution of remaining oil saturation can be mapped more accurately and quantitatively by using the‘four-points and five-types’classification method,providing a basis for potential tapping of various remaining oil types of oil reservoirs in late-stage of development with high water-cut.

Soil-vegetation-atmosphere interaction over a hilly forest in the southern Huaihe River Basin:Long-term field experiment and preliminary analysis of basic observations

To improve the understanding of the CO_(2) exchange and the cycling of energy and water between the land surface and atmosphere over a typical hilly forest in southeastern China,a long-term field experimental observatory was established in Huainan,Anhui Province.Here,the authors briefly describe the three parts of ongoing research activities:the environmental monitoring at the site,the meteorological observations on a high tower,and particularly the intensive measurement of soil-vegetation-atmosphere interaction on a lower tower.Specifically,the diurnal variation of basic meteorological variables on a typical clear day(13 July 2018),and their temporal variation in the first three months of the low tower’s operation(4 June to 31 August 2018),and in combination with simultaneous data from the high tower,are analyzed.Results show that the data demonstrate reasonable variabilities,and the variables exhibit significant diurnal variation,characteristics of summer values,and considerable differences in summer months.The daily and monthly average albedos above the forest canopy were both 0.13.The daily average soil CO_(2) concentration was 1726 and 4481 ppm at 2 and 10 cm,respectively.The soil CO_(2) concentration changed with soil volumetric moisture contents,but showed a weak correlation with soil temperature in summer 2018.As the observatory continues to run and data continue to be collated,further investigation of the long-term variation of monsoon characteristics should be performed in the future.The experiment is useful in ecosystem and atmosphere interaction research,as well as for the development and evaluation of climate models,in the transitional climate zone of the Huaihe River basin.

Performance of the Wind Farm Parameterization Scheme Coupled with the Weather Research and Forecasting Model under Multiple Resolution Regimes for Simulating an Onshore Wind Farm

We use the Wind Farm Parameterization(WFP) scheme coupled with the Weather Research and Forecasting model under multiple resolution regimes to simulate turbulent wake dynamics generated by a real onshore wind farm and their influence at the local meteorological scale. The model outputs are compared with earlier modeling and observation studies. It is found that higher vertical and horizontal resolutions have great impacts on the simulated wake flow dynamics. The corresponding wind speed deficit and turbulent kinetic energy results match well with previous studies. In addition, the effect of horizontal resolution on near-surface meteorology is significantly higher than that of vertical resolution. The wake flow field extends from the start of the wind farm to downstream within 10 km, where the wind speed deficit may exceed 4%. For a height of 150 m or at a distance of about 25 km downstream, the wind speed deficit is around 2%. This indicates that, at a distance of more than 25 km downstream, the impact of the wind turbines can be ignored. Analysis of near-surface meteorology indicates a night and early morning warming near the surface, and increase in near-surface water vapor mixing ratio with decreasing surface sensible and latent heat fluxes. During daytime, a slight cooling near the surface and decrease in the near-surface water vapor mixing ratio with increasing surface sensible and latent heat fluxes is noticed over the wind farm area.