The distribution characteristics of the oil-water contact are the basis for the reservoir exploration and development and reserves evaluation. The reservoir with a tilted oil-water contact has a unique formation mecha...The distribution characteristics of the oil-water contact are the basis for the reservoir exploration and development and reserves evaluation. The reservoir with a tilted oil-water contact has a unique formation mechanism, and the understanding of its distribution and formation mechanism will directly affect the evaluations for the reservoir type, well deployment, selection of well pattern and type, determination of test section, and reserves evaluation. Based on the analysis of reservoir characteristics, petrophysical properties and geological structure in 40 reservoirs worldwide with tilted oil-water contacts, the progress of the research on the formation mechanisms of titled oil-water contacts is summarized in terms of the hydrodynamic conditions, reservoir heterogeneity, neotectonic movement and oil-gas exploitation. According to the formation mechanism of tilted oil-water contacts and the needs of exploration research, different aspects of research methods are summarized and classified, such as the calculation of equipotential surfaces for oil and water in the formation, analysis of formation pressure and analysis of reservoir physical properties and so on. Based upon statistical analysis, it is suggested that the degree of the inclination of the oil-water contact be divided based on the dip of oil-water contact(DipTOWC). The tilted oil-water contact is divided into three categories: large dip(DipTOWC≥55 m/km), medium dip(4 m/km≤DipTOWC55 m/km), and small dip(DipTOWC4 m/km). The classification and evaluation method can be combined with structure amplitude and reservoir property. The formation mechanism of domestic and international reservoirs with tilted oil-water contacts are summarized in this paper, which have important significance in guiding the exploration and development of the oilfield with tilted oil-water contacts, reserves evaluation, and well deployment.展开更多
Interactions between water and solid substrates are of fundamental importance to various processes in nature and industry.Electric control is widely used to modify interfacial water,where the influence of surface char...Interactions between water and solid substrates are of fundamental importance to various processes in nature and industry.Electric control is widely used to modify interfacial water,where the influence of surface charges is inevitable.Here we obtain positively and negatively charged surfaces using Li Ta O_(3) crystals and observe that a large net surface charge up to 0.1 C/m;can nominally change the contact angles of pure water droplets comparing to the same uncharged surface.However,even a small amount of surface charge can efficiently increase the water contact angle in the presence of aerosols.Our results indicate that such surface charges can hardly affect the structure of interfacial water molecular layers and the morphology of the macroscopic droplet,while adsorption of a small amount of organic contaminants from aerosols with the help of Coulomb attraction can notably decrease the wettability of solid surface.Our results not only provide a fundamental understanding of the interactions between charged surfaces and water,but also help to develop new techniques on electric control of wettability and microfluidics in real aerosol environments.展开更多
The Puguang (普光) gas field is the largest gas field found in marine carbonate in China. The Puguang gas field experienced complicated evolution history from paleo-oil pool to gas pool. The purpose of this article ...The Puguang (普光) gas field is the largest gas field found in marine carbonate in China. The Puguang gas field experienced complicated evolution history from paleo-oil pool to gas pool. The purpose of this article is to reveal the evolution history of Puguang gas field through systematic study on the relationship between paleo-oil-water contact (POWC) and present-day gas-water contact (PGWC). POWC was recognized by observing the change of relative content of residual solid bitumen in the cores, and PGWC was observed using log and drilling stem test data. Two types of relationship between POWC and PGWC were observed in the Puguang gas field: POWC is above PGWC, and POWC is below PGWC. The former is normal as oil cracking may cause gas-water contact to move downward. The latter can be interpreted by lateral gas re-migration and re-accumulation caused by changes in structural configuration. The relationship between POWC and PGWC suggests that during oil charge, the southwestern and northwestern parts of the Puguang gas field were structurally lower than the northeastern and southeastern parts. Thrusting from Xuefengshan (雪峰山) since Yanshanian movement and from Dabashan (大巴山) since Himalayan movement resulted in the relative uplift of the southwestern and northwestern parts of the Puguang structure, which significantly changed the structural configuration. Based on the paleo-structure discussed in this article, the most probable migration directions of paleo-oil were from the northwest to the southeast and from the southwest to the northeast. Consequently, the evolution history of the Puguang gas field can be divided into three stages, namely,oil charging (200-170 Ma), cracking oil to gas (155-120 Ma), and gas pool adjustment (12-0 Ma).展开更多
Wettability of a solid surface is highly important to its practical application,especially for the surface that shows thermoresponsive properties.In this paper,we describe a thermo-responsive stick-slip behavior of wa...Wettability of a solid surface is highly important to its practical application,especially for the surface that shows thermoresponsive properties.In this paper,we describe a thermo-responsive stick-slip behavior of water droplets on the surfaces of poly(N-isopropylacrylamide)(PNIPAM)-grafted polypropylene membranes.Field emission scanning electron microscope(FESEM) images elucidate that the morphology of PNIPAM-grafted membrane surface is thermo-responsive,i.e.,the surface becomes rougher above the lower critical solution temperature(LCST) of PNIPAM.On the surface of nascent polypropylene membranes,the water droplet shows a smooth motion resulting in advancing and receding water contact angles of 111° and ~65°,respectively.On the PNIPAM-grafted membrane surfaces,the water droplet shows a stick-slip pattern above the LCST,whereas it advances smoothly below the LCST.This phenomenon is reproducible and can be ascribed to the energy barriers enhanced by the shrink of PNIPAM chains above the LCST.We also find that the slip contact angle decreases from 102° to 92° after several stick-slip cycles.This decrease is attributed to the water adsorption on the grafted PNIPAM layer,which is confirmed by the continuous decrease of the receding water contact angle.展开更多
It is known that contact lines keep relatively still on solids until static contact angles exceed an interval of hysteresis of static contact angle (HSCA), and contact angles keep changing as contact lines relatively ...It is known that contact lines keep relatively still on solids until static contact angles exceed an interval of hysteresis of static contact angle (HSCA), and contact angles keep changing as contact lines relatively slide on the solid. Here, the effects of HSCA and boundary slip were first distinguished on the micro-curvature force (MCF) on the seta. Hence, the total MCF is partitioned into static and dynamic MCFs correspondingly. The static MCF was found proportional to the HSCA and related with the asymmetry of the micro-meniscus near the seta. The dynamic MCF, exerting on the relatively sliding contact line, is aroused by the boundary slip. Based on the Blake-Haynes mechanism, the dynamic MCF was proved important for water walking insects with legs slower than the minimum wave speed . As insects brush the water by laterally swinging legs backwards, setae on the front side of the leg are pulled and the ones on the back side are pushed to cooperatively propel bodies forward. If they pierce the water surface by vertically swinging legs downwards, setae on the upside of the legs are pulled, and the ones on the downside are pushed to cooperatively obtain a jumping force. Based on the dependency between the slip length and shear rate, the dynamic MCF was found correlated with the leg speed U, as , where and are determined by the dimple depth. Discrete points on this curve could give fitted relations as (Suter et al., J. Exp. Biol. 200, 2523-2538, 1997). Finally, the axial torque on the inclined and partially submerged seta was found determined by the surface tension, contact angle, HSCA, seta width, and tilt angle. The torque direction coincides with the orientation of the spiral grooves of the seta, which encourages us to surmise it is a mechanical incentive for the formation of the spiral morphology of the setae of water striders.展开更多
We conducted a transient experimental investigation of steam–water direct contact condensation in the absence of noncondensible gas in a laboratory-scale column with the inner diameter of 325 mm and the height of 104...We conducted a transient experimental investigation of steam–water direct contact condensation in the absence of noncondensible gas in a laboratory-scale column with the inner diameter of 325 mm and the height of 1045 mm. We applied a new analysis method for the steam state equation to analyze the molar quantity change in steam over the course of the experiment and determined the transient steam variation. We also investigated the influence of flow rates and temperatures ofcooling water on the efficiency ofsteam condensation. Our experimental results show that appropriate increasing of the cooling water flow rate can significantly accelerate the steam condensation. We achieved a rapid increase in the total volumetric heat transfer coefficient by increasing the flow rate of cooling water, which indicated a higher thermal convection between the steam and the cooling water with higher flow rates. We found that the temperature ofcooling water did not play an important role on steam condensation. This method was confirmed to be effective for rapid recovering ofsteam.展开更多
This paper concentrates on the development of glasses with self-cleaning surfaces exhibiting high water contact angles. In this study, we prepared super-hydrophobic nano-ceramic coated glass based on titania & sil...This paper concentrates on the development of glasses with self-cleaning surfaces exhibiting high water contact angles. In this study, we prepared super-hydrophobic nano-ceramic coated glass based on titania & silica using simple sol-gel & dip coating methods and studied the best composition of the coatings by altering ratios of titanium tetraisopropoxide (TTIP)/tetraethyl orthosilicate (TEOS) with different homogenizing agents. We characterized the coatings by surface roughness measurement, percentage of optical transmission, static contact angle, near-infrared (NIR) transmission, and diffuse reflectance. The fabrication of coatings on glass substrates played an important role in increasing the water contact angle of about 95° and visible & NIR transmission of about 90%. We compared our modified glass substrate with commercial low emissivity (Low E) glass using X-ray diffraction (XRD) analysis, which showed pure amorphous surface claiming excellent wettability and thus the prepared glass substrate could have a variety of applications in different fields.展开更多
文摘The distribution characteristics of the oil-water contact are the basis for the reservoir exploration and development and reserves evaluation. The reservoir with a tilted oil-water contact has a unique formation mechanism, and the understanding of its distribution and formation mechanism will directly affect the evaluations for the reservoir type, well deployment, selection of well pattern and type, determination of test section, and reserves evaluation. Based on the analysis of reservoir characteristics, petrophysical properties and geological structure in 40 reservoirs worldwide with tilted oil-water contacts, the progress of the research on the formation mechanisms of titled oil-water contacts is summarized in terms of the hydrodynamic conditions, reservoir heterogeneity, neotectonic movement and oil-gas exploitation. According to the formation mechanism of tilted oil-water contacts and the needs of exploration research, different aspects of research methods are summarized and classified, such as the calculation of equipotential surfaces for oil and water in the formation, analysis of formation pressure and analysis of reservoir physical properties and so on. Based upon statistical analysis, it is suggested that the degree of the inclination of the oil-water contact be divided based on the dip of oil-water contact(DipTOWC). The tilted oil-water contact is divided into three categories: large dip(DipTOWC≥55 m/km), medium dip(4 m/km≤DipTOWC55 m/km), and small dip(DipTOWC4 m/km). The classification and evaluation method can be combined with structure amplitude and reservoir property. The formation mechanism of domestic and international reservoirs with tilted oil-water contacts are summarized in this paper, which have important significance in guiding the exploration and development of the oilfield with tilted oil-water contacts, reserves evaluation, and well deployment.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12025407,11934003,9185012011774328)+1 种基金the Key R&D Program of China(Grant No.2016YFA0300902)the Chinese Academy of Sciences。
文摘Interactions between water and solid substrates are of fundamental importance to various processes in nature and industry.Electric control is widely used to modify interfacial water,where the influence of surface charges is inevitable.Here we obtain positively and negatively charged surfaces using Li Ta O_(3) crystals and observe that a large net surface charge up to 0.1 C/m;can nominally change the contact angles of pure water droplets comparing to the same uncharged surface.However,even a small amount of surface charge can efficiently increase the water contact angle in the presence of aerosols.Our results indicate that such surface charges can hardly affect the structure of interfacial water molecular layers and the morphology of the macroscopic droplet,while adsorption of a small amount of organic contaminants from aerosols with the help of Coulomb attraction can notably decrease the wettability of solid surface.Our results not only provide a fundamental understanding of the interactions between charged surfaces and water,but also help to develop new techniques on electric control of wettability and microfluidics in real aerosol environments.
基金supported by the National Basic Research Program of China (No. 2005CB422105)the National NaturalScience Foundation of China (No. 40772089)
文摘The Puguang (普光) gas field is the largest gas field found in marine carbonate in China. The Puguang gas field experienced complicated evolution history from paleo-oil pool to gas pool. The purpose of this article is to reveal the evolution history of Puguang gas field through systematic study on the relationship between paleo-oil-water contact (POWC) and present-day gas-water contact (PGWC). POWC was recognized by observing the change of relative content of residual solid bitumen in the cores, and PGWC was observed using log and drilling stem test data. Two types of relationship between POWC and PGWC were observed in the Puguang gas field: POWC is above PGWC, and POWC is below PGWC. The former is normal as oil cracking may cause gas-water contact to move downward. The latter can be interpreted by lateral gas re-migration and re-accumulation caused by changes in structural configuration. The relationship between POWC and PGWC suggests that during oil charge, the southwestern and northwestern parts of the Puguang gas field were structurally lower than the northeastern and southeastern parts. Thrusting from Xuefengshan (雪峰山) since Yanshanian movement and from Dabashan (大巴山) since Himalayan movement resulted in the relative uplift of the southwestern and northwestern parts of the Puguang structure, which significantly changed the structural configuration. Based on the paleo-structure discussed in this article, the most probable migration directions of paleo-oil were from the northwest to the southeast and from the southwest to the northeast. Consequently, the evolution history of the Puguang gas field can be divided into three stages, namely,oil charging (200-170 Ma), cracking oil to gas (155-120 Ma), and gas pool adjustment (12-0 Ma).
基金support from the National Natural Science Foundation of China for Distinguished Young Scholars (Grant No.50625309)The Zhejiang Provincial Natural Science Foundation of China (Grant No.Z406260)supports from the National Postdoctoral Science Foundation of China (Grant Nos.20070421172 & 20081466)
文摘Wettability of a solid surface is highly important to its practical application,especially for the surface that shows thermoresponsive properties.In this paper,we describe a thermo-responsive stick-slip behavior of water droplets on the surfaces of poly(N-isopropylacrylamide)(PNIPAM)-grafted polypropylene membranes.Field emission scanning electron microscope(FESEM) images elucidate that the morphology of PNIPAM-grafted membrane surface is thermo-responsive,i.e.,the surface becomes rougher above the lower critical solution temperature(LCST) of PNIPAM.On the surface of nascent polypropylene membranes,the water droplet shows a smooth motion resulting in advancing and receding water contact angles of 111° and ~65°,respectively.On the PNIPAM-grafted membrane surfaces,the water droplet shows a stick-slip pattern above the LCST,whereas it advances smoothly below the LCST.This phenomenon is reproducible and can be ascribed to the energy barriers enhanced by the shrink of PNIPAM chains above the LCST.We also find that the slip contact angle decreases from 102° to 92° after several stick-slip cycles.This decrease is attributed to the water adsorption on the grafted PNIPAM layer,which is confirmed by the continuous decrease of the receding water contact angle.
文摘It is known that contact lines keep relatively still on solids until static contact angles exceed an interval of hysteresis of static contact angle (HSCA), and contact angles keep changing as contact lines relatively slide on the solid. Here, the effects of HSCA and boundary slip were first distinguished on the micro-curvature force (MCF) on the seta. Hence, the total MCF is partitioned into static and dynamic MCFs correspondingly. The static MCF was found proportional to the HSCA and related with the asymmetry of the micro-meniscus near the seta. The dynamic MCF, exerting on the relatively sliding contact line, is aroused by the boundary slip. Based on the Blake-Haynes mechanism, the dynamic MCF was proved important for water walking insects with legs slower than the minimum wave speed . As insects brush the water by laterally swinging legs backwards, setae on the front side of the leg are pulled and the ones on the back side are pushed to cooperatively propel bodies forward. If they pierce the water surface by vertically swinging legs downwards, setae on the upside of the legs are pulled, and the ones on the downside are pushed to cooperatively obtain a jumping force. Based on the dependency between the slip length and shear rate, the dynamic MCF was found correlated with the leg speed U, as , where and are determined by the dimple depth. Discrete points on this curve could give fitted relations as (Suter et al., J. Exp. Biol. 200, 2523-2538, 1997). Finally, the axial torque on the inclined and partially submerged seta was found determined by the surface tension, contact angle, HSCA, seta width, and tilt angle. The torque direction coincides with the orientation of the spiral grooves of the seta, which encourages us to surmise it is a mechanical incentive for the formation of the spiral morphology of the setae of water striders.
文摘We conducted a transient experimental investigation of steam–water direct contact condensation in the absence of noncondensible gas in a laboratory-scale column with the inner diameter of 325 mm and the height of 1045 mm. We applied a new analysis method for the steam state equation to analyze the molar quantity change in steam over the course of the experiment and determined the transient steam variation. We also investigated the influence of flow rates and temperatures ofcooling water on the efficiency ofsteam condensation. Our experimental results show that appropriate increasing of the cooling water flow rate can significantly accelerate the steam condensation. We achieved a rapid increase in the total volumetric heat transfer coefficient by increasing the flow rate of cooling water, which indicated a higher thermal convection between the steam and the cooling water with higher flow rates. We found that the temperature ofcooling water did not play an important role on steam condensation. This method was confirmed to be effective for rapid recovering ofsteam.
文摘This paper concentrates on the development of glasses with self-cleaning surfaces exhibiting high water contact angles. In this study, we prepared super-hydrophobic nano-ceramic coated glass based on titania & silica using simple sol-gel & dip coating methods and studied the best composition of the coatings by altering ratios of titanium tetraisopropoxide (TTIP)/tetraethyl orthosilicate (TEOS) with different homogenizing agents. We characterized the coatings by surface roughness measurement, percentage of optical transmission, static contact angle, near-infrared (NIR) transmission, and diffuse reflectance. The fabrication of coatings on glass substrates played an important role in increasing the water contact angle of about 95° and visible & NIR transmission of about 90%. We compared our modified glass substrate with commercial low emissivity (Low E) glass using X-ray diffraction (XRD) analysis, which showed pure amorphous surface claiming excellent wettability and thus the prepared glass substrate could have a variety of applications in different fields.