There are three abnormally high porosity zones developed in buried Paleogene nearshore subaqueous fan and sublacustrine fan clastic＇reservoirs at 2,800-3,200 m, 3,250-3,700 m and 3,900- 4,400 m, respectively, within ...There are three abnormally high porosity zones developed in buried Paleogene nearshore subaqueous fan and sublacustrine fan clastic＇reservoirs at 2,800-3,200 m, 3,250-3,700 m and 3,900- 4,400 m, respectively, within the Shengtuo area of the Dongying Sag. Here the porosity of reservoirs buried deeper than 4,000 m can still be greater than 20%. Investigation of these three abnormally high porosity （AHP） zones in the 3rd to 4th member of the Paleogene Shahejie Formation in the Shengtuo area was carried out with utilization of core observation, thin section identification, SEM observation, image analysis, core physical property testing and other technical methods. The results show that, the AHP zones in 2,800-3,200 m and 3,250-3,700 m are visible pores primary AHP zones dominated by significant primary intergranular pores （more than 50% of the total porosity）, while secondary pores and micropores in authigenic clays may develop in some reservoirs. AHP reservoirs in the AHP zone of 3,900-4,400 m are dominated by micropores in matrix, visible pores are mainly grain dissolution pores but with low absolute content （〈 1%）, so this zone belongs to the micropores primary AHP zone. The genesis of the three AHP zones was studied to distinguish between porosity enhancement and porosity preservation. Our research shows that, in deeply buried clastic reservoirs in the Shengtuo area, mineral dissolution occurred in a relatively closed diagenetic system with high temperature and high salinity. Reservoir rocks underwent extensive feldspar dissolution, while detrital carbonate grains and carbonate cements show no evidence of extensive dissolution. Although significant feldspar dissolution pores developed, feldspar dissolution enhanced porosity only a little due to the precipitation of almost isovolumetric dissolution products in the nearby primary intergranular pores in forms of authigenic clays and quartz cements. Net enhanced porosity originating from feldspar dissolution is generally less than 0.25%. Thus, the subsurface dissolution has little impact on the mid-deep buried high porosity reservoirs. Reservoirs in braided channels of middle fans in sublacustrine fans and reservoirs in the middle-front of fan bodies of nearshore subaqueous fans provide the basis for the development of AHP zones. The shallow development of fluid overpressure and early hydrocarbon emplacement have effectively retarded compaction and carbonate cementation, so that the high porosity in the superficial layers is preserved in the mid-deep layers. These are the main controlling factors in the development of AHP zones.展开更多
Objective:There is a high incidence of birth defects in China,and prenatal diagnosis is an important method of intervention.This study aims to describe the clinical indications and cytogenetic results of amniocentesis...Objective:There is a high incidence of birth defects in China,and prenatal diagnosis is an important method of intervention.This study aims to describe the clinical indications and cytogenetic results of amniocentesis cases in central China.Methods:We retrospectively reviewed cases at the Maternal and Child Care Service Centre in Henan Province from January 2012 to December 2014.A total of 4497 at-risk mothers(risk factors:advanced maternal age,history of intrauterine fetal death or aborted fetuses,chromosomal abnormality in one of the parents,high-risk maternal serum screening results,and abnormal ultrasonographic findings in the first or second trimester)were recruited for amniocentesis(AS).The subjects included were between 11–14 and 18–22 weeks of gestation.All cases were divided into two groups based on instrument-independent or instrument-dependent indications.Results:A total of 4146 cases were analyzed.Of these,chromosomal abnormalities were detected in 232 cases(5.6%),and autosomal aneuploidy,including trisomy 21 and trisomy 18,was found to be the most common(55.7%)chromosomal abnormality.The mean age of 29.94 years was not expected as all mothers older than 35 years old were routinely offered amniocentesis at the time of the study.Amniocentesis was carried out in 1711 cases because of instrument-independent indications,and 285 of these cases were diagnosed with chromosomal abnormality.In 2376 cases,amniocentesis was conducted because of instrumentdependent indications,and 176 of these were diagnosed with chromosomal abnormality.Thus,5.6%of the cases were diagnosed with chromosomal abnormalities,and autosomal aneuploidy,including trisomy 21 and trisomy 18,were the most common chromosomal abnormalities detected in the present study Conclusion:Our result indicated the significance of instrument-independent indications in the screening of chromosomal abnormalities,especially in developing areas.Birth defects may be reduced by paying more attention to the patients’history of medication.展开更多
-Variations of monsoon wind field in the sea area along the southeastern coast of China during the ENSO events and its influence on the sea level and sea surface temperature (SST) are explored mainly on the basis of t...-Variations of monsoon wind field in the sea area along the southeastern coast of China during the ENSO events and its influence on the sea level and sea surface temperature (SST) are explored mainly on the basis of the data of monthly mean wind at 850 hPa and five coastal stations during 1973-1987. The results from the analyses of the data and theoretical estimation show that the southwest wind anomalies appeared in the study area during the events, and northeast wind anomalies occurred in general before the events. With the coastline of the area being parallel basically to the direction of the wind, an Ekman transport will result in an accumulation of the water near the coast or a departure of the water from the coast. As a result , the sea level and SST there will be affected markedly. During the events, southwest wind will intensify in the summer, and northeast wind will weaken in the winter. Their total effect is that a large negative anomaly of the sea level and SST will occur. The estimations indicate that the monsoon wind is stronger in the summer and weaker in the winter than the normal by 1-1. 5 m/s during the events, and this anomaly will cause a decrease of the sea level by 7-11 cm . Changes of the wind field, therefore, is mainly responsible for a large negative anomalies of the sea level and SST there during the ENSO events.展开更多
基金financially supported by the National Natural Science Foundation of China (No. U1262203, No. 41102058)a National Science and Technology Special Grant (No. 2011ZX05006-003)Foundation for the Author of National Excellent Doctoral Dissertation of China
文摘There are three abnormally high porosity zones developed in buried Paleogene nearshore subaqueous fan and sublacustrine fan clastic＇reservoirs at 2,800-3,200 m, 3,250-3,700 m and 3,900- 4,400 m, respectively, within the Shengtuo area of the Dongying Sag. Here the porosity of reservoirs buried deeper than 4,000 m can still be greater than 20%. Investigation of these three abnormally high porosity （AHP） zones in the 3rd to 4th member of the Paleogene Shahejie Formation in the Shengtuo area was carried out with utilization of core observation, thin section identification, SEM observation, image analysis, core physical property testing and other technical methods. The results show that, the AHP zones in 2,800-3,200 m and 3,250-3,700 m are visible pores primary AHP zones dominated by significant primary intergranular pores （more than 50% of the total porosity）, while secondary pores and micropores in authigenic clays may develop in some reservoirs. AHP reservoirs in the AHP zone of 3,900-4,400 m are dominated by micropores in matrix, visible pores are mainly grain dissolution pores but with low absolute content （〈 1%）, so this zone belongs to the micropores primary AHP zone. The genesis of the three AHP zones was studied to distinguish between porosity enhancement and porosity preservation. Our research shows that, in deeply buried clastic reservoirs in the Shengtuo area, mineral dissolution occurred in a relatively closed diagenetic system with high temperature and high salinity. Reservoir rocks underwent extensive feldspar dissolution, while detrital carbonate grains and carbonate cements show no evidence of extensive dissolution. Although significant feldspar dissolution pores developed, feldspar dissolution enhanced porosity only a little due to the precipitation of almost isovolumetric dissolution products in the nearby primary intergranular pores in forms of authigenic clays and quartz cements. Net enhanced porosity originating from feldspar dissolution is generally less than 0.25%. Thus, the subsurface dissolution has little impact on the mid-deep buried high porosity reservoirs. Reservoirs in braided channels of middle fans in sublacustrine fans and reservoirs in the middle-front of fan bodies of nearshore subaqueous fans provide the basis for the development of AHP zones. The shallow development of fluid overpressure and early hydrocarbon emplacement have effectively retarded compaction and carbonate cementation, so that the high porosity in the superficial layers is preserved in the mid-deep layers. These are the main controlling factors in the development of AHP zones.
文摘Objective:There is a high incidence of birth defects in China,and prenatal diagnosis is an important method of intervention.This study aims to describe the clinical indications and cytogenetic results of amniocentesis cases in central China.Methods:We retrospectively reviewed cases at the Maternal and Child Care Service Centre in Henan Province from January 2012 to December 2014.A total of 4497 at-risk mothers(risk factors:advanced maternal age,history of intrauterine fetal death or aborted fetuses,chromosomal abnormality in one of the parents,high-risk maternal serum screening results,and abnormal ultrasonographic findings in the first or second trimester)were recruited for amniocentesis(AS).The subjects included were between 11–14 and 18–22 weeks of gestation.All cases were divided into two groups based on instrument-independent or instrument-dependent indications.Results:A total of 4146 cases were analyzed.Of these,chromosomal abnormalities were detected in 232 cases(5.6%),and autosomal aneuploidy,including trisomy 21 and trisomy 18,was found to be the most common(55.7%)chromosomal abnormality.The mean age of 29.94 years was not expected as all mothers older than 35 years old were routinely offered amniocentesis at the time of the study.Amniocentesis was carried out in 1711 cases because of instrument-independent indications,and 285 of these cases were diagnosed with chromosomal abnormality.In 2376 cases,amniocentesis was conducted because of instrumentdependent indications,and 176 of these were diagnosed with chromosomal abnormality.Thus,5.6%of the cases were diagnosed with chromosomal abnormalities,and autosomal aneuploidy,including trisomy 21 and trisomy 18,were the most common chromosomal abnormalities detected in the present study Conclusion:Our result indicated the significance of instrument-independent indications in the screening of chromosomal abnormalities,especially in developing areas.Birth defects may be reduced by paying more attention to the patients’history of medication.
文摘-Variations of monsoon wind field in the sea area along the southeastern coast of China during the ENSO events and its influence on the sea level and sea surface temperature (SST) are explored mainly on the basis of the data of monthly mean wind at 850 hPa and five coastal stations during 1973-1987. The results from the analyses of the data and theoretical estimation show that the southwest wind anomalies appeared in the study area during the events, and northeast wind anomalies occurred in general before the events. With the coastline of the area being parallel basically to the direction of the wind, an Ekman transport will result in an accumulation of the water near the coast or a departure of the water from the coast. As a result , the sea level and SST there will be affected markedly. During the events, southwest wind will intensify in the summer, and northeast wind will weaken in the winter. Their total effect is that a large negative anomaly of the sea level and SST will occur. The estimations indicate that the monsoon wind is stronger in the summer and weaker in the winter than the normal by 1-1. 5 m/s during the events, and this anomaly will cause a decrease of the sea level by 7-11 cm . Changes of the wind field, therefore, is mainly responsible for a large negative anomalies of the sea level and SST there during the ENSO events.
