2005 Vol. 23, No. 3
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Display Method:
2005, 23(3): 371-379.
Abstract:
The sandstone structure and scale vary with different depositional systems, and have different contribution to uranium mineralization. According to outcrop research, drilling core analysis, and sand distributed system drawing,we analyzed the lowermember of Zhiluo Formation, northeastern Ordos basin. The results show that the lowermember of Zhiluo Formation is not formed by braided stream in traditional recognition. In fact, it can be divided into the upper and lower sub-members. Although the upper and lower sub-members have well inheritance in provenance and sand distributed direction-which is NW-SE, they have different genesis. The lower sub-member of Zhiluo Formation com-prise braided stream system and braided delta regime, and braided stream delta plain is the main body; the upper sub-member of Zhiluo Formation comp rise meandering river system and meandering river delta regime, and meandering river delta plain is the main body, meandering river delta front take up some space also, which is the result of lake extension to northwest. So, the low sub-member has larger scale and better connectivity, while up sub-member has smaller scale and higher heterogeneity. The practices of sandstone-type uranium exploration also p rove that the ore mainly occurred in low sub-member of Zhiluo Formation. Therefore, the genetic recognition is favorable for the rule summary and space orientation of uranium mineralization.
The sandstone structure and scale vary with different depositional systems, and have different contribution to uranium mineralization. According to outcrop research, drilling core analysis, and sand distributed system drawing,we analyzed the lowermember of Zhiluo Formation, northeastern Ordos basin. The results show that the lowermember of Zhiluo Formation is not formed by braided stream in traditional recognition. In fact, it can be divided into the upper and lower sub-members. Although the upper and lower sub-members have well inheritance in provenance and sand distributed direction-which is NW-SE, they have different genesis. The lower sub-member of Zhiluo Formation com-prise braided stream system and braided delta regime, and braided stream delta plain is the main body; the upper sub-member of Zhiluo Formation comp rise meandering river system and meandering river delta regime, and meandering river delta plain is the main body, meandering river delta front take up some space also, which is the result of lake extension to northwest. So, the low sub-member has larger scale and better connectivity, while up sub-member has smaller scale and higher heterogeneity. The practices of sandstone-type uranium exploration also p rove that the ore mainly occurred in low sub-member of Zhiluo Formation. Therefore, the genetic recognition is favorable for the rule summary and space orientation of uranium mineralization.
2005, 23(3): 397-405.
Abstract:
Chang 4 + 5 sandstones of Yanchang Formation in Yanchi-Jiyuan area are mainly composed of platform-type and slope-type delta front sandbodies. Lithic feldspathic and feldspathic sandstones are chief rock types, of which the average content of quartz, feldspar and rock fragments are 24.7%, 43.2% and 10. 0%, respectively, and meta-morphic and igneous fragments are dominant constitutes, accounting for 88. 0% of total fragment content. At present, these sandstones are in the late period of the Early diagenetic B stage (Ro = 0. 8% and T = 70290℃), so they are under the control of acidic diagenetic environment, being of abundant secondary dissolution porosity. On the basis of the statistics of sandstone compositions, it is indicated by the quantitative calculation that compaction is the dominant reason for the loss of the primary porosity in the study area, and next cementation, whereas the increasing ratio of porosity caused by the dissolution is relatively small ( < 10%). In combination with the results of sedimentary facies, three types of sedimentary-diagenetic facies zone could be divided, i. e. slope-type delta front-chlorite film primary porosity facies, slope-type delta front-late ferrous calcite cemented secondary porosity facies and platform delta front late ferrous calcite cemented facies, and the favorable reservoir facies ismainly distributed in the joint area of the former two facies zones.
Chang 4 + 5 sandstones of Yanchang Formation in Yanchi-Jiyuan area are mainly composed of platform-type and slope-type delta front sandbodies. Lithic feldspathic and feldspathic sandstones are chief rock types, of which the average content of quartz, feldspar and rock fragments are 24.7%, 43.2% and 10. 0%, respectively, and meta-morphic and igneous fragments are dominant constitutes, accounting for 88. 0% of total fragment content. At present, these sandstones are in the late period of the Early diagenetic B stage (Ro = 0. 8% and T = 70290℃), so they are under the control of acidic diagenetic environment, being of abundant secondary dissolution porosity. On the basis of the statistics of sandstone compositions, it is indicated by the quantitative calculation that compaction is the dominant reason for the loss of the primary porosity in the study area, and next cementation, whereas the increasing ratio of porosity caused by the dissolution is relatively small ( < 10%). In combination with the results of sedimentary facies, three types of sedimentary-diagenetic facies zone could be divided, i. e. slope-type delta front-chlorite film primary porosity facies, slope-type delta front-late ferrous calcite cemented secondary porosity facies and platform delta front late ferrous calcite cemented facies, and the favorable reservoir facies ismainly distributed in the joint area of the former two facies zones.
2005, 23(3): 412-419.
Abstract:
Based on the influencing factors of diagenesis and the reality in Kuqua dep ression, in this paper, the research on the origin of the secondary porosity has been performed for the deep-buried high quality reservoir. The mineral and rock fragment components of the sandstone carbonate cement formed under the past climate and their effects on the secondary porosity have been described. The overp ressure, crevice, authigenic mineral assemblage and their origins, characters, effects on the diagenetic environment and secondary porosity have measured to evaluate the feld-spar and calcite dissolution condition, the rep lacement of dolomite to calcite, the effects of compaction and cementation of the sandstone and so on. Lots of information suggests that the dissolution of calcite cement be responsible for the porosity abnormity at deep depth. Furthermore, on the basis of the study of fluid inclusion and all the worksmentioned above, we established the model of diagenesis and porosity evolution in this area.
Based on the influencing factors of diagenesis and the reality in Kuqua dep ression, in this paper, the research on the origin of the secondary porosity has been performed for the deep-buried high quality reservoir. The mineral and rock fragment components of the sandstone carbonate cement formed under the past climate and their effects on the secondary porosity have been described. The overp ressure, crevice, authigenic mineral assemblage and their origins, characters, effects on the diagenetic environment and secondary porosity have measured to evaluate the feld-spar and calcite dissolution condition, the rep lacement of dolomite to calcite, the effects of compaction and cementation of the sandstone and so on. Lots of information suggests that the dissolution of calcite cement be responsible for the porosity abnormity at deep depth. Furthermore, on the basis of the study of fluid inclusion and all the worksmentioned above, we established the model of diagenesis and porosity evolution in this area.
2005, 23(3): 429-436.
Abstract:
The secondary pores that account for a great p roportion of the Funing Formation in Gaoyou Depression is the main part of reservoir spaces. The development mechanism of secondary pores may have three types: the first is the leakage ofwater from ground; the second is dissolution from the thermal evolution of organic matter in mudstones; the third is dissolution related to the clays. The interactions of all factors have important effect on secondary pores.Based on the analysis ofmechanism of secondary pore, the method used to calculate secondary pore is got from the datum of AC, EDN, and CNL. Above of all, the formation of Fu 3 Member is the best in Funing Formation and the secondary porosity is the highest, so the area to be exp lored should be located in the region from the south of Shanian to the north of Fumin.
The secondary pores that account for a great p roportion of the Funing Formation in Gaoyou Depression is the main part of reservoir spaces. The development mechanism of secondary pores may have three types: the first is the leakage ofwater from ground; the second is dissolution from the thermal evolution of organic matter in mudstones; the third is dissolution related to the clays. The interactions of all factors have important effect on secondary pores.Based on the analysis ofmechanism of secondary pore, the method used to calculate secondary pore is got from the datum of AC, EDN, and CNL. Above of all, the formation of Fu 3 Member is the best in Funing Formation and the secondary porosity is the highest, so the area to be exp lored should be located in the region from the south of Shanian to the north of Fumin.
2005, 23(3): 461-466.
Abstract:
On the basis of experimental ana lysis, a new method, twice grain size segregation plus X-ray diffraction of randomly oriented powers of clay minerals, was put forward to calculate the total amount in clastic reservoir rock.Firstly, particles of which radius less than 10μm and 10 to 64μm w are separated from the samples by the way of traditional segregation of clay minerals, and then weigh them respectively. Secondly, the weight of the part of clay minerals in the particles with radius 10 to 64μm can abe available by means of analysis of X-ray diffraction of randomly or-iented powers of clay m ineral. Finally, the first part of clay minerals. weight plus the second part, the total amount of clay of the sample can be obtained. In order to concretely discuss the course and the effect of practical application of the method, clastic reservoirs in WN oil field was introduced. The study result ind icates that themethodment ioned in the paper has simpler principle,higher precision, good theorization and show s a satisfactory effect, so it is a reliab le approach for the total amount of clay in clastic reservoir rocks.
On the basis of experimental ana lysis, a new method, twice grain size segregation plus X-ray diffraction of randomly oriented powers of clay minerals, was put forward to calculate the total amount in clastic reservoir rock.Firstly, particles of which radius less than 10μm and 10 to 64μm w are separated from the samples by the way of traditional segregation of clay minerals, and then weigh them respectively. Secondly, the weight of the part of clay minerals in the particles with radius 10 to 64μm can abe available by means of analysis of X-ray diffraction of randomly or-iented powers of clay m ineral. Finally, the first part of clay minerals. weight plus the second part, the total amount of clay of the sample can be obtained. In order to concretely discuss the course and the effect of practical application of the method, clastic reservoirs in WN oil field was introduced. The study result ind icates that themethodment ioned in the paper has simpler principle,higher precision, good theorization and show s a satisfactory effect, so it is a reliab le approach for the total amount of clay in clastic reservoir rocks.
2005, 23(3): 475-482.
Abstract:
9 popu lar species ofmodern bivalves living in Yellow Sea were selected for their shell mineral analyses. By means of X-ray powder diffraction method, the types ofminerals in the shells were discerned and their components were calculated. The result shows that aragonite or calcite is the dominant mineral in the shells. According to the component of mineral, shells were divided into three sub-type, namely, aragonite shell, calcite shell and mixed shell with component of mineral by > 98% aragonite, > 90% calcite, 37% aragonite and 63% calcite, respectively. Species in Veneroida, Arcida had aragonite shell. Species in Pterioida had calcite shell. And species in Mytiloida had mixed shell. This research suggests that mineral component of bivalve shell closely relates to its living pattern. Bivalves that live in the sand sediments are apt to form aragonite shell. In contrast, bivalves that live by attaching themselves on the hard bottom are apt to form calcite shell ormixed shell. Furthermore, this research a lso suggests that at least in some species the shell size has no sign ificant influence on the mineral component of the shell.
9 popu lar species ofmodern bivalves living in Yellow Sea were selected for their shell mineral analyses. By means of X-ray powder diffraction method, the types ofminerals in the shells were discerned and their components were calculated. The result shows that aragonite or calcite is the dominant mineral in the shells. According to the component of mineral, shells were divided into three sub-type, namely, aragonite shell, calcite shell and mixed shell with component of mineral by > 98% aragonite, > 90% calcite, 37% aragonite and 63% calcite, respectively. Species in Veneroida, Arcida had aragonite shell. Species in Pterioida had calcite shell. And species in Mytiloida had mixed shell. This research suggests that mineral component of bivalve shell closely relates to its living pattern. Bivalves that live in the sand sediments are apt to form aragonite shell. In contrast, bivalves that live by attaching themselves on the hard bottom are apt to form calcite shell ormixed shell. Furthermore, this research a lso suggests that at least in some species the shell size has no sign ificant influence on the mineral component of the shell.
2005, 23(3): 490-497.
Abstract:
This paper discusses the high-resolution sequence in nearshore subaqueous fans sedimentary system, exemp lifying T85 nearshore subaqueous fans of the third middle member of Shhejie Formation in Shengbei fault's downthrown side ofDongying depression. The research shows that the high-resolution sequence stratigraphic units are divided into parasequence set, parasequence, bed set and bed in the fan-delta. Types and comparison methods of parase-quence and bed set are especially studied. The type of bed set is divided into Fu, Cu and Hu, and parasequence into Cu-Fu, Cu-Fu and Cu-Hu. Two comparison methods of parasequence are provided that are facies change paralleling to source area and incision perpendicular to source area and fourmodels of bed set which are correlation of overstacking,correlation of facies change, correlation of thin sandstone bed and correlation of similar changing of lithology
This paper discusses the high-resolution sequence in nearshore subaqueous fans sedimentary system, exemp lifying T85 nearshore subaqueous fans of the third middle member of Shhejie Formation in Shengbei fault's downthrown side ofDongying depression. The research shows that the high-resolution sequence stratigraphic units are divided into parasequence set, parasequence, bed set and bed in the fan-delta. Types and comparison methods of parase-quence and bed set are especially studied. The type of bed set is divided into Fu, Cu and Hu, and parasequence into Cu-Fu, Cu-Fu and Cu-Hu. Two comparison methods of parasequence are provided that are facies change paralleling to source area and incision perpendicular to source area and fourmodels of bed set which are correlation of overstacking,correlation of facies change, correlation of thin sandstone bed and correlation of similar changing of lithology
2005, 23(3): 507-513.
Abstract:
It is an important content that recovering paleoclimatic environment change by using high-resolution substitute p roxy. The paper established a high-resolution sequence of the color records of the lacustrine sediments from 13 to 4.5Ma through the measurement of continuous 2060 samples collected in L inxia basin at an interval of 10cm. Based on the analyses of sediment colorwith the sediment composition, and compare the color recordswith the content variation curves of chlorineion, aeolian quartz, calcium carbonate and pollen in the L inxia basin as well as aeolian silt from ODP885 /886 drill in North Pacific Ocean, the relationship between the color records of lacustrine sediments and climate changes are discussed, and the two climatic shifts about 8 and 6.2Myr are revealed.
It is an important content that recovering paleoclimatic environment change by using high-resolution substitute p roxy. The paper established a high-resolution sequence of the color records of the lacustrine sediments from 13 to 4.5Ma through the measurement of continuous 2060 samples collected in L inxia basin at an interval of 10cm. Based on the analyses of sediment colorwith the sediment composition, and compare the color recordswith the content variation curves of chlorineion, aeolian quartz, calcium carbonate and pollen in the L inxia basin as well as aeolian silt from ODP885 /886 drill in North Pacific Ocean, the relationship between the color records of lacustrine sediments and climate changes are discussed, and the two climatic shifts about 8 and 6.2Myr are revealed.
2005, 23(3): 523-530.
Abstract:
In monsoon area of eastern Asia, the interstadial of the Last Glacial, that is M IS3a or 40-22 kaBP, was a warm and wet stage. There was probably more precipitation at this interval than the present in South-east Monsoon are-a. In the Tibetan plateau there were more precipitation during 40-22 kaBP than the MegathermalMaximum in the Hol-ocene reconstructed with hydrological and energy balance of closed lake basin. Evidence from gravel-sand bars around lakes shows that HuangqihaiLake have experienced high-level stage during 40-22 kaBP. These gravel-sand bars are mainly found at the foot of mountain, Libaisi northern hill and Gu hill,such as. At the Libaisi northern hill, the sand-bar, with a. s. l 1310-1318 m, covered by stripe-like meadow, was dated 24.43～2.33 ka BP by OSL method. This paper calculated palaeo-precip itation of this stage in Huangqihai basin, in order to analyze the difference of precipitation in the monsoon area of eastern Asia and the Tibetan plateau. Based on the modern relief map, if the high lake level stand on the 1310-1318 m, 50 m higher than the present, Huangqihai Paleolake had an area of 450～515 km2 ( average 466 km2), 4.4-5.1 times of that of the present (1950-1961A. D). Using J. E. Kutzbach's equation of energy balance to compute the land evaporation and water surface evaporation with step-after-step app roachingmethod to obtain the parameters, we modeled the combined hydrological and energy balance of Huangqihai basin, and the following estimates of precip itation were yielded: 479-497mm / a during 40-22 ka BP, higher 126-144 mm / a than the present. But we do not think the precipitation is more than that of the highest lake level stage in Holocene. The p recip itation, however, in the Tibetan Plateau, was higher at 40-24 kaBP than at 1424.0 ka BP. Certainly, the reestablished palaeo-precipitation, is only when the high lake level stand at a. s. l 1310-1318 m during some stage of 40-22 ka BP, not that of stage of 40-22 ka BP when lake level was lower than 1310-1318 m.
In monsoon area of eastern Asia, the interstadial of the Last Glacial, that is M IS3a or 40-22 kaBP, was a warm and wet stage. There was probably more precipitation at this interval than the present in South-east Monsoon are-a. In the Tibetan plateau there were more precipitation during 40-22 kaBP than the MegathermalMaximum in the Hol-ocene reconstructed with hydrological and energy balance of closed lake basin. Evidence from gravel-sand bars around lakes shows that HuangqihaiLake have experienced high-level stage during 40-22 kaBP. These gravel-sand bars are mainly found at the foot of mountain, Libaisi northern hill and Gu hill,such as. At the Libaisi northern hill, the sand-bar, with a. s. l 1310-1318 m, covered by stripe-like meadow, was dated 24.43～2.33 ka BP by OSL method. This paper calculated palaeo-precip itation of this stage in Huangqihai basin, in order to analyze the difference of precipitation in the monsoon area of eastern Asia and the Tibetan plateau. Based on the modern relief map, if the high lake level stand on the 1310-1318 m, 50 m higher than the present, Huangqihai Paleolake had an area of 450～515 km2 ( average 466 km2), 4.4-5.1 times of that of the present (1950-1961A. D). Using J. E. Kutzbach's equation of energy balance to compute the land evaporation and water surface evaporation with step-after-step app roachingmethod to obtain the parameters, we modeled the combined hydrological and energy balance of Huangqihai basin, and the following estimates of precip itation were yielded: 479-497mm / a during 40-22 ka BP, higher 126-144 mm / a than the present. But we do not think the precipitation is more than that of the highest lake level stage in Holocene. The p recip itation, however, in the Tibetan Plateau, was higher at 40-24 kaBP than at 1424.0 ka BP. Certainly, the reestablished palaeo-precipitation, is only when the high lake level stand at a. s. l 1310-1318 m during some stage of 40-22 ka BP, not that of stage of 40-22 ka BP when lake level was lower than 1310-1318 m.
2005, 23(3): 537-541.
Abstract:
The application value of traditional method to explore the oil and gas source using carbon isotope was bounded by the type and maturity of source rock. The method to combine the kinetics of carbon isotope with that of hydrocarbon generation has great advantages in discussing the source of oil and gas. In this paper, the thermal simulation experiment to the source rock was done, the results of kinetics calculation of hydrocarbon generation and carbon isotope have shown that the gas of Suligemiao gas field in the Upper Paleozoic stratum in Ordos basin mainly belong to stage accumulation gaswhich come from around areas, the contributions to the gas field from high maturity southern area and Tianhuan depression are 49% and 22% respectively, and the accumulation gas come from Suligemiao area is only make up of 29%.
The application value of traditional method to explore the oil and gas source using carbon isotope was bounded by the type and maturity of source rock. The method to combine the kinetics of carbon isotope with that of hydrocarbon generation has great advantages in discussing the source of oil and gas. In this paper, the thermal simulation experiment to the source rock was done, the results of kinetics calculation of hydrocarbon generation and carbon isotope have shown that the gas of Suligemiao gas field in the Upper Paleozoic stratum in Ordos basin mainly belong to stage accumulation gaswhich come from around areas, the contributions to the gas field from high maturity southern area and Tianhuan depression are 49% and 22% respectively, and the accumulation gas come from Suligemiao area is only make up of 29%.
2005, 23(3): 548-553.
Abstract:
Petroleum generation, evolution, migration and reservoir forming conditions and its controlling factors of Damintun Depression were discussed. Based on the basin evolution histories and conduit framework and potential source-rock, not only studied the evolution of the energy fields, but also the kinetic and dynamic processes, by integrated geological, geophysical and geochemical means and computer modeling advanced techniques. Detailed oil-source correlation showed that high2wax oil originates from " oil shale" of E2 s24, and its reasons of generation are mainly due to organic matter and sedimentary environment. The well coup ling relationship of particular conformation-sediment development history and app rop riate geothermal-pressure circumstance is very avail of high-wax oil accumulation. Petroleum migration paths are mainly near-source charging and its charging history is about 37～33Ma. High-wax oil accumulation and distribution is as a result of fluid flow styles controlled by the energy field evolvement, valid source rocks and fluid conduit systems
Petroleum generation, evolution, migration and reservoir forming conditions and its controlling factors of Damintun Depression were discussed. Based on the basin evolution histories and conduit framework and potential source-rock, not only studied the evolution of the energy fields, but also the kinetic and dynamic processes, by integrated geological, geophysical and geochemical means and computer modeling advanced techniques. Detailed oil-source correlation showed that high2wax oil originates from " oil shale" of E2 s24, and its reasons of generation are mainly due to organic matter and sedimentary environment. The well coup ling relationship of particular conformation-sediment development history and app rop riate geothermal-pressure circumstance is very avail of high-wax oil accumulation. Petroleum migration paths are mainly near-source charging and its charging history is about 37～33Ma. High-wax oil accumulation and distribution is as a result of fluid flow styles controlled by the energy field evolvement, valid source rocks and fluid conduit systems
2005, 23(3): 389-396.
Abstract:
The diagenetic field was defined as the whole of diagenetic intensity in the space at a certain moment according to the basic principle of field theory, which could be described by diagenetic intensity ID. A new multivariate non-leanermodel, porosity Φ= F ( Trask So, diagenetic intensity ID, pressure P), was set up on the basis of diagenetic field analysis, sedimentary parameters quantitative study, pressure and porosity correlation investigation. As the porosity prediction of beach bar sandstones of ShaerMember ( Es2 ) in the Qibei depression shows the predicted error of porosity for the sandstones with the cement of more than 10% is less than 2%, and the predicted porosity of sand bodies in the eastern Qibei depression is 15%-20%, which are the favorable reservoir area developed in the depression.
The diagenetic field was defined as the whole of diagenetic intensity in the space at a certain moment according to the basic principle of field theory, which could be described by diagenetic intensity ID. A new multivariate non-leanermodel, porosity Φ= F ( Trask So, diagenetic intensity ID, pressure P), was set up on the basis of diagenetic field analysis, sedimentary parameters quantitative study, pressure and porosity correlation investigation. As the porosity prediction of beach bar sandstones of ShaerMember ( Es2 ) in the Qibei depression shows the predicted error of porosity for the sandstones with the cement of more than 10% is less than 2%, and the predicted porosity of sand bodies in the eastern Qibei depression is 15%-20%, which are the favorable reservoir area developed in the depression.
2005, 23(3): 406-411.
Abstract:
On the western margin ofAkekule Up lift, the Donghe Sandstone develops very well, however, its lithology and reservoir features are different from that of other areas in Tarim basin. The main rocks are sandstone, mudstone and muddy siltstone or siltymudstone. And the sandstone is the main reservoir in this area. The analysis data of physical p roperties demonstrate that the reservoir properties of the rock in this region are middle to poor. And the properties have intensive heterogeneity vertically and laterally. Integrated analysis show that the reservoir non-homogeneity is controlled by not only the system tract in the sequence framework and also the diagenetic p rocess, especially by the cementation of carbonate and the eluviation's p rocess of the fresh water on the sequence boundary of typel. On the other hand, high frequent sea-level changes induced to form the special rhythm intervals of reservoir physical properties vertically.
On the western margin ofAkekule Up lift, the Donghe Sandstone develops very well, however, its lithology and reservoir features are different from that of other areas in Tarim basin. The main rocks are sandstone, mudstone and muddy siltstone or siltymudstone. And the sandstone is the main reservoir in this area. The analysis data of physical p roperties demonstrate that the reservoir properties of the rock in this region are middle to poor. And the properties have intensive heterogeneity vertically and laterally. Integrated analysis show that the reservoir non-homogeneity is controlled by not only the system tract in the sequence framework and also the diagenetic p rocess, especially by the cementation of carbonate and the eluviation's p rocess of the fresh water on the sequence boundary of typel. On the other hand, high frequent sea-level changes induced to form the special rhythm intervals of reservoir physical properties vertically.
2005, 23(3): 420-428.
Abstract:
One dimension experimental apparatus composed of fluid input/output system, experimental nomenon, T/P controlling system, as one of the very effective methods studying the subsurface hydrocarbon origin, migration, accumulation and reservoir reconstruction is adopted to simulate oilmigration and accumulation in deep zones in this paper. And the interaction of oil-water-rock under actual high temperature and high pressure (120℃, 45MPa) was simulated. The results showed thatmany changes including their chemical components and rock inner structure etc., under certain temperature and pressure, occurred during petroleum migration from the bottom up along the apparatus with the increased charging quantities, and interaction with sandstone and formation water in apparatus. And the specific changeswere as follows: 1. Many changes took place in the rock structure and its chemical components of inner hydrocarbon. Vertically, saturated hydrocarbon content of oily-sands gradually increased from the bottom up, and the peak value12.78%. And the biomarkers and family components of all samples derived from experiment show the existence of geochromatographic effect during the oilmigration along the apparatus. 2. A certain extent dissolution has acted on mineral component of oily-sands during the oil-water2rock interaction, and it strengthens gradually during hydrocarbon migration from the bottom up along the apparatus. Just because of this dissolution, the property of deep reservoirswith low porosity and permeability has been greatly imp roved, and it supplies effective space for deep hydrocarbon migration and accumulation.
One dimension experimental apparatus composed of fluid input/output system, experimental nomenon, T/P controlling system, as one of the very effective methods studying the subsurface hydrocarbon origin, migration, accumulation and reservoir reconstruction is adopted to simulate oilmigration and accumulation in deep zones in this paper. And the interaction of oil-water-rock under actual high temperature and high pressure (120℃, 45MPa) was simulated. The results showed thatmany changes including their chemical components and rock inner structure etc., under certain temperature and pressure, occurred during petroleum migration from the bottom up along the apparatus with the increased charging quantities, and interaction with sandstone and formation water in apparatus. And the specific changeswere as follows: 1. Many changes took place in the rock structure and its chemical components of inner hydrocarbon. Vertically, saturated hydrocarbon content of oily-sands gradually increased from the bottom up, and the peak value12.78%. And the biomarkers and family components of all samples derived from experiment show the existence of geochromatographic effect during the oilmigration along the apparatus. 2. A certain extent dissolution has acted on mineral component of oily-sands during the oil-water2rock interaction, and it strengthens gradually during hydrocarbon migration from the bottom up along the apparatus. Just because of this dissolution, the property of deep reservoirswith low porosity and permeability has been greatly imp roved, and it supplies effective space for deep hydrocarbon migration and accumulation.
2005, 23(3): 447-453.
Abstract:
Some se ismo-depositional layers are discovered in the alluvial facies of the Paleogene Zhubidian Formation in Yishu fault zone area of Anqiu City, Shandong. They are a set of seismites with seismo-depositional characterist ics such as vibration liquefied sand dykes, liquef ied sand veins, sandy cong lom erate dykes caused by fissure filling, seism ic fallm-asses, seismic small-scale fractures and collapse structures and so on. These Pa leogene seismites indicate that tectonic activity was in tense and strong earthquakesw ere frequently in Yishu Fault Zone during theEarly Cenozoic E ra. Seismic events recorded by these seism ites are the responses to theH imalayan Tectonic Cycle after the Yanshan tectonic cycle. The discovery of seismites in the Paleogene Zhubidian Formation ofAnqiu g ives some new materials for studying the active history of Yishu Fault Zone and regional stratigraphy.
Some se ismo-depositional layers are discovered in the alluvial facies of the Paleogene Zhubidian Formation in Yishu fault zone area of Anqiu City, Shandong. They are a set of seismites with seismo-depositional characterist ics such as vibration liquefied sand dykes, liquef ied sand veins, sandy cong lom erate dykes caused by fissure filling, seism ic fallm-asses, seismic small-scale fractures and collapse structures and so on. These Pa leogene seismites indicate that tectonic activity was in tense and strong earthquakesw ere frequently in Yishu Fault Zone during theEarly Cenozoic E ra. Seismic events recorded by these seism ites are the responses to theH imalayan Tectonic Cycle after the Yanshan tectonic cycle. The discovery of seismites in the Paleogene Zhubidian Formation ofAnqiu g ives some new materials for studying the active history of Yishu Fault Zone and regional stratigraphy.
2005, 23(3): 467-474.
Abstract:
In the past， the Chinese geologists followed the pre-soviet union specifications to consider ball clay as a variety of re fractory kaolinite clay. Thus we Chinese geologists were misled in searching for ball clay and China has to import ball clay from U. S. A. In fact, ball clay is crystal logenetically varied to kaolinite or refractory clay and the physical properties are also varied. Ball clay should be classified to a separate ore type according to international standard. Previously, the highly ordered kaolin ite is thought to be hydrothermal kaolinite and the disordered, sedimentary kaolinite. The au thor and his colleagues have worked in the large kaolinite deposits in China revealing that large size kaolin ite deposits with homogeneous h igh ly ordered kaolin ite are sedimentary purp le stone band ( palaeozoic soft clay). Such kind of clay can be used as highmobilitymaterial in paper industry. And karst d iaspore bauxite deposits belong to bioorganic sedimen tary deposits.
In the past， the Chinese geologists followed the pre-soviet union specifications to consider ball clay as a variety of re fractory kaolinite clay. Thus we Chinese geologists were misled in searching for ball clay and China has to import ball clay from U. S. A. In fact, ball clay is crystal logenetically varied to kaolinite or refractory clay and the physical properties are also varied. Ball clay should be classified to a separate ore type according to international standard. Previously, the highly ordered kaolin ite is thought to be hydrothermal kaolinite and the disordered, sedimentary kaolinite. The au thor and his colleagues have worked in the large kaolinite deposits in China revealing that large size kaolin ite deposits with homogeneous h igh ly ordered kaolin ite are sedimentary purp le stone band ( palaeozoic soft clay). Such kind of clay can be used as highmobilitymaterial in paper industry. And karst d iaspore bauxite deposits belong to bioorganic sedimen tary deposits.
2005, 23(3): 483-489.
Abstract:
By apply ing the base-level cycle theory of high-resolution sequence stratig raphy, we have delicately analyzed the fluctuat ion of base-level cycle. The oscillation of the base level results in their relative variation of accommodation space and sedimentary alimentation. The variation rates of them have also changed, then lead to the difference of facies sequence, the degree of stratig raphic preservation and stacking pattern at the same territory in different ages,or the difference of phase area at different territories at the same age. U sing stratig raphic base level defined by Cross and their physical attributions of re lated parameters: sed imentary alimentation, the variation rate of accommodation space, the rate of sed imentary a limentation and sedim entary fluxes, this paper has established the correspond ing function models, deduced their functional equations, illustrated their relations, and generalized their variability and geologic implications. All those contribute to understand the process of sed imentary change and the high-resolution correlation and partition in high revolution stratigraphic sequence
By apply ing the base-level cycle theory of high-resolution sequence stratig raphy, we have delicately analyzed the fluctuat ion of base-level cycle. The oscillation of the base level results in their relative variation of accommodation space and sedimentary alimentation. The variation rates of them have also changed, then lead to the difference of facies sequence, the degree of stratig raphic preservation and stacking pattern at the same territory in different ages,or the difference of phase area at different territories at the same age. U sing stratig raphic base level defined by Cross and their physical attributions of re lated parameters: sed imentary alimentation, the variation rate of accommodation space, the rate of sed imentary a limentation and sedim entary fluxes, this paper has established the correspond ing function models, deduced their functional equations, illustrated their relations, and generalized their variability and geologic implications. All those contribute to understand the process of sed imentary change and the high-resolution correlation and partition in high revolution stratigraphic sequence
2005, 23(3): 498-506.
Abstract:
The slope belt developped in large-type down-warped lake basin is similar to the slope in the marine basin.The Songliao Basin can be identified as two slope belts, and this paper analyzes the origin and evolution of slope belt and its effect on sediment system and stratigraphy distribution. The two slope belts are all influenced by the fault during the early periods. With the development of slope belt Taobao-Shuangang high water level slope is controlled by the direction of provenance and erosion, but the sediment supply and the differential compaction are main controlling factors in the development of Honggang-Haituozi low water level slope. The evolvement of the sediment system is controlled by the Taobao-Shuangang high water level slope and groove, but the Honggang-Haituozi low water level slope controls the range of lower system tract.
The slope belt developped in large-type down-warped lake basin is similar to the slope in the marine basin.The Songliao Basin can be identified as two slope belts, and this paper analyzes the origin and evolution of slope belt and its effect on sediment system and stratigraphy distribution. The two slope belts are all influenced by the fault during the early periods. With the development of slope belt Taobao-Shuangang high water level slope is controlled by the direction of provenance and erosion, but the sediment supply and the differential compaction are main controlling factors in the development of Honggang-Haituozi low water level slope. The evolvement of the sediment system is controlled by the Taobao-Shuangang high water level slope and groove, but the Honggang-Haituozi low water level slope controls the range of lower system tract.
2005, 23(3): 514-522.
Abstract:
Eighteen sediment vibrocores, 0.2～6 m long, were collected from the Yangtze estuary in different sedimentary facies, including tidal flat, flood tidal channel, delta front, prodelta and delta-shelf transition zone, to examine the modern depositional characteristics in the study area. Measurement of 210 Pb was performed for all sediment vibrocores and 137Cs app lied for 6 of them. CIC ( constant initial concentration) datingmodelwas used to calculate the sedimentation rate using 210 Pb data. The results obtained show the silty clay and clayey silt in the tidal flat and tidal channel, fine sand and silt in the delta front facies. Fine-grained sediment, mostly the clayey silt, consists of the pro-delta facies, and clay-silt-sand constitutes the delta-shelf transition zone. On the basis of relative continuous sediment record, our radiometric measurement demonstrates that the highest sedimentation rates ( ～2.0 to 6.0 cm /yr) were found in the prodelta facies, reflecting p rocesses of the interface of estuarine mixed water and the seawater. Lower sedimentation rate of 0.81 cm /yr can be recognized form the prodelta margin, but the rate is hardly recorded in the delta-transition zone due to terminatingmodern sedimentation seaward.The higher sedimentation rates (1.03～1.94 cm /yr) occur in the tidal flat of Hengsha Island and Nanhui, and lower ones (0.51～0.76 cm /yr) in the Chongming Island,indicating the southeastward transport of the suspended sediment in the Changjiang estuary. The sedimentation rate in the flood tidal channel is about 0.69～0.86 cm /yr, showing the rapid deposition due to the discrete flood and ebb currents. The sedimentation rates proposed here is of significance to evaluate the sediment budget from the up stream in the past centennial time scale and in particular is to provide an analogue for after Damming study at Three-Gorges
Eighteen sediment vibrocores, 0.2～6 m long, were collected from the Yangtze estuary in different sedimentary facies, including tidal flat, flood tidal channel, delta front, prodelta and delta-shelf transition zone, to examine the modern depositional characteristics in the study area. Measurement of 210 Pb was performed for all sediment vibrocores and 137Cs app lied for 6 of them. CIC ( constant initial concentration) datingmodelwas used to calculate the sedimentation rate using 210 Pb data. The results obtained show the silty clay and clayey silt in the tidal flat and tidal channel, fine sand and silt in the delta front facies. Fine-grained sediment, mostly the clayey silt, consists of the pro-delta facies, and clay-silt-sand constitutes the delta-shelf transition zone. On the basis of relative continuous sediment record, our radiometric measurement demonstrates that the highest sedimentation rates ( ～2.0 to 6.0 cm /yr) were found in the prodelta facies, reflecting p rocesses of the interface of estuarine mixed water and the seawater. Lower sedimentation rate of 0.81 cm /yr can be recognized form the prodelta margin, but the rate is hardly recorded in the delta-transition zone due to terminatingmodern sedimentation seaward.The higher sedimentation rates (1.03～1.94 cm /yr) occur in the tidal flat of Hengsha Island and Nanhui, and lower ones (0.51～0.76 cm /yr) in the Chongming Island,indicating the southeastward transport of the suspended sediment in the Changjiang estuary. The sedimentation rate in the flood tidal channel is about 0.69～0.86 cm /yr, showing the rapid deposition due to the discrete flood and ebb currents. The sedimentation rates proposed here is of significance to evaluate the sediment budget from the up stream in the past centennial time scale and in particular is to provide an analogue for after Damming study at Three-Gorges
2005, 23(3): 531-536.
Abstract:
Saturated hydrocarbon fractions of free oil, sealing oil and bound oil, which are extracted from six oil sands of Yanchang Format ion in Xifeng oilfield of northw estern Ordos Basin, North west China, have been analyzed by GC /MSD( 6890N /5973N ) in order. The long chain alkyl benzenes in six samples show an even carbon number predominance rang ing from C16 to C20 in carbon number. Our study show s thatmaturity has an effect on the evo lution of long chain alkyl benzenes, that is, with the increase of maturity, the carbon number distribution of alkyl benzenes shifts to the lower homologues isomers; relative abundance of alky lbenzenes isomeride decreases, whereas n-alky benzenes increase.Long chain alkyl benzenes is the product of cyclization-decarboxy lation-aromatization of fatty acid, with the help of claym inerals catalytic effect, which comes from bacteria, seaseed and higher plant lipid; or the reaction product ofmonocy licarom atics and fatty acid alkyl group under the same conditions. The formed long and linear chain alkyl benzene changes into benzene methy l and alkene through B-sc ission andmonomo lecular homo lysis, and then benzenemethyl shifts to the position of A-Carbon in the long cha in alkyl benzene through H-transfers. The finding of long chain alkyl benzene proves the relatively strong reducing environments during deposit ion at that time. The distribution character istics of long chain alkyl benzene in different state hydrocarbon can be used for petroleum accumulation dating.
Saturated hydrocarbon fractions of free oil, sealing oil and bound oil, which are extracted from six oil sands of Yanchang Format ion in Xifeng oilfield of northw estern Ordos Basin, North west China, have been analyzed by GC /MSD( 6890N /5973N ) in order. The long chain alkyl benzenes in six samples show an even carbon number predominance rang ing from C16 to C20 in carbon number. Our study show s thatmaturity has an effect on the evo lution of long chain alkyl benzenes, that is, with the increase of maturity, the carbon number distribution of alkyl benzenes shifts to the lower homologues isomers; relative abundance of alky lbenzenes isomeride decreases, whereas n-alky benzenes increase.Long chain alkyl benzenes is the product of cyclization-decarboxy lation-aromatization of fatty acid, with the help of claym inerals catalytic effect, which comes from bacteria, seaseed and higher plant lipid; or the reaction product ofmonocy licarom atics and fatty acid alkyl group under the same conditions. The formed long and linear chain alkyl benzene changes into benzene methy l and alkene through B-sc ission andmonomo lecular homo lysis, and then benzenemethyl shifts to the position of A-Carbon in the long cha in alkyl benzene through H-transfers. The finding of long chain alkyl benzene proves the relatively strong reducing environments during deposit ion at that time. The distribution character istics of long chain alkyl benzene in different state hydrocarbon can be used for petroleum accumulation dating.
2005, 23(3): 542-547.
Abstract:
Based on the analyses of the four crude oil samp les in Shengli oil fields, it is found that microbe can degradate the crude oil in laboratory. After the microbe degradation, the crude oil samp les have low saturated hydrocarbon contents and low saturated hydrocarbon / aromatic hydrocarbon ratios, and high aromatic hydrocarbon, non-hydrocarbon and asphaltene. It also shows that the normal paraffin hydrocarbon of crude oil has a deep degradation aftermicrobe degradation, and a low Pr /Ph value and a low ΣC21 - /ΣC22 + ratio. After the action of microorganisms on crude oil, some surface-active substances produced, and caused low surface tension.
Based on the analyses of the four crude oil samp les in Shengli oil fields, it is found that microbe can degradate the crude oil in laboratory. After the microbe degradation, the crude oil samp les have low saturated hydrocarbon contents and low saturated hydrocarbon / aromatic hydrocarbon ratios, and high aromatic hydrocarbon, non-hydrocarbon and asphaltene. It also shows that the normal paraffin hydrocarbon of crude oil has a deep degradation aftermicrobe degradation, and a low Pr /Ph value and a low ΣC21 - /ΣC22 + ratio. After the action of microorganisms on crude oil, some surface-active substances produced, and caused low surface tension.
2005, 23(3): 554-558.
Abstract:
Calculating ratio of source-mixed natural gas is important in study ing source-mixed gas reservoir. For a two-source-mixed gas reservoir, the follow ing w orkmust be done: (1) analyzing the geological factors of formation of source-mixed gas reservoir, confirm ing potential source rocks, (2) based on experimental data of ascertained source rocks andmeasured data of natural gas, f ind ing geochemical modes of different end-gas and source-mixed gas, then using themodes to calculate ratios of source-mixed gas andmaturity of source rocks, (3) using the ratios to analyze the format ion process of source-mixed gas reservoir, proposing geochemical trappingmechanism. The natural gas in Ordovician weathering crust reservoir in the Central Portion Gas Field in Ordos basin is source-m ixed gas of Upper Paleozoic coal-typed gas with Lower Paleozoic oil-typed gas. Starting w ith analyzing geoloical factors and process of the source-mixed reservoir, with geochemical parameters of percentages and carbon isotope composit ions of methane and ethane, a calculating model of rat ios w as established and a calcu lating graph of ratios was given in this paper. 13 gas samples collected from Jianbian gas field were analyzed using the method. The percentages of Upper Paleozo ic coal-typed gas and Lower Paleozoic oil-typed gas are 22~ 84 percent and 16~ 78 percen,t respective ly, according to 11 samples ( samples collected from Well Shan21 and Shan5 were excluded). Based on the result, we could draw a conclusion that Lower Paleozoic oil-typed gas, with the percentage of 63.2, is dom inant in Ordovician weathering crust reservoir in the Centra lPotion gas field in Ordos basin
Calculating ratio of source-mixed natural gas is important in study ing source-mixed gas reservoir. For a two-source-mixed gas reservoir, the follow ing w orkmust be done: (1) analyzing the geological factors of formation of source-mixed gas reservoir, confirm ing potential source rocks, (2) based on experimental data of ascertained source rocks andmeasured data of natural gas, f ind ing geochemical modes of different end-gas and source-mixed gas, then using themodes to calculate ratios of source-mixed gas andmaturity of source rocks, (3) using the ratios to analyze the format ion process of source-mixed gas reservoir, proposing geochemical trappingmechanism. The natural gas in Ordovician weathering crust reservoir in the Central Portion Gas Field in Ordos basin is source-m ixed gas of Upper Paleozoic coal-typed gas with Lower Paleozoic oil-typed gas. Starting w ith analyzing geoloical factors and process of the source-mixed reservoir, with geochemical parameters of percentages and carbon isotope composit ions of methane and ethane, a calculating model of rat ios w as established and a calcu lating graph of ratios was given in this paper. 13 gas samples collected from Jianbian gas field were analyzed using the method. The percentages of Upper Paleozo ic coal-typed gas and Lower Paleozoic oil-typed gas are 22~ 84 percent and 16~ 78 percen,t respective ly, according to 11 samples ( samples collected from Well Shan21 and Shan5 were excluded). Based on the result, we could draw a conclusion that Lower Paleozoic oil-typed gas, with the percentage of 63.2, is dom inant in Ordovician weathering crust reservoir in the Centra lPotion gas field in Ordos basin
