2015 Vol. 21, No. 4

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THE STUDY AND EXPLORATION OF THE MESO-CENOZOIC TECTONIC PROBLEMS IN EASTERN CHINA
LIN Zong-man
2015, 21(4): 453-462.
Abstract (139) HTML (61) PDF (1025KB)(24)
Abstract:
Based on the theory of geomechanics, the Meso-cenozoic tectonic characteristics and evolution in eastern China were concluded. This research shows that the history of the Meso-cenozoic deformation is divided into two stages in eastern China and the demarcation is the movement in Late Jurassic. There are two different structural patterns, Cathaysian and Neocathaysian, and there exists the tectonic unconformity between the two stages. The main tectonic characteristics is the overriding of the deformation structure layers in dual-structure, Cathaysian and Neocathaysian in this area.
THE CLASTIC COMPOSITION CHARACTERISTICS OF UPPER PALAEOZOIC GLUTENITE IN NORTHEAST QAIDAM EDGE AND THE STRUCTURAL ATTRIBUTES OF SOURCE AREA
SUN Jiao-peng, CHEN Shi-yue, ZHUANG Yu-kai, LIU Jin, HU Zhong-ya, MA Shuai
2015, 21(4): 463-472.
Abstract (174) HTML (59) PDF (1204KB)(13)
Abstract:
Combining the microscopic analysis of one hundred and twenty-six clastic rock samples from the Upper Paleozoic in Delingha region with the petrology and sedimentology features of Maoniushan formation, Chengqianggou formation, Huaitoutala formation, Keruk formation and Zhabugaxiu formation, we concluded the provenance of the Upper Palaeozoic clastic rocks in Northeast Qaidam edge and made further discussion on the basin-mountain framework in this area. The resluts showed that fan dalta-beach barrier sedimentary system widely developed in Delingha region, the northeastern margin of Qaidam basin. The texture maturity sandstone of glutenite was low and the gravity flow was widespread with obvious evidence. The value of Q/(R+F) in each gravel layer was between 1.89 and 3.74, reflecting the low texture maturity. The clastic composition and the near-source sedimentary evidence consistently showed that the Yuka-Shaliuhe Caledonian orogenic belt was the provenance of the study area in Late Paleozoic which existed at least 195 Ma, including the uplift stage from 465 Ma to 430 Ma ago and the denudation stage between 430 Ma and 270 Ma ago. Qaidam basin and Delingha basin are two independent basin, with depositional system of opposite direction distribution. The Yuka-Shaliuhe HP-UHP metamorphic belt should be the exploration border of the Upper Paleozoic petroleum system in Delingha region.
RELATIONSHIP BETWEEN FAULT-ACTIVITY AND HYDROCARBON ACCUMULATION IN MINFENG FAULT ZONE OF DONGYING SAG
LI Hong-lin, JIANG You-lu, GUO Fu-xin, LU Zhi-yong, CUI Xiao-jun
2015, 21(4): 473-480.
Abstract (124) HTML (95) PDF (1034KB)(17)
Abstract:
Based on integration of 3D seismic, drilling and logging data and in combination with the history of hydrocarbon accumulation, we analyzed the features of faults activity by fault growth index and discussed the relationship between fault activity and hydrocarbon accumulation.The result shows that faults have sustaining and successive characterization, and there are two activity peak periods:one occurred in the later Es3 period and the other occurred in Ed period. There exist obvious differences in different faults and different locations of the same fault. The No.10 fault is the most important oil source fault which is larger in scale and the fault activity is the strongest in regular change pattern of "strong-weak-strong" from west to east. And the activity period of No.10 fault is matched with the main hydrocarbon expelling period of source rocks, which provide good conditions for vertical oil migration; While other faults are the secondary adjusting faults which develope in the thrown wall of No.10 fault, they are not conducive to the accumulation of hydrocarbon because their fault activities are weak and in poor matching with the main hydrocarbon expelling period.
RESERVOIR-FORMING PATTERN OF THE SOUTH UPLIFT IN ENPING SAG
XIE Fei, WU Zhi-ping, YAN Shi-yong, HE Min, SONG Jia
2015, 21(4): 481-491.
Abstract (148) HTML (67) PDF (1131KB)(13)
Abstract:
The south uplift is the main hydrocarbon accumulation-forming zone of Enping sag. Using the basic data, we analyzed the conditions and characteristics of hydrocarbon accumulation in the south uplift and summarized the pattern of hydrocarbon accumulation. Hydrocarbon in the south uplift of Enping sag is mainly generated from the deep lacustrine source rock in Eocene Wenchang formation in the north EP17 sag. Although the south uplift lacks Wenchang formation deposits, there exists hydrocarbon favorable storage area. Hydrocarbon migrates mainly along the fractures which connect the favorable storage area. There are three patterns of hydrocarbon accumulation model:vertical migration along induced fracture zone of upper storage area and hanging wall, lateral migration along connected sand bodies, lateral sealing by gliding fracture zone, fault block reservoir; vertical migration along induced fracture zone of upper storage area and hanging wall, lateral migration along connected sand bodies, anticline reservoir trapped from other sources; vertical migration along induced fracture zone of upper storage area and footwall, lateral migration along connected sand bodies, lateral sealing by gliding fracture zone, fault nose reservoir.
PALEO-PRESSURE RESTORATION AND DYNAMIC MECHANISM FOR HYDROCARBON MIGRATION AND ACCUMULATION OF Es3 MEMBER IN NORTH DONGPU SAG
ZHU Rong-wei, JIANG You-lu, LIU Jing-dong, HU Hong-jin, XU Juan-juan
2015, 21(4): 492-501.
Abstract (120) HTML (58) PDF (1257KB)(16)
Abstract:
With the application of fluid inclusions and basin simulation method, we restored the paleo-formation pressure of the third member of Shahejie formation (Es3) in North Dongpu sag, and analyzed the dynamic mechanism for hydrocarbon migration and accumulation. The results showed as follows:The formation pressure of Es3 during accumulation period was mainly controlled by the structural framework and the centers of subsidence and hydrocarbon generation, and the overpressure amplitude was largest in the sub-sag area with relatively larger in the central uplift belt and smallest in the west slope area. Controlled by the salt layer, the residual pressure of the lower formation was relatively high in Puwei and Wenliu. The overpressure and buoyancy were the main driving forces for the hydrocarbon accumulation of Es3, and the normal pressure zone and transitional zone were the main hydrocarbon accumulation places. There are three types of dynamic mechanism for hydrocarbon migration and accumulation in the study area including overpressure drive, overpressure-buoyancy drive and buoyancy drive. Overpressure zone including the slope zone and the sub-sag zone is mainly overpressure driven. Overpressure transition zone including part of the central uplift belt is mainly overpressure-buoyancy driven. And normal pressure zone including the west slop and part of the central uplift belt is mainly buoyancy driven.
DETERMINATION OF THE EARLY PALEOZOIC GRANITE IN ZHIFANG AREA, EAST JUNGGAR, XINJIANG AND ITS GEOLOGICAL IMPLICATIONS
XU Qin-qin, ZHAO Lei, NIU Bao-gui
2015, 21(4): 502-516.
Abstract (101) HTML (51) PDF (1349KB)(7)
Abstract:
Zhifang granite pluton outcrops in the northern part of Kalamaili tectonic belt, East Junggar Xinjiang. The latest strata intruded by the granite pluton are the Middle-Upper Ordovician Huangcaopo formation and it is unconformably covered by the Upper Silurian and Lower Devonian strata. Zircon SHRIMP U-Pb data showed that the weighted mean 206Pb/238U age was (463±7)~(436±4) Ma, which indicated that the granite pluton was emplaced during Late Ordovician and Early Silurian and it was the product of the early Paleozoic magmatic activity. Combining the existing regional geological data, the emplacement age of the granite pluton and the contact relation with the country rocks, it is speculated that the forming time of the granite pluton roughly corresponds to that of the regional angular unconformity in the Kalamaili tectonic belt and the Zhifang granite pluton might be formed during the early Paleozoic orogenic stage. The geochemical characteristics of high Sr, low Yb and weak negative Eu anomalies also suggests that it is the Adak-type syn-orogenic granite. Therefore determination of the syn-orogenic granite in Zhifang defines the presence of early Paleozoic orogenesis in Kalamaili tectonic belt, East Junggar.
STUDY ON FLUID INCLUSIONS AND GENETIC TYPE OF HAOYAOERHUDONG GOLD DEPOSIT, INNER MONGOLIA
WANG De-quan, WANG JIAN-GUO, WANG YI-ZHONG, LIU Jian-chao, ZHANG Hai-dong
2015, 21(4): 517-526.
Abstract (159) HTML (83) PDF (1066KB)(8)
Abstract:
The first and second members of Bilute formation are the major ore-bearing horizons in Haoyaoerhudong gold deposit. The rock types contain carbonaceous meta-siltstone, silty slate, carbonaceous slate and phyllite, etc. Au content is 7.14 times of the crustal abundance in the formation and the carbon content is higher, with values of 1% to 7%. The metallogenic process can be divided into four stages:The homogenization temperature of fluid inclusions in the early quartz vein stage and the quartz-pyrite stage are from 245.2 to 323.3℃ and from 236.9 to 317.5℃ respectively; And the homogenization temperature are between 231.7 and 324.5℃ in the quartz-polymetallic sulfide stage and between 187.6 and 312.9℃ in the quartz-carbonate stage. According to the results of laser raman microprobe, The main liquid phase composition are H2O with minor amounts of CO2 and the main gas phase composition are CO2 with minor amounts of CH4 and N2 in fluid inclusions. Hydrogen and oxygen isotopic features indicate that the ore-forming fluid is closely related to magmatic hydrothermal. A large number of organic compounds in the gas phase composition may be generated in the thermal degradation of organic matter prompted by the magma invasion. The deposit type belongs to the black rock-hosted gold, with a high comparability of that in central Asian metallogenic belt.
COMPARATIVE ANALYSIS OF THE RETAINING WALL SEISMIC STABILITY OF NUCLEAR SAFETY RELATED SLOPE AND COMMON SLOPE
CHEN Li-wei
2015, 21(4): 527-535.
Abstract (147) HTML (35) PDF (891KB)(8)
Abstract:
Based on the theory of retaining wall stability calculation, the earthquake coefficient stated in Code for seismic design of nuclear power plants (GB 50267-97) was used. The calculation formulas of soil pressure and seismic angle for retaining wall of safety related slope were deduced and applied in a practical project. Comparative analysis shows that the values of the earthquake coefficient and the seismic angle are of great difference when the earthquake-resistance of retaining wall is checked in case of the safety related slope and the common slope. The earthquake force of the safety related retaining wall is highly greater than that of the common retaining wall, while the stability coefficient of them is reverse.
IRON INFORMATION EXTRACTION IN LARSEMANN HILLS OF ANTARCTIC BASED ON WORLDVIEW-Ⅱ AND ASTER DATA
WEI Xue-juan, XU Gang
2015, 21(4): 536-545.
Abstract (122) HTML (45) PDF (1143KB)(10)
Abstract:
Combined with the Aster data of complementary bands, we studied the iron extraction information in Larsemann Hills at Antarctic continental margin using the WorldView-Ⅱ remote sensing images with high spatial and spectral resolution. The results show that it could achieve the complementary advantages when ferric iron information is extracted by using the principal components analysis with comparison of the WorldView-Ⅱ and Aster data and ferrous ion information is extracted by using band calculations of the WorldView-Ⅱ and Aster synergetic data. The iron information extraction results show that the iron-bearing minerals mainly existed in mixed gneiss and paragneiss area, accounting for 79.44% and 17.44% of the total area, which is consistent with the field survey results.
STUDY ON ACID FRACTURE CONDUCTIVITY WITH LENGTH VARIATION IN CARBONATE RESERVOIR
WANG Yu-fang, DU Jian-jun, NIU Xin-nian
2015, 21(4): 546-554.
Abstract (156) HTML (65) PDF (1063KB)(17)
Abstract:
Based on the method of Nierode-Kruk theory, the change law between fracture conductivity and fracture length in different types of carbonate reservoir was obtained through fitting the change trend of the acid fracture conductivity with length variation, and the fracture-cave scale of the carbonate reservoir was semi-quantitatively determined based on this law. The fitting results combined with seismic and log interpretation has great significance on qualitative and quantitative judgment of the fracture-cave scale in the reservoir.