石油实验地质

EFFECTS OF EPISODIC DIFFERENTIAL SUBSIDENCE ON THE CHANGES OF LAKE LEVEL AND WATER DEPTH IN RIFT LAKE BASINS

CAO Ying-chang, JIANG Zai-xing, XIA Bin

2003, 25(4): 323-327. doi: 10.11781/sysydz200304323

Abstract(544) PDF-CN(308)

Abstract:
Relative and absolute lake level and water depth are two essential parameters controlling lake-basin sedimentation. In a rift lake basin, the differential subsidence of basement in the gentle slope zone of the basin resulted from the episodic movement of boundary faults in the basin can lead to the discordant changes of relative and absolute lake level, water depth and other parameters, that is, the discordant changes of relative lake level, absolute lake level and water depth and those of relative lake level or water depth at different structural location of the lake basin. In the same sedimentary time unit, the water depth of a lake basin had both increasing and decreasing zones, or not only rising but also falling zones existed in relative lake level; but the absolute lake level to the same lake basin had concordant changes. Episodic diffe-rential subsidence controlled the changes of accommodating space in a basin. This kind of discordant changes were the comprehensive response of the neogenic volume of accommodating space(△V_a), the net incurrent volume of external water(△V_w)and the infilling volume of sediments(△V_s)three parameters du-ring a certain period of time. Especially when △V_a>△V_w>△V_s, the differential subsidence of basement resulted in forced regression in a lake basin and formed sequence interfaces.

RELATIONSHIP OF RESERVOIR FORMATION WITH UNCONFORMITIES AND THEIR GEOPHYSICAL RESPONDENCE IN THE JUNGGAR BASIN

WU Kong-you, ZHA Ming, HONG Mei

2003, 25(4): 328-332. doi: 10.11781/sysydz200304328

Abstract(590) PDF-CN(392)

Abstract:
Several unconformities were formed as a result of several tectonic movements in the Junggar Basin. Five types of unconformity were recognized, with different reflection characters in seismic sections for each one. Unconformity structures are vertically divided into three layers, and every layer is consisted of several kinds of rocks with different logging responses in electrofacies. These unconformities not only are the pathways for oil and gas migration, but also provide accommodation for oil and gas accumulation. Although reservoir-forming conditions of the unconformity have the similar parts, the different types of unconformity show different oil and gas reservoir-forming patterns due to different stress behaviours and deformation levels when the unconformities were formed.

ORIGIN AND CHARACTERISTICS OF ABNORMAL PRESSURE IN THE JUNGGAR BASIN

QU Jiang-xiu, ZHA Ming

2003, 25(4): 333-336. doi: 10.11781/sysydz200304333

Abstract(691) PDF-CN(218)

Abstract:
Due to differences in tectonic movement and sedimentation, multiple types of abnormal pressure were developed in the Junggar Basin. According to their forming mechanisms, the abnormal pressure systems of the whole basin may be divided into four types. In the center of the basin,diagenesis and hydrocarbon generation are the key factors resulting in overpressure. Undercompaction and uplift controlled the development of abnormal high pressure in the south and in east of the basin, strong lateral compressive stress from Bogeda Mountain brought on overpressure in a large area. Besides, abnormal low pressure was found in Junggar basin for the first time. Different from wide distribution of abnormal high pressure, low pressure is mainly limited in Wucaiwan Depression at front of Kelameili Mountain. This low pressure belt is related to deep geosyncline of foreland basin formed in Carboniferous and Permian Periods.

LITHOFACIES PALEOGEOGRAPHY OF THE CRETACEOUS IN THE JUNGGAR BASIN

GU Yun-fei, MA Ming-fu, SU Shi-long, XU Huai-min, HU Bin, YAO Wei-jiang

2003, 25(4): 337-342. doi: 10.11781/sysydz200304337

Abstract(695) PDF-CN(379)

Abstract:
Based on the outcrop, drilling, logging and seismic data, the lithofacies paleogeographical cha racteristics of the Cretaceous in the Junggar Basin were analysed. The basin developed alluvial fan, braided stream, alluvial plain, delta, shore shallow lake and semideep lake sedimentary facies. Lithologically, the alluvial fan was dominated by sand conglomerate, the braided stream by gravelly sandstone and moderate fine sandstone, the delta by microsandstone and siltstone, and the allluvial plain, the shore shallow lake and the semideep lake by mudstone. Alluvial fan, braided stream and alluvial plain deposits were developed in basal conglomerate layers. During the sedimentary periods of the Qingshuihe Group, the Hutubihe Group and the Shengjinkou Lianmuqin Group, delta, shore shallow lake and semideep lake deposits were developed, And braided stream and flood plain deposits were developed in the sedimentary period of the Donggou Group. The delta sandbodies of the Qingshuihe Group and the Hutubihe Group were the favorable reservoirs and exploration targets of the Gretaceous in the basin.

CHARACTERISTICS OF THE TECTONIC MOVEMENT SURFACE BETWEEN THE CARBONIFEROUS AND THE UNDERLYING SEQUENCES IN THE TARIM BASIN

LI Hong-nan, WANG Yi

2003, 25(4): 343-347. doi: 10.11781/sysydz200304343

Abstract(552) PDF-CN(273)

Abstract:
The unconformity between Carboniferous and the underling sequences was a tectonic movement surface caused by Early Hercynian tectonic movement. It revealed the property, intensity and influenced scope of the tectonic movement. And it also represented a very important tectonic reversal event in the Tarim Basin. Using seismic section, fission track of apatite samples and vitrinite reflectance(R_o), the denudation thickness of the basin was restored. The results showed that the isopach strike of denudation thickness is nearly from east to west and it is similar to the direction of compressionalreversal structure of the basin. In the middle and north part of the basin the denudation was very intense, and the maximum denudation thickness could reach to 1 200 m. According to the distribution characteristics of the unconformity, the intensity of the tectonic movement was strong in the north and south, but was weak in the middle of the basin. Meanwhile it showed migration of tectonic uplift from south to north and from west to east in time succession.

ANALYSIS OF THE EARLY TERTIARY PROTOTYPE BASIN IN THE DONGYING-HUIMIN SAG OF THE BOHAIWAN BASIN

TAN Ming-you

2003, 25(4): 348-352. doi: 10.11781/sysydz200304348

Abstract(601) PDF-CN(269)

Abstract:
Dongying-Huimin Sag is located in the south of Jiyang Depression of the Bohaiwan Basin. Commercial oil and gas has been found in the Palaeocene and Lower Eocene Kongdian formation. Hydrocarbon potential of Kongdian formation is closely related to the Early Tertiary basin prototype that controlled formation of oil and gas reservoirs. Based on analysis of tectonic evolution and sedimentary facies, prototype basin in that period was recognized as an extending half graben that was faulted in the north and onlapped in the south. The major controlling faults included the north-northeast struck Ningnan fault, the western part of Wunan fault and Chennan fault. The Shicun fault, the east part of Chennan fault and Wunan fault that struck to northwest have also played a great part. The influence of northwest direction structures was more obvious in the east and in the early period than that in the west and in the later stage. The geodynamic background of prototype basin development of Dongying-Huimin sag was the sharpening uplift of upper mantle resulted from the subduction of Pacific plate to Eurasian plate, the conversion of continental margin of east Asia from Andean type to west Pacific type, and the shift of Tancheng-Lujiang fault belt from left-lateral strike-slip to right-lateral strike-slip.

DIFFERENCES OF HYDROCARBON ACCUMULATIONS IN THE DONGYING AND THE ZHANHUA DEPRESSIONS OF THE BOHAIWAN BASIN AND THEIR CONTROL FACTORS

ZHU Guang-you, JIN Qing, GUO Chang-chun, ZHANG Lin-ye, QU Jiang-xiu, ZHANG Ying-li

2003, 25(4): 353-356. doi: 10.11781/sysydz200304353

Abstract(787) PDF-CN(349)

Abstract:
Closely neighbouring in the Bohaiwan Basin, the Dongying and the Zhanhua Depressions have distinct discrepancies in the composition of hydrocarbon source rocks and the distribution of oil and gas pools. The master source rocks of the Dongying Depression consist of the Upper Sha 4 and the Lower Sha 3 Members, and the oil and gas pools mainly distributed in the Eogene(accounting for 91%)are dominated by lithological, structural anticline and fault block ones. However, the wource rocks of the Zhanhua Depression consist of the Sha 3 and the Sha 1 Members, and the oil and gas pools mainly distributed in the Neogene(accounting for 90%)are dominated by buried hill draping structure ones. The analyses of subsi dence processes and fault depression extension features showed that the distribution of hydrocarbon was controlled by fault depression tectogenesis, depocenter wandering and effective source rocks.

EVOLUTION OF BASE-LEVEL CYCLES AND LITHOLOGIC TRAPS OF THE SHA-3 MEMBER IN THE CENTRAL SAG OF THE DONGYING DEPRESSION, THE BOHAIWAN BASIN

WANG Ju-feng, CAI Xi-yuan, DENG Hong-wen, SU Fa-qing

2003, 25(4): 357-361. doi: 10.11781/sysydz200304357

Abstract(611) PDF-CN(282)

Abstract:
Based on study of drilling data and seismic data, the high-resolution sequence stratigraphical framework of Sha-3 member in the central sag of Dongying depression has been established. The middle member of Sha-3 can be divided into one long-term and six short-term of base level cycles. In accordance with the characteristics of the base levels and the forming mechanism of the sandbody, the lithologic traps can be divided into three types: slump turbidite trap, slope-moving turbidity fan trap and sublacustrine fan trap. The formation of traps was related to the evolution of base levels. The sub-lacustrine fan and slope-moving turbidity fan which consisted of the main reservoirs were formed during rising stage of the base level, and the slump turbidite was formed during the falling of base level.

FORMATION AND DISTRIBUTION OF HYDROCARBON RESERVOIRS IN THE NORTHERN SLOPE OF THE YIHEZHUANG ARCH, THE BOHAIWAN BASIN

ZHANG Jia-zhen, WANG Yong-shi, WANG Xue-jun

2003, 25(4): 362-365. doi: 10.11781/sysydz200304362

Abstract(517) PDF-CN(435)

Abstract:
The northern slope of the Yihezhuang Arch is a typical multiple oil and gas accumulation zone consisted of multiple oil-bearing series and multiple reservoirs types. Due to influence of tectonic movements, sedimentary break and other factors, traps and reservoirs were complicated and diversified. Based on the study of pool-forming factors such as reservoir, oil-source, trap and so on, the types, control factors and distribution of hydrocarbon accumulations in the northern slope of the Yihezhuang Arch were summarized. It was suggested that the subtle reservoirs such as those formed in buried-hill, unconformity and stratigraphic overlap were major targets for future exploration in the area.

POOL-FORMING PATTERNS OF HYDROCARBON AND CONTROLLING FACTORS OF HYDROCARBON ENRICHMENT IN THE DONGYING AND THE HUIMIN SAGS

TAN Li-juan, JIANG You-lu

2003, 25(4): 366-370. doi: 10.11781/sysydz200304366

Abstract(647) PDF-CN(253)

Abstract:
As two adjacent continental listric faults in the southern part of the Jiyang Depression, the Dongying and the Huimin sags have similar tectonic framework. They have similar petroleum geological characteristics, but their hydrocarbon-enrichment degree is apparently different. The major factors controlling hydrocarbon-enrichment include oil-source conditions, structural features, volcanic activities and the collocation of source rock-reservoir-caprock assemblages to structures. Among them, the collocation of source rock-reservoir-caprock assemblages to structures is the direct reason to result in the differences of major hydrocarbon bearing horizons and hydrocarbon pool types in different tectonic position. Combined with oil-source features, source rock-reservoir-caprock assemblages and conveyance system characteristics, the pool-forming patterns of hydrocarbon in the Dongying and the Huimin Sags can be classified as five kinds, that is, the self-generating and self-reserving lateral migration pool-forming pattern in swale zones, the upper generating and lower reserving vertical migration pool-forming pattern in swale areas, the lower generating and upper-reserving vertical migration pool-forming pattern in central uplift and northern steep-slope zones, the lower generating and upper-reserving composite migration pool-forming pattern in southern slope zones and the new generating and paleo-reserving composite pool-forming pattern in circumferential convex areas.

CHARACTERISTICS OF FRACTURES AND THEIR HYDROCARBON RESERVOIR MEANINGS FOR THE ARCHEAN OUTCROP IN LAIWU AREA, SHANDONG PROVINCE

ZHANG Jin-xuan, JIN Qiang

2003, 25(4): 371-374. doi: 10.11781/sysydz200304371

Abstract(575) PDF-CN(255)

Abstract:
Metamorphic rock, whose reservoir space is dominated by fractures, is often the reservoir rock for bedrock buried-hill oil pools. The scale and distributive rules of fractures in reservoirs are difficult problems to petroleum geological research, and the study on surface outcrop will be helpful to the understanding of underground reservoirs. In this paper, the outcrop fractures which having the same horizon, structural background and lithology with buried-hill oil pools were analysed qualitatively and quantitatively, and the fracture description parameters obtained took a directive role in revealing the distribution of reservoir space in the bedrock buried-hill fractures of Shengli oilfield.

STUDY ON THE SEDIMENTARY MICROFACIES OF THE SHA-3 MEMBER IN BONAN OILFIELD

DONG Chun-mei, SONG Chun-gang

2003, 25(4): 375-380. doi: 10.11781/sysydz200304375

Abstract(600) PDF-CN(226)

Abstract:
Aimed at high exploration degree of the Sha-3 Member in Bonan oilfield, the Bonan Sag of the Middle Zhanhua Depression, the sedimentary microfacies were studied on the base of high-resolution sequence stratigraphical research, and sedimentary lobes were found as important targets for hydrocarbon exploration. During the Sha-3 period of the Bonan Sag, the essential sources from the Gudao convex and the secondary sources from the Luojia Nose formed the deep-lake turbidite-fan sedimentary system, including endofan, mesofan and exofan three subfacies and endofan feeding channel, endofan terrace, endofan natural levee, mesofan braided channel, mesofan lobe and exofan sheet sand six microfacies. Among them, the turbidite-fan mesofan subfacies was dominant. The mesofan lobes were lens-shaped and enclosed by the hydrocarbon source rocks of the Sha-3 Member. They formed excellent oil and gas pools of lithologic traps, and were new targets for hydrocarbon exploration in Bonan oilfield.

STUDY ON THE EVOLUTION OF THE MICROVADOSE FIELD IN THE RESERVOIRS OF THE SECOND DISTRICT OF SHENGTUO OILFIELD

Xu Shou-yu

2003, 25(4): 381-384. doi: 10.11781/sysydz200304381

Abstract(644) PDF-CN(283)

Abstract:
Taking the reservoirs of the Sha-2 Member in the second district of Shengtuo oilfield long-term developed by waterflood as an example and using the data of core analysis and physical vadose simulation in laboratory, the evolutionary rules of the microvadose field in the reservoirs long-term developed by waterflood were studied from the changes of rock wettability, pore structure and relative permeability three respects. It was considered that the rock wettability and hydrophicity in reservoirs got enhanced with the degree of waterflood development increasing. The pore structure of reservoirs had the evolutionary trend that pore uniformity degree, throat isotropic degree, pore-throat connectivity and the ability to control fluid flow got better. The saturability of bound water tended to rising, and the relative permeability of water phase in residual oil tended to descending; but the shanges were not great. The evolution of the vadose field in reservoirs controlled and affected the amount and space distribution of residual oil in reservoirs.

ANALYSIS ON THE PETROCHEMICAL CHARACTERISTICS AND GENESES OF THE TERTIARY IGNEOUS ROCK IN THE JIYANG DEPRESSION, THE BOHAIWAN BASIN

LIU Hui-min, XIE Zhong-huai

2003, 25(4): 385-389. doi: 10.11781/sysydz200304385

Abstract(646) PDF-CN(243)

Abstract:
Based on the chemical composition, REE and isotopic analyses of rocks, the petrochemical cha-racteristics and geneses of the Tertiary igneous rock in the Jiyang Depression, the Bohaiwan Basin were discussed. The Tertiary basalt in the Jiyang Depression can be divided into tholeiite and alkali two series. The alkali series basalt was mainly agpaitic series, and the Tertiary basaltic magmatite of this area whose eruptive depth was 150-230km was mainly continental tholeiite of continental rift genesis. The differentiation degree of magma decreased when the horizon of volcanic rock in the Jiyang Depression got newer. The magma formed later basically represented primary magma. The Tertiary basalt of different horizons and its basic intrusive rock had the source areas of upper mantle, and intrusive rock was of same sources with volcanic rock. During the forming process of magma, mixing reaction happened among different source area, and melting degree decreased gradually from the Paleocene to the Oligocene, which suggested that the mantle source depth of magma increased gradually. These cognitions will of important reference significance to hydrocabon exploration in magmatic rock.

STUDY OF VOLCANIC RESERVOIRS IN THE EASTERN DEPRESSION OF THE LIAOHE BASIN

QIU Long-wei, JIANG Zai-xing, XIONG Zhi-dong, LI Xiao-hong, LIU Feng-zhong, JIA Yu-zhi

2003, 25(4): 390-394. doi: 10.11781/sysydz200304390

Abstract(855) PDF-CN(372)

Abstract:
Eastern Depression is the area with the most fierce volcanic activity in Tertiary and with the most volcanic reservoirs in Liaohe basin. Reservoirs were formed by fissure, fissure-porosity and weathering-leaching. Volcanic rocks are laid between good oil-source rocks with great thickness, or capped by the source rocks. Primary and secondary porosity and fissure were well developed in some lithofacies in the volcanic rocks, which provided sufficient space for oil migrating and accumulation. Therefore, the volcanic rocks in the area are favourable for hydrocarbon accumulation. Lava of subaquatic eruption and volcanoclastic rocks near the faults, and volcanic cone are suitable for formation and preservation of reservoirs in the area.

APPLICATION OF SEQUENCE STRATIGRAPHY TO THE PREDICTON OF SUBTLE RESERVOIRS IN THE BIYANG DEPRESSION

ZHANG Ming-an, XIAN Ben-zhong

2003, 25(4): 395-398. doi: 10.11781/sysydz200304395

Abstract(591) PDF-CN(371)

Abstract:
Sequence stratigraphy provides an effective theory and method for studying subtle reservoirs e-xisting in strata. The distribution of oil and gas is mainly controlled by surfaces of sequence, i.e. sequence boundary (SB), first flooding surface (FFS) and maximum flooding surface (MFS). The FFS is the most important control factor, and the range of the distribution of subtle reservoirs in the lowstand system tract (LST) is greatly controlled by the range of effective enclosing of the first flooding mudstones for oil and gas. A method for forecasting subtle reservoirs,"four confirmations and one integration", is put forward on the basis of sequence stratigraphy and sedimentation, and five subtle reservoirs are summarized in the end. Among the five types, the reservoir formed by the"faults cutting sausage"and sealed by FFS mudstone is always occurred in LST and is strictly controlled by FFS, and the onlap reservoir and the unconformity reservouir are developed in transgressive system tract (TST) and highstand system tract (HST) respectively and both have close relationship with SB. The lithologic reservoirs are developed in various different system tracts.

STUDY ON THE BRAIDED-RIVER SEDIMENTATION AND RESERVOIR HETEROGENEITY OF DUANLIUBO OILFIELD IN DAGANG AREA

HOU Jia-gen, JIAO Qiao-ping, XIN Hua-gang, WANG Xiu-juan

2003, 25(4): 399-402. doi: 10.11781/sysydz200304399

Abstract(666) PDF-CN(335)

Abstract:
The Zao-0 oil group in the Kong-1 Member of Duanliubo oilfield, Dagang area is braided-river deposit. By observing core and loging data, the characteristics of braided-river deposit in the area were a-nalysed, braided-river sandbar, braided channel, braided-river branch, interchannel, natural levee and flood plain six sedimentary microfacies were divided, and the sedimentary and plane distributive characteristics of each microfacies were studied. As braided-river deposit has lower energy, fine lithology and multiple cyclicity, it shows stronger intrastratal and interstratal heterogeneity. The heterogeneity of reservoirs was mainly controlled by sedimentary microfacies on the plane. As braided-river facies changed rapidly, the plane heterogeneity of reservoirs in the area was stronger.

STUDY ON THE HYDROCARBON GENERATION KINETICS OF SOURCE ROCKS FROM THE DONGYING DEPRESSION, THE BOHAIWAN BASIN

WANG Jian-bao, XIAO Xian-ming, GUO Ru-tai, LU Hong-you, GAO Xi-long

2003, 25(4): 403-409. doi: 10.11781/sysydz200304403

Abstract(696) PDF-CN(364)

Abstract:
Lot of research work has shown that great risk will be introduced by a direct use of thermal simulation of petroleum generation pattern of a source rock. Kinetics method of hydrocarbon generation can be used to exptrapolation of the kinetics of oil and gas formation from laboratory experiments to sedimentary basins. Thus, the data obtained by this method are greater valuable for source rock evaluation. In this paper, the petroleum generation pattern of kerogen of the Lower Tertiary brown black shale from the Dong-ying Depression was studied using a golden tube-high pressure stove, and the petroleum generation kine-tics parameters of the kerogen for the four group compositions of C₁,C_1-5,C_6-12 and C₁₃⁺ were deduced by a patented software Kinetics. A comparison was made between this result and the geological data, showing that petroleum generation model obtained by this method can match with petroleum generation pattern of the source rocks in geological conditions. The kinetics method of petroleum generation will have wide application in source rock evaluation.

JIN Yan-xin, ZHANG Li-hong, ZHAO Li

2003, 25(4): 410-412. doi: 10.11781/sysydz200304410

Abstract(592) PDF-CN(305)

Abstract:
Experiment of two fluid phase displacements is very important for the study of formation mechanism of remaining oil. The photoetched pore micromodel has widely been used because of its good similarity and its convenient design. According to the similarity theory, the photoetched pore micromodel should have not only the similar pore structure with the target core, but also the other similar parameters such as permeability and percolation velocity. Two similarity rules were suggested in accordance with the above parameters. Following the rules, the photoetched pore micromodel will have more flexibility in design and will produce a more precise experiment result.

CALCULATION OF RESERVOIR PARAMETERS BY THE NEURAL NETWORK MODEL WITH THE LOGGING DATA OF MULTIPLE WELLS

TANG Ping

2003, 25(4): 413-416. doi: 10.11781/sysydz200304413

Abstract(1193) PDF-CN(305)

Abstract:
The neural network has been widely used in reservoir parameter calculation with logging data and has got good effects. But under the control of logging data from multiple wells, it is crucial to construct a unified mathematical model, which helps to promote the contrast of calculating outputs among all the wells and in turn to promote the accuracy of interwell prediction. Based on the edition, standardization, normalization and depth correction of logging data, this research constructed a unified BP neural network model for each sand group. Compared with real samples, the predicting effect was good.

2003 Vol. 25, No. 4

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