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881.
[摘要]本文通过对狮子庙金矿田地层特点的分析,对矿田地层科学地进行了分类,针对不同类
型的地层,从护壁机理、钻具级配和钻进参数等方面入手,探索和研究出了不同的泥浆配方,改进钻头级
配,有效地解决了该地区的钻探施工技术难题,降低了事故率,提高了钻进效率。 相似文献
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An analytical procedure involving Rock-Eval pyrolysis of whole-rocks was adopted on fresh outcrop samples covering the three lithostratigraphic units in the Afikpo Basin of the Lower Benue Trough. Three petroleum systems are present in the Cretaceous delta frame: the Asu-River Group, the Eze-Aku Group and proto-Niger Delta sequences. The Afikpo Basin has been correlated to three petroleum systems in the Lower Congo Basin, Niger Delta and the Anambra Basin. The organic geochemistry of the shales, carbonaceous mudstones and coal beds show relatively moderate to high total organic carbon contents. The best potential hydrocarbon source rocks are the Eze-Aku Group and proto-Niger Delta shales, carbonaceous mudstones and coal beds where maturation was attained. The high total or-ganic contents, thermal maturity and terrigenous characters of the Asu-River Group, Eze-Aku Group and proto-Niger Delta sediments, suggest the presence of a large amount of natural gas with a small quantity of oil accumulation. Variations in source rock facies were observed from one lithostratigraphic unit to another, and initial HI values as a function of TOC were proposed for each lithostratigraphic unit. The results also show that TOC, HI, OI, S2 and Tmax vary from older to younger rocks. The Tmax values discriminate the rocks into immature and mature source rocks. Source rocks with high Tmax suggest high geothermal gradient/or recycled organic matter. Also high Tmax and S2 yield indicate late and post maturity. Recycled organic matter is characterized by low Tmax. The principal source rocks for gas in the Afikpo Basin are the Eze-Aku Group and proto-Niger Delta beds deltaic systems, consisting mainly of III to IV kerogens with a subordinate amount of type II organic matter. Based on the obtained results, it is concluded that the Cretaceous shales, carbonaceous mudstones and coals in the Afikpo Basin of the Lower Benue Trough are capable of generating and expelling hydrocarbons in the case of sufficient maturity. 相似文献
885.
Effects of Near-Surface Absorption on Reflection Characteristics of Continental Interbedded Strata: the Dagang Oilfield as an Example 总被引:1,自引:0,他引:1
<正>Due to the effects of seismic wave field interference,the reflection events generated from interbedded and superposed sand and shale strata no longer have an explicit corresponding relationship with the geological interface.The absorption of the near-surface layer decreases the resolution of the seismic wavelet,intensifies the interference of seismic reflections from different sand bodies,and makes seismic data interpretation of thin interbedded strata more complex and difficult. In order to concretely investigate and analyze the effects of the near-surface absorption on seismic reflection characteristics of interbedded strata,and to make clear the ability of current technologies to compensate the near-surface absorption,a geological model of continental interbedded strata with near-surface absorption was designed,and the prestack seismic wave field was numerically simulated with wave equations.Then,the simulated wave field was processed by the prestack tune migration, the effects of near-surface absorption on prestack and poststack reflection characteristics were analyzed,and the near-surface absorption was compensated for by inverse Q-filtering.The model test shows that:(1) the reliability of prediction and delineation of a continental reservoir with AVO inversion is degraded due to the lateral variation of the near-surface structure;(2) the corresponding relationships between seismic reflection events and geological interfaces are further weakened as a result of near-surface absorption;and(3) the current technology of absorption compensation probably results in false geological structure and anomaly.Based on the model experiment,the real seismic data of the Dagang Oil Field were analyzed and processed.The seismic reflection characteristics of continental interbedded strata were improved,and the reliability of geological interpretation from seismic data was enhanced. 相似文献
886.
产现代智人化石的“柳江人洞”遗址现存8m多厚堆积层可分为4个单元,即上部钙板-粘土层;中上部切入下伏地层的楔状角砾堆积体;中部钙质胶结的含化石和角砾粉砂质粘土层;下部河流相砂层。覆盖楔状角砾堆积和含角砾粉砂质粘土层的第2钙板层年代大约为70kaB.P.。中部地层的上部有两个被楔状角砾堆积切断的钙板残层,年代分别约为150kaB.P.和220kaB.P.,表明在大约150kaB.P.之后该地点曾发生冲刷-再沉积事件。据前人报告,“柳江人”化石出土于楔状角砾堆积,其年代大约为150~70kaB.P.。另外,不能排除人类化石埋藏于中部地层的可能性,如是,其年代应早于150kaB.P.。无论上述两种可能性何者成立,“柳江人”化石的年代都不会晚于约70kaB.P.。这大大早于以前的估计,并使“柳江人“成为迄今已知东亚南部最早的具有现代人解剖特征的化石智人。与“柳江人”化石共生的哺乳动物群原先归属晚更新世,现应调整为晚更新世早期至中更新世晚期。 相似文献
887.
在海河隐伏断裂精确定位的基础上 ,文中利用天津地区晚第四纪地层中的 4个海相地层作为标志层 ,通过地质钻孔勘探、微体古生物鉴定、地层对比及年代学测定和研究 ,获得了海河断裂的晚第四纪活动特征。研究表明 ,海河断裂在天津市区段的上断点埋深为 2 1m ,对应的最新活动时代为晚更新世晚期至全新世早、中期 ,塘沽区段的上断点埋深为 16 4m ,最新活动时代已进入了全新世早、中期 ;天津市区段在晚更新世晚期 (36 2 90aBP)以来 ,垂直运动速度为 0 2 4 8mm/a ,塘沽区段全新世(72 0 0aBP)以来的平均垂直运动速率为 0 333mm/a。这表明海河断裂塘沽区段 (东段 )的活动性明显高于市区段 (西段 相似文献
888.
西秦岭南亚带层控金-硒矿床的赋矿地层年代与成矿时代 总被引:2,自引:0,他引:2
西秦岭南亚带层控金硒矿床的赋矿地层为太阳顶群 ,为一套主要由炭质硅岩和炭质板岩组成的硅岩建造。对于太阳顶群的时代 ,至今仍众说纷纭 ,莫衷一是 ,大多数人认为属晚寒武世—奥陶纪 ,也有认为属晚震旦—早寒武世。作者通过对古杯类化石的鉴定以及Rb Sr、Sm Nd同位素等时线年龄测定后认为 ,赋矿的太阳顶群时代应属早寒武世 ,而非晚寒武世—奥陶纪 ,更不可能为晚震旦世。对金硒矿床中 2个成矿阶段石英样品进行40 Ar/ 3 9Ar快中子活化测定后获得马鞍型谱线特征。其中坪年龄 (71 .4 5± 0 .5 5 )~ (80 .0 5± 0 .6 5 )Ma、最小视年龄 (70 .2 4± 1 .93)~ (78.5 9± 2 .85 )Ma和等时线年龄 (6 9.4 5± 0 .38)~ (81 .6 1± 0 .5 5 )Ma均十分接近 ,说明所测 2件石英样品的40 Ar/ 3 9Ar年龄真实可靠 ,表明太阳顶群中层控金硒矿床的成矿时间主要发生于燕山运动晚期 相似文献
889.
MENG Xianghu GE Ming LIU Yanxue KUANG Hongwei LIU Weifu Francoise G. BOURROUILH-LE JAN Robert BOURROUILH Institute of Sedimentary Basins China University of Geosciences Beijing Chinese Academy of Geological Sciences Beijing Department of Geophysics Yangzi University Jingzhou Hubei Laboratoire Cibamar Universite Bordeaux Avenue des Facultes TALENCE Cedex France 《《地质学报》英文版》2004,78(3)
Based on a study of Neoproterozoic carbonates in the Jilin-Liaoning-Xuzhou-Huaiyang area, especially its cyclic sequence stratigraphy and Sr isotopes, two maximum sea flooding events (at 820 Ma and 835 Ma) have been identified. The resulting isochronous stratigraphic correlation proves that these Precambrian strata were connected between the Qingbaikou and the Nanhuan systems with a time range from 750 Ma to 850 Ma. The disappearance of microsparite carbonate and coming of a glacial stage offer important evidence for worldwide stratigraphic correlation and open a window for further correlation of the stratigraphic successions across the Sino-Korean and Yangtze Plates. A new correlation scheme is therefore provided based on our work. 相似文献
890.
正20141520 Bo Ying(Key Laboratory of Metallogeny and Mineral Assessment,MLR,Beijing 100037,China);Liu Chenglin Saline Spring Hydrochemical Characteristics and Indicators for Potassium Exploration in Southwestern and Northern Tarim Basin,Xinjiang(Acta Geoscientica Sinica,ISSN1006-3021,CN11-3474/P,34(5),2013,p.594-602,5 illus.,3 tables,28 refs.) 相似文献