埃及阿布吉拉迪盆地下白垩统三角洲碎屑岩储层特征 及控制因素——以Alam El Shawish West区块为例

针对埃及阿布吉拉迪盆地Alam El Shawish West区块（简称AESW区块）下白垩统Kharita组三角洲碎屑岩储层特征认识不明确,预测难度大等问题,综合利用岩心、铸体薄片、扫描电镜、X-射线衍射、物性分析、地震及测井等资料,对砂岩储层特征及控制因素进行了研究。结果表明：Kharita组砂岩以石英砂岩为主,成分及结构成熟度较高。剩余原生粒间孔、次生的粒间及粒内溶孔为主要储集空间,形成以孔隙型为主的砂岩储层。储层发育及分布明显受沉积古地貌、沉积层序、沉积微相及成岩作用等多种因素控制。沉积古地貌低部位砂岩储层厚度大,分布范围广,易于形成规模型砂岩储集体。砂岩储层主要发育于水进体系域内部,厚度较大且物性较好。三角洲前缘水下分支河道及分支河口坝微相物性条件好,席状砂、支流间湾及前三角洲泥等微相较差。压实及胶结作用导致储层物性变差,溶蚀作用对储层物性具有重要的改善作用,所形成的次生粒间及粒内溶孔为重要的储集空间。     

孤西地区中生界火山岩储层发育机制

针对研究区火山岩储层横纵向变化快、储层非均质性强、储层发育模式不清等问题,通过开展对区内28 口井观察取样,进行200 余块薄片的镜下观察及87 块物性样品统计分析,明确了不同岩性的储集物性特征,综合判定研究区总体为中低孔低渗特低渗储层,并总结了火山岩储层孔隙演化过程及物性变化规律;明确了冷凝固结、热液充填作用、构造作用/风化淋滤、埋藏充填、埋藏溶蚀等控储主要因素,最终结合油气运移过程建立起火山岩储层在岩性、不整合、断裂等综合因素控制下的发育模式,为下步有利储层的综合预测打下基础。     

二连盆地致密油形成特征及勘探潜力

二连盆地普遍发育低孔、低渗透性储层,位于洼槽区及构造翼部的下白垩统巴彦花群腾格尔组下段与巴彦花群阿尔善组顶部特殊岩性段与致密砂砾岩段储层尤为致密,空气渗透率一般小于0.5 mD。巴彦花群腾格尔组下段与巴彦花群阿尔善组顶部发育含云灰质为特征的特殊岩性段和湖相黏土质泥岩两类优质烃源岩,致密储层与优质烃源岩构成源储一体或互层状分布,利于油气就近运移成藏。致密储层段孔喉结构复杂,呈低产低压特征;特殊岩性段白云石含量较高、脆性大,含油性及原油物性较好,利于储层压裂改造。虽然单个凹陷分布规模较小,但总体规模较大,资源预测结果表明,致密油资源量达到近10×108 t。在今后较长时间内,勘探工作应为致密油与岩性油藏并重。     

分步开挖卸荷作用下软硬岩互层边坡的稳定性分析

以沪蓉高速公路某软硬互层边坡为例,基于开挖卸荷理论,采用FLAC3D软件进行数值模拟,研究分步开挖卸荷作用对软硬互层边坡稳定性的影响规律。结果表明:最大不平衡力、最大水平位移值、剪应变最大值随开挖步数的增加累积增大,最大值出现在开挖卸荷面软弱夹层剪出口位置,与开挖量呈正相关关系;每步开挖后瞬间会产生最大不平衡力\"尖点\",然后逐渐减小接近于零,边坡平衡;塑性区主要分布在软弱夹层位置,拉应力区分布于开挖卸荷面附近以及整体边坡的坡顶面附近20 m以内,且总体拉应力不大,低于灰岩卸荷后的抗拉强度;基于卸荷理论计算得到每步开挖后边坡的稳定性系数比不考虑卸荷对边坡岩体劣化作用的稳定性系数分别降低了0.07、0.08、0.102、0.106。综合分析得出软硬岩互层边坡稳定性的关键问题是开挖卸荷对软弱夹层力学性能的影响以及边坡面附近的拉应力区,开挖卸荷作用对岩体物理力学性能的劣化程度直接决定着边坡的稳定性。     

Chronological record of the Early Mesozoic underplating in the northern margin of North China─U-Pb chronometry of zircons in the Late Mesozoic andesite from Western Liaoning

Cathodoluminescence spectroscopic analysis of zircons in the uppermost sanukites of the early Cretaceous Yixian Formation in Western Liaoning reveals zoning structures of the zircons in the volcanic rocks. LA-ICP-MS chronometry shows that the central part of the zircons is remnant zircon with a U-Pb dating of 254 Ma, which is consistent with the age of the Early Mesozoic underplating granulites, and that the periphery is zircon crystallizing out of the host magma with a U-Pb dating of 116 Ma, which is highly consistent with the Ar-Ar dating of the host volcanic rocks. Compositions of the clinopyroxenes xenocrystals in the sanukites are similar to those of the clinopyroxenes in the underplating granulites, indicating that the granulites accreted to the lower crust in the Early Mesozoic have been reformed and disrupted by the upwelling diapers of the asthenosphere and taken part in formation of the sanukites in the Late Mesozoic.     

Effects of nitrogen sources and glucose on the consumption of ethylene and methane by temperate volcanic forest surface soils

There is limited knowledge with regard to the consumption of ethylene (C2H4) and methane (CH4) in volcanic forest soils containing low microbial carbon-to-organic carbon ratio, and to the responses of both consumptions to nitrogen and carbon additions. Temperate volcanic forest surface soils under three forest stands (e.g. Pinus sylvestris L., Cryptomeria japonica and Quercus serrata) were used to compare CH4 and C2H4 consumption by forest soils, and to study the effects of nitrogen sources and glucose on both consumptions. There was a good parallel between CH4 and C2H4 consumption by for- est soils, but mineralization reduced CH4 consumption rather than C2H4 consumption in forest soils, particularly in a Pinus forest soil. The stimulatory effect of glucose addition on both CH4 and C2H4 consumption by forest soils was increased by increasing the pre-incubation period after glucose addi- tion, and a largest stimulation occurred in the Pinus forest soil. The addition of KNO3-N at the rate of 100 μg·g1 significantly reduced the consumptions of both C2H4 and CH4 by forest soils (P≤0.05). In the presence of urea plus dicyandiamide, the consumption rates of C2H4 and CH4 by forest soils were higher than those in the KNO3-N and urea-N treated soils at the same N rate (P≤0.05), but were similar to those of the control. Hence, under experimental conditions, there was a strong inhibitory effect of NO3 rather than NH4 addition on the CH4 and C2H4 consumption in these forest soils. When amount of the added NO3-N increased up to more than 2―3 times the soil initial NO3-N concentrations, both C2H4 and CH4 consumption rates were reduced to 10%―20% of the rates in soils without nitrate addition. By comparing the three forest stands, it was shown that there was a smallest effective concentration of the added nitrate that could inhibit C2H4 and CH4 consumption in the Pinus forest soil, which indicated that C2H4 and CH4 consumption of the soil was more sensitive to NO3-N addition.     

SHRIMP U-Pb zircon age of tuff from the Kunyang Group in central Yunnan： Evidence for Grenvillian orogeny in South China

Whether or not Grenvillian orogeny occurred in South China still remains highly controversial because high-quality,discriminating data are lacking,and therefore,the key to resolve this matter is to find datable volcanic and/or sedimentary rocks related to Grenvillian orogeny. Such rocks are apparently present in the Fuliangpeng Member from the lower-middle part of Kunyang Group in central Yunnan; here the unit is more than 100 m thick and consists of andesitic ignimbrite,tuffite,terrigeous clastic rocks and carbonates. These volcanic rocks,developed south of the Sibao fold-thrust belts,represent the earliest calc-alkaline volcanic activity in late Precambrian time from central Yunnan and are coeval with both a change in sedimentary facies from detritus to carbonates and the beginning of seismite development elsewhere. Two samples for SHRIMP analysis were collected from this volcanic unit. Sample G3-29-2,from the bottom of Fuliangpeng Member,is an ignimbrite,and about 100 zircon crys-tals recovered from it have euhedral shapes and display relatively simple sector zonation under cathodoluminescent (CL) imaging,suggesting a magmatogenic origin. Twenty-five of the zircons were analyzed and a weighed-mean U-Pb age of 1032±9 Ma was obtained. Sample G3-29-3 from uppermost part of Fuliangpeng Member is a tuffite,and many rounded,evidently detrital zircons were recovered. Nine of these zircons were analyzed,and the oldest single-grain U-Pb zircon age is 1938±26 Ma,im-plying that Paleoproterozoic basement developed in Cathaysia. The dating result,combined with the geotectonic research on the Fuliangpeng Member,leads us to conclude that late Mesoproterozoic orogenic volcanic activity occurred in the western part of South China,and that the related collision of Yangtze and Cathaysian cratons was an integral part of the assembly of Rodinia.     

SHRIMP U-Pb geochronology of the detrital zircons from the Longshoushan Group and its tectonic significance

Sixty-two geologically meaningful U-Pb dates were obtained by using SHRIMP technique for the detrital zircons in three metasedimentary rocks from stratigraphically uppermost parts of the Longshoushan Group in the present study. Eighty percents of these dates range from 1.7 Ga to 2.2 Ga with a peak at 1.8-2.0 Ga and twenty percents from 2.3 Ga to 2.7 Ga. The youngest detrital zircon is dated at 1724±19 Ma which is interpreted as the maximum depositional age of the metasedimentary rocks. Therefore, the age for the diagenesis and lithification of the original sedimentary rocks of the Longshoushan Group before the metamorphism must be younger than 1724±19 Ma. Comparison of the age histograms of these detrital zircons with the ages of the igneous rocks on the surrounding older massifs suggests that the sediments of the Longshoushan Group were most likely derived from the Alaxa Block and Tarim Craton. This implies that the affinity between Alaxa Block and Tarim Craton was strong and that they might have been a unified craton during middle-early Proterozoic time.     

深井松散煤巷超高强预应力组合锚杆支护技术

深井松散煤巷支护一直是制约矿井安全生产的难题,常规的锚杆支护方式及支护强度已很难适应其变形特征.文中以丁集煤矿1262(1)巷道为例,在新型锚杆强化支护体系的应用研究中,采用了超高强预应力组合锚杆支护技术,通过加大支护强度及采取各种补强措施,进一步优化围岩应力场,充分调动围岩自身承载能力,有效控制了巷道围岩变形,实现了巷道长期稳定,满足了矿井的安全高效生产,并为该类煤层巷道推行锚杆支护技术提供了参考和借鉴.     

苏鲁造山带岩浆岩的锆石U Pb定年及构造意义

锆石U-Pb定年和地球化学分析结果显示,苏鲁造山带南缘连云港锦屏山片麻状花岗岩形成于(806.0±14.0)Ma,海州群云台组变质火山岩形成于(800.8±7.8)Ma,张八岭隆起的张八岭群西冷组变质火山岩形成于(751.6±7.1)Ma和(767.0±15.0)Ma.这些岩浆岩总体上具有高钾钙碱性系列、右倾型REE(Rare Earth Elements)模式、Nb、Ta、Sr、P和Ti强烈亏损、中等负铕异常、重稀土弱到中等亏损、低Sr、高Yb等特点,与浙闽型岩浆岩反映的区域伸展环境和下地壳部分熔融是一致的.这次构造岩浆活动820～740Ma,是晋宁期主碰撞造山后Rodinia超大陆裂解和岩石圈减薄演化的记录.