应用随机反演技术精细刻画河道砂体——以大庆油田萨北开发区萨二组为例

以大庆油田萨北开发区萨二组为例,研究了随机地震反演技术及其对河道砂体的精细刻画。研究表明:纵向上,不同厚度砂体的随机反演结果符合率差异较大:厚度大于3 m的砂体符合率为89.6%,厚度为2~3 m的砂体符合率为79.1%,厚度小于2 m的砂体符合率为71.5%;平面上,各沉积单元平均的砂体符合率能达到75%以上,且分流平原亚相的符合率要高于内前缘亚相。地震、测井及地质资料的充分结合,能够对河道的走向、复合河道砂体的单一河道边界及井间砂体叠置关系精细刻画,显示了井震结合预测河道砂体的适用性。     

Influence of bare soil and cultivated land use types upstream of a bank gully on soil erosion rates and energy consumption for different gully erosion zones in the dry-hot valley region,Southwest China

This study assessed temporal variation in soil erosion rates in response to energy consumption of flow (ΔE). It employed an in situ bank gully field flume experiment with upstream catchment areas with bare (BLG) or cultivated land (CLG) that drained down to bare gully headcuts. Water discharge treatments ranged from 30 to 120 L Min⁻¹. Concentrated flow discharge clearly affected bank gully soil erosion rates. Excluding minimal discharge in the CLG upstream catchment area (30 L min⁻¹), a declining power function trend (p ≤ 0.1) was observed with time in soil erosion rates for both BLG and CLG upstream catchment areas and downstream gully beds. Non-steady state soil erosion rates were observed after an abrupt collapse along the headcut slope after prolonged scouring treatments. However, as the experiment progressed, ΔE and energy consumption of flow per unit soil loss (ΔEu) exhibited a logarithmic growth trend (p < 0.1) at each BLG and CLG position. Although similar temporal trends in soil erosion and infiltration rates were observed, values clearly differed between BLG and CLG upstream catchment areas. Furthermore, Darcy–Weisbach friction factor (f) values in the CLG upstream catchment area were higher than the corresponding BLG area. In contrast to the BLG upstream catchment area, lower ΔEu and higher soil erosion rates were observed in the CLG upstream catchment area as a result of soil disturbances. This indicated that intensive land use changes accelerate soil erosion rates in upstream catchment areas of bank gullies and increase soil sediment transport to downstream gullies. Accordingly, reducing tillage disturbances and increasing vegetation cover in upstream catchment areas of bank gullies are essential in the dry-hot valley region of Southwest China.

     

早古生代古亚洲洋俯冲作用:来自新疆哈尔里克侵入岩的锆石U-Pb年代学、岩石地球化学和Sr-Nd同位素证据

新疆哈尔里克造山带的形成时间(早古生代/晚古生代)及其构造属性(岛弧/弧后盆地)一直是有争议的问题。本文选择位于哈尔里克带内的奥尔达乌台克侵入体,对其成因及所揭示的地质意义进行了探讨。奥尔达乌台克岩体由一套成份连续的岩石组合构成,包括辉长岩、辉长闪长岩、闪长岩和花岗闪长岩。对闪长岩及其内部暗色包体进行的LA-ICP-MS锆石U-Pb定年结果显示两者同时形成于~450Ma,为晚奥陶世岩浆活动的产物。岩石学和地球化学证据反映奥尔达乌台克岩体普遍具有富H2O、高fO2的湿岩浆性质,富集LREE、Sr、Ba等大离子亲石元素(LILE)而亏损Nb、Ta、Ti等高场强元素(HFSE),与典型的岛弧岩浆岩类似。高放射成因Nd(εNd(t)=+4.4~+5.9)和低初始Sr(0.7032~0.7044)同位素组成表明偏基性的岩浆很可能起源于年轻的俯冲带岩石圈地幔,生成的镁铁质岩浆一部分与壳源长英质熔体发生混合形成各类岩浆,另一部分则是经历演化后(分离结晶)直接添加到地壳中。因此,壳幔岩浆混合作用和幔源物质的直接加入是古亚洲洋俯冲阶段陆壳增生的两种主要方式。Sr-Nd同位素模拟排除了区内存在古老前寒武纪陆壳的可能,陆壳主体应该是年轻的古生代大洋岛弧和洋壳。哈尔里克早古生代岛弧的确立改变了该带是泥盆纪岛弧或弧后盆地的原有认识,将古亚洲洋俯冲作用的时间追溯至奥陶纪。     

西藏拉抗俄斑岩铜钼矿床辉钼矿Re-Os同位素测年及其地质意义

西藏冈底斯成矿带拉抗俄斑岩铜钼矿床位于西藏特提斯构造域拉萨地块东段中南部,是近年来青藏高原地质大调查项目评价的重点矿床之一。本文在钻孔地质编录的基础上,采用辉钼矿Re-Os同位素测年技术,对拉抗俄铜钼矿床中8件产于花岗闪长斑岩中的辉钼矿进行定年,获得了拉抗俄矿床辉钼矿成矿年龄,辉钼矿Re-Os模式年龄为(13.20±0.20)Ma~(13.64±0.21)Ma,加权平均值为(13.38±0.15)Ma,等时线年龄为(13.12±0.44)Ma,代表了拉抗俄斑岩铜钼矿床的成矿时代,成矿作用发生于中新世。辉钼矿中Re的含量为343.6×10-6~835.7×10-6,平均557.8×10-6,指示其成矿物质中有幔源物质加入。拉抗俄斑岩铜钼矿床形成于印度—亚洲大陆碰撞造山带碰撞过程的伸展背景,其成矿年龄与冈底斯斑岩铜矿带东段中亚带众多斑岩-矽卡岩成矿系统年龄基本一致(17~12 Ma),相对于同一矿集区的驱龙、甲玛、邦铺斑岩-矽卡岩型铜多金属矿的成矿年龄小2~3 Ma,但其形成受控于相同的成矿地球动力学背景。     

福建煤田深孔钻探施工技术探讨

福建煤田地质构造复杂,断层发育,岩层极其破碎且较松软,泥岩受挤压破碎为薄片状或烂泥状,给钻探施工造成许多困难,比如泥页岩水化膨胀,孔壁失稳导致孔内坍塌严重等。采用绳索取心技术,优选金刚石钻头,科学确定泥浆配比和钻进参数,成功解决了这些孔内技术难题,提高了钻探效率,降低了生产成本,取得的施工经验可供该矿区或该类地层的钻探施工借鉴。     

东准噶尔双泉金矿LA-ICP-MS锆石U-Pb测年及赋矿岩石地球化学特征

为了解双泉金矿成矿时代及成矿环境,分别对双泉金矿含金石英脉和赋矿岩石进行采样测试分析。高精度LA-ICP-MS锆石U-Pb法测年结果表明,双泉金矿含金石英脉加权平均206Pb/238U年龄为(303.53±0.79)Ma,代表了含金石英脉形成年龄,属晚石炭世前后挤压推覆构造体系产物。与双泉金矿主成矿期年龄对比,结合矿区成矿条件及黄铁矿、毒砂等矿物形态特征,认为该金矿的形成不是一期结果,而是经历了预富集、富集的演化历程。赋矿岩石地球化学分析结果表明,岩石的SiO2、K2O、CaO(SiO2=58.82%~89.25%,K2O=1.12%~4.47%,CaO=0.52%~4.47%)含量高,Na2O含量低(Na2O=0.43%~1.76%),A/CNK值大于1,δ值小于3.3,属过铝质、钙碱性岩石,具富钾钙、贫钠镁特点;Ba相对Rb,Th亏损,K2O含量接近活动陆缘K2O含量,TiO2含量与岛弧TiO2含量接近,推断岩体形成于活动陆缘或岛弧环境;稀土元素具弱的负Eu、负Ce异常,(La/Sm)N值较(Gd/Yb)N值大,轻稀土元素分馏程度高于重稀土元素,表明岩浆具壳幔混熔特点。东准噶尔后碰撞阶段早石炭世至二叠纪晚期发生的陆-陆碰撞造山及伸展张弛构造运动可能是造成此结果的主要构造因素。     

Study on the Fracturing Parameters and Productivity of Horizontal Wells

<正>1 Introduction Hydraulic fracturing refers to the parting of geomaterials due to excessively high fluid pressure.The most common application of hydraulic fracturing is enhanced oil recovery,in which increase in functional permeability of the ground is achived by the formation of permeable     

Method on Pore Structure of Tight Reservoir

<正>1 Introduction The physical properties of tight reservoir depends largely on its micro and super-micro pore structures,which mainly includes the size of pores and throats and their distribution,the collection form of pores and throats space,the connectivity among pores and throats and so on.The size of     

Fine Geological Modeling of the Tight Oil Reservoir

<正>1 Introduction The study area of Northern Honggang is located in the Daan-Honggang terrace in the central depression of the southern Songliao basin,covering an area of 110km2.The oil field is categorized as an ultra-low permeability reservoir and the target horizon is the Fuyu oil layer.The reservoir is characterized as poor physical property,strong     

The Constitute of Thick Tight Sandstone Belt and the Main Controlling Factors of Effective Reservoir

<正>1 Introduction The western 3D region of the Sulige gas field is located in the Yi-shan slope north of northern Su47 and south of Su48 medium sand belt of the Ordos Basin,the area of it is about 431 km2.The average thickness of He8 is 69.1m,the thickness of it is 83.9m;The effective sand thickness is14.4 m,the thickness of it is 21.5m.