Stabilization of Bottom Hole Temperature With Finite Circulation Time and Fluid Flow   总被引：4，自引：1，他引：3  

P. Y. Shen  A. E. Beck 《Geophysical Journal International》1986,86(1):63-90

As an alternative to finite element or finite difference modelling, analytical solutions are derived by the method of Laplace transformation and numerical results obtained for several models of the bottom hole temperature stabilization. Included in the models are the finite circulation time, the thermal property contrast between the borehole mud and the surrounding formation, and the presence of radial or lateral fluid flow in the formation, all of which are found to have significant effects on the dissipation of the thermal disturbance induced by drilling.
The mud circulation is considered to have the effect of either maintaining the borehole mud at a constant temperature or supplying a constant amount of heat per unit length per unit time to the borehole. For small circulation times, the former reduces to the 'zero circulation' model in which the mud circulation creates an instantaneous temperature anomaly at the hole bottom; for small borehole radii, the latter reduces to the line source model and the traditional 'Homer plot'.
For typical drilling operations in which the bottom hole temperatures are measured several hours to several tens of hours after the hole is shut in, the new models generally predict higher equilibrium formation temperatures than does the Horner plot. However, predictions from the various models converge if the BHTs are taken after the hole has been shut in for a period which is greater than about five times the circulation period.  相似文献   

A method for the quantitative estimation of bacteria from mangrove sediments     

A.H. Dye 《Estuarine, Coastal and Shelf Science》1983,17(2):207-212

A simple and rapid method for the quantitative extraction of bacteria from high silt/clay-content muds associated with mangrove swamps is described. Mud samples are homogenized in filtered sea water and the supernatant is diluted and stained with Acridine Organge. The stained material is trapped on a 0·45 μm membrane filter and bacteria are counted under a fluorescence microscope. Samples may be pre-fixed in 5% formalin if they cannot be examined immediately.  相似文献   

Food supply and dispersal in the determination of wintering population levels of oystercatchers, Haematopus ostralegus     

William J. Sutherland 《Estuarine, Coastal and Shelf Science》1982,14(2):223-229

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Enteromorpha and the cycling of nitrogen in a small estuary     

N.J.P. Owens  W.D.P. Stewart 《Estuarine, Coastal and Shelf Science》1983,17(3):287-296

The nitrogen relations of Enteromorpha spp. growing on intertidal mud flats have been examined over a twelve-month period. Nitrogen assimilation rates using ¹⁵N have been used to calculate the production of the alga and were between 0·046 and 0·217 mg $\text{NH}{}_4{}^{\mathrm{+}}\text{N}$ (g dry wt alga)^?1 h^?1 A considerable quantity of the alga was buried beneath the sediment over the growth season and was calculated to be equivalent to an input of up to 9·52 g N m^?2 per month and 32 g N m^?2 over one complete growth season. Based on carbon, this latter value represented an input of approximately 320 g C m^?2 annually. Low rates of nitrogenase activity (acetylene reduction) were found to be associated with the Enteromorpha. The organisms responsible for the nitrogenase activity were probably heterotrophic bacteria but they did not contribute significant quantities of nitrogen to the alga.  相似文献   

陆相汕藏中砂泥岩互层时移地震遮掩效应及其对时移地震资料解释的影响     

王大伟  刘震  赵伟  夏庆龙 《现代地质》2006,20(4):635-640

从差异波形特征的角度出发,分析时移地震差异波形特征与砂泥岩互层油藏中油层速度变化的关系.通过建立由5层地层组成的楔形地质模型,运用褶积公式及时移地震求差公式,得到泥岩速度为2 400 m/s和砂岩速度为2 700 m/s条件下,互层中砂岩速度变化±150 m/s的时移地震响应.研究结果表明砂泥岩互层的差异波形是一个多峰复合波,泥岩夹层的厚度是决定差异波形特征的一个主要因素,并且存在一个临界值,即四分之一主波长;如果泥岩夹层的厚度小于这一临界值,就会发生遮掩效应,即顶部油层的时移地震响应可以掩盖中、下部油层的时移地震响应.  相似文献   

环境同位素和模糊聚类法研究堤坝渗漏          下载免费PDF全文

樊哲超  陈建生  李世兴 《水科学进展》2006,17(1):37-42

利用环境同位素方法对高水河堤防几个典型段进行了渗漏分析,查明了其地下水的渗漏来源,结果表明,江都船厂段T1#孔、小菜谭段T23#孔中的地下水为河水补给来源,T5#孔附近的黑鱼塘水为当地降雨补给,万寿宫段T7#孔中的地下水为河水和当地降雨的混合。由于环境同位素的分析方法只能定性的说明问题,笔者尝试应用模糊聚类方法,选取环境同位素和水化学值作为指标特征值,并赋与不同的权重,进行模糊聚类分析,分析结果与环境同位素、水化学分析结论一致。  相似文献   

上犹江水电站坝基渗漏检测与分析     

戴前伟  冯德山  曾登峰  朱洪广  朱洪萧 《水文地质工程地质》2006,33(2):19-21,26

本文以上犹江水电站左岸地下水渗漏检测及分析为例。介绍以伪随机流场法、综合水量均衡法、水质和析出物化学分析法等相结合的渗漏检测与分析的方法技术，检测的结果与已有的工程地质资料以及水工观测资料是一致的。该方法技术体系不仅能查明水库渗水来源，还对渗漏通道、渗漏原因进行推断分析。避免以往单一方法的片面性，为检测分析水库坝基的渗漏提供了一种新的思路。  相似文献   

热源法探测陡河水库左坝肩绕坝渗漏通道     

陈建生  樊哲超  董海洲  吴庆林  孟文琦  乔冠军 《水文地质工程地质》2006,33(5):61-65

通过热源法对陡河水库渗漏通道的探测发现,陡河水库左坝肩存在着绕坝渗漏通道。在左坝肩基岩10m高程附近存在低温场异常,通过对水库底部附近温度场分布测量,判定出低温水来自上游右支河水的补给,通过低温区分布确定出绕坝渗漏强渗漏通道的位置,在库水位保持在32m时,根据热源法计算出渗漏通道的渗漏量在3.59×105~4.74×105m3/d之间,钻孔发现水库边基岩中的水位比库水位低22m,水位差是造成了水库跌窝事故的主要原因,在11#钻孔中发现了来自河床的细砂,在11#和9#孔中的连通试验证实基岩中的强渗漏通道。  相似文献   

地下水中硝基苯污染的防控技术—泥浆回灌法构筑阻截墙     

李绪谦  马莉  蒋惠忠  宗芳  李爽  刘利 《吉林大学学报(地球科学版)》2006,(Z1)

硝基苯污染可使地下水环境质量急剧恶化。利用阻截墙控制地下水中的硝基苯污染范围的扩大,是控制地下水环境继续恶化的经济、有效方法之一。以粘土、沸石、铁粉、硫酸钙等与水调配成泥浆,利用压力向井中回灌,将泥浆注入到含水层中,可有效地阻截地下水中硝基苯的扩散。  相似文献   

李家峪储灰库粉煤灰水渗漏治理措施研究     

张丽霞高相佐  王集宁 《中国煤田地质》2007,19(1):39-41

以河北省唐山市陡河电厂李家峪储灰场为例，利用火力发电厂排出的粉煤灰自身较好的防渗性能，结合储灰库区渗漏途径和渗漏段的分布，沿库区周边分期、分段进行针对性排灰，并根据地下水动态监测结果适时调整，使库区周围地下水环境逐步得到改善，得出周边排灰在山区储灰库防渗中具有可行性，其成本低效果显著值得在山区储灰库的防渗工作中推广。  相似文献