现浇透水性生态混凝土在河道边坡工程中的应用

针对传统护坡工程方法在河道边坡工程生态环境保护和修复方面的缺陷,提出了新型现浇透水性生态混凝土护坡技法,优化设计了该技法组成材料,并对生态混凝土的耐久性、植生能力和净水性能进行了综合分析。通过该技法在泰州周山河河道边坡生态治理工程中的实际应用,认为所提出的现浇透水性生态混凝土护坡技法不仅能充分保证护坡工程的安全性,还可维持和改善周边生态环境与生态系统。     

低渗透油藏CO2驱过程中含水率变化规律

通过国内外多个油田水驱后实施CO2驱的矿场实例研究,发现注入CO2后很多油井存在含水率下降的现象;这种现象发生在CO2驱的整个开发阶段,包括注气初期阶段CO2未到达生产井、生产井见气阶段以及高气油比阶段。重点讨论了生产井见气前的开发规律,在该阶段油藏内以油水两相渗流为主,不受三相渗流作用的影响。通过现场动态反应并结合室内细管和长岩心实验,揭示了CO2与油、水2种介质的相互作用,得到了两个结论:第一是始于低含水阶段的CO2驱过程中气体穿越地层水驱替地层油到达生产井;第二是始于高含水阶段的CO2驱替规律在不同级别低渗透岩心中的差异非常明显:对于特低渗岩心,CO2突破前的采出程度占CO2驱总采出程度的73.27%,CO2突破后的采出程度占26.73%,对于一般低渗岩心,CO2突破前的采出程度仅占CO2驱总采出程度的16.72%,而CO2突破后的采出程度占到了CO2驱总采出程度的83.28%。     

岩石变形破坏过程中渗透率演化规律的试验研究

利用伺服试验机对灰岩和砂岩进行了应力应变全过程渗透性试验,研究了岩样变形和破坏过程中的轴向应变与渗透率之间的关系,分析了岩样环向应变对渗透率的影响规律,探讨了岩样变形破坏前后渗透压差随时间的变化关系。结果表明,岩样渗透率与应力状态密切相关,渗透率的峰值滞后或超前于应力应变峰值,这与岩石介质本身的特性有关;渗透率-环向应变曲线与渗透率-轴向应变曲线有相同的变化趋势,但岩石环向变形比轴向变形更能灵敏地反映渗透率的演化规律;岩样变形破坏峰值前后的渗透压差与时间均遵循负指数关系。最后对岩石变形破坏过程中的渗透机理作了讨论。     

双河油田储层渗流单元分析及应用

双河油田已进入开发后期 ,为了精确预测层内潜力分布状况 ,解剖更小级别的储层非均质单元的分布 ,提出了储层渗流单元分析法。研究表明 ,双河油田储层可划分出 4种渗流单元类型 ,渗流单元与成因砂体之间的关系不是简单的对应关系 ,平面上渗流单元分布很复杂 ,表现为极强的非均质性。储层渗流单元模型可应用于数值模拟网格划分和定性预测剩余油的分布 ,从而大大提高剩余油分布预测的精度和工作效率     

不同介质底床上的波浪衰减

采用近年来的研究成果比较了良在不同介质底床上传播时的波浪衰减规律,对不同介质底床上的波浪衰减机理进行了总结,推荐了计算波浪衰减的公式和方法,根据实验和计算结果解释淤泥质海岸可能存在的波浪传播现象。     

大北油田萨尔图油层特低渗储层宏观非均质性研究

大北油田萨尔图油层属于特低渗透储层。从沉积微相的角度对萨尔图油层宏观非均质性研究表明,储层非均质性较强,而其非均质性主要受控于沉积环境、成岩作用及裂缝发育情况等因素。萨尔图油层在本区发育水下分流河道、席状砂、远砂坝和浊积扇(滑塌沉积)等4种储层微相,油层非均质性在各种沉积微相之间的过渡部位及浊积扇微相中较强;其次为席状砂微相和远砂坝微相,在水下分流河道中相对较弱。     

鄂尔多斯盆地低渗透油气藏形成研究现状与展望

鄂尔多斯盆地是中国规模最大的低渗透油气资源勘探与开发基地,其低渗透油气藏具有油层物性差、非均质性强、油藏成藏因素复杂、油藏分布受多种因素联合控制等特点。在回顾鄂尔多斯盆地低渗透油气藏成藏理论研究和勘探历史经验基础上,认为目前鄂尔多斯盆地低渗透油气藏成藏研究存在两大理论体系,即沉积学控制成藏理论和运移动力学控制成藏理论,前者从沉积特征出发,强调储层砂体沉积相、非均质性和成岩作用在低渗透性油藏形成中的控制作用,后者从石油运移与聚集过程出发,强调运移动力学在初次运移和二次运移中的重要作用。但是目前低渗透油气成藏研究存在一定的局限性和片面性,过分强调了单个地质因素的作用,其中沉积学控制成藏理论局限于沉积相划分和沉积模式建立方面,过多地强调了沉积相对成藏因素静态的控制作用,而忽视了油气成藏过程的动态属性;运移动力学控制成藏理论却过分强调了油气流体运移过程的模式化和公式化,过分夸大和随意解释了油气运移成藏记录——油气包裹体的作用及其原始地质意义,轻视了深部地层条件下油气运移的复杂性和油气包裹体记录的多解性。因此,传统的单因素控制油气成藏理论和相应的勘探研究方法已经不能确切揭示油气富集规律和有效指导勘探工作。低渗透油气藏成藏理论研究趋势是要重视分析油气藏地质记录,动态研究油气藏形成和演化历史过程,总结油气富集规律,为油气勘探战略部署提供重要资料。     

导向钻进铺管技术在浅层低渗透性含水层地下水开采中的应用

水平水井是开采浅层低渗透性含水层地下水的有效方法,水平水井施工包括钻进、护壁、扩孔、井管安装、填砾、洗井等步骤.对导向钻进铺管技术在浅层低渗透性含水层地下水开采中的工艺进行了详细探讨.通过研究,研制出了适合水平水井施工的过滤器,提出了相适应的钻进方法和成井工艺,为浅层低渗透性含水层地下水开采提供了一种新方法.     

Design measures to mitigate the impact of shallow groundwater on hydrologic performance of permeable pavements

Permeable pavements (PPs) are widely implemented in urban areas to mimic natural hydrologic processes through enhancing infiltration, and reducing, delaying, and retaining surface runoff. However, its performance can be affected by shallow groundwater since high soil moisture may inhibit its infiltration and exfiltration. This study built a numerical model, which was calibrated and validated based on laboratory experiment data, to evaluate the water balance and retention of PP in shallow groundwater conditions. It assessed the impacts of shallow groundwater and the hydrologic effectiveness of different PP design measures (i.e., building a PP with a smaller storage depth, implementing an underdrain at different elevations, and installing an impermeable liner) on relieving the impacts. Shallower groundwater led to larger amounts of surface runoff and underdrain flow, and a higher chance of saturating the PP reservoir. The three design measures had both benefits and drawbacks in mimicking natural hydrologic cycle and retaining the performance of PP under extreme conditions (e.g., areas of very shallow groundwater tables and/or extreme rainfalls). A PP with a smaller storage depth resulted in less underdrain flow but was prone to saturation. It is, thus, more recommended for PP with more-permeable subsoils, which can avoid frequent pavement saturation. Although a shallower PP corresponds to a smaller storage volume and shorter hydraulic retention time, it can increase the applicability of PP to shallow groundwater areas, which is beneficial to the regional hydrologic environment. Installing an underdrain generated underdrain flow, which is a burden to the downstream drainage system. However, it significantly reduced the surface runoff and the chance of saturating the PP reservoir, which, thus, is more recommended for PP with less-permeable subsoils. Comparatively, elevating the underdrain is recommended in areas of shallow groundwater because it can reduce the frequency and amount of groundwater-induced underdrain flow. In addition, a higher underdrain together with an impermeable liner can create a storage depth, increase the retention duration, enhance exfiltration and evaporation without increasing the saturation risk.     

On the causes of pressure oscillations in low‐permeable and low‐compressible porous media

Nonphysical pressure oscillations are observed in finite element calculations of Biot's poroelastic equations in low‐permeable media. These pressure oscillations may be understood as a failure of compatibility between the finite element spaces, rather than elastic locking. We present evidence to support this view by comparing and contrasting the pressure oscillations in low‐permeable porous media with those in low‐compressible porous media. As a consequence, it is possible to use established families of stable mixed elements as candidates for choosing finite element spaces for Biot's equations. Copyright © 2011 John Wiley & Sons, Ltd.