提液措施对聚驱效果的影响

油藏数值模拟是研究聚合物驱影响因素的重要手段之一.利用数模方法建立一注四采典型模型,研究聚驱合理的提液时机、不同渗透率级差对提液效果的影响程度以及提液对油井剖面改善情况的影响,为油田提供聚合物驱动态调整依据及有效手段.研究认为:无论单层还是多层非均质地层,聚驱时提液的增油效果均好于聚驱不提液的效果,提高采收率7.25%～8.77%;多层非均质地层比单层聚驱效果差;纵向渗透率2倍级差和5倍级差时,提液最佳时机为整体见效后;10倍级差时,注聚时提液和见效时提液效果相同;对于纵向非均质程度高的地层,高峰期后提液不利于扩大中低渗透层波及体积.     

聚驱跟踪调整措施的优化设计

针对聚合物驱过程中不同阶段出现的油层非均质性严重、注入压力低、存在高渗透层或高吸水层、层间渗透率级差大、注采困难、生产井流压较高等问题进行了跟踪措施调整,在总结已有现场试验和做法的基础上,通过数值模拟与矿场试验相结合,对注聚合物工业化区块的开发及调整措施效果进行了综合评价分析,建立了聚合物驱过程中综合调整措施优化方法,完成了聚合物驱降本增效技术的筛选．     

砾岩油藏微观结构对聚驱后剩余油影响研究

采用岩心饱和度分析、荧光薄片分析和核磁共振分析方法研究了砾岩油藏不同岩性及微观孔隙结构与聚驱后剩余油分布规律的关系,研究表明,纵向上正韵律油层中顶部驱油效率低,剩余油饱和度较大,而反韵律油层剩余油分布较均匀.聚合物驱对不同岩性砂砾岩均具有较好的驱油效果,对自由态剩余油驱替效果最好,复模态结构砾岩储集层不利于聚合物驱替束缚态和半束缚态剩余油.不可及孔隙体积对聚合物驱剩余油分布有一定影响,在低渗透砾岩油藏聚合物分子量大容易造成聚合物注不进去,在注聚过程中,应考虑聚合物的分子量与地层渗透率的匹配关系.     

非均质地层泡沫调驱提高采收率实验

利用并联岩心驱替实验,研究了不同参数对非均质地层泡沫调驱提高采收率效果的影响。结果表明,泡沫调驱过程中采收率增加值主要来自于低渗层,高渗层采收率增加较少;从提高采收率和经济角度考虑,泡沫调驱注入量应在0．3PV～0．5PV;泡沫调驱适用的渗透率级差范围应小于15,当级差为10时,采收率提高幅度最大;随着含水率的提高,采收率提高值呈现先上升后降低的趋势,含水率为80％～90％时注入泡沫提高采收率效果最好。注入泡沫过程中,连续注入的方式要优于段塞注入和气液交替注入。     

非均质储层中聚合物流度控制对驱油效果影响

为了进一步研究非均质储层中聚合物溶液流度控制对低渗透层的作用, 采用室内岩心实验模型, 应 用数值模拟方法, 采用有效渗透率分别为10 0 0×1 0-3、 3 0 0×1 0-3、 5 0×1 0-3 μm2 岩心模拟非均质储层条件, 注入3 种质量浓度的聚合物溶液, 通过改变注入3种质量浓度聚合物溶液的方式实现流度控制。注入方案分析了注入聚合 物段塞大小, 注入顺序对驱油效果的影响。结果表明, 在注入聚合物溶液P V数相同的条件下, 高、 中、 低质量浓度段 塞比例2∶3∶4时, 低渗透层驱油效果最好。改变注入聚合物溶液的段塞大小对高渗透层驱油效果影响不大, 对低 渗透层驱油效果影响明显。分析认为, 合理的流度控制可以有效地提高低渗透层采收率。     

不同尺寸段塞组合等流度二元驱驱油效果评价

辽河油田锦16块实施二元复合驱以来,仍存在部分注入井单层吸液量过大,使注入液在各层中的推进速度不一致,从而导致相应的采油井聚合物质量浓度上升较快的问题。通过室内驱替实验,采用均质岩心和非均质岩心,对比不同段塞组合的等流度二元驱驱油方法在非均质岩心上的驱油效果。结果表明,在相同聚合物用量和总注入孔隙体积倍数条件下,在三层非均质岩心上等流度驱油方法比常规单段塞驱油方法化学驱采出程度高出3.54%;多段塞等流度驱油方法可以明显提高中、低渗层分流率,降低高渗层分流率。因此,合理段塞组合等流度二元驱油方法可有效提高高渗透非均质油藏的采收率。     

氮气泡沫驱发泡剂优选及油层适应性室内实验

氮气泡沫驱是普通稠油开采后期的一种经济可行的接替技术,可以大幅度提高剩余油采收率。氮气泡沫驱取得效果的一个重要前提是选择发泡性能好,泡沫阻力大的发泡剂。采用静态和动态实验对几种初选的发泡剂进行了优选,选出了性能最优的发泡剂;并进行了可视化实验,对氮气泡沫驱油层适应性进行了研究,表明非均质模型泡沫驱效率均低于均质模型,但在残余油状态下,非均质模型泡沫驱增油效果要明显高于均质模型。储层非均质性越严重,水驱残余油状态下,泡沫驱油的增产效果越显著。对于非均质严重的储层,矿场泡沫驱油增产效果更好。     

空气泡沫驱油技术在低渗透油藏中的应用研究

空气泡沫驱油技术在中高渗透油藏中取得了很好的应用效果, 但在低渗透油藏中的应用较少, 通过 文献调研对低渗透油藏空气泡沫驱增油机理和注入方式进行总结, 并结合室内实验以及现场试验对空气泡沫驱技 术在低渗透油藏中进行可行性分析。结果表明, 空气泡沫驱在高渗层的剩余油饱和度低于2 0%时, 泡沫液体系能够 很好地发挥作用, 封堵高渗层, 空气泡沫驱阶段驱替出大量低渗透层中的原油, 驱油效率由水驱阶段的8. 3 3% 升高 至5 0. 5 5%; 矿场井组含水率由9 8%下降至5 4%, 日产液量由3. 5m3 下降至1m3, 日产油量由0. 0 7m3 升高至0. 4 6 m3。空气泡沫驱在低渗透油藏开发中具有巨大潜力, 对同类油藏的增油控水具有一定的借鉴作用。     

利用组合模型研究储层非均质性对驱油效率的影响

通过组合模型,研究了鄂尔多斯长8储层非均质性对储层驱油效率的影响,认为组合试验中不同渗透率岩心进水量差别非常大,高渗岩心不但进水量比低渗岩心大的多,而且进水量的增长速度也比低渗岩心快,这说明,在油层合注开采过程中,随时间的推移,高渗层段由于大量水的冲刷,使水相渗透率逐渐提高,水窜程度加重,而低渗层段进水量增长缓慢,水驱效果难以得到改善.组合试验还发现高渗岩心驱油效率高于其单独试验的驱油效率,而低渗岩心的驱油效率低于其单独试验的驱油效率,且高渗岩心进水量的增量明显大于低渗岩心,说明现场高低渗透率层合注开采时,必然是好油藏驱油效率高,水驱动用程度大,差油藏驱油效率低,水驱动用程度小,一旦在高渗层形成水窜条带,将很难进一步提高水驱效率,因此应尽量控制注水层位的渗透率级差程度,或分层注水,以降低水驱的非均质程度.     

严重非均质油藏开发层系组合界限研究

严重非均质油藏随开发时间延长,层间干扰越来越严重,需要对开发层系进行调整重组.根据油藏动、静态资料,对胡7南沙三中严重非均质油藏储层渗透率、极差分布进行分析,设计长岩芯水驱油实验,利用实验确定不同渗透率岩芯动用规律;在实验基础上利用修正的数值模拟模型进行多层联合水驱动用条件下分层动用规律研究;提出用综合影响因子来反映非均质性对低渗透层动用特征、驱替效果的定量影响程度;找出不同渗透层组合的合理界限,以指导此类严重非均质油藏开发政策的制定.     

注水井流量测量的研究

开发一种井下涡轮流量计并研究其在油田注水井分层流量测量中的应用．文中分析了一维流体空间流场分布特点,并详细阐述井下涡轮流量计设计及计算方法．     

Quantitative description of steam channels after steam flooding

Steam channeling is one of the main barriers for EOR after steam flooding.In order to enhance the oil recovery in steam flooded reservoirs,steam channel volumes should be precisely known.In this paper,a set of methods has been established in order to study steam channeling quantitatively by using dynamic data.Firstly,steam channeling wells are identified through curves of watercut and temperature.Then,considering the hysteresis phenomenon,channeling relations are identified with the correlation coefficients between injection wells and production wells under different conditions.Lastly,an analytic model,in which steam condensation,pressure and temperature are considered,is established to calculate the steam channel volumes.A production well named L31615 in some block in Henan Oilfield in China is systematically analyzed by using the method established.The whole block is further analyzed,and the distribution map of steam channels and the steam channel volumes are obtained.The results show that steam channeling does not only occur inside a well group,but also sometimes occurs between wells in different well groups.The calculation of the steam channel volumes provides a theoretical basis for bringing a remedial action like plugging into operation.     

竖直窄矩形流道液泛研究

为了研究窄小流道内气液两相逆向流动问题,以空气-水为工质,对竖直窄矩形流道内液泛过程及液泛特征点进行了实验研究和理论分析,并与传统流道液泛进行了比较.结果表明,竖直窄矩形流道内液泛起始点符合Wallis关系式,与传统流道液泛起始点以压差突变进行判断不同,窄矩形流道内液泛起始点的判断以有水被携带出流道为标志.窄矩形流道内完全携带点与水流量大小、实验段入口条件无关,只与气体流量大小有关;流向反转点与试验段壁面干燥程度有关,与水流量大小及气体入口条件无关.     

暴雨山洪水动力学模型及初步应用

建立暴雨山洪水动力学数值模型.基本控制方程采用二维浅水方程,并考虑降雨和下渗;在空间上采用能有效捕捉激波的WAF TVD二阶格式;在时间上采用一阶龙格库塔法,并采用自适应时间步长满足数值稳定性要求,使模型对复杂地形也能保持高计算效率.基于该模型,提出新的方法确定山洪灾害的临界降雨条件,并应用于典型山洪易发区的暴雨山洪预报.计算结果表明该研究方法具有理论先进性和实际可操作性,为有效防御山洪灾害提供了新的技术.     

碱／聚合物复合驱溶液中聚丙烯酰胺的稳定性

ＨＰＡＭ在高温聚合物驱中应用的关键问题是化学稳定性。针对大港油田聚合物驱先导试验暴露的问题,实验研究了不同水质配制聚合物时溶液粘度的损失规律,归纳分析了国外提高ＨＰＡＭ化学稳定性的添加剂类型及其作用机理,从几十种试验配方中筛选出了几个稳定性较好的碱／聚合物复合驱油体系,评价了它们在６５℃、有氧条件下的长期稳定性。     

Experimental study of chemical concentration variation of ASP flooding

A physical modeling system of long slim tube was established. Several pressure measuring and sampling points were laid out at different positions along the tube. Through real-time measurements of pressures and chemical concentrations at different points, the mass transfer and chemical concentration of ASP flooding in porous media are studied. The concentration of chemicals declines gradually during the fluid flow from the inlet to the outlet of the model. The concentration increases in the front edge of the slug faster than the concentration decreases in the rear edge of the slug. The concentration variation of the chemicals is an asymmetrical and offset process. The order of motion velocities of the chemicals from fast to slow is polymer, alkali and surfactant. The motion lag and comprehensive diffusion are strong in the vicinity of the inlet, the motion velocities of the chemicals are high, the difference of flow velocities among the three chemicals is significant and the chromatographic separation of the chemicals is obvious. In the area near the outlet, the comprehensive diffusion and motion lag become weak, the concentrations of the chemicals decrease, the motion velocities of the chemicals are slow, the difference among the motion velocities of the chemicals becomes small, the chromatographic separation is not obvious, the adsorption and retention of chemicals gradually increase as the chemical slug moves further along the tube, the adsorption and retention of polymer is the most serious. Supported by the National Basic Research Program of China (“973” Project) (Grant No. 2005CB221300)     

Theory and technology of preventing water from flooding roadways

According to the principle of effective stress action of rock and soil, we established a mechanical model of water flooding into roadways, analyzed the constitutive relation of hydrodynamic pressure and contact pressure of rock and soil and discovered that the process of pre-grouting of a roadway curtain is a dynamically balancing process in which effective stress keeps gradually increasing and pore water pressure gradually declines. In such a grouting process, the initial water plugging effect is realized when the effective stress and total stress reaches equilibrium. A rigid-flexible packing layer is designed behind the brickwork to increase the effective stress and reduce pore water pressure in order to have a permanent water proof performance. This provides a theoretical basis for roadway driving and permanent water prevention. The monitoring and application results show that the initial and permanent waterproof theory has provided an effective method for roadway driving and making it waterproof.     

Timing of advanced water flooding in low permeability reservoirs

It is very important to design the optimum starting time of water injection for the development of low permeability res-ervoirs. In this type of reservoir the starting time of water injection will be affected by a reservoir pressure-sensitive effect. In order to optimize the starting time of water injection in low permeability reservoirs, this effect of pressure change on rock permeability of low permeability reservoirs was, at first, studied by physical simulation. It was shown that the rock permeability decreases expo-nentially with an increase in formation pressure. Secondly, we conducted a reservoir engineering study, from which we obtained analytic relationships between formation pressure, oil production rate, water production rate and water injection rate. After our physical, theoretical and economical analyses, we proposed an approach which takes the pressure-sensitive effect into consideration and designed the optimum starting time of water injection, based on the principle of material balance. Finally, the corresponding software was developed and applied to one block of the Jiangsu Oilfield. It is shown that water injection, in advance of production, can decrease the adverse impact of the pressure-sensitive effect on low permeability reservoir development. A water-flooding pro-ject should be preferably initiated in advance of production for no more than one year and the optimum ratio of formation pressure to initial formation pressure should be maintained at a level between 1.05 and 1.2.     

碱/聚合物复合驱溶液中聚丙烯酰胺的稳定性

HPAM在高温聚合物驱中应用的关键问题是化学稳定性.针对大港油田聚合物驱先导试验暴露的问题,实验研究了不同水质配制聚合物时溶液粘度的损失规律,归纳分析了国外提高HPAM化学稳定性的添加剂类型及其作用机理,从几十种试验配方中筛选出了几个稳定性较好的碱/聚合物复合驱油体系,评价了它们在65 ℃、有氧条件下的长期稳定性.