【作者】 段宏；

【导师】 王立军； 裴晓晗；

【作者基本信息】 大庆石油学院 ， 油气田开发工程， 2007， 硕士

【摘要】 大大庆油田聚合物驱技术始于70年代初,于90年代中期开始工业化推广应用,目前已成为世界上应用聚合物驱油规模最大的油田。在大庆油田聚驱开发过程中发现,聚合物驱可在一定程度上使注入剖面得到改善,但由于油层非均质性和井网完善程度等多种因素的影响,层间矛盾无法从根本上得以解决。主力油层聚驱结束后,驱替对象已转向二、三类油层。从实际注入情况看,二类油层注聚普遍注入压力较高。从杏十三区试验区看,在注聚中后期,压力有持续缓慢上升的趋势。分析其原因是由于目前大庆油田在优选与聚合物驱层系匹配的聚合物分子量时,只能考虑聚合物分子量与该套层系相匹配的渗透率下限,即该套层系75%左右的有效厚度能够顺利注入聚合物而不发生堵塞所对应的聚合物分子量。而油层对中分子量聚合物适应性较差,虽然大多数油层能够注入1200万-1500万分子量的聚合物,但对于低渗透油层,随着吸附捕集作用增加,阻力系数增大,使油层渗流能力大幅度降低。从现场注入情况看,段塞推进速度缓慢,油井供液严重不足,注入压力持续上升。这些问题,单纯地增加低渗透层注入量,必然加剧低渗透层的堵塞程度。要保证低渗透层的顺利注入,提高动用程度,只能通过分层分子量的调节,对应低渗透层注入低分子量的聚合物,也就是实现聚合物的分质注入。本文通过分析聚合物剪切降解原理,设计聚合物分子量调节元件,实现聚合物分质注入。采用分子量调节装置,可在地面单管单泵注入高分子量聚合物的前提下,降低注入低渗透油层的分子量,提高低渗透油层的动用程度,从而实现分质注入的目的。通过进行室内原理性试验,得出聚合物分子量调节元件的基本水力学特性。进行岩心驱油实验,得出未经剪切聚合物溶液与经过剪切的聚合物溶液的驱油效果及注入压力。利用量纲分析原理及相似理论,建立聚合物溶液在聚合物分子量调节元件内流动的视粘度损失Δη和流量Q、压降ΔP和流量Q的数学关联理论公式和关系曲线。根据聚合物分子量调节元件的结构尺寸,研制主体随管柱下入井下,通过投捞堵塞器,可调整降解强度的分子量调节器。该聚合物分子量调节装置适用于二、三类油层的聚合物分质注入,对于进一步提高聚合物驱效果可起到积极作用。更多还原

【Abstract】 The polymer flooding in Daqing Oilfield was begun in 1970’s, it has been industrialized in 1990’s. Now Daqing Oilfield is the biggest polymer-flooding Oilfiled. Polymer injection practices had indicated: due to the effect of layer heterogeneous property, during general polymer injection, thick layers in the main reservoirs were exploited very well, while low permeable laminas were not exploited well. To further improve the oil recovery ratio of polymer flooding, separate layer injection is needed. After polymer flooding for main reservoirs, the object of polymer flooding in Daqing Oilfield has turned to the lower permeable laminas. Due to laminas’lower permeability, with more absorbing, and bigger coefficient of remains resistance, seepage capability drop and employ extent is lower in laminas, which affects polymer flooding effect. Molecule weight should be lowered appropriately to ensure no block in oil layers and has enough injection rate. Hereby the idea of different polymer molecule weight injection was brought forward. That is, for the low permeable laminas, polymer molecule weight can be reduced. So the technology can improve control extent of polymer injection and progress the whole development effect. According to mechanical principle, designed adjustable unit of nuzzle type. Through changing nuzzle diameter, controlled degraded intensity and degraded molecular weight. Through analyzing the principle of shearing polymer, we designed device for adjusting polymer molecule weight in order to realize polymer injection with different polymer molecule weight. By using device for adjusting polymer molecule weight, at precondition of injecting by single bump, single string and high polymer molecule weight, lower permeable layers can injecte lower molecular weight, the effect of oil extraction can be enhanced, at last, we achieve the goal of injection with different polymer molecule weight. We got essential hydraulics characteristic of device for adjusting polymer molecule weight through indoor experiment. And we got flooding effect and injecting pressure of sheared polymer and normal polymer solution through flooding experiment in core. Making use of dimension analyse principle and similitude principle, we got formula and relation curve ofΔηverse Q andΔP verse Q. Finally,based on the character of device for adjusting polymer molecule weight. we designed the eccentric mandrel molecular weight regulator. Through changing nuzzle diameter, we controlled degraded intensity. This device for adjusting polymer molecule weight is suitable to separate polymer injection inⅠ,Ⅱreservoirs, it will take very negative effect on improving the oil recovery ratio of polymer flooding.更多还原