基于油藏化学驱能耗分配原理的理想流度控制型驱油剂研究Ⅰ:聚/表二元复合驱油体系的渗流阻力调控机理及应用

Study on ideal oil displacement agents for mobility control based on principle of reservoir chemical flooding energy consumption distributionⅠ:flow resistance regulation mechanism and application of surfactant/polymer combination system

针对驱油剂的深部流度控制能力与近井地带注入性之间的矛盾,提出了理想流度控制型驱油剂应满足低黏度配制/输送、近井地带低吸附量长期稳定注入和低浓度产出液的技术要求,同时,在渗流过程中能够在储层深部不同位置建立多级渗流阻力峰值,并且前缘后驱替相渗流阻力应始终保持在较低水平。基于固/液界面吸附作用与分子间相互作用的协同效应,设计了在渗流过程中具备动态改变体系组成和微观溶液结构,从而改变其渗流阻力特征的疏水缔合聚合物/阴离子型表面活性剂二元体系。相较于HP-1(1500 mg/L),表观黏度相近、组成不同的二元体系HP-1(1500 mg/L)/SDSB(150 mg/L)和HP-1(1500 mg/L)/SDSB(200 mg/L),在段塞注入及其后续水驱过程中可以在多孔介质的中、后部构建数值更高、空间分布更优的动态渗流阻力,说明二元体系具备运移增黏特征和延迟突破特征,其前缘的流度控制能力更强,并且渗流阻力在储层的空间分布更合理,从而延长了段塞整体突破时间,有利于提高波及体积和驱油效率。在相对稠油、强非均质性和水驱含水率为80%的渤海某油田油藏条件下,采用基本相同剂量、相近成本的化学剂工业产品进行的驱油实验表明:二元体系后续水驱突破之前驱油剂段塞渗流阻力的空间动态分布特征是影响驱油效率的关键因素,二元体系(AP-P4(1400 mg/L)/ZX-27(300 mg/L),黏度为6.4 mPa·s)比疏水缔合聚合物AP-P4(1750 mg/L,黏度为62.9 mPa·s)多提高10%的原油采收率。

In response to the contradiction between the deep mobility control capability and near-well-bore area injectability of oil displacement agents,this paper proposed that an ideal oil displacement agent for mobility control should fulfill the technical requirements of low viscosity preparation/transportation,low adsorption in the near-well-bore area for long-term stable injection,and produced liquid with low concentrations of the component.Meanwhile,multi-level flow resistance peaks(Δpmax)at different positions in the deep reservoir should be established during the flow process,and flow resistance of fluid after displacing front should be maintained at a lower level.Based on the synergistic effect of the adsorption at the solid/liquid interface and the inter-molecular interaction,a hydrophobically associating water-soluble polymer/anionic surfactant binary system was designed with the characteristics of dynamically changing the system constituent and microscopic solution structure,thereby changing flow resistance.Compared with HP-1(1500 mg/L),the binary systems HP-1(1500 mg/L)/SDSB(150 mg/L)and HP-1(1500 mg/L)/SDSB(200 mg/L),with similar apparent viscosity and different constituents can construct dynamic flow resistance with higher values and better spatial distribution in the middle-rear position of the porous medium flow during the slug injection and subsequent water flooding processes.It verified that the binary system had the characteristics of viscosity increasing and delayed breakthrough during migration,and the mobility control capability in the displacing front was more powerful.In addition,the spatial distribution of flow resistance in the reservoir becomes more reasonable,which prolonged the overall breakthrough time of the slugs,thus expanding the swept volume and enhancing the oil displacement efficiency.Oil displacement experiments were conducted in a Bohai Oilfield with heavy oil,strong heterogeneity,and 80%water cut during water flooding,with chemical industrial products with basically the same dosage and similar cost adopted.The results show that the spatial dynamic distribution characteristics of the binary system before subsequent water flooding breakthrough are a crucial factor affecting oil displacement efficiency,and the binary system(APP4(1400 mg/L)+ZX-27(300 mg/L),viscosity of 6.4 mPa·s)can improve the oil recovery by more than 10%compared with hydrophobically associating water-soluble polymer AP-P4(1750 mg/L,viscosity of 62.9 mPa·s).