弱碱替代强碱的三元复合驱研究

通过实验对比了不同碳链长度表面活性剂和混合碳链表面活性剂(NS)的界面张力,优选出NS表面活性剂.研究了NS表面活性剂在弱碱条件下的界面张力,从而确定了弱碱三元复合体系中,弱碱和表面活性剂的浓度.参照强碱三元复合驱室内驱油模拟实验,进行了弱碱三元体系驱油模拟实验.讨论了弱碱(NaHCO3)条件下,不同浓度NS表面活性剂对驱油效果的影响.最后,得出一种弱碱三元复合驱油体系配方.     

聚/表复合驱提高普通稀油油藏采收率技术研究

针对辽河油田JH16块普通稀油油藏条件,在室内进行了聚/表复合二元驱提高原油采收率研究。对聚合物进行基本参数检测以确保聚合物符合行业标准。对3种表面活性剂LH1、LH2、LH3进行筛选,筛选出对该地层原油具有最佳界面张力的表面活性剂LH1、LH3。将表活剂与聚合物进行配伍,得到最佳复合驱配方:0.18%P+0.20%LH1,油水界面张力可降至超低,达到10-3m N·m~(-1)。驱油结果表明,聚/表复合驱可以大幅度提高原油采收率,增幅大于15%。     

弱碱三元体系性能特征及其影响因素研究

针对大庆油田弱碱三元驱工业化推广应用中存在问题和实际需求,进行了弱碱三元体系影响因素研究及其性能特征评价。结果表明,与强碱三元体系相比较,弱碱三元体系与原油间界面张力下降速度较慢,第45～60 d后界面张力才能下降到10~(-3)mN/m数量级。碱、聚合物间与表面活性剂色谱分离较大,碱与聚合物之间相对较小。在三元体系黏度相同条件下,随碱和表面活性剂浓度增加即界面张力降低,三元体系与原油间乳化作用增强,附加渗流阻力增大,传输运移能力变差。随三元体系黏度增加,中低渗透层分流率增加,液流转向能力增强。随三元体系界面张力降低,高渗透层洗油效率提高,剩余油饱和度降低,水相渗透率增加,渗流阻力减小,分流率增加,液流转向效果变差。在岩心非均质性和界面张力相同条件下,随三元体系黏度增加,三元驱采收率增大。在岩心非均质性和黏度相同条件下,随界面张力降低,三元驱洗油效率提高,采收率增幅增加。在黏度和界面张力相同条件下,随岩心非均质性加剧,水驱采收率降低,三元驱采收率增加。     

新型弱碱表面活性剂在三次采油中的应用

以α-烯烃为初始原料，经过烷基化，再经磺化、中和研制出了组分相对单一、结构合理的新型弱碱烷基苯磺酸盐表面活性剂。室内评价结果表明，该表面活性剂具有良好的界面活性，配制的复合体系在较宽的表面活性剂浓度和碱浓度范围可与原油形成10^-3mN／m数量级的超低界面张力。同时，该表面活性剂对大庆油田不同区块、不同油层的油水条件表现出了很强的适应性。另外，由于表面活性剂组成较为单一，可大大降低表面活性剂在地层中因吸附滞留而产生的色谱分离效应。室内天然岩心驱油实验表明，三元复合体系平均驱油效率可比水驱提高约20％。所开展的小井距三元复合驱矿场试验，取得了比水驱提高采收率24．66％的显著效果，为三元复合驱技术在大庆油田的工业化推广，特别是在二类油层的应用奠定了坚实基础。     

新型表面活性剂驱油效果研究

通过对氟碳表面活性剂界面张力的研究,确定了一种用于提高原油采收率最佳的驱油体系QY-1：0．1％氟碳表面活性剂＋1600mg／L聚硅酮＋1．0％碱浓度。进行了室内静态驱油实验和岩心动态驱油实验。结果表明,驱油剂QY-1可以显著提高原油的采收率。     

石油磺酸盐与激活剂的协同作用研究

室内合成了一种用于增强石油磺酸盐(KPS)性能的激活剂(D8),分子模拟软件对分子间的界面稳定性研究表明,激活剂界面稳定性优于石油磺酸盐,二者可以发生协同增效作用;激活剂以及复配体系界面性能研究表明,超低界面张力下的Na Cl和Na2CO3浓度窗口分别为0.4%⁵%,0.6%5%,0.6%¹.2%,复配比1∶91.2%,复配比1∶9⁹∶1范围内具有较好的界面性能,复配过程中分子间以"插层"作用实现表面活性剂间的正的协同作用,固/液界面吸附研究结果同时验证了复配体系存在相互协同作用;应用该协同作用配制的最佳三元复合驱配方为:0.3%S(KPS∶D8=8∶2)+0.18%HPAM+1.2%Na2CO3,配方体系碱浓度窗口为0.6%9∶1范围内具有较好的界面性能,复配过程中分子间以"插层"作用实现表面活性剂间的正的协同作用,固/液界面吸附研究结果同时验证了复配体系存在相互协同作用;应用该协同作用配制的最佳三元复合驱配方为:0.3%S(KPS∶D8=8∶2)+0.18%HPAM+1.2%Na2CO3,配方体系碱浓度窗口为0.6%¹.4%,对不同原油具有较好的适应性;配方体系具有较好的抗稀释性能以及乳化能力;聚驱后进行二元复合驱可提高采收率7.57%,聚驱后进行三元复合驱可提高采收率9.78%,该配方体系在聚驱后具有较好的应用前景。     

聚合物驱后二元复合体系驱油效果研究

主要通过室内物理实验,分析了聚合物/表面活性剂二元复合体系的粘弹性和界面张力对采收率的影响,并对聚合物驱后聚合物/表面活性剂二元复合体系驱油效果进行了研究。     

二元复合驱化学分析及提高石油采收率技术研究

为提高二元复合驱的驱油效率,采用了一种新型的聚合物和表面活性剂组成的复合驱油剂,对其进行了化学分析及其对现场稠油的驱替效果评价。通过界面张力测量及动态界面张力分析,优选了表面活性剂PS-2作为最优选择,并确立其最优质量分数范围为0.2%～0.4%。通过黏浓特性和黏温特性实验,优选出聚合物KYPAM,并确定其最佳质量浓度为1 000 mg·L^-1。随后通过研究聚表二元复合体系的界面张力和流变性,发现该体系能够有效降低油水界面张力,并具有良好的流变性。采用单岩心驱替实验方法,对比分析了聚合物-表面活性剂二元复合驱、单一聚合物驱替及单一表面活性剂驱替对于现场高黏度原油提高采收率的效能。结果表明,聚表二元复合驱的采收率最高,达到32.1%,比水驱提高了16.2%。     

不同表面活性剂二元复合体系对驱油效果的影响

随着油田的开采,大多数区块已经进入高含水期,水驱后地层中含油大量的剩余油,因此,开展水驱后提高采收率具有重大意义。由于三元复合体系中存在结垢问题,通过室内实验的方法,优选出无碱二元体系,对比不同类型表面活性剂/聚合物体系的界面张力、润湿反转、驱油效果。表面活性剂与聚合物可以使油水界面张力下降,实验表明,不同类型的表面活性剂组成的无碱二元体系对驱油效果存在较大的差异。     

高30断块表面活性剂体系筛选

华北油田高30断块油藏目前已进入高含水开发后期,含水率97.0%,标定采收率仅为29.4%。当前,可大幅度提高油层波及体积和驱油效率的复合驱,是提高油藏最终采收率的有效途径和方法。已有研究表明,动态界面张力达到1-0 2mN/m数量级的复合体系的驱油效果与1-0 3mN/m数量级平衡界面张力的复合体系的驱油效果基本相当。实验表明,随着表面活性剂浓度的增加,表面活性剂/原油的界面张力逐渐降低,当界面张力达到最低值后又逐渐升高并达到平衡状态。筛选出了适合于高30断块的表面活性剂体系-0.05%石油磺酸盐CDS-1体系,该体系与原油的瞬时动态界面张力和平衡界面张力达到可以大幅度降低残余油饱和度的1-0 2~1-0 3mN/m数量级。     

Progress in research of sulfobetaine surfactants used in tertiary oil recovery

The synthesis of sulfobetaine surfactants and their application in tertiary oil recovery (TOR) are summarized in this paper. The synthesis of sulfobetaine surfactants was classified into three categories of single hydrophobic chain sulfobetaine surfactants, double hydrophobic chain sulfobetaine surfactants and Gemini sulfobetaine surfactants for review. Their application in TOR was classified into surfactant flooding, microemulsion flooding, surfactant/polymer (SP) flooding and foam flooding for review. The sulfonated betaine surfactants have good temperature resistance and salt tolerance, low critical micelle concentration (cmc) and surface tension corresponding to critical micelle concentration (γ_cmc), good foaming properties and wettability, low absorption, ultralow interfacial tension of oil/water, and excellent compatibility with other surfactants and polymers. Sulfobetaine surfactants with ethoxyl structures, hydroxyl and unsaturated bonds, and Gemini sulfobetaine surfactants will become an important direction for tertiary oil recovery because they have better interfacial activity in high-temperature (≥90°C) and high-salinity (≥10⁴ mg/L) reservoirs. Some problems existing in the synthesis and practical application were also reviewed.     

化学-酶催化法合成基于鱼鳞胶原蛋白的脂肽类表面活性剂及其在提高原油采收率中的应用

利用碱性蛋白酶Protex 6L或6 mol/L HCl对鱼鳞胶原蛋白进行水解,获得水解度为0, 5%, 10%和100%的多肽水解产物,分别用不同链长的烷基酰氯(油酰氯、月桂酰氯和癸酰氯)和苯甲酰氯对多肽进行酰化修饰,制备出16种具有不同亲水基和亲油基的脂肽表面活性剂,对其乳化性能、静态洗油和动态驱油性能进行评价. 结果表明,与常用于驱油的化学表面活性剂十二烷基苯磺酸钠(SDBS)的乳化指数E24最大仅20%相比,脂肽的乳化性能更好,500 mg/L水解度5%的油酰脂肽的E24达60%以上. pH值11.0、水解度10%的油酰脂肽和月桂酰脂肽的洗油能力最强,40℃下150 r/min转速20 min内可将35%以上的原油从油砂上洗脱,远高于SDBS的洗油率(<10%). 水驱采油后注入水解度10%的油酰脂肽或月桂酰多肽,可显著提高原油的采收率,增产油率分别达52.35%和41.18%.     

聚/表二元体系注入时机对驱油效果影响研究

随着化学驱技术的进一步发展,聚驱后仍有大量的剩余油存在地下,需要进一步对剩余油进行挖潜。聚/表二元驱作为聚驱后进一步提高采收率的方法,能有效的提高驱油效果。对于聚驱后储层非均质性更加严重的储层,聚/表二元驱能够进一步扩大波及体积,提高洗油效率,进而达到提高采收率的目的。以室内物理模拟为技术手段,分析了不同聚/表二元注入段塞尺寸对岩心驱油效果的影响。     

高盐油藏提高采收率的室内研究

高盐油藏在水驱采油之后仍有相当一部分原油滞留在地层中,很难将其采出,因此可选用化学方法动用,但高盐油藏地层水矿化度相对较高,温度相对较高,普通表面活性剂很难满足如此苛刻条件下的油藏环境。因此需要将表面活性剂进行复配,充分发挥各种活性剂的优势,进而达到提高采收率的目的。针对玉门油田鸭儿峡L油藏地层水矿化度的特点,采用阴离子-两性表面活性剂复配,通过测定不同复配比和活性剂浓度下的油水界面张力,最终确定了适用于L油藏的表面活性剂驱油复配体系。实验表明在石油磺酸盐A与C14BE复配比为1:4、1:3,总浓度为0.6%、0.1%时,油水界面张力达到了10-3 m N/m级别。此驱油配方适用于L油藏提高采收率的要求。     

表面活性剂驱油效率的影响因素研究

在83℃下测定了3种表面活性剂DL-S、HL-Y/NNR、GZ-16的油水界面张力、乳化能力以及改变油藏岩石润湿性的能力。利用低渗透岩心驱油实验研究表面活性剂的这3种特性对驱油效率的影响。结果表明,表面活性剂的浓度在1 000 mg/L时,DL-S的油水界面张力达到10-3mN/m超低数量级,HL-Y/NNR表现出较为优越的乳化性能,GZ-16具有较好的润湿性能。在驱油实验中,具有最好乳化性能的HL-Y/NNR提高采收率的幅度最大为12.91%,其次为具有超低界面张力的DL-S,相较而言,改变润湿性的能力对驱油效率的影响最小。     

新型两性表面活性剂的驱油体系界面特性变化规律研究

随着三次采油技术的不断发展,复合体系的表面活性性能和含量是在提高采收率技术研究中日趋重要。本文针对新型两性表面活性剂一元及聚合物/表面活性剂二元体系同油的界面特性展开了研究。结果表明：一元体系中表面活性剂质量浓度越高,界面张力达到稳定所需时间越短;随着体系中表面活性剂质量浓度的增加,稳定界面张力值越低。聚合物对两性表面活性剂同模拟油之间的界面张力有影响,且有利于体系同模拟油间的界面张力的降低;但界面张力并不是随着聚合物质量浓度的增加一直单纯降低,当质量浓度为1.0g/L时界面张力最低。     

Viscoelastic Surfactants with High Salt Tolerance,Fast‐Dissolving Property,and Ultralow Interfacial Tension for Chemical Flooding in Offshore Oilfields

Injected chemical flooding systems with high salinity tolerance and fast‐dissolving performance are specially required for enhancing oil recovery in offshore oilfields. In this work, a new type of viscoelastic‐surfactant (VES) solution, which meets these criteria, was prepared by simply mixing the zwitterionic surfactant N‐hexadecyl‐N,N‐dimethyl‐3‐ammonio‐1‐propane sulfonate (HDPS) or N‐octyldecyl‐N,N‐dimethyl‐3‐ammonio‐1‐propane sulfonate (ODPS) with anionic surfactants such as sodium dodecyl sulfate (SDS). Various properties of the surfactant system, including viscoelasticity, dissolution properties, reduction of oil/water interfacial tension (IFT), and oil‐displacement efficiency of the mixed surfactant system, have been studied systematically. A rheology study proves that at high salinity, 0.73 wt.% HDPS/SDS‐ and 0.39 wt.% ODPS/SDS‐mixed surfactant systems formed worm‐like micelles with viscosity reaching 42.3 and 23.8 mPa s at a shear rate of 6 s^?1, respectively. Additionally, the HDPS/SDS and ODPS/SDS surfactant mixtures also exhibit a fast‐dissolving property (dissolution time <25 min) in brine. More importantly, those surfactant mixtures can significantly reduce the IFT of oil–water interfaces. As an example, the minimum of dynamic‐IFT (IFT_min) could reach 1.17 × 10^?2 mN m^?1 between the Bohai Oilfield crude oil and 0.39 wt.% ODPS/SDS solution. Another interesting finding is that polyelectrolytes such as sodium of polyepoxysuccinic acid can be used as a regulator for adjusting IFT_min to an ultralow level (<10^?2 mN m^?1). Taking advantage of the mobility control and reducing the oil/water IFT of those surfactant mixtures, the VES flooding demonstrates excellent oil‐displacement efficiency, which is close to that of polymer/surfactant flooding or polymer/surfactant/alkali flooding. Our work provides a new type of VES flooding system with excellent performances for chemical flooding in offshore oilfields.     

Complexation of Surfactant/β‐Cyclodextrin to Inhibit Surfactant Adsorption onto Sand,Kaolin, and Shale for Applications in Enhanced Oil Recovery Processes. Part III: Oil Displacement Evaluation

This proof of concept research evaluates the performance of a surfactant/β‐cyclodextrin (β‐CD) inclusion complex during chemical flooding for enhanced oil recovery. It was hypothesized that the encapsulated surfactant propagates well through the porous media. Sodium dodecyl sulfate (SDS) was used to study the surfactant/β‐CD complexations. Phase behavior analysis was carried out to prepare the most favorable chemical slug formulation. A series of core flooding tests were conducted to determine the efficiency of the SDS/β‐CD inclusion complex in displacing residual oil. Surfactant flooding was conducted as tertiary oil recovery mode (after mature water flooding) by injecting 0.3 pore volume (PV) of the optimum surfactant slug that was chased by 0.3 PV of a polymer slug; followed by continuous water flooding until oil production stopped. The experimental results indicate that the encapsulated surfactant propagates well through the sandpack system and consistently produces higher incremental oil recoveries that range from 40 to 82 % over the incremental oil recovery achieved by conventional surfactant flooding.     

From Phase Behavior to Understand the Dominant Mechanism of Alkali-Surfactant-Polymer Flooding in Enhancing Heavy Oil Recovery

The primary objective of this work was to understand the dominant mechanism(s) of alkali‐surfactant‐polymer (ASP) flooding in enhancing heavy oil recovery. Chemical formulations were first optimized based on phase behavior studies. The data indicated that alkali and surfactant created a synergistic effect at the oil/water interface, which further decreased the interfacial tension (IFT) and improved the emulsification. However, it was also found that the addition of alkali was detrimental to the viscous properties of the chemical systems and caused the ultimate oil recovery to decrease. In other words, the macroscopic sweep efficiency as a result of viscosity was the primary factor determining the overall recovery of heavy oil followed by emulsification, which was verified by the phase behavior of the effluent. Based on the experimental results, we found that for this targeted heavy oil reservoir, surfactant‐polymer (SP) flooding was more appropriate than ASP flooding and it was not necessary to decrease the IFT to the ultralow level (10^?3 mN/m) using alkali. Through chemical flooding, the incremental oil recovery was increased up to 27% of original oil in place, indicating the potential of this technique in heavy oil reservoirs.