油气储层岩石表面气体润湿性研究进展

在调研大量相关文献的基础上,详细综述了国内外石油界面化学研究者在油气储层岩石气润湿性反转提高采收率方面的研究进展。自2000年李克文首次提出气体润湿性名词及通过气润湿反转提高凝析气藏产能的思路后,国内外石油界面化学研究者们相继在气润湿性反转机理和控制方法、气润湿性反转提高采收率、气润湿性反转对岩石表面性质的影响以及对毛细管力、油/气/水分布和渗流规律的影响等方面取得了许多重要研究成果,基本形成气体润湿性理论体系,为提高油气采收率奠定理论基础。     

润湿反转技术在低渗透油田的应用与展望

本文从分析润湿性转变的机理出发,对目前通过改变油藏岩石润湿性以提高原油采收率方面的相关技术及研究进行了详细调研,系统总结了改变油藏岩石润湿性以提高原油采收率的方法。经过归纳总结,认为有针对性地调节油藏岩石的润湿性,可以达到提高采收率的目的。提出了应用润湿反转技术,可改善弹性开采油田压裂效果;通过改变岩石表面润湿性,增加毛细管力,可改善低渗透油层水驱开发效果的观点。     

SiO_2纳米颗粒在碳酸盐岩储层中强化采油实验研究

改变润湿性可以有效提高亲油性碳酸盐岩储层中原油采收率。然而纳米颗粒在这一领域的应用处于起步阶段。为此,本文研究了纳米流体的浓度对润湿性和界面张力的影响,从而确定注入岩心的纳米流体的最佳浓度。结果表明,浓度为4g·L~(-1)的纳米流体的浓度可以显著地改变岩心的润湿性,使之从强亲油状态到强亲水状态。此外,本文还研究了纳米流体在亲油岩心塞下增强采收率方面的潜力。结果表明,向充满纳米流体的老化岩心再次注入水,能采出大量的石油。     

用亚甲基蓝吸附法测量油层岩石的润湿性

储层岩石润湿性影响油、水在储层中的分布，对原油开采过程均具有至关重要的作用。测量储层岩石润湿性的标准方法（Amott and US-BM法）属于经验方法，包括在润湿相和非润湿相共存时让油、水两相相互驱替。测量结果可能与流体的饱和度和实验过程有关，而产生某些不确定性。本文提出根据亚甲基蓝在储层岩石表面的吸附面积分数，测量固体表面的润湿性。该法具有一定的理依据，测量结果不受流体的饱和度和实验过程的影响。     

纳米技术在化学强化采油中的最新应用进展

近年来,纳米技术在提高采收率中的潜在应用越来越受到关注。为此,许多研究报道纳米颗粒在化学提高采收率过程中有很好的应用前景。本文综述了纳米粒子在表面活性剂、聚合物、表面活性剂、碱性表面活性剂、低矿化度水驱等领域的最新应用研究进展,为有兴趣开发纳米粒子技术的研究人员指明了方向。阐述了纳米粒子在润湿性改变、层间张力降低和原油采收率提高方面的作用,并讨论了纳米流体驱油过程中影响多孔介质中岩石/流体相互作用行为的因素。     

油田用润湿反转剂的应用与展望

本文主要论述油田用润湿反转剂的种类、作用机理及在油田现场中的应用效果和展望。对比了阳离子、阴离子及非离子表面活性剂等在界面的作用机理。化学剂在矿物表面的吸附、沉积或化学反应是岩石表面润湿性反转的基础。润湿性改变的方向和程度主要取决于所使用润湿反转剂的类型与浓度。岩石矿物成分、原油组分、地层水的化学组成及pH值等是润湿性改变方向和程度的影响因素。研究表明,表面活性剂在油层中的润湿性反转作用,使亲油表面变为亲水表面,润湿性的改变可大大影响油藏的最终采收率。     

润湿反转技术在低渗透油田的应用与展望

针对QJ油田大规模缝网压裂井压后返排率低,产量递减快的实际,依据润湿性转变的机理,现场应用生物酶技术,通过改变储层润湿性,实现压裂能量的置换,恢复油井产能,现场试验取得了较好效果。在此基础上,提出了致密储层体积压裂改造形成复杂缝网的前提下,应用润湿反转技术,发挥压裂液存留液的渗析置换作用,进一步发挥致密储层压裂效果的观点,并对影响压裂液油水置换的关键影响因素进行了调研分析,为油田提高致密储层采收率提供借鉴思路。     

纳米材料用于提高稠油采收率的研究进展

详细介绍和评述了以纳米催化剂、智能纳米流体和纳米-微生物驱为代表的纳米材料在提高稠油采收率方面的应用。纳米催化剂的高催化活性能使稠油有效地水热裂解,提高稠油品质。智能纳米流体是通过改变岩石的润湿性,降低表面张力,改善流度比的方法来提高最终采收率。而纳米-微生物驱则是包含了纳米材料和微生物驱的优点,在二者的协同作用下,提高稠油采收率。最后指出了纳米技术在进一步现场应用存在的问题,并对今后的研究方向进行了展望。     

纳米材料用于提高稠油采收率的研究进展

详细介绍和评述了以纳米催化剂、智能纳米流体和纳米-微生物驱为代表的纳米材料在提高稠油采收率方面的应用。纳米催化剂的高催化活性能使稠油有效地水热裂解,提高稠油品质。智能纳米流体是通过改变岩石的润湿性,降低表面张力,改善流度比的方法来提高最终采收率。而纳米-微生物驱则是包含了纳米材料和微生物驱的优点,在二者的协同作用下,提高稠油采收率。最后指出了纳米技术在进一步现场应用存在的问题,并对今后的研究方向进行了展望。     

纳米技术在提高采收率方面的应用

近年来,纳米技术在石油工业中的应用越来越多。主要集中报道了纳米颗粒在提高采收率方面的作用。它可以改变岩石表面的润湿性,降低油水之间的界面张力。综述了近几年来纳米颗粒在提高石油采收率的应用。     

Enhanced Wettability Alteration by Surfactants with Multiple Hydrophilic Moieties

The main production mechanism during water flooding of naturally fractured oil reservoirs is the spontaneous imbibition of water into matrix blocks and resultant displacement of oil into the fracture system. This is an efficient recovery process when the matrix is strongly water-wet. However, in mixed- to oil-wet reservoirs, secondary recovery from water flooding is often poor. Oil production can be improved by dissolving low concentrations of surfactants in the injected water. The surfactant alters the wettability of the reservoir rock, enhancing the spontaneous imbibition process. Our previous study revealed that the two main mechanisms responsible for the wettability alteration are ion-pair formation and adsorption of surfactant molecules through interactions with the adsorbed crude oil components on the rock surface. Based on the superior performance of surfactin, an anionic biosurfactant with two charged groups on the hydrophilic head, it was hypothesized that the wettability alteration process might be further improved through the use of dimeric or gemini surfactants, which have two hydrophilic head groups and two hydrophobic tails. We believe that when ion-pair formation is the dominant wettability alteration mechanism, wettability alteration in oil-wet cores can be improved by increasing the charge density on the head group(s) of the surfactant molecule since the ion-pair formation is driven by electrostatic interactions. At a concentration of 1.0 mmol L⁻¹ a representative anionic gemini surfactant showed oil recoveries of up to 49% original oil-in-place (OOIP) from oil-wet sandstone cores, compared to 6 and 27% for sodium laureth sulfate and surfactin, respectively. These observations are consistent with our hypothesis.     

A review on the application of nanofluids in enhanced oil recovery

Enhanced oil recovery (EOR) has been widely used to recover residual oil after the primary or secondary oil recovery processes. Compared to conventional methods, chemical EOR has demonstrated high oil recovery and low operational costs. Nanofluids have received extensive attention owing to their advantages of low cost, high oil recovery, and wide applicability. In recent years, nanofluids have been widely used in EOR processes. Moreover, several studies have focused on the role of nanofluids in the nanofluid EOR (N-EOR) process. However, the mechanisms related to N-EOR are unclear, and several of the mechanisms established are chaotic and contradictory. This review was conducted by considering heavy oil molecules/particle/surface micromechanics; nanofluid-assisted EOR methods; multiscale, multiphase pore/core displacement experiments; and multiphase flow fluid-solid coupling simulations. Nanofluids can alter the wettability of minerals (particle/surface micromechanics), oil/water interfacial tension (heavy oil molecules/water micromechanics), and structural disjoining pressure (heavy oil molecules/particle/surface micromechanics). They can also cause viscosity reduction (micromechanics of heavy oil molecules). Nanofoam technology, nanoemulsion technology, and injected fluids were used during the EOR process. The mechanism of N-EOR is based on the nanoparticle adsorption effect. Nanoparticles can be adsorbed on mineral surfaces and alter the wettability of minerals from oil-wet to water-wet conditions. Nanoparticles can also be adsorbed on the oil/water surface, which alters the oil/water interfacial tension, resulting in the formation of emulsions. Asphaltenes are also adsorbed on the surface of nanoparticles, which reduces the asphaltene content in heavy oil, resulting in a decrease in the viscosity of oil, which helps in oil recovery. In previous studies, most researchers only focused on the results, and the nanoparticle adsorption properties have been ignored. This review presents the relationship between the adsorption properties of nanoparticles and the N-EOR mechanisms. The nanofluid behaviour during a multiphase core displacement process is also discussed, and the corresponding simulation is analysed. Finally, potential mechanisms and future directions of N-EOR are proposed. The findings of this study can further the understanding of N-EOR mechanisms from the perspective of heavy oil molecules/particle/surface micromechanics, as well as clarify the role of nanofluids in multiphase core displacement experiments and simulations. This review also presents limitations and bottlenecks, guiding researchers to develop methods to synthesise novel nanoparticles and conduct further research.     

Emerging applications of nanomaterials in chemical enhanced oil recovery:Progress and perspective

In enhanced oil recovery, different chemical methods utilization improves hydrocarbon recovery due to their fascinating abilities to alter some critical parameters in porous media, such as mobility control, the interaction between fluid to fluid, and fluid to rock surface. For decades the use of surfactant and polymer flooding has been used as tertiary recovery methods. In the current research, the inclusion of nanomaterials in enhanced oil recovery injection fluids solely or in the presence of other chemicals has got colossal interest. The emphasis of this review is on the applicability of nanofluids in the chemical enhanced oil recovery. The responsible mechanisms are an increment in the viscosity of injection fluid, decrement in oil viscosity, reduction in interfacial and surface tension, and alteration of wettability in the rock formation. In this review, important parameters are presented,which may affect the desired behavior of nanoparticles, and the drawbacks of nanofluid and polymer flooding and the need for a combination of nanoparticles with the polymer are discussed. Due to the lack of literature in defining the mechanism of nanofluid in a reservoir, this paper covers majorly all the previous work done on the application of nanoparticles in chemical enhanced oil recovery at home conditions. Finally, the problems associated with the nano-enhanced oil recovery are outlined, and the research gap is identified, which must be addressed to implement polymeric nanofluids in chemical enhanced oil recovery.     

Emerging applications of nanomaterials in chemical enhanced oil recovery: Progress and perspective

In enhanced oil recovery, different chemical methods utilization improves hydrocarbon recovery due to their fascinating abilities to alter some critical parameters in porous media, such as mobility control, the interaction between fluid to fluid, and fluid to rock surface. For decades the use of surfactant and polymer flooding has been used as tertiary recovery methods. In the current research, the inclusion of nanomaterials in enhanced oil recovery injection fluids solely or in the presence of other chemicals has got colossal interest. The emphasis of this review is on the applicability of nanofluids in the chemical enhanced oil recovery. The responsible mechanisms are an increment in the viscosity of injection fluid, decrement in oil viscosity, reduction in interfacial and surface tension, and alteration of wettability in the rock formation. In this review, important parameters are presented, which may affect the desired behavior of nanoparticles, and the drawbacks of nanofluid and polymer flooding and the need for a combination of nanoparticles with the polymer are discussed. Due to the lack of literature in defining the mechanism of nanofluid in a reservoir, this paper covers majorly all the previous work done on the application of nanoparticles in chemical enhanced oil recovery at home conditions. Finally, the problems associated with the nano-enhanced oil recovery are outlined, and the research gap is identified, which must be addressed to implement polymeric nanofluids in chemical enhanced oil recovery.     

Surfactant Enhanced Oil Recovery in a High Temperature and High Salinity Carbonate Reservoir

The goal of this work was to find an effective surfactant system for enhanced oil recovery after water injection substituting for oil at a vuggy fractured reservoir with a high temperature and high salinity (220,000 mg/L). Four types of surfactants with concentrations (less than 0.2 %) were screened. Washing oil experiments were conducted in Amott cells. A surfactant system was established by mixing a surfactant with best ultimate recovery and one with best recovery rate. The optimized surfactant system could recover 50 % of remaining oil. To study the mechanism of enhanced oil recovery after water injection substituting oil, interfacial tension (IFT) and contact angle were measured. Experimental results showed that surfactants with good washing ability had low IFT, but surfactants with low IFT may not have a good washing ability. IFT had no obvious relationship with the increased oil recovery or washing ability. The optimized system could not alter carbonate to decrease the oil‐wetting capability. Though octadecyl trimethyl ammonium chloride had a good ability wet the carbonate with water, it could not recover much oil. Therefore, except for interfacial tension and wettability alteration, there must be other parameters dominating oil recovery after water injection substituting for oil.     

Evaluation of the polymer hydrogels as a potential relative permeability modifier

Excessive water production poses a significant challenge in the oil industry, especially in Pre-salt carbonate reservoirs, leading to reduced oil recovery, corrosion, and well abandonment. We explore the potential of polymeric preformed particle gels (PPGs) as innovative relative permeability modifiers (RPMs) for carbonate reservoirs. RPMs involve applying polymeric hydrogels to alter reservoir wettability, reducing water flow while enhancing oil productivity. PPGs offer a promising surface-based production alternative with improved control and minimized formation damage compared to traditional in-situ gels. We conducted crosslinking experiments using poly(acrylamide-acrylic acid-2-methyl propane sulfonate) terpolymer (AM-AA-AMPS) and aluminum (III) ions, assessing their impact on hydrogel properties. We also investigated the swelling behavior of these hydrogels and their interactions with rock samples. Results showed that crosslinking significantly affects PPG viscoelastic properties and swelling behavior. Adsorption tests revealed the formation of a polymeric film on rock surfaces, potentially altering wettability. Contact angle measurements demonstrated PPGs' ability to shift rock wettability, particularly in carbonate samples, from strongly oil-wet to water-wet conditions. This study underscores PPGs' potential as RPMs, offering valuable insights into improving oil extraction efficiency and addressing water production challenges in the industry.     

Preparation and Performance Evaluation of Fatty Amine Polyoxyethylene Ether Diethyl Disulfonate for Enhanced Oil Recovery in High‐Temperature and High‐Salinity Reservoirs

To enhance oil recovery in high‐temperature and high‐salinity reservoirs, a novel fatty amine polyoxyethylene ether diethyl disulfonate (FPDD) surfactant with excellent interfacial properties was synthesized. The interfacial tension (IFT) and contact angle at high temperature and high salinity were systematically investigated using an interface tension meter and a contact angle meter. According to the experimental results, the IFT between crude oil and high‐salinity brine water could reach an ultra‐low value of 10^?3 mN m^?1 without the aid of extra alkali at 90°C after aging. The FPDD surfactant has strong wettability alternation ability that shifts wettability from oil‐wet to water‐wet. The FPDD surfactant with a high concentration also has good emulsion ability under high‐temperature and high‐salinity conditions. Through this research work, we expect to fill the lack of surfactants for high‐temperature and high‐salinity reservoirs and broaden its great potential application area in enhanced oil recovery.     

Experimental study of secondary and tertiary modes combined low salinity water and polymer flooding in sandstone porous media

Combined low salinity water (LSW) and polymer (LSP) flooding is the most attractive method of enhanced oil recovery (EOR). Considerable research has investigated effective mechanisms of LSP flooding. In this study, 10 laboratory core flood tests were carried out to evaluate the effects of LSW injection into samples without any clay particles, the timing of LSW injection, and the advantages of adding polymer to the injection water for EOR. Secondary and tertiary LSW injections were performed on sandpack samples with different wettability states and water salinity. Tertiary LSW injection after secondary synthetic seawater (SSW) injection in oil-wet samples resulted in 13% more oil recovery, while the water-wet sample showed no effect on the oil recovery. Secondary LSW injection in oil-wet porous media improved oil recovery by 8% of the original oil in place (OOIP) more than secondary SSW injection. Tertiary LSP flooding after secondary SSW injection in the oil-wet sample provided a recovery of 67.3% of OOIP, while secondary LSW injection followed by tertiary LSP flooding yielded the maximum ultimate oil recovery of about 77% of OOIP. The findings showed that the positive EOR effects of LSW and LSP flooding were the results of wettability alteration, pH increase, improved mobility ratio, better sweep efficiency, and oil redistribution. In addition, results showed that wettability alteration is possible without the presence of clay particles. The findings of this study can help for a better understanding of fluid propagation through the porous media and an investigation of delays in reaching ultimate oil recovery.     

Review on application of nanoparticles for EOR purposes: A critical review of the opportunities and challenges

Nanoparticles have already gained attentions for their countless potential applications in enhanced oil recovery.Nano-sized particles would help to recover trapped oil by several mechanisms including interfacial tension reduction, impulsive emulsion formation and wettability alteration of porous media. The presence of dispersed nanoparticles in injected fluids would enhance the recovery process through their movement towards oil–water interface. This would cause the interfacial tension to be reduced. In this research, the effects of different types of nanoparticles and different nanoparticle concentrations on EOR processes were investigated. Different flooding experiments were investigated to reveal enhancing oil recovery mechanisms. The results showed that nanoparticles have the ability to reduce the IFT as well as contact angle, making the solid surface to more water wet. As nanoparticle concentration increases more trapped oil was produced mainly due to wettability alteration to water wet and IFT reduction. However, pore blockage was also observed due to adsorption of nanoparticles, a phenomenon which caused the injection pressure to increase. Nonetheless, such higher injection pressure could displace some trapped oil in the small pore channels out of the model. The investigated results gave a clear indication that the EOR potential of nanoparticle fluid is significant.     

Lab simulation of profile modification and enhanced oil recovery with a quaternary ammonium cationic polymer

Long-term water flooding in oilfield exploitation generally results in a marked increase of interlayer and/or inner-layer heterogeneity of oil reservoirs and premature polymer production in large quantities from flooding reservoirs. This paper presents a novel quaternary ammonium cationic polymer (NCP), which was prepared by using maize starch and (2,3-epoxypropyl)trimethylammonium chloride as raw materials. The effect of NCP on water plugging and profile modificaton after polymer HPAM (partially hydrolyzed polyacrylamide) flooding was evaluated by laboratory simulation tests of enhanced oil recovery. The experimental results indicate that crosslinking gel system formed after HPAM-NCP alternate injection could effectively seal off the high permeability zone to force the successive liquid to flow to mid-low permeability zones and get profile control in depth. In addition, the contact angle measurements reveal that the adsorption of NCP on the montmorillonite changed its surface wettability and enhanced its hydrophilicity, which promoted enhance oil recovery significantly.