Yiqiang Li

As an essential replacement for conventional crude oils, accurately grasping the flow behavior and threshold pressure characteristics of high-pour-point (high-PPT) oil is pivotal for studying the pressure field and remaining oil distribution in development, and formulating effective strategies. This paper delves into the internal factors contributi...

This research aims to analyze the forces that affect oil droplets to illustrate that augmenting the mass of an oil droplet fosters favorable conditions for interaction between displaced and displacing fluids. This, in turn, impedes the bypassing of the displacing fluid around the oil droplets. In this investigation, the concept of augmenting the ma...

The process of imbibition agents entering pore throats under capillary pressure, displacing and extracting crude oil through spontaneous imbibition, is an important mechanism for enhancing oil recovery in tight reservoirs. Current research primarily focuses on the mechanism of imbibition to improve oil recovery in tight reservoirs, with relatively...

Macroscopic sand production laws often fail to reveal the microscopic essence of sand production. To investigate the microscopic sand production process and oil production capacity of unconsolidated sandstone reservoirs, a visual plate model was designed to explore the influence of displacement rate and oil viscosity. Results show that the evolutio...

Compared with onshore oil fields, offshore oil fields have lower well pattern completeness, larger well spacing, and stronger heterogeneity, necessitating a profile control and flooding system as well as corresponding laboratory evaluation methods to achieve deep reservoir regulation and efficient development. This study compared the performance of...

To address the issue of steam override and low oil-steam ratios in the middle to late stages of steam flooding development in heavy oil reservoirs, experiments and numerical simulation studies on flue gas-assisted steam flooding were conducted following steam flooding. This study investigates a heavy oil reservoir block in the Xinjiang Oilfield as...

Viscosity is a fundamental fluid property affecting the multiphase flow behavior and enhanced oil recovery (EOR) efficiency. A higher invading fluid to defending fluid viscosity ratio is often associated with a more effective invading efficiency in porous media. However, a higher viscosity ratio of displacing fluid in chemical EOR does not necessar...

Image identification is a major means to achieve quantitative characterization of the microscopic oil displacement process. Traditional digital image processing techniques usually uses a series of pixel-based algorithms, which is difficult to achieve real-time processing of large-scale images. Deep learning methods have the characteristics of fast...

The rheological characteristics of high-pour-point (high-PPT) oil are crucial for its economical and safe production and transportation. However, current research on the viscosity–temperature prediction and viscoelastic-yielding transition of high-PPT oil is insufficient. The Arrhenius formula faces challenges in accurately depicting the viscosity–...

Viscous fingering of the injected fluid will significantly reduce the swept volume. Increasing the injected fluid viscosity can impress viscous fingering, but the reservoir and economy limit its application. Exploring a simple, effective, and universal viscous fingering impression method can effectively improve secondary oil recovery efficiency. Th...

The reservoir and fluid properties determine that a single injected fluid will inevitably undergo channeling during displacement. Whether it is water flooding, gas flooding, or steam flooding, it is necessary to control the injection-production profile. This paper aims to design the multi-agent and multi-slug combination displacement to achieve the...

Conglomerate is characterized by a multiscale grain stacking structure and various pore size distribution modes (PSDMs), significantly affecting multiphase fluid movement and transport in porous media. The multimodal structure and complicated PSDM are related to grain size distribution. However, the relationship between grain size distribution and...

Oxygen-reducing air is cheap and environmentally friendly, and is one of the important media to realize multi-cycle huff-and-puff development of tight oil reservoirs. However, the characteristics of reservoir damage and the influence of cumulative damage of multi-cycle huff-and-puff on productivity are unknown. Based on one-dimensional long core an...

As one of the leading technologies for chemical enhanced oil recovery (cEOR), surfactant–polymer (SP) flooding technology has long attracted the interest of petroleum scientists and engineers. However, most of its application scenarios are based on the five-spot well pattern. The EOR potential in an inverted seven-spot well pattern is seldom ever r...

As one of the leading technologies for chemical enhanced oil recovery (cEOR), surfactant-polymer (SP) flooding technology has drawn the attention of petroleum scientists and engineers for many years. However, most of its application scenarios are based on the five-spot well pattern. Rarely reported is its EOR potential in an inverted seven-spot wel...

The invasion patterns of immiscible fluids in porous media determine the swept volume and displace efficiency, which is complexly affected by fluids, reservoir, and injection parameters. Unfortunately, there is a sparse understanding of the crossover zone during the imbibition process, description of the whole displacement process, and the method o...

Particle migration in porous media is of great significance in the areas of formation-water filtration and oil field development. The current theories and methods ignore the effect of particle elasticity on its flow resistance, which is the key point for particle parameters design toward reservoir profile control. Therefore, this paper focuses on t...

Water flooding increases the recovery factor of crude oil and has been proven to be an economical and viable technique for enhancing the oil recovery of oil fields. The process has been systematically studied previously, in which the oil was considered a substance of constant composition. However, the molecular selectivity during the water flooding...

There are more than 40% remaining oil trapped in the reservoir in the mature oilfield even after second and tertiary recovery processes. High performance chemical agent was required for the trapped oil further mobilization. Polymeric surfactant was synthesized by grafting the active ground into the polymer skeleton. It has the advantages of surfact...

Injecting CO2 into the underground for oil displacement and shortage is an important technique for carbon capture, utilization and storage (CCUS). One of the main problems during the CO2 injection is the channeling plugging. Finding an effective method for the gas channeling plugging is a critical issue in the CO2 EOR process. In this work, an acid...

Gas-assisted gravity drainage (GAGD) is an effective method for oil recovery. Gravity increases the stability of the Gas-Oil Contact (GOC), thus delaying gas breakthrough and promoting crude oil production. Studying the effects of fluid and reservoir parameters on the stability of GOC could help understand the mechanism of GAGD. In this study, a se...

Surfactant-polymer (SP) flooding has been regarded as an efficient technique for enhanced oil recovery in the development of mature oil fields, especially for those with heterogeneous conglomerate reservoirs. However, people are still unclear about the optimal SP flooding initiation timing (OSPT) that is expected to contribute to the maximum ultima...

Surfactant-enhanced mobilization features in various complicated pore structures were rarely investigated. In this work, from the perspective of pore heterogeneity, taking conglomerate with complicated pore-throat distribution as an example, micromodels with three pore structures were fabricated, and polymer and polymer-surfactant (SP) solutions we...

Water-alternating-gas (WAG) injection is recommended as a means of improving gas mobility control. This paper describes a series of coreflood tests conducted to investigate the potential for continuous gas injection and WAG injection in ultra-high water-cut saline reservoirs. The mechanisms of immiscible water-alternating-nitrogen injection on resid...

The effects of different oxygen-containing air on enhanced oil recovery were evaluated by artificial cores with low permeability in displacement experiments. The results show that with the increment of oxygen content, more crude oil could be driven at the higher temperature and pressure, but the effect of oxygen concentration on oil displacement ef...

The capillary number experiment curve QL is the supplementation and perfection of the classic capillary number experiment curve. The establishment of an experiment core microscopic oil/water distribution platform has deepened the understanding of the capillary number experiment curve. On the basis of field displacement experiments, software describ...

Flow regimes of two immiscible liquids are experimentally investigated in a rectangular microchannel using a water–oil system. Oil-water viscosity ratios are varied from 0.2 to 75, accompanied by varied oil–water velocity ratios from 10⁻² to 10² and varied capillary numbers from 10⁻³ to 10⁻⁵. Four flow regimes are distinguished, including threading...

Gas-assisted gravity drainage (GAGD) is an effective method of oil recovery that is influenced by the properties of the fluids and formations involved. In this paper, a direct numerical simulation method is employed to investigate immiscible GAGD in an oil-wet porous medium. The interface between oil and gas is tracked via the phase-field method. A...

As a good deep profile control and displacement agent, polymer microspheres have broad application prospects in oil fields. Three kinds of microspheres (MG-1 to MG-3) with different particle sizes are synthesized and evaluated. The microspheres observed by SEM are regular spheres with initial particle sizes of 3μm, 6μm, and 10μm, respectively, and...

Enhancing oil recovery from thick heterogeneous carbonate reservoirs poses great challenges, be it through waterflooding or gasflooding. In this study, a three-layer 3D physical model was established based on artificial core technology and scaling criteria, taking into account the mineral composition, petrophysical properties, pore structure, wetta...

Polymer microspheres (PMs) can be a very promising, cost-effective in-depth fluid diversion strategy in the development of heterogeneous reservoir. The key to success for the PMs application is to fully understand the PMs-migration and -plugging mechanisms through the confined space. The plugging rate is widely used to evaluate the performance of P...

Alkali-surfactant-polymer (ASP) flooding is very promising chemical enhanced oil recovery (EOR) technology which can make an incremental oil recovery factor (IORF) of 30% original oil in place (OOIP). How to choose alkali in ASP flooding remains a question for a long time. As the world’s only and largest ASP flooding application place, Daqing Oilfi...

Recently, there are increasing interests in chemical enhanced oil recovery (EOR) especially surfactant-polymer (SP) flooding. Although alkali-surfactant-polymer (ASP) flooding can make an incremental oil recovery factor (IORF) of 18% original oil in place (OOIP) according to large-scale field tests in Daqing, the complex antiscaling and emulsion br...

Heterogeneity is well known to reduce sweep efficiency during oil development processes. Self-adaptive micro gel (SMG) as a agent for in-depth profile control is significantly limited to strict matching between complicated pore structure and particle size. A new matching factor considering size and distribution of particle and pore is presented to...

Heavy oil recovery is the most challenging part for the petroleum industry and several techniques including steam and water injection are currently used that are either energy intensive, expensive, or less efficient. This study aims to evaluate a novel amphiphilic viscosity reducing polymer (DN-1) used along with hot water flooding for promoting vi...

Conventional polymer flooding (e.g. using polyacrylamide) has been widely used in the oil fields as an economical means for enhanced oil recovery. However, its efficacy is affected by the polymer properties and increasingly harsh reservoir conditions. In this study, a high-molecular-weight modified polyacrylamide polymer (GF-1) encapsulated in a wa...

Compared with other enhanced oil recovery (EOR) techniques like gas flooding, chemical flooding, and thermal production, the prominent advantages of microbial enhanced oil recovery (MEOR) include environment-friendliness and lowest cost. Recent progress of MEOR in laboratory studies and microbial flooding recovery (MFR) field tests in China are rev...

In-situ formation of emulsions has been observed in a large amount of chemical flooding pilots, and their effect on oil recovery is of great interest to petroleum engineers and researchers. In this study, microfluidic and transparent sand pack models were used to investigate mechanisms of emulsion propagation and plugging in both pore and macro sca...

Relative permeability is a concept used to convey the reduction in flow capability due to the presence of multiple mobile fluids. The study of the mechanism and characteristics of discontinuous flow in multiphase flow have great significance in reservoir engineering, geotechnical engineering, biomedical engineering, chemical engineering. In this ar...

Surfactant/polymer (SP) floods have significant potentials to recover remaining oil after water flooding. Their efficiency can be maximized by fully utilizing synergistic effect of polymer and surfactant. Various components adsorbed on the rock matrix due to chromatographic separation can significantly weaken the synergistic effect. Due to scale an...

Monitoring of CO 2 sequestration process has been identified as one of the highest priorities needs to provide safe and secure storage of CO 2. Soil gas monitoring, as an effective and timely near surface monitoring technique, have been validated by many pilot projects. Periodic monitoring of the soil CO 2 within and around the pilot area can verif...

After adding a surfactant to the polymer solution, the interaction between them has a significant influence on the oil recovery of polymer/surfactant (SP) flooding. The study of the micro-physicochemical interaction between sodium dodecylbenzene sulfonate (SDBS) and partially hydrolyzed polyacrylamide (HPAM) can contribute toward an understanding o...

Although the alkali/surfactant/polymer (ASP) flooding technique used for enhanced oil recovery (EOR) was put forward many years ago, it was not until 2014 that it was first put into practice in industrial applications with hundreds of injectors and producers in the Daqing Oil Field in China. In this study, 30 ASP-flooding field tests in China were...

This paper provides field scale EOR survey in China which is in line with biennial worldwide EOR survey published by Oil& Gas Journal (OGJ). The EOR progress in China is not available due to language difference and other reasons in OGJ EOR survey. From 2018, EOR survey in China will be published biennially. The first part of this survey mainly focu...

Chemical flooding, as one of the most promising EOR techniques in both laboratory research and field practice has been widely applied to enhance residual oil displacement in conglomerate and sandstone reservoirs. To fully understand the displacement mechanism of chemical flooding in reservoirs with different lithologies, it is critical to understan...

Phase separation, which decreases the synergistic effect, are observed during amount of surfactant/polymer (SP) or alkali/surfactant/polymer (ASP) flooding field applications and laboratory experiments. The idea of adding hydrophobic groups to a water-soluble polymer is to make polymeric surfactant that could be applied in Enhanced Oil Recovery (EO...

In this paper, physical experiments and numerical simulations were applied to systematically investigate the non-Newtonian flow characteristics of heavy oil in porous media. Rheological experiments were carried out to determine the rheology of heavy oil. Threshold pressure gradient (TPG) measurement experiments performed by a new micro-flow method...

Although Alkali-Surfactant-Polymer (ASP) flooding enhance oil recovery (EOR) technique has been put forward many years ago, it was not until 2014 that it is first put into industrial application in Daqing Oilfield in China. Under such low oil price, ASP flooding advance in China provides confidence for ASP flooding as a chemical EOR technology. In...

Capillary number theory is very important for chemical flooding enhanced oil recovery. The difference between microscopic capillary number and the microscopic one is easy to confuse. After decades of development, great progress has been made in capillary number theory and it has important but sometimes incorrect application in EOR. The capillary nu...

Alkali/surfactant/polymer (ASP) flooding is one of the most-promising enhanced-oil-recovery (EOR) technologies. Strong alkali (NaOH) was used in early field tests mainly because of its stronger emulsification ability and wider surfactant range, which can meet the requirements of ultralow interfacial tension (IFT). However, subsequent field tests in...

In low oil price era, it seems that ASP flooding has little market. However, ASP progress in China shows that ASP flooding is good technology to help oil companies thrive and make profit. Since 2014, ASP flooding has entered industrial application in Daqing oilfield. ASP flooding production in 2015 is 3.5 million ton, 9% of the oilfield’s total pro...

ASP flooding is one of the most promising EOR technologies. Lots of laboratory studies and pilot tests have been finished in Daqing oilfield which is the largest oilfield in China. Comparison of two typical strong alkali ASP (WASP) and weak alkali ASP (SASP) pilots are presented with detained information. ASP flooding could not only remarkably impr...

Modified sulfonated asphalt particles have a bright application prospect of the profile control of thick reservoirs due to the low cost, extensive sources, and good compatibility with reservoir. Nevertheless, the matching relationship between asphalt particles and reservoir pore has seldom been investigated till now. Oversized particles always bloc...

Laboratory experiments were conducted to investigate the mechanism(s) of water flood with horizontal injection wells. The experiment was performed using a three-dimensional (3D) physical model made by artificial sandstone of the dimension of 60 cm × 30 cm × 5 cm. The saturation profile of oil and water phases was monitored by measuring the electric...

Some progress concerning low permeability flow in pore structure and interaction with formation fluid, micro-scale effect, threshold pressure gradient, relative permeability curve is reviewed. Pore structure and distribution patterns have no distinct difference in different permeability rocks while pore-throats have. In low permeability formation c...

After decades of development, great progress has been made in capillary number theory and it has important but often incorrect application in EOR. Investigation into progress on capillary number theory and some misuse of capillary number theory helps to make better use of it. Latest progress concerning with capillary number theory and its applicati...

Compared with other EOR technique like gas flooding, chemical flooding, and thermal production in heavy oil, the prominent advantages MEOR has environment-friendliness and lowest cost. MEOR has various applications not only in sandstone but also carbonate reservoirs, light oil reservoirs as well as heavy oil reservoirs. This paper mainly reviewed p...

In the mid- to late period of oil field development, it is important to consider the microscopic distribution of remaining oil of the reservoir in time, for it is the foundation of enhanced oil recovery. Focusing on the present insufficient research status of microscopic distribution of remaining oil after polymer flooding, this article first put f...