Heavy Oil Water Research Articles

Facile fabrication of superhydrophobic–superoleophilic ZnCo2O4 nickel foam for highly efficient oil/water separation

AbstractIn recent years, the fabrication of hydrophobic materials and their excellent applications in oil spill cleanup has attracted widespread attention. Herein, we report the rapid and straightforward preparation of ZnCo2O4 nickel foam by hydrothermal synthesis. The prepared sample surfaces possess excellent superlipophilicity and superhydrophobicity after modification by stearic acid, so it can efficiently absorb light and heavy oil in water, and the absorption efficiency is over 99%. Besides, the unmodified ZnCo2O4 nickel foam could be subjected to effective oil–water separation at standard temperature and pressure, and its separation efficiency can be more than 97.4%. After 20 continuous filtration cycles, it can maintain stable high separation efficiency and even work under harsh environmental conditions, like acid, alkali, salt solution, high and low temperature, and ultraviolet radiation. Compared with other methods of manufacturing hydrophobic materials, this method is facile, lower cost, environmentally durable, and highly efficient. Therefore, the as‐prepared ZnCo2O4 nickel foam has good application value in treating oily wastewater.

Research and Application of Bottom Water Control and Suppression Technology by CO2 Huff-and-Puff

In order to solve the problems about rapid increasement rate of water cut and large production decline in bottom water heavy oil reservoir due to active bottom water and high crude oil viscosity, the research on CO2 huff-and-puff technology is carried out. The results showed that the mechanism of CO2 huff-and-puff was mainly to reduce the viscosity of heavy crude oil, carbonate reacted with bottom water and formed interlayer to achieve viscosity reduction and precipitation. The comprehensive water cut was decreased by 35%, and the average oil production of a single well was increased by 3∼4 times. Therefore, CO2 huff-and-puff technology was one of technologies about bottom water control and oil production stabilization, and it is of great significance to enhance oil production in heavy oil bottom water reservoirs.

Waterflooding of Heavy Oil Reservoirs

Waterflooding or polymer flooding is sometimes dismissed as an ineffective process for heavy oil fields, with development plans focused on more exotic and expensive recovery mechanisms such as chemical or thermal processes. There are a number of unique mechanisms that operate in heavy oil fields under water and polymer flood. It is, therefore, possible to succesfully flood heavy oil reservoirs with viscosities up to and beyond 10,000 cp oil viscosity. This work elaborates on the unique mechanisms operating in heavy oil water and polymer floods, presents a workflow for successfull implementation and supports its conclusions with a number of case studies, namely, actual successful field examples from Canadian heavy oil fields. The hope is that, this experience can be translated to heavy oil fields in other parts of the world including Turkey.

A collaborative emulsification system capable of forming stable small droplets of oil-in-water emulsions for enhancing heavy oil recovery

Water flooding for heavy oil development has a relatively low recovery effect. Emulsification system flooding is a very effective method for enhanced heavy oil recovery after water flooding. However, the sizes of oil-in-water (O/W) emulsion droplets formed by conventional emulsification systems and heavy oil are relatively large. Large droplet emulsions result in higher additional resistance when flowing in the porous media of the reservoir, which restricts the development effect on heavy oil recovery. In this study, a primary alcohol ethoxylate (AEO12) + sodium dodecyl sulfate (SDS) + alkali (NaOH) mixed collaborative emulsification (CE) system was developed and its formula was optimized. The optimal collaborative emulsification system formula is primary alcohol ethoxylate (0.25%) + sodium dodecyl sulfate (0.25%) + NaOH (0.05%). Through interfacial tension measurements, microemulsion state observations, emulsion particle size distribution tests, multiple light scattering, and fluidity experiments in simulated reservoir porous media, the oil-in-water emulsion stability and the mechanism of collaborative emulsification for improving heavy oil recovery were studied. Compared with the surfactant, the collaborative emulsification system can be more closely arranged at the heavy oil–water interface, so that the system can significantly reduce interfacial tension (IFT) (0.008 mN/m), formed a more stable and smaller oil-in-water emulsion (0.2 μm). It can greatly reduce the influence of additional resistance on its fluidity in reservoir porous media, and still has an excellent viscosity reduction rate at high temperatures (99.50% at 20 °C; 88.55% at 100 °C). Finally, through microscopic visualization experiments, it was shown that the collaborative emulsification system has an excellent ability to improve the sweep coefficient, and the residual heavy oil can be emulsified into oil droplets that are much smaller than pore throats. The developed collaborative emulsification system has excellent potential for enhancing heavy oil recovery after water/hot water flooding.

Feasibility Investigation on the N2 Injection Process to Control Water Coning in Edge Water Heavy Oil Reservoirs

N2 injection process is a potential technique to control the water coning behavior in heavy oil reservoirs. In this paper, by using the methods of experiment and numerical simulation, the N2 injection process for controlling the edge water coning behavior is investigated. First, through a visual fluid flow experimental device, the flow behavior of N2-water in porous media is discussed. Also, the effects of temperature, pressure, and injection rate were studied. Then, based on the experimental results, aiming at an actual edge water heavy oil reservoir, a reservoir simulation model is developed. Thus, the water coning behavior of edge aquifer is systematically studied. Also, two novel indicators are proposed to evaluate the water coning behavior. Then, a series of numerical models are developed to investigate the performance of N2 injection process in edge water heavy oil reservoirs after water coning, and the adaptability and the optimal operation parameters are analyzed. Results indicate that under the effect of porous media, N2 can cut into a series of small gas bubbles. It is a typical dispersed phase and can effectively plug the water coning path. Compared with pressure and injection rate, temperature is a more sensitive factor to affect the plugging performance of N2. From the simulation results, it is observed that the permeability, water/oil ratio, and distance between well and aquifer can significantly affect the performance of water coning behavior. N2 injection process can effectively control the edge water coning and improve the CSS performance. Furthermore, from the simulation results, it is found that the optimal operation parameters for a N2 injection process is that the total N2 injection volume should be higher than 6,000 m3 within one operation cycle and the optimal N2 injection rate should be lower than 700 m3/day. This investigation further clarifies the mechanisms of N2 injection process to control the water coning behavior in heavy oil reservoirs. It can provide a useful reference for the EOR process of the heavy oil reservoirs with edge water.

Research on the Water Production Tracking Method of Horizontal Well in Heavy Oil Reservoir with Bottom Water

Abstract At present, the model of heterogeneous fluid production in horizontal wells in bottom water reservoirs does not comprehensively consider the influence of parameters such as flow, length, and position of each production section, resulting in the distortion of interpretation results. Using the Green function and the Newman product method, this paper derives heterogeneous fluid production in horizontal wells in the bottom water heavy oil reservoir. The Stehfest numerical inversion algorithm was used to obtain the bottom fluid pressure solution of the horizontal well production in the bottom water heavy oil reservoir with the wellbore storage effect and skin effect. By drawing the typical chart of horizontal well test in sections, the new model can be divided into five typical flow stages: wellbore storage stage, transition stage, radial flow stage, linear flow stage, and late stable flow stage. Based on the interpretation of conventional parameters, such as permeability, well storage, and skin effect, the new model can further diagnose the parameters such as liquid production length, liquid production position, and liquid production volume of each horizontal section. The field application examples verify the validity of the research results and broad application prospects.

Inference of reaction kinetics for supercritical water heavy oil upgrading with a two‐phase stirred reactor model

AbstractWe present the development and application of a two‐phase stirred reactor model for heavy oil upgrading in the presence of supercritical water (SCW), with coupled phase‐specific thermolysis reaction kinetics and multicomponent hydrocarbon–water phase equilibrium. We demonstrate the inference of oil and water phase kinetics parameters for a compact lumped reaction kinetics scheme through the application of this model to two different sets of batch reactor experiments reported in the literature. We infer that, although SCW can suppress the formation of newer polynuclear aromatics (PNA) from distillate range species, it is broadly ineffective in deterring the combination of pre‐existing PNA fragments in the oil feed. Quantification of the conversion to distillate liquids before the onset of coke formation helps arrive at a clear conclusion on whether the use of SCW in the batch reactor leads to better product outcomes for different oil feeds and operating conditions.

A Population Balance Model for Emulsion Behavior of Alkaline Water–Heavy Oil Systems in Bulk Phase

A Population Balance Model for Emulsion Behavior of Alkaline Water–Heavy Oil Systems in Bulk Phase

Prediction models for multiphase‐flow‐induced corrosion of API X80 steel in CO2/H2S environment

AbstractIn the offshore oil and gas industry, mainly focusing on the use of rigid or flexible pipes of subsea infrastructure applied to risers or flowlines, one of the greatest difficulties is the interpretation of the combined effects of the various correlated phenomena (hydrodynamic effects of intermittent flow, the effects of corrosivity of the environment in addition to variations in pressure, temperature, and dynamic loading). On the basis of this scenario, defining the degree of severity of each of the correlated system variables becomes of fundamental importance for establishing reliable criteria for selecting materials for subsea application. The established flow pattern directly affects the corrosion rate (or the pipe material mass loss), but the balance of other variables including possible changes in the physical and transported fluid chemical properties may increase the damage up to an order of magnitude, which is a piece of information normally not foreseen in design criteria. Therefore, to improve the understanding of the corrosion study influenced by multiphase flow, a testing loop was designed and assembled at the Corrosion and Protection Laboratory of the Institute for Technological Research, in which API X80 steel coupons were positioned in locations with a 0° and 45° inclinations. Tests were conducted by varying the partial pressure of the gaseous phase containing blends of CO2 and H2S with N2 balance, mixed with the liquid phase containing light oil and heavy oil in water with salinity (NaCl)‐simulating oil well conditions with 80% water cut. The main objective of this study is to establish models that can predict the corrosion intensity in conditions close to those obtained experimentally. To achieve results, the multiple regression and Box–Cox transformation methods were applied. These models will make possible damage prediction and optimization of matrix parameters for the multiphase‐loop test.

Mechanisms on the stability and instability of water-in-oil emulsion stabilized by interfacially active asphaltenes: Role of hydrogen bonding reconstructing

Chemical demulsification is the most commonly used demulsification method for the separation of oil–water emulsions (W/O) in petroleum industry. Previous experiments demonstrate that the interfacially active asphaltenes (IAA) play the key role in stabilizing the heavy oil–water emulsions. Herein, the molecular dynamic simulation has been applied to reveal the molecular mechanisms on the stability and instability of the IAA-stabilized oil–water emulsions. It is found that IAA could accumulate at the oil–water interface and self-aggregate to form viscoelastic interfacial film through π-π stacking, hydrogen bonds (intermolecular and intramolecular) and other non-covalent bonds. Different types of hydrogen bonds (i.e., S = O…H-O, R-OH…H-O, N-H…N-R, S-H…S = O, S-H…S-R) are found between the IAA molecules due to the presence of heteroatoms (e.g., N, O, S) in IAA. Increasing the IAA concentration would increase the thickness of the IAA film which plays the key roles in stabilizing the emulsions. When the newly synthesized demulsifier (i.e., MJTJU-2) was added into the oil–water emulsion system, the oxygen groups (i.e., hydroxyl, ester groups, carboxyl groups, ether group) in demulsifier could weaken (at least 50%) or even break the hydrogen bonds and π-π stacking between IAAs and form new stronger hydrogen bonds with water molecules. This hydrogen bond reconstruction facilitates the breaking of the IAA film at the oil–water interface, allowing the coalescence of the water droplets in oil phase. This work would provide fundamental understanding for developing new way to efficiently demulsify the petroleum or similar oil–water emulsions.

Mechanism of Ultrasonic Physical-Chemical Viscosity Reduction for Different Heavy Oils.

In this study, the mechanism of physical–chemical viscosity reduction of different heavy oils under ultrasonic wave is explored. Experiments of viscosity reduction and viscosity recovery of different heavy oils under ultrasonic excitation were carried out, and the optimal ultrasonic parameters, ultrasonic physical disturbance, and cavitation viscosity reduction extent of different oil samples were determined. Based on the element analysis methods, four-component analysis, gas chromatography analysis, and formation water pH value test, the micro-mechanism of the oil chemical structure change and water samples under ultrasonic wave was analyzed. The results show that the water content, temperature, and initial viscosity of heavy oil are the key to reduce the viscosity of heavy oil. The higher viscosity of the initial oil sample, the higher water content, and the temperature were needed. Compared with the lower viscosity oil sample, the higher viscosity oil sample has higher extent of cavitation viscosity reduction and lower extent of physical disturbance viscosity reduction under ultrasonic wave. After ultrasonic treatment, the contents of heteroatoms, resins, and asphaltenes in heavy oil samples with high viscosity decreased significantly, and the conversion extent of high carbon chain to low carbon chain was greater. In addition, the pH of water in heavy oils decreased after ultrasonic treatment, and the pH of water in high viscosity heavy oil decreased more significantly after ultrasonic treatment.

Reversible Wettability between Underwater Superoleophobicity and Superhydrophobicity of Stainless Steel Mesh for Efficient Oil-Water Separation.

Design and fabrication of smart materials with reversible wettability for oil–water separation have attracted worldwide attention due to the increasingly serious water pollution problem. In this study, a rough oxide coating with micro/nanoscale structures is developed on the 304 stainless steel mesh (SSM) by laser ablation. The smart surface with ethanol immersion and natural drying treatments shows the wetting conversion between underwater superoleophobicity and superhydrophobicity. Based on the wettability transition behavior, both light and heavy oil–water mixtures can be separated with the high separation efficiency. Moreover, after being exposed to various corrosive solutions and high temperatures, the smart surface still shows prominent environmental stability. Switchable surface with excellent properties should be an optimal choice to solve the environmental conditions that need to be addressed urgently.

Recent progress in using hybrid silicon polymer composites for wastewater treatment

Heavy metal ions, oil and organic pollutants in water does not only cause serious water pollution, but also pose serious threats to ecosystems and human health. To this end, water pollution has gradually gained human attention, and various wastewater treatment methods are emerging. Organosilicon polymer composites are a class of materials that contain organic-inorganic hybrid structures with the characteristics of hydrophobicity, thermal stability and easy modification, which provides a brand new solution for wastewater treatment. In this review, various structural features including amorphous, linear, and cage structure of silicon containing polymer composites and the removal mechanism targeting at heavy metal ions, oil and organic pollutants of silicon containing polymer composites are summarized. The viewpoints and challenges in adsorption and engineering application are discussed, and possible solutions are proposed.

A Surfactant for Enhanced Heavy Oil Recovery in Carbonate Reservoirs in High-Salinity and High-Temperature Conditions

In view of the difficulty of producing heavy oil from carbonate reservoirs, the surfactant SDY-1 was synthesized by homogeneous solution polymerization with a homogeneous solution polymerization technique using aliphatic amine polyoxyethylene ether (PAEn) H(OCH2CH2)nNR(CH2CH2O)nH as the raw material, epichlorohydrin as the reaction intermediate, tetrabutylammonium bromide and pentamethyldivinyltriamine as the promoters, and alkylphenol as the catalyst. Based on the analysis of reservoir fluid and rock properties, the performance of the surfactant SDY-1 was evaluated in terms of its heat resistance, its salinity tolerance, its ability to change the heavy oil–water interfacial tension and rock wettability and its oil washing efficiency. The results show that when the salinity of the formation water is 2.23 × 105 mg/L, the addition of surfactant SDY-1 can lower the super-heavy oil–water interfacial tension with an asphaltene concentration of 30.19 wt.%, which is aged at a temperature of 140 °C for 3 days, from 22.41 to 0.366 mN/m. In addition, the surfactant SDY-1 can change the contact angle of super-heavy oil–water–rock from 129.7 to 67.4° and reduce the adhesion of crude oil to the rock surface by 99.26%. The oil displacement experiment indicates that the oil washing efficiency of the surfactant SDY-1 can reach 78.7% after ageing at a temperature of 140 °C for 3 days. Compared with petroleum sulfonate flooding, the addition of SDY-1 can improve the displacement efficiency by 33.6%, and the adsorption loss is only 0.651 mg/g oil sand. It has broad application prospects for heavy oil reservoirs with high temperatures, high pressures and high asphaltene contents.

Measurement of water content in heavy oil with cavity resonator

The study of optical microcavity sensors in current micro optical electromechanical systems (MOEMS) devices is an important research direction in this field. In this study, a surface plasmon optical waveguide structure with MIM (Metal Insulator Metal), semi-circular resonator, and T-shaped resonator was examined. The effects of the coupling distance, the geometrical size of the T-shaped cavity and its asymmetry, and the radius of the semi-circular cavity on the Fano resonance spectrum were analyzed numerically. The sensitivity of the refractive index sensor was up to1066.67nm/RIU. The detection of the water content of the heavy oil found that the Fano resonance line shifted to the short-wave direction as the volume percentage of the contained water increased. The volume percentage resolution of the sensor's heavy oil water content could be as low as2.05×10-9. The proposed structure can overcome the shortcomings of common refractive index sensors and therefore has great application prospects in chemical and biological sensing.

A General in Situ Deposition Strategy for Synthesis of Janus Composite Fabrics with Co(CO3)0.5OH·0.11H2O Nanoneedles for Oil–Water Separation

For a fixed porous framework, developing an efficient composite material with selective removal of oil and water from an oil–water mixture is of significance but challenging because of the effect of its decreased pore size and porosity and single wettability. Herein, a Janus fabric via a general strategy of surface hydrophobization, oxidation treatment, and chemical bath deposition is constructed. The obtained composite fabric consists of a hydrophilic Co(CO3)0.5OH·0.11H2O nanoneedle/cotton fiber side and a hydrophobic cotton fiber side, which endows it with a unidirectional water transportation capability and exhibits an effective separation for both light and heavy oil–water mixtures under gravity. Especially using the water wetted composite fabric as a separation cell, the built-in lyophobic layer originating from fluid passed through the nonwetting region of wetted fabric decreases the unfavorable contact between lyophobic interface and separated liquid, and the permeation flux is enhanced by 214.5% for water and by 112.5% for oil, respectively, compared to that in the pristine fabric, whereas it has no effect on the separation efficiency of a heavy oil–water mixture. Meanwhile, the Janus composite fabric exhibits an excellent oil–water separation stability and durability and is easily recycled for long-term use. The facile Janus material synthesis strategy is available on various substrates including melamine sponge, Ni foam, cellulose paper, and other nanosheet arrays on cotton fabric. Thus, this work provides a route to develop multifunctional materials for potential application in quick oily wastewater remediation.

Evaluation of Early High Speed Development of Bottom Water Heavy Oil Reservoir

The bottom water heavy oil reservoir has high natural energy, and the bottom water body multiple of the reservoir is 300 times or even higher. The natural energy of the reservoir can keep the superior condition that the formation energy does not decrease under the condition of large liquid volume and high recovery rate. In view of this reservoir condition, we take C oilfield as an example to carry out the oilfield development effect under the condition of large liquid volume and high-speed production, and analyze the influence of high-speed production and medium low-speed production on recovery rate of similar heavy oil bottom water-reservoir. The results show that the rising trend of water cut in oilfield is the same whether high-speed development with large liquid volume or conventional low-speed development is adopted. Under the condition of high liquid production, the sweep efficiency of water flooding is high in the same period of time, which has certain advantages of enhanced oil recovery. The development mode of early large liquid production is explored, which provides certain guidance for the efficient development of heavy oil reservoir with bottom water.

Coupling analysis of a new skin effect electric heat tracing system for deep water heavy oil pipeline

In order to ensure the safety of fluid flow in deep-water submarine pipelines, a safe and energy-saving built-in skin effect electric heat tracing technology was adopted as the thermal management strategy. By analyzing the multi-physics conditions of

On-Demand Oil-Water Separation by Environmentally Responsive Cotton Fabrics.

Environmentally responsive cotton fabrics were fabricated by dip-coating ABC miktoarm star terpolymers, which contain reactive poly(3-triisopropyloxysilylpropyl methacrylate) blocks, hydrophobic poly(dimethylsiloxane) (PDMS) blocks, and hydrophilic poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) blocks. The functionalized cotton fabrics with perfectly alternating PDMS and PDMAEMA blocks show underoil superhydrophobicity and underwater superoleophobicity. The wettability and permeability of the functionalized fabrics can be readily adjusted by the contacting medium. More interestingly, surface reconstruction causes a reduction in the breakthrough pressure of the nonwetting phase. The adaptive permeability endows the functionalized cotton fabrics with the capability to separate heavy oil–water–light oil ternary mixtures.

Overview of emulsified viscosity reducer for enhancing heavy oil recovery

Chinese water flooding heavy oil reserves are abundant and the output is increasing year by year, but the heavy oil water flooding recovery rate is low. It is of great significance to improve the heavy oil water flooding recovery rate to improve the development level of heavy oil reservoirs. This paper reviews heavy oil emulsified viscosity reduction technology, emulsified viscosity reduction theory, viscosity reducer flooding microscopic mechanism and structural characteristics of surfactants for heavy oil emulsified viscosity reduction. Meanwhile, the research focus of emulsified viscosity reducer in the future is put forward.