Studies on the Stability of the Foamy Oil in Developing Heavy Oil Reservoirs

2017 ◽  
Vol 371 ◽  
pp. 111-116 ◽  
Author(s):  
Bashir Busahmin ◽  
Brij Maini ◽  
Rama Rao Karri ◽  
Maziyar Sabet

In the process of natural energy depletion, foamy oil is characterized of low production Gas Oil Ratio, high oil viscosity, high daily production rate and high primary recovery factor. The stability of the foam turns out to be the prevailing factor that governs the life of the ‘foamy oil’. To enumerate the main factors affecting the stability of the foam, a high-temperature–high-pressure visualized experiment model for foamy oil stability test was developed. A serial of experiments was conducted to evaluate the performance of the foam stability. The effects of oil viscosity, height of the oil column, dissolved gas content and dispersed gas were investigated and recorded. These experiments were conducted using a Hele-Shaw, a high pressure cell. The volume of foamy oil produced, either by a step reduction in pressure or by a gradual (linear) reduction in pressure, and its subsequent decay was observed, visually. The experimental results show that foamy oil stability increases with higher oil viscosity, higher oil column, higher dissolved gas content and higher pressure decline rate. Asphaltene content was not observed to increase the foamy oil stability significantly. The results also show that the foam quality of foamy oils is much lower than aqueous foams.

2021 ◽  
Author(s):  
Xueqing Tang ◽  
Ruifeng Wang ◽  
Zhongliang Cheng ◽  
Hui Lu

Abstract Halfaya field in Iraq contains multiple vertically stacked oil and gas accumulations. The major oil horizons at depth of over 10,000 ft are under primary development. The main technical challenges include downdip heavy oil wells (as low as 14.56 °API) became watered-out and ceased flow due to depleted formation pressure. Heavy crude, with surface viscosities of above 10,000 cp, was too viscous to lift inefficiently. The operator applied high-pressure rich-gas/condensate to re-pressurize the dead wells and resumed production. The technical highlights are below: Laboratory studies confirmed that after condensate (45-52ºAPI) mixed with heavy oil, blended oil viscosity can cut by up to 90%; foamy oil formed to ease its flow to the surface during huff-n-puff process.In-situ gas/condensate injection and gas/condensate-lift can be applied in oil wells penetrating both upper high-pressure rich-gas/condensate zones and lower oil zones. High-pressure gas/condensate injected the oil zone, soaked, and then oil flowed from the annulus to allow large-volume well stream flow with minimal pressure drop. Gas/condensate from upper zones can lift the well stream, without additional artificial lift installation.Injection pressure and gas/condensate rate were optimized through optimal perforation interval and shot density to develop more condensate, e.g. initial condensate rate of 1,000 BOPD, for dilution of heavy oil.For multilateral wells, with several drain holes placed toward the bottom of producing interval, operating under gravity drainage or water coning, if longer injection and soaking process (e.g., 2 to 4 weeks), is adopted to broaden the diluted zone in heavy oil horizon, then additional recovery under better gravity-stabilized vertical (downward) drive and limited water coning can be achieved. Field data illustrate that this process can revive the dead wells, well production achieved approximately 3,000 BOPD under flowing wellhead pressure of 800 to 900 psig, with oil gain of over 3-fold compared with previous oil rate; water cut reduction from 30% to zero; better blended oil quality handled to medium crude; and saving artificial-lift cost. This process may be widely applied in the similar hydrocarbon reservoirs as a cost-effective technology in Middle East.


SPE Journal ◽  
2019 ◽  
Vol 25 (01) ◽  
pp. 416-431 ◽  
Author(s):  
Songyan Li ◽  
Qun Wang ◽  
Zhaomin Li

Summary Foam flooding is an important method used to protect oil reservoirs and increase oil production. However, the research on foam fluid is generally focused on aqueous foam, and there are a few studies on the stability mechanism of oil-based foam. In this paper, a compound surfactant consisting of Span® 20 and a fluorochemical surfactant is determined as the formula for oil-based foam. The foam volume and half-life in the bulk phase are measured to be 275 mL and 302 seconds, respectively, at room temperature and atmospheric pressure. The stability mechanism of oil-based foam is proposed by testing the interfacial tension (IFT) and interfacial viscoelasticity. The lowest IFT of 18.5 mN/m and the maximum viscoelasticity modulus of 16.8 mN/m appear at the concentration of 1.0 wt%, resulting in the most-stable oil-based foam. The effect of oil viscosity and temperature on the properties of oil-based foam is studied. The foam stability increases first and then decreases with the rising oil viscosity, and the stability decreases with rising temperature. The apparent viscosity of oil-based foam satisfies the power-law non-Newtonian properties, and this viscosity is much higher than that of the phases of oil and CO2. The flow of oil-based foam in porous media is studied through microscopic-visualization experiments. Bubble division, bubble merging, and bubble deformation occur during oil-based-foam flow in porous media. The oil-recovery efficiency of the oil-based-foam flooding is 78.3%, while the oil-recovery efficiency of CO2 flooding is only 28.2%. The oil recovery is enhanced because oil-based foam reduces CO2 mobility, inhibits gas channeling, and improves sweep efficiency. The results are meaningful for CO2 mobility control and for the application of foam flooding for enhanced oil recovery (EOR).


2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Liang Zhang ◽  
Jun Kang ◽  
Yin Zhang ◽  
Panfeng Zhang ◽  
Shaoran Ren ◽  
...  

The CO2 foam generated by the conventional surfactants usually does not show long-term stability due to the substantial solubility and diffusivity of CO2 in water. Silica nanoparticles with different wettability and high adsorption energy on the gas–water interface can be used as a stabilizer to enhance the stability of the CO2 foam. In this study, nine kinds of nonionic amine surfactants were employed to generate the CO2 foam, while three kinds of silica nanoparticles were selected and added to improve the CO2 foam stability. The influences of various factors, including pressure, temperature, pH, surfactant, and nanoparticle, on the CO2 foam stability have been investigated. The experimental results show that without nanoparticles, the CO2 foam stability decreases with the increase of the number of EO groups in the ethoxylated amine surfactant, especially under high-temperature and high-pressure (HTHP) conditions. In general, the nanoparticles with a low concentration (<0.5 wt %) have little influence on the CO2 foam stability, but when the concentration of nanoparticle is enhanced high enough (1.0 wt %), the CO2 foam stability can be improved significantly. In particular, by adding 1.0 wt % nanoparticle of QS-150 to 0.5 wt % surfactant of C18N(EO)2/10, the CO2 foam stability has been increased 5–6 times, while the volume of generated CO2 foam has been increased by 17–31%. Therefore, in this study, the synergetic mechanisms between the amine surfactants and the silica nanoparticles to generate and stabilize CO2 foam have been identified.


2021 ◽  
Vol 16 (1) ◽  
pp. 92-101
Author(s):  
Guanghui Xia ◽  
Xinhua Li ◽  
Zhen Zhang ◽  
Yuhang Jiang

Abstract Polygonatum odoratum (Mill.) Druce (POD) is a natural plant widely used for food and medicine, thanks to its rich content of a strong antioxidant agent called homoisoflavones. However, food processing methods could affect the stability of POD flavones, resulting in changes to their antioxidant activity. This study attempts to evaluate the antioxidant activity of POD flavones subject to different processing methods and determines which method could preserve the antioxidant activity of POD flavones. Therefore, flavones were extracted from POD samples, which had been treated separately with one of the four processing methods: extrusion, baking, high-pressure treatment, and yeast fermentation. After that, the antioxidant activity of the flavones was subject to in vivo tests in zebrafish embryos. The results show that yeast fermentation had the least disruption to the antioxidant activity of POD flavones, making it the most suitable food processing method for POD. By contrast, extrusion and high-pressure treatment both slightly weakened the antioxidant activity of the flavones and should be avoided in food processing. The research results provide a reference for the development and utilization of POD and the protection of its biological activity.


Author(s):  
Wangzhi Zou ◽  
Xiao He ◽  
Wenchao Zhang ◽  
Zitian Niu ◽  
Xinqian Zheng

The stability considerations of centrifugal compressors become increasingly severe with the high pressure ratios, especially in aero-engines. Diffuser is the major subcomponent of centrifugal compressor, and its performance greatly influences the stability of compressor. This paper experimentally investigates the roles of vanes in diffuser on component instability and compression system instability. High pressure ratio centrifugal compressors with and without vanes in diffuser are tested and analyzed. Rig tests are carried out to obtain the compressor performance map. Dynamic pressure measurements and relevant Fourier analysis are performed to identify complex instability phenomena in the time domain and frequency domain, including rotating instability, stall, and surge. For component instability, vanes in diffuser are capable of suppressing the emergence of rotating stall in the diffuser at full speeds, but barely affect the characteristics of rotating instability in the impeller at low and middle speeds. For compression system instability, it is shown that the use of vanes in diffuser can effectively postpone the occurrence of compression system surge at full speeds. According to the experimental results and the one-dimensional flow theory, vanes in diffuser turn the diffuser pressure rise slope more negative and thus improve the stability of compressor stage, which means lower surge mass flow rate.


1996 ◽  
Vol 14 (2) ◽  
pp. 157-169 ◽  
Author(s):  
Yuan Gu ◽  
Sizu Fu ◽  
Jiang Wu ◽  
Songyu Yu ◽  
Yuanlong Ni ◽  
...  

The experimental progress of laser equation of state (EOS) studies at Shanghai Institute of Laser Plasma (SILP) is discussed in this paper. With a unique focal system, the uniformity of the laser illumination on the target surface is improved and a laser-driven shock wave with good spatial planarity is obtained. With an inclined aluminum target plane, the stability of shock waves are studied, and the corresponding thickness range of the target of laser-driven shock waves propagating steadily are given. The shock adiabats of Cu, Fe, SiO2 are experimentally measured. The pressure in the material is heightened remarkably with the flyer increasing pressure, and the effect of the increasing pressure is observed. Also, the high-pressure shock wave is produced and recorded in the experimentation of indirect laser-driven shock waves with the hohlraum target.


2013 ◽  
Vol 634-638 ◽  
pp. 3110-3113
Author(s):  
Shu Huan Wang ◽  
He Jun Zhang ◽  
Ding Guo Zhao

According to the actual situation of refining high nitrogen steel with the laboratory high pressure reaction axe, the molten steel flow field in the high-pressure and bottom-blowing nitrogen reactor was simulated by using the software Fluent. The rules of the influence of pressure factor on the molten steel flow field characteristics, turbulent kinetic energy and gas content were explored. According to the characteristics of the flow field and gas-liquid two phase structure, the rules of the influence of pressure factor on nitrogen concentration distribution were analyzed. So some useful theoretical basis and guidance were provided for laboratory refining high nitrogen steel and industrial production in the future.


1981 ◽  
Vol 21 (04) ◽  
pp. 410-414 ◽  
Author(s):  
David L. Holcomb ◽  
Ed Callaway ◽  
Lynn L. Curry

Abstract Laboratory equipment has been designed specificallyto study effectively the microscopic structure offlowing foams at high pressures. In addition, application of foaming-agent optimization techniquesto design stable foams at varying foam qualities isdemonstrated at high pressures - i.e., 500 to 2,000psig (3448 to 13 792 kPa). Capillary viscosity datafor these foams is established and correlated with avideo-photomicroscopic study of the flowing foamand their designated bubble qualities. Foaming-agent screening information from the tests is providedindicating the foaming-agent generic chemistry thatallows optimal foam stability under high-pressure conditions. Introduction The study of contemporary foam rheology has arather interrupted history beginning with Fried'swork in 1961 on a foam drive process, which was followed by Raza and Marsden's 1965 paper onrheology and streaming potential. During 1969Blauer et al. studied foam flow properties andmade successful comparisons of data obtained incapillary viscometer tests and actual oilfield tubulardata. These investigations lead to the development ofdata and calculated procedures for using high-qualityfoams as fracturing fluids to transport proppanteffectively with extremely low formation damage as aresult of smaller amounts of water or liquid incontact with the formation. With all the theoretical depiction of flowing foamstructure, it was felt that a study was needed to showvisually the actual flowing foam under pressure. Thiswas undertaken in a study' where oil-foamingsurfactant concentrations were optimized using anapparatus similar to ours. (The majority of foamstimulation treatments use aqueous bases, and thisstudy was conducted exclusively with them.) The goal of this project was to design equipmentthat could be adapted to a TV camera/microscopesystem to allow videotaping of flowing foam in aview cell under pressure. To study effectively thechemical nature of four different surfactant foams, the temperature was kept at 80 deg. F (26.7 deg. C)throughout the study. Also, one foam quality of88%, or 88% nitrogen and 12% water was chosenusing 2% KCl water as the liquid phase. Selected pictures from the videotape are presented to show thesuccession of bubble-structure change with pressure.In addition, the effect of surfactant concentration (which had been thought to play a small role, if any, in the rheology of foams) is shown. This allows aneven greater ability to optimize surfactant concentration in the production of stable foams forstimulation. The subjective bubble-quality scale of Holcomb etal. is refined by showing the average bubblediameters at various study pressures and is demonstrated photographically in Figs. 1 through 3.For the viscosity tests through the capillaryviscometer system, a constant 1,000-psi input pressure was maintained for the generation of foam. Testing Apparatus, Procedure, and Chemical Additives The high-pressure test apparatus was designed tomeet the rate requirements for a laboratory testsample of 700 cm (liquid) or more. The system iscapable of pressures to 3,000 psi (20 683 kPa). The pump is a Williams Oscillamatic TM single-strokemodel with a pressure rating to 10,000 psi (68 946kPa). All main lines are 6.35 mm in diameter. Trunklines to the gauges are 3.175-mm-diameter tubing.All tubing in the apparatus is 316 stainless steel. (SeeFig. 4.) SPEJ P. 410^


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