The Alteration of Reservoir-Cap’s System During CO2 Charging in Huangqiao Region, China

2020 ◽  
Author(s):  
Bing Zhou ◽  
Zengmin Lun
Keyword(s):  
Oil Recovery ◽  
Rock Interaction ◽  
Rock System ◽  
Micro Cracks ◽  
Average Porosity ◽  
Calcite Veins ◽  
Longtan Reservoir ◽  
Authigenic Mineral ◽  
Cap Rock ◽  
Enhance Oil Recovery

<p>Revealing the alteration mechanism of reservoir-cap rock system during CO<sub>2</sub>-rich fluid charging is meaningful to the study of CO<sub>2</sub> geological storage, as well as when CO<sub>2</sub> enhance oil recovery. The study is taking the Permian Longtan reservoir formation and Dalong cap layer of Huangqiao and Jurong region in Lower Yangtze area in China as comparative study objects, in order to understand the differences between presence and absence of CO<sub>2</sub> in the similar geological background. The samples of reservoirs and cap rock in both regions are analysized through petrological and geochemistry method. The authigenic minerals in the reservoirs of Huangqiao region are mainly overgrowth quartz and kaolinite. A small amount of dawsonite is developed in Huangqiao, while undeveloped in Jurong region due to the absent of CO<sub>2</sub>. The content of secondary quartz is lower in Jurong than in Huangqiao. The reservoir’s average porosity in Huangqiao is obviously higher than in Jurong, because of the feldspar’s dissolution during CO<sub>2</sub> charging. The cap rocks in the two areas are both black block mudstones. There were micro-cracks developed in the cap rocks of Huangqiao region, in which have been refilled with calcite veins. Carbon isotope data shows that calcite was formed from CO<sub>2</sub>-water-rock interaction. The result indicates that CO<sub>2</sub> charging could cause a major dissolution of feldspar in reservoir, and precipitate a typical authigenic mineral assemblage of dawsonite, secondary quartz and kaolinite. The continuous activity of the CO<sub>2</sub>-rich fluid leads to re-precipitation of carbonate minerals in cap rock, which is improving its sealing ability.</p>

scholarly journals Investigation on the effect of active-polymers with different functional groups for EOR

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 61-68
Author(s):  
Dong Zhang ◽  
Jian Guang Wei ◽  
Run Nan Zhou
Keyword(s):  
Functional Groups ◽  
Oil Recovery ◽  
Molecular Size ◽  
Type I ◽  
Cleaning Efficiency ◽  
Sweep Efficiency ◽  
Profile Control ◽  
Branched Chain ◽  
Swept Volume ◽  
Enhance Oil Recovery

AbstractActive-polymer attracted increasing interest as an enhancing oil recovery technology in oilfield development owing to the characteristics of polymer and surfactant. Different types of active functional groups, which grafted on the polymer branched chain, have different effects on the oil displacement performance of the active-polymers. In this article, the determination of molecular size and viscosity of active-polymers were characterized by Scatterer and Rheometer to detect the expanded swept volume ability. And the Leica microscope was used to evaluate the emulsifying property of the active-polymers, which confirmed the oil sweep efficiency. Results show that the Type I active-polymer have a greater molecular size and stronger viscosity, which is a profile control system for expanding the swept volume. The emulsification performance of Type III active-polymer is more stable, which is suitable for improving the oil cleaning efficiency. The results obtained in this paper reveal the application prospect of the active-polymer to enhance oil recovery in the development of oilfields.

Black Rice Huskash is a Useful Template for Foam Stability to Enhance Oil Recovery (EOR)

2021 ◽  
Vol 56 (6) ◽  
pp. 962-970
Author(s):  
Ishaq Ahmad ◽  
Liu Chengwen ◽  
Wu Mingxuan ◽  
Xu Zhengxiao ◽  
Atif Zafar ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Foam Stability ◽  
Black Rice ◽  
Enhance Oil Recovery

A Temperature Operating Window Concept for Application of Nonionic Surfactants for EOR in Unconventional Shale Reservoirs

2021 ◽  
Author(s):  
I Wayan Rakananda Saputra ◽  
David S. Schechter
Keyword(s):  
Crude Oil ◽  
Nonionic Surfactant ◽  
Cloud Point ◽  
Oil Recovery ◽  
Nonionic Surfactants ◽  
Spontaneous Imbibition ◽  
Reservoir Temperature ◽  
Rock System ◽  
Temperature Operating ◽  
Operating Window

Abstract Surfactant performance is a function of its hydrophobic tail, and hydrophilic head in combination with crude oil composition, brine salinity, rock composition, and reservoir temperature. Specifically, for nonionic surfactants, temperature is a dominant variable due to the nature of the ethylene oxide (EO) groups in the hydrophilic head known as the cloud point temperature. This study aims to highlight the existence of temperature operating window for nonionic surfactants to optimize oil recovery during EOR applications in unconventional reservoirs. Two nonylphenol (NP) ethoxylated nonionic surfactants with different EO head groups were investigated in this study. A medium and light grade crude oil were utilized for this study. Core plugs from a carbonate-rich outcrop and a quartz-rich outcrop were used for imbibition experiments. Interfacial tension and contact angle measurements were performed to investigate the effect of temperature on the surfactant interaction in an oil/brine and oil/brine/rock system respectively. Finally, a series of spontaneous imbibition experiments was performed on three temperatures selected based on the cloud point of each surfactant in order to construct a temperature operating window for each surfactant. Both nonionic surfactants were observed to improve oil recovery from the two oil-wet oil/rock system tested in this study. The improvement was observed on both final recovery and rate of spontaneous imbibition. However, it was observed that each nonionic surfactant has its optimum temperature operating window relative to the cloud point of that surfactant. For both nonionic surfactants tested in this study, this window begins from the cloud point of the surfactant up to 25°F above the cloud point. Below this operating window, the surfactant showed subpar performance in increasing oil recovery. This behavior is caused by the thermodynamic equilibrium of the surfactant at this temperature which drives the molecule to be more soluble in the aqueous-phase as opposed to partitioning at the interface. Above the operating window, surfactant performance was also inferior. Although for this condition, the behavior is caused by the preference of the surfactant molecule to be in the oleic-phase rather than the aqueous-phase. One important conclusion is the surfactant achieved its optimum performance when it positions itself on the oil/water interface, and this configuration is achieved when the temperature of the system is in the operating window mentioned above. Additionally, it was also observed that the 25°F operating window varies based on the characteristic of the crude oil. A surfactant study is generally performed on a single basin, with a single crude oil on a single reservoir temperature or even on a proxy model at room temperature. This study aims to highlight the importance of applying the correct reservoir temperature when investigating nonionic surfactant behavior. Furthermore, this study aims to introduce a temperature operating window concept for nonionic surfactants. This work demonstrates that there is not a "one size fits all" surfactant design.

Graphene: Outlook in the enhance oil recovery (EOR)

2021 ◽  
Vol 321 ◽  
pp. 114519 ◽  
Author(s):  
Surajudeen Sikiru ◽  
Amir Rostami ◽  
Hassan Soleimani ◽  
Noorhana Yahya ◽  
Yusuf Afeez ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Enhance Oil Recovery

Water-Flooding Fluid Diversion Copolymeric Microsphere Prepared by Inverse Suspension Polymerization

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Huang Zhiyu ◽  
Lu Hongsheng ◽  
Zhang Tailiang
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Oil Recovery ◽  
High Salinity ◽  
Suspension Polymerization ◽  
Oil Reservoirs ◽  
Water Flooding ◽  
Toughness Index ◽  
Inverse Suspension Polymerization ◽  
Enhance Oil Recovery

Abstract In order to enhance oil recovery in high-temperature and high-salinity oil reservoirs, the copolymeric microspheres containing acrylamide (AM), acrylonitrile (AN) and AMPS was synthesized by inverse suspension polymerization. The copolymeric microsphere was very uniform and the size could be changed according to the condition of polymerization. The lab-scale studies showed that the copolymeric microsphere exhibit good salt-tolerance and thermal-stability when immersed in 20×105 mg/L NaCl(or KCl) solution, 7500 mg/L CaCl2 (or MgCl2) solution or 2000 mg/L FeCl3 solution, respectively. The copolymeric microsphere showed satisfactory absorbency rates. The sand-pipes experiments confirmed that the average toughness index was 1.059. It could enhance the oil recovery by about 3% compared with the corresponding irregular copolymeric particle.

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