Dynamic imbibition with aid of surfactant in tight oil fracture network model

Sun, Yongpeng; Gao, Kai; Yu, Zhihao; Fang, Yanchao; Chang, Yilin; Chen, Ang; Dai, Caili; Wang, Chuanxi; Chen, Chao; Xu, Yingbiao

doi:10.1016/j.petrol.2020.107393

Cited by 15 publications

(5 citation statements)

References 22 publications

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“…Only when the speed of these two processes matched could the maximum recovery be achieved. Compared with the previous dynamic imbibition study with matrix-fracture model [34], if the surfactant flow rate was too fast or too slow, the oil recovery rate was not the best. Only at a suitable surfactant flow rate, the oil recovery by surfactant imbibition could reach the maximum oil recovery.…”

Section: Effect Of Surfactant Flow Ratementioning

confidence: 70%

“…The smaller the IFT, the smaller the E, the smaller the adhesion work, and the smaller the imbibition resistance. When the IFT increased from 0.16 mN/m to 0.59 mN/m, the contact angle only decreased from 96.07 • to 86.65 • [34], and the E increased from 0.013 to 0.040. However, at the same time, because tight reservoirs were usually accompanied by the development of microfractures, when the surfactant flowed along the microfractures during the injection process, a higher recovery rate could be obtained, but at this time, we should also pay attention to the dynamic adsorption amount of surfactant molecules in microfractures.…”

Section: Discussionmentioning

confidence: 94%

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Experimental Study on Oil Drop Discharge Behavior during Dynamic Imbibition in Tight Oil Sandstone with Aid of Surfactant

et al. 2022

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The pore and throat structure of tight oil reservoir cores is complex, and the resistance of oil drop to discharge from the core is very high during dynamic imbibition. Surfactant has good ability in interfacial tension reduction and wettability reversal. It can reduce oil drop discharge resistance and enhance oil recovery effectively during dynamic imbibition in tight reservoirs. Here, we first analyzed the pore throat structure and mineral composition of tight core, and then the oil drop visualization instrument was used to study the discharge behavior of oil drop during dynamic imbibition. The oil drop discharge form was analyzed, and the influence of various factors on the oil drop discharge behavior was explored, and then the dynamic imbibition performance of surfactant in tight cores was obtained. The core throat diameter was mainly distributed in 0.07–1.1 μm, and the hydrophilic mineral content in core reached 50.8%. In the case of fluid flow in fracture, the oil drop discharge from near fracture matrix was faster, and its growth rate in height and width was faster than that without external fluid flow. Within a certain range, with the increase of IFT, the rate of core imbibition increased gradually. When the IFT increased from 0.32 mN/m to 0.59 mN/m, the oil drop rapture time decreased by 66.3%. The growth rate of oil drop discharged from the top and side of the core was faster than that from the bottom surface. Furthermore, it was easier to discharge. With the core thickness reduced by half, the rapture time of oil drop was reduced by 74.7%. For tight reservoirs, hydraulic fracturing can create more fracture surfaces and reduce the size of matrix blocks, which contributes to reduce the oil drop discharge resistance during imbibition and improve the oil recovery. This study provides a basis for surfactant to improve dynamic imbibition and oil production performance of tight sandstone oil reservoir.

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Section: Effect Of Surfactant Flow Ratementioning

confidence: 70%

Section: Discussionmentioning

confidence: 94%

Experimental Study on Oil Drop Discharge Behavior during Dynamic Imbibition in Tight Oil Sandstone with Aid of Surfactant

et al. 2022

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“…Their results show that the pressurized seepage rate is higher than the spontaneous seepage, and pressure has a great influence on the seepage recovery of large and medium pores. Sun et al 19 studied the dynamic seepage pattern under complex fracture networks, adopted the NMR technique to analyze the distribution of oil in the matrix, analyzed the effect of interfacial tension and wettability on the recovery rate of seepage suction, and concluded that surfactants mainly enhance the recovery rate of the matrix near the fracture. Dong et al 20 studied the effect of interfacial tension on seepage recovery on the basis of static seepage experiments.…”

Section: Introductionmentioning

confidence: 99%

Investigation on Imbibition Mechanism of Tight Core Based on NMR Test

et al. 2023

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Seepage is important to improve the postpressure production enhancement effect of tight oil and gas reservoirs. To study the microscopic percolation law of different pores, this paper first characterizes the pore structure of tight cores. High-pressure spontaneous percolation experiments and nuclear magnetic resonance (NMR) tests were combined. The T 2 spectra at different times of percolation were used. The percolation law of different pore types was quantitatively characterized from a microscopic perspective. The effect of different interfacial tensions on the percolation was clarified. Results show that the pore size has a good match with the NMR T 2 relaxation time. The core pore development is dominated by submicrometer pores, which account for more than 70%. The percolation rate is fast at the beginning and then decreases and stabilizes at 48 h. The pore size of the submicropore is small, the capillary force is large, and the recovery rate of percolation is high, followed by those of the micropore and the medium-pore. The higher the porosity and permeability of the core, the greater the overall seepage recovery rate. The sensitivity of submicrometer pores to interfacial tension is great, and the recovery rate increases by 40.9% when the interfacial tension decreases from 17.1 to 1.46 mN/m. Furthermore, as the interfacial tension decreases, the recovery rate of different pores appears to increase first and then decrease. The surfactant formulation must be selected reasonably in practical production.

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“…As an important unconventional resource, tight oil has gradually emerged as a focus of global exploration and development in unconventional oil and gas, following the attention on shale gas. , Tight oil in China started late but developed rapidly, mainly being distributed in the Junggar, Sichuan, Qaidam, Ordos, and Jiuquan basins. − Preliminary estimates indicate that China’s tight oil geological resource amounts to 1.782 billion metric tons, with a technically recoverable resource of 176.5 million metric tons. , …”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Surfactant-Aided Dynamic Spontaneous Imbibition in Tight Oil Reservoirs: The Effect of Fluid Flow, Displacement Pressure, Temperature, and Fracture

Wang,

Zeng,

Wang

et al. 2023

Energy Fuels

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Spontaneous imbibition has emerged as a crucial mechanism for enhancing oil recovery in tight oil reservoirs. However, most of the existing spontaneous imbibition experiments have been static in nature. The dynamic effects of fluid flow, fluid type, displacement pressure, and fractures on the imbibition oil recovery have not been adequately addressed in previous studies. To fill this gap in knowledge and gain a comprehensive understanding of the mechanisms underlying surfactant-aided dynamic spontaneous imbibition, we conducted a series of experiments on tight cores extracted from the Chang 8 formation in the Ordos Basin in Northwest China. The experiments comprised static imbibition, dynamic imbibition, and water flooding displacement, and the impacts of fractures, temperature, type of imbibition fluid, and flow rate on imbibition recovery were analyzed. The results of the experiments showed that fractures have a significant impact on the imbibition oil recovery rate, with the ultimate recovery factor of the fractured core ranging from 16 to 29%, which is higher than that of the matrix core. Dynamic imbibition, on average, resulted in a recovery of 16%, which was higher than that with static imbibition. The use of surfactant solutions enhanced the oil recovery of cores, particularly in dynamic imbibition processes. This was attributed to the acceleration of emulsification between surfactants and crude oil, which led to an increased imbibition rate and oil recovery factor. Displacement was found to be an effective method for recovering the oil not produced through imbibition. The total oil recovery factors of the core samples after imbibition and displacement are in the ranges of 25% and 61%. This study is aimed at investigating the underlying mechanisms of various imbibition processes and examining the influence of various factors on the efficiency of spontaneous imbibition, with the ultimate goal of recovery enhancement in tight oil reservoirs.

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Dynamic imbibition with aid of surfactant in tight oil fracture network model

Cited by 15 publications

References 22 publications

Experimental Study on Oil Drop Discharge Behavior during Dynamic Imbibition in Tight Oil Sandstone with Aid of Surfactant

Experimental Study on Oil Drop Discharge Behavior during Dynamic Imbibition in Tight Oil Sandstone with Aid of Surfactant

Investigation on Imbibition Mechanism of Tight Core Based on NMR Test

Experimental Study of Surfactant-Aided Dynamic Spontaneous Imbibition in Tight Oil Reservoirs: The Effect of Fluid Flow, Displacement Pressure, Temperature, and Fracture

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