注入介质和注入方式对致密油提高采收程度影响实验研究——以大庆扶余储层为例

doi:10.13809/j.cnki.cn32-1825/te.2025.04.003

Abstract

Abstract:

Tight oil reservoirs, as a key focus in China’s current oil and gas development, present significant exploration challenges due to their poor physical properties, limited connectivity, and strong heterogeneity. During the exploration of tight oil reservoirs, the influence of different injection media and production methods on recovery mechanisms and performance remains unclear, severely restricting their efficient exploration of these reservoirs. Taking the Fuyu reservoir in the Daqing oilfield of PetroChina as a case study, laboratory experiments involving dynamic core injection were conducted using various injection media (CO₂ and surfactants) and methods (displacement, huff-n-puff, and gas-water alternating injection) to investigate their effects on oil recovery mechanisms and efficiency in tight reservoirs. The results indicated that gas-water alternating displacement improved underground oil recovery by 4.14% compared to CO₂ displacement and by 15.38% compared to surfactant displacement. Similarly, gas-water alternating huff-n-puff increased oil recovery by 0.54% over CO₂ huff-and-puff and by 5.09% compared to surfactant huff-n-puff. Displacement methods, after forming preferential oil flow channels, exhibited larger sweep volumes and higher oil displacement efficiency than huff-and-puff methods. Moreover, gas-water alternating injection effectively reduced fluid channeling compared to single-media injection and enhanced the sweep of fine pore spaces. Due to CO₂’s superior viscosity reduction and dissolved gas drive effects on reservoir crude oil, CO₂ injection achieved higher recovery than surfactant injection. Under identical injection-production conditions, low-viscosity crude oil exhibited a higher recovery compared to high-viscosity crude oil, as increased viscosity significantly raised flow resistance. The study reveals the differences in recovery performance associated with various injection media and methods, providing experimental evidence and theoretical support for the efficient development of tight oil reservoirs.

Key words: tight oil reservoir, surfactant, displacement, huff-n-puff, gas-water alternating injection, enhanced oil recovery

CLC Number:

TE357

TANG Yong,YUAN Chengang,HE Youwei, et al. Experimental study on injection media and methods for enhanced oil recovery in tight oil reservoirs: A case study of Fuyu reservoir in Daqing[J]. Petroleum Reservoir Evaluation and Development, 2025, 15(4): 554-563.

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井号	地层压力/MPa	饱和压力/MPa	原始气油比	地层温度/℃	体积系数	原油密度/(g/cm³)	原油黏度/(mPa·s)	溶解系数/[(m³/m³)/MPa]	CO₂最小混相压力/MPa
塔21-4外扩区块	18.90	7.58	31.45	98.0	1.15	0.768	2.53	4.052	32.12
葡483-481区块	15.64	4.09	14.84	85.4	1.09	0.808	5.03	3.630	31.30

岩心编号	长度/cm	直径/cm	渗透率/10^-3μm²	孔隙度/%	孔隙体积/cm³
3-1	8.16	2.5	1.20	12.37	4.99
9-1	8.20	2.5	1.02	16.15	6.50
5-4	6.20	2.5	0.98	11.14	3.39
7-3	8.25	2.5	0.92	12.34	5.08

岩心编号	长度/cm	直径/cm	渗透率/10^-3 μm²	孔隙度/%	孔隙体积/cm³
43-3	8.06	2.5	0.85	14.37	2.348
26-4	7.91	2.5	1.03	11.15	2.230
47-1	7.90	2.5	1.20	12.14	2.242
28-1	8.20	2.5	1.18	11.34	3.577

Experimental study on injection media and methods for enhanced oil recovery in tight oil reservoirs: A case study of Fuyu reservoir in Daqing

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