多因素下多级交替注入酸液指进实验研究

摘要/Abstract

摘要：

酸液黏性指进演化特征及最终形态受多种工程地质因素影响,利用可视化指进实验装置,以分形维数和多重分形谱宽度表征指进形态,综合考虑酸液浓度、注入级数、温度、施工排量、前置液酸液黏度比和裂缝倾角六个因素,探究多因素下酸液黏性指进演化特征及最终形态的变化规律。结果表明：各个因素对分形维数的影响程度由高到低依次为：黏度比、注入级数、温度、酸液浓度、施工排量、裂缝倾角;各个因素对多重分形谱宽度的影响程度由高到低依次为：黏度比、裂缝倾角、施工排量、酸液浓度、注入级数、温度;要实现黏性指进酸压,应当提高黏度比至100∶1~150∶1,控制注入级数为2~3级,设计酸液用量占比0.3左右,并在注入酸液前注入大量前置液降低裂缝壁面温度。

关键词: 酸压, 酸液指进, 物理模拟, 分形维数, 多重分形谱宽度

Abstract:

The evolution characteristics and the final shape of acid viscosity fingering are influenced by many engineering and geological factors. So that, we used the visual experimental device to explore the change rules under the multifactor. Six factors were considered, those are the concentration of acid, the injection series, the temperature, the construction displacement, the viscosity ratio of the liquid, and the inclination of crack. The fractal dimension and multifractal spectrum width were used to describe the morphological of fingering. It is concluded that the influence degree of each factor on fractal dimension from high to low is in the order of: viscosity ratio, injection series, temperature, acid concentration, construction displacement, and crack inclination. The influence degree of each factor on the multifractal spectrum width from high to low is in the order of: viscosity ratio, crack inclination, construction displacement, acid concentration, injection series, and temperature. In order to achieve the viscosity fingering of acid fracturing, the viscosity ratio should be increased to the value between 100∶1 and 150∶1, the controlled injection series are at level 2 to level 3, and the designed acid dosage is about 0.3. Meanwhile, a large number of pre-liquid was injected to reduce the crack wall's temperature before the acid injection.

Key words: acid fracturing, acid's fingering, physical simulation, fractal dimension, multifractal spectrum width

中图分类号:

TE319

罗志锋,余洋,赵立强等. 多因素下多级交替注入酸液指进实验研究[J]. 油气藏评价与开发, 2018, 8(4): 36-41.

Zhifeng Luo,Yang Yu,Liqiang Zhao, et al. Multifactorial experiment of acid's fingering phenomenon in the multi-stage alternating injection of acid fracturing[J]. Reservoir Evaluation and Development, 2018, 8(4): 36-41.

图/表 12

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参考文献 15

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指标名称	符号	单位	定义	物理意义
分形维数	Daf	无因次	图像标度变换下的不变量	表征酸液填充裂缝空间的能力和整体的无序性、复杂性
多重分形谱宽度	Waf	无因次	多重分形奇异性指数极值之差	表征指进区域酸液分布不均匀程度,刻画不同层次、不同区域特性

模拟参数	酸压典型参数	室内试验参数
裂缝宽度/mm	5	1
裂缝高度/m	50	33
裂缝长度/m	100	1
流体黏度/（mPa·s）	10 ~ 250	10 ~ 250
酸液浓度,%	15 ~ 20	1 ~ 5
流体密度/（kg·m^-3）	1 050	1 050
实验排量/（m³·min^-1）	3 ~ 7	45 ~ 105 mL/min
实验温度/℃	150	30 ~ 90
射孔数/（孔/m）	16	15
注入级数	2 ~ 3	1 ~ 5

因素	注入级数	黏度比	倾角/°	温度/℃	排量/（mL·min^-1）	酸液浓度,%	分形维数	多重分形谱宽度
实验1	1	150	30	40	20	1	1.981 8	0.422 5
实验2	1	10	45	50	40	2	1.992 9	0.366 3
实验3	1	50	60	60	60	3	1.971 4	0.369 2
实验4	1	100	75	70	80	4	1.9689	0.355 9
实验5	1	200	90	80	100	5	1.978 7	0.403 4
实验6	2	150	45	60	80	5	1.956 5	0.409 7
实验7	2	10	60	70	100	1	1.991 3	0.364 7
实验8	2	50	75	80	20	2	1.987 7	0.375 7
实验9	2	100	90	40	40	3	1.951 7	0.360 3
实验10	2	200	30	50	60	4	1.912 2	0.426 9
实验11	3	150	60	80	40	4	1.962 7	0.401 7
实验12	3	10	75	40	60	5	1.971 9	0.364 3
实验13	3	50	90	50	80	1	1.984 1	0.364 7
实验14	3	100	30	60	100	2	1.957 4	0.375 2
实验15	3	200	45	70	20	3	1.940 7	0.410 2
实验16	4	150	75	50	100	3	1.899 9	0.395 5
实验17	4	10	90	60	20	4	1.993 7	0.357 5
实验18	4	50	30	70	40	5	1.978 6	0.376 7
实验19	4	100	45	80	60	1	1.934 0	0.406 2
实验20	4	200	60	40	80	2	1.933 6	0.400 9
实验21	5	150	90	70	60	2	1.960 1	0.388 6
实验22	5	10	30	80	80	3	1.988 9	0.349 9
实验23	5	50	45	40	100	4	1.974 5	0.374 2
实验24	5	100	60	50	20	5	1.953 1	0.376 7
实验25	5	200	75	60	40	1	1.900 9	0.410 2

影响因素		注入级数	黏度比	裂缝倾角/°	温度/℃	排量/（mL·min^-1）	酸液浓度,%
分形维数	VIP	0.93	2.17	0.09	0.56	0.21	0.24
分形维数	影响程度	0.22	0.52	0.02	0.13	0.05	0.06
多重分形谱宽度	VIP	0.12	2.29	0.76	0.02	0.32	0.23
多重分形谱宽度	影响程度	0.03	0.61	0.20	0.004	0.09	0.06