闭合酸蚀裂缝导流能力模拟研究

摘要/Abstract

摘要：

酸蚀裂缝导流能力是影响酸压改造效果的关键所在。由于岩石性质、刻蚀形态及闭合压力等因素影响,很难对酸蚀裂缝导流能力进行准确的预测。目前,对于酸蚀裂缝几何形态和酸穿距离的计算模型较多,而就酸蚀裂缝导流能力的计算模型研究较少。为此,基于自仿射分形理论建立裂缝酸压模型,进行酸压模拟,利用局部立方规律（LCL）对闭合酸蚀裂缝导流能力进行预测,对影响闭合酸蚀裂缝导流能力的主要因素进行了正交模拟计算。结果表明,影响闭合酸蚀裂缝导流能力主要因素的影响程度从大到小依次为：闭合压力>分形维数>注酸时间>地层基质渗透率>注酸排量>标准偏差>地层基质孔隙度。

关键词: 分形理论, 酸蚀裂缝, 酸压模拟, 导流能力

Abstract:

The conductivity of acid cracks was the key to the transformation effects of acid fracturing. Due to the influences of rock properties, etching morphology and closing pressure, it was difficult to accurately predict the conductivity of acid fractures. Currently, there were many computational models for acid fractures geometry and acid penetration distance, but there were few researches on the computational model of flow capacity. For this reason, we built the acid fracturing model of cracks based on the improved self-affine fractal theory and applied it to the fractal fractures. And then, by the local cubic law（LCL）, we built the acid fracture conductivity calculation model and applied the quadrature analysis to the main factors which affected the conductivity of the acid fracture after closure. The results showed that the influencing degree of those factors which affected the acid fracture conductivity were as follows: closure stress>fractal dimension>injection time>matrix permeability>injection rate>standard deviation>matrix porosity.

Key words: fractal theory, acid cracks, acid fracturing simulation, conductivity

中图分类号:

TE357.2

赵立强,缪尉杰,罗志锋,龚云蕾,汪鹏,李屹洋. 闭合酸蚀裂缝导流能力模拟研究[J]. 油气藏评价与开发, 2019, 9(2): 25-32.

Zhao Liqiang,Miao Weijie,Luo Zhifeng,Gong Yunlei,Wang Peng,Li Qiyang. Simulation study on conductivity of closed acid cracks[J]. Reservoir Evaluation and Development, 2019, 9(2): 25-32.

图/表 9

图1

图2

表1

图3

图4

图5

表2

表3

正交试验次序及试验结果"

水平数	影响因素							闭合酸蚀裂缝导流能力/ （μm² $·$ cm）
水平数	分形维数	标准偏差/ m	岩石基质渗透率/ 10^-3μm²	岩石基质孔隙度, %	注酸排量/ （m³·min^-1）	注酸时间/ min	闭合压力/ MPa	闭合酸蚀裂缝导流能力/ （μm² $·$ cm）
1	2.0	0.000 010	5	5	2.0	10	55	28.82
2	2.0	0.000 012	10	7.5	2.5	20	60	12.84
3	2.0	0.000 014	15	10	3.0	30	65	40.49
4	2.0	0.000 016	20	12.5	3.5	40	70	33.50
5	2.0	0.000 018	25	15	4.0	50	75	63.24
6	2.0	0.000 020	30	17.5	4.5	60	80	82.92
7	2.25	0.000 010	10	10	3.5	50	80	11.51
8	2.25	0.000 012	15	12.5	4.0	60	55	8.36
9	2.25	0.000 014	20	15	4.5	10	60	15.35
10	2.25	0.000 016	25	17.5	2.0	20	65	28.24
11	2.25	0.000 018	30	5	2.5	30	70	4.89
12	2.25	0.000 020	5	7.5	3.0	40	75	88.50
13	2.5	0.000 010	15	12.5	4.0	60	55	6.99
14	2.5	0.000 012	20	15	4.5	10	60	6.11
15	2.5	0.000 014	25	17.5	2.0	20	65	12.12
16	2.5	0.000 016	30	5	2.5	30	70	26.22
17	2.5	0.000 018	5	7.5	3.0	40	75	47.69
18	2.5	0.000 020	10	10	3.5	50	80	69.20
19	2.7	0.000 010	20	15	4.5	10	60	2.82
20	2.7	0.000 012	25	17.5	2.0	20	65	3.94
21	2.7	0.000 014	30	5	2.5	30	70	10.28
22	2.7	0.000 016	5	7.5	3.0	40	75	22.84
23	2.7	0.000 018	10	10	3.5	50	80	29.76
24	2.7	0.000 020	15	12.5	4.0	60	55	47.38
25	2.8	0.000 010	25	17.5	2.0	20	65	1.19
26	2.8	0.000 012	30	5	2.5	30	70	2.71
27	2.8	0.000 014	5	7.5	3.0	40	75	10.06
28	2.8	0.000 016	10	10	3.5	50	80	15.20
29	2.8	0.000 018	15	12.5	4.0	60	55	17.90
30	2.8	0.000 020	20	15	4.5	10	60	1.36
31	2.9	0.000 010	30	5	2.5	30	70	55.86
32	2.9	0.000 012	5	7.5	3.0	40	75	62.28
33	2.9	0.000 014	10	10	3.5	50	80	42.83
34	2.9	0.000 016	15	12.5	4.0	60	55	3.98
35	2.9	0.000 018	20	15	4.5	10	60	2.70
36	2.9	0.000 020	25	17.5	2.0	20	65	1.08

表3

表4

参考文献 18

[1]	Jiayao Deng . Mechanical behavior of small-scale channels in acid-etched fractures[D]. Texas A&M University, 2010.
[2]	R A Beier, H H Hardy . Comparison of 2D and 3D fractal distributions in reservoir simulations[J]. SPE Reservoir Engineering, 1994,9(3):195-200. doi: 10.2118/25236-PA
[3]	张黎明, 任书泉 . 岩矿颗粒酸溶蚀反应分形模型初探[J]. 石油钻采工艺, 1996,(1):59-65+107.
[4]	蒲洪江 . 新场气田复杂砂岩气藏平衡酸压闭合酸化工艺及模拟技术研究[D]. 西南石油学院博士学位论文. 2007.
[5]	徐学成 . 裂缝性砂岩油藏储层表征研究[D]. 西南石油学院博士学位论文. 2003
[6]	胡泽根, 王永清, 陈晖 . 砂岩储层裂缝宽度预测新方法[J]. 内蒙古石油化工. 2009,( 1):127-130.
[7]	Chengli Dong . Acidizing of naturally- fractured carbonate formations[D]. The University of Texas at Austin, 2001.
[8]	Jianye Mou . Modeling acid transport and non-uniform etching in a stochastic domain in acid fracturing[D]. Texas A&M University, 2009.
[9]	A D Hill , Ding Zhu, Y Wang. The effect of wormholing on the fluid loss coefficient in acid fracturing[J]. SPE Production & Facilities, 1995,10(4):257-264.
[10]	J Deng, A D Hill, D Zhu . A theoretical study of acid-fracture conductivity under closure stress[J]. SPE Production & Operations, 2011,26(1):9-17.
[11]	L J Pyrak-Nolte, L R Myer, D D Nolte . Fractures: Finite-size scaling and multifractals[J]. Pure & Applied Geophysics, 1992,138(4):679-706.
[12]	Ming Gong . Mechanical and hydraulic behavior of acid fractures-experimental studies and mathematical modeling[D]. The University of Texas at Austin, 1997.
[13]	李年银, 赵立强, 张倩 , 等. 酸压过程中酸蚀裂缝导流能力研究[J]. 钻采工艺. 2008,31(6):59-62. doi: 10.3969/j.issn.1006-768X.2008.06.019
[14]	孙洪泉, 谢和平 . 断层粗糙表面的分形模拟. 中国矿业大学学报. 1999,5(29):433-436.
[15]	孙洪泉 . 地质统计学及其应用[M]. 中国矿业大学出版社, 1990
[16]	韩大匡, 陈钦雷, 闫存章 . 油藏数值模拟基础[M]. 石油工业出版社, 1993
[17]	赵立强, 高俞佳, 袁学芳 , 等. 高温碳酸盐岩储层酸蚀裂缝导流能力研究[J]. 油气藏评价与开发, 2017,7(1):20-26.
[18]	罗志锋, 张楠林, 赵立强 , 等. 前置液酸压缝内酸液指进数值模拟[J]. 油气藏评价与开发, 2017,5(7):26-31.

参数	数值	参数	数值
分形维数	2.5	酸液黏度/（mPa·s）	3
标准偏差/m	0.000 016	酸液密度/（kg·m³）	1 070
裂缝尺寸	30 m×100 m	酸液溶解能力	0.082 m³（岩石）/m³（酸液）
岩石密度/（kg·m³）	2 710	酸岩反应速度常数/（m·s^-1）	1.0×10^-5
地层压力/MPa	45	有效传质系数/（m²·s^-1）	1.0×10^-9
地层基质渗透率/10^-3μm²	10	注酸排量/（m³·min^-1）	3.5
地层基质孔隙度,%	5	注酸时间/min	40
酸液类型	15 %HCl

水平数	影响因素
水平数	分形维数	标准偏差/ m	岩石基质渗透率/ 10^-3μm²	岩石基质孔隙度, %	注酸排量/ （m³·min^-1）	注酸时间/ min	闭合压力/ MPa
K1	261.81	107.18	260.20	128.99	75.394	57.156	113.42
K2	156.86	96.443	181.34	244.22	113.01	59.410	41.17
K3	168.32	131.13	125.09	208.99	271.86	140.65	87.06
K4	117.02	189.98	61.833	118.10	202.00	264.88	133.67
K5	48.628	166.18	109.81	91.57	147.84	231.74	294.61
K6	168.73	290.44	183.09	129.49	111.25	251.42	251.42
k1	43.635	17.864	43.367	21.498	12.566	9.5259	18.90
k2	26.143	16.074	30.224	40.703	18.834	9.9017	6.86
k3	28.053	21.854	20.848	34.832	45.311	23.422	14.51
k4	19.503	21.664	10.305	19.683	33.667	44.146	22.28
k5	8.1047	27.697	18.301	15.262	24.640	38.624	49.10
k6	28.122	48.407	30.514	21.582	18.542	41.904	41.90
极差R	35.530	32.333	33.061	25.441	32.745	34.620	42.24
主次顺序	G>A>F>C>E>B>D