储层溶洞对水力裂缝扩展路径影响的实验研究

摘要/Abstract

摘要：

为了研究溶洞和泵注排量对水力裂缝扩展路径及起裂压力的影响,以水泥、细沙和水为原材料制作了A、B 两组200 mm×200 mm×200 mm的立方体水力压裂试件,每组为相同2个。其中,A组为完整试件,B组为带溶洞试件（浇筑过程中预埋PVC管,养护好后凿除以模拟天然溶洞）,对每组两个试件分别在排量为7.5 mL/min和10.0 mL/min时进行了压裂实验。研究表明：对于完整岩样,泵注排量越大,起裂压力越大,产生的水力裂缝越平直;对于带溶洞的岩样,溶洞会影响水力裂缝的扩展路径,对水力裂缝产生吸引作用,导致水力裂缝偏向溶洞,随着泵注排量的增加,该吸引作用逐渐减小;相同条件下,完整岩样的起裂压力高于带溶洞岩样。缝洞型储层中溶洞为油气资源的主要储集区,合理设置压裂作业参数,产生沟通溶洞和井眼的水力裂缝是提高缝洞型油气藏中油气资源采收率的关键。该项研究对于优化压裂作业参数具有一定的指导意义。

关键词: 水力压裂, 缝洞型油藏, 裂纹扩展, 溶洞, 泵注排量

Abstract:

In order to study the effects of caves and flow rates on hydraulic fractures propagation and initiation pressure, two sets of cube hydraulic fracturing specimens—A and B（the size is 200 mm×200 mm×200 mm）—with two same specimens in each group are made by the mixture of cement, fine sand and water. The specimens in group A are intact, while that in group B is with Karst cave（the PVC pipe is pre-buried during pouring, and then, when the cube is formed, the pipe is removed to simulate natural caverns）. Fracturing experiments are carried out for two specimens in each group when the displacement was 7.5 and 10.0 mL/min respectively. The results indicate that for intact rock mass, the initial pressure will rise up with the increase of flow rate, and the induced hydraulically fractures will be more straightness; for the rock mass with caves, the caves will affect the extended path of hydraulic fractures and exert a kind of “attraction” on hydraulic fractures, which will make the hydraulic fractures extend towards caves, and the effect of “attraction” will decrease with the increase of the displacement. The initial pressure of fracturing in intact rock mass is higher than that in rock mass with caves under the same conditions. Caves are the main storage area for petroleum resources. The key to enhance oil and gas recovery in fractured-vuggy reservoirs is to set up fracturing operation parameters reasonably and produce hydraulic fractures that communicate caverns and boreholes. This study has certain guiding significance for optimizing the fracturing operation parameters.

Key words: hydraulic fracturing, fractured-vuggy reservoir, fracture propagation, caves, pump injection displacement

中图分类号:

TE357

翁振,张耀峰,伍轶鸣,范坤,汪芳. 储层溶洞对水力裂缝扩展路径影响的实验研究[J]. 油气藏评价与开发, 2019, 9(6): 42-46.

WENG Zhen,ZHANG Yaofeng,WU Yiming,FAN Kun,WANG Fang. Experimental study on effects of caves in reservoirs on hydraulic fractures propagation[J]. Reservoir Evaluation and Development, 2019, 9(6): 42-46.

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参考文献 23

[1]	HUBBERT M K . Mechanics of hydraulic fracturing[J]. Developments in Petroleum Science, 1972,210(7):369-390. doi: 10.1038/s41598-019-49093-1 pmid: 31467396
[2]	李廷微, 姜振学, 付晓飞 , 等. 水力破裂作用及在板中北储气库评价中的应用[J]. 科学技术与工程, 2017,17(28):58-67.
[3]	康志江, 赵艳艳, 张允 , 等. 缝洞型碳酸盐岩油藏数值模拟技术与应用[J]. 石油与天然气地质, 2014,35(6):944-949. doi: 10.11743/ogg20140621
[4]	唐潮, 陈小凡, 杜志敏 , 等. 缝洞型油藏单井缝洞单元压降试井解释模型研究[J]. 油气藏评价与开发, 2017,7(2):31-35.
[5]	许文俊, 李勇明, 赵金洲 , 等. 页岩气水平井分段压裂复杂缝网形成机制[J]. 油气藏评价与开发, 2017,7(5):64-73.
[6]	何泽轩 . 页岩储层水力压裂裂缝相互作用数值模拟研究[J]. 石油化工应用, 2017,36(9):43-45.
[7]	马耕, 张帆, 刘晓 , 等. 裂缝性储层中水力裂缝扩展规律的试验研究[J]. 采矿与安全工程学报, 2017,34(5):993-999.
[8]	黄灿 . 考虑邻井干扰的页岩气多段压裂水平井数值试井方法[J]. 特种油气藏, 2018,25(3):92-96.
[9]	席一凡, 李连崇, 张潦源 , 等. 裂缝性储层中水力裂缝扩展规律的数值模拟研究[J]. 武汉理工大学学报, 2016,38(12):47-51.
[10]	马耕, 张帆, 刘晓 , 等. 天然裂缝对煤岩体水力裂缝扩展影响研究[J]. 河南理工大学学报:自然科学版, 2016,35(2):178-182.
[11]	侯冰, 程万, 陈勉 , 等. 裂缝性页岩储层水力裂缝非平面扩展实验[J]. 天然气工业, 2014,34(12):81-86.
[12]	宋晨鹏, 卢义玉, 夏彬伟 , 等 .天然裂缝对煤层水力压裂裂缝扩展的影响[J]. 东北大学学报:自然科学版, 2014,35(5) 756-760.
[13]	DEHGHAN A N, GOSHTASBI K, AHANGARI K , et al. Erratum to: Experimental investigation of hydraulic fracture propagation in fractured blocks[J]. Bulletin of Engineering Geology & the Environment, 2015,74(3):887-895. doi: 10.1016/j.ijmst.2015.11.014 pmid: 27648341
[14]	DEHGHAN A N, GOSHTASBI K, AHANGARI K , et al. The effect of natural fracture dip and strike on hydraulic fracture propagation[J]. International Journal of Rock Mechanics & Mining Sciences 2015,75:210-215. doi: 10.1073/pnas.1808402115 pmid: 30442660
[15]	GUO J C, NIE R S, JIA Y L. Dual permeability flow behavior for modeling horizontal well production in fractured-vuggy carbonate reservoirs[J]. Journal of Hydrology, 2012, 464-465(13):281-293. doi: 10.1016/j.jhydrol.2012.07.021
[16]	WANG L, WANG X, LUO E , et al. Analytical modeling of flow behavior for wormholes in naturally fractured-vuggy porous media[J]. Transport in Porous Media, 2014,105(3):539-558. doi: 10.1007/s11242-014-0383-7
[17]	杨敏, 张烨 . 缝洞型油藏超大规模酸压技术[J]. 地质科技情报, 2011,30(3):89-92.
[18]	张帆, 马耕, 刘晓 , 等. 泵注排量对煤储层水力压裂影响的试验研究[J]. 煤矿安全, 2017,48(7):13-15.
[19]	卜向前, 周大伟, 李向平 , 等. 地应力改变对水力裂缝扩展的模拟实验研究[J]. 科学技术与工程, 2015,15(35):24-28.
[20]	HU J, CHEN M, ZHANG G , et al. Impact of oriented perforation on hydraulic fracture initiation and propagation[J]. Chinese Journal of Rock Mechanics & Engineering, 2009,28(7):1321-1326. doi: 10.1016/j.scitotenv.2019.136080 pmid: 31869621
[21]	王跃 . 基于大型水力压裂实验系统的室内模拟研究[J]. 地球物理学进展, 2017,32(1):408-413.
[22]	XUE L . An experimental study of fracture initiation mechanisms during hydraulic fracturing[J]. Petroleum Science, 2011,8(1):87-92. doi: 10.1007/s12182-011-0119-z
[23]	马旭杰, 刘培亮, 何长江 . 塔河油田缝洞型油藏注水开发模式[J]. 新疆石油地质, 2011,32(1):63-65.

编号	排量/ （mL·min^-1）	起裂压力/ MPa	扩展压力/ MPa	水力裂缝与竖直方向的夹角/（°）
A-1	10.0	6.8	4.8	0
A-2	7.5	5.2	3.6	10
B-1	10.0	6.3	3.2	20
B-2	7.5	4.6	2.6	45