前置液阶段的支撑剂段塞降低页岩储层压裂摩阻实验研究

doi:10.13809/j.cnki.cn32-1825/te.2020.01.012

摘要/Abstract

摘要：

针对涪陵地区页岩储层在水力压裂前期井口注入压力过高的问题,开展了基于支撑剂段塞技术的降阻实验研究。采用前期自研的射流装置和靶件,建立了一套利用支撑剂段塞打磨孔眼的近井裂缝降阻的物理模拟实验方法,并进行了正交实验。针对现场需要,建立了首尾压降与平均压降速率两个参数对实验结果进行表征,并据此进行了分析。结果表明,各因素对降阻效果的影响由大到小排序为：砂比、粒径、段塞组数（打磨时间）、支撑剂类型;石英砂降阻效果优于陶粒,降阻效果随着支撑剂粒径变粗、砂比的增加而增加,随着打磨时间的延长先减小后增大。基于正交实验结果,筛选出了一组支撑剂类型为石英砂,粒径为40/70目,砂比为9 %,打磨时间为9 min的最佳作业参数,此时获得压降速率0.439 MPa/min,首尾压降1.04 MPa的最佳降低摩阻效果。该实验研究为页岩储层水力压裂的施工设计提供了一定的参考。

关键词: 页岩, 孔眼, 降阻, 弯曲裂缝, 支撑剂段塞, 水力压裂

Abstract:

In order to solve the problem that the injection pressure of shale reservoir in Fuling area is too high in the early stage of hydraulic fracturing, researches on the resistance reduction based on proppant slug technology was carried out. By using the previous self-developed jet device and target, a set of physical simulation method for reducing fracture resistance in near well by grinding perforation with proppant slug was established and the orthogonal experiment was carried out. For the on-site needs, fore-tail pressure drop and average pressure drop rate are established to characterize the experimental results, and then analyzed accordingly. The results show that the influence of various factors on the resistance reduction effect from large to small is in the following orders: sand ratio, particle size, number of slugs（grinding time） and proppant type. The effect of reducing resistance of quartz sand is better than that of ceramsite. Drag reduction increases with the thickening of proppant particle size and the increase of sand ratio, and decreases at first and then increases with the prolongation of grinding time. Based on the results of orthogonal experiment, the optimal operating parameters of quartz sand with particle size of 40/70 mesh, sand ratio of 9 % and grinding time of 9 min are selected. On this condition, the optimal friction reduction effect of pressure drop rate of 0.439 MPa/min and head-tail pressure drop of 1.04 MPa are obtained. The experimental study provides a certain reference for the construction design of hydraulic fracturing of shale reservoir.

Key words: shale, perforation, friction reduction, tortuous fracture, proppant slug, hydraulic fracturing

中图分类号:

TE357

杨兆中,高晨轩,李小刚,刘觐瑄,廖梓佳. 前置液阶段的支撑剂段塞降低页岩储层压裂摩阻实验研究[J]. 油气藏评价与开发, 2020, 10(1): 77-83.

YANG Zhaozhong,GAO Chenxuan,LI Xiaogang,LIU Jinxuan,LIAO Zijia. Laboratory study on reducing fracturing friction of shale reservoir by proppant slug during pad[J]. Reservoir Evaluation and Development, 2020, 10(1): 77-83.

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参考文献 17

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组别	支撑剂类型	粒径/目	砂比/%	打磨时间/min
实验1	石英砂	70/140	3	3
实验2	石英砂	80/120	6	6
实验3	石英砂	40/70	9	9
实验4	陶粒	70/140	6	9
实验5	陶粒	80/120	9	3
实验6	陶粒	40/70	3	6
实验7	石英砂	70/140	9	6
实验8	石英砂	80/120	3	9
实验9	石英砂	40/70	6	3

组别	压降速率/（MPa·min^-1）	首尾压降/MPa
实验1	0	0
实验2	0.125	0.48
实验3	0.439	1.04
实验4	0.096	0.54
实验5	0.209	0.67
实验6	0.034	0.31
实验7	0.168	0.46
实验8	0.044	0.33
实验9	0.193	0.77

表征参数	压降速率/（MPa·min^-1）				首尾压降/MPa
表征参数	均值1	均值2	均值3	极差	均值1	均值2	均值3	极差
支撑剂	0.162	0.113		0.049	0.513	0.507		0.006
粒径	0.088	0.126	0.222	0.134	0.333	0.493	0.707	0.374
砂比	0.026	0.138	0.272	0.246	0.213	0.597	0.723	0.510
时间	0.134	0.109	0.193	0.084	0.480	0.417	0.637	0.220