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| 关井效应对酸压裂缝刻蚀形貌与导流能力影响 |
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刘超1,2,3,苟波4,管晨呈4,郭建春4,李骁4,王香增1,2,魏登峰1,2,郝世彦1,2,申峰1,2,王念喜1,2
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(1. 陕西延长石油(集团)有限责任公司研究院,陕西西安 710065;2. 陕西省陆相页岩气成藏与开发重点实验室(筹),陕西西安 710065;3.西南石油大学博士后科研流动站,四川成都 610500;4. 西南石油大学油气藏地质及开发工程国家重点实验室,四川成都 610500)
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| 摘要: |
| 为了揭示酸压关井时酸液在酸压裂缝中的滞留对酸刻蚀形态与导流能力的影响,选取鄂尔多斯盆地延安气田奥陶系马家沟组马五1亚段露头岩样,采用研发的装置“酸压裂缝导流能力测试系统”,用粗糙岩板模拟粗糙水力裂缝,研究不同注酸时间下,关井效应对酸刻蚀裂缝形态和导流能力的影响。结果表明:马五1亚段储层存在使导流能力及保持水平最佳的注酸时间60 min；当注酸时间小于等于最佳注酸时间时,关井效应可增加酸蚀裂缝面迂曲度和平均酸蚀缝宽,导流能力也相应提高；当注酸时间大于最佳注酸时间时,关井效应使酸蚀裂缝面过度溶蚀,迂曲度和平均酸蚀缝宽减小,高闭合压力下导流能力削弱；马五1亚段储层酸压时,根据注酸时间确定关井和返排时间,发挥关井效应对酸蚀裂缝导流能力的有益作用,改善酸压效果。 |
| 关键词: 致密碳酸盐岩 关井效应 酸蚀裂缝形貌 导流能力 返排时间 延安气田 鄂尔多斯盆地 |
| DOI：10.3969/j.issn.1673-5005.2021.02.011 |
| 分类号::TE 357.2 |
| 文献标识码:A |
| 基金项目: |
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| Effect of well shut-in on acid etching morphology and conductivity |
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LIU Chao1,2,3, GOU Bo4, GUAN Chencheng4, GUO Jianchun4, LI Xiao4, WANG Xiangzeng1,2, WEI Dengfeng1,2, HAO Shiyan1,2, SHEN Feng1,2, WANG Nianxi1,2
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(1.Research Institute of Yanchang Petroleum (Group)Company Limited, Xi 'an 710065, China;2.Shaanxi Key Laboratory of Lacustrine Shale Gas Accumulation and Exploitation(Under Planning), Xi 'an 710065, China;3.Post-Doctoral Research Center, Southwest Petroleum University, Chengdu 610500, China;4.State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China)
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| Abstract: |
| In order to reveal the influence of acid retention time on acid-etching morphology and conductivity of acid-fractures during shut-in period, acid-etching and conductivity experiments were conducted, using a laboratory self-made device, , under different acid-injection time considering well shut-in effects. The rock samples used were from the outcrop rock samples of the Mawu-1 subsegment of the Ordovician Majiagou Formation in Yan 'an gas field (Ordos Basin), which were cut into rough slabs to simulate rough hydraulic fractures. The experimental results indicate that, for the Mawu-1 subsegment reservoir, there is an optimal acid-injection time of 60 minutes, in which the conductivity can reach to the maximum and optimum level. When the acid-injection time is less than the its optimal time, the shut-in effect can increase the tortuosity of the acid-etching fracture surface and the fracture-width, hence further enhancing the conductivity. When the acid-injection time is longer than the optimal acid-injection time, the shut-in effect will cause excessive dissolution of the acid-etching fracture surface, causing decrease of the tortuosity and average acid-etching fracture width and reducing the conductivity under high closure stress. The shut-in and flow back time should be determined according to the actual acid-injection time during acid fracturing, which can make full use of the shut-in effect on the acid-fracture conductivity, improving the response of acid-fracturing. |
| Key words: carbonate rocks shut-in effect acid-etching fracture morphology conductivity flow back time Yan 'an gas field Ordos Basin |
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