| 摘要: |
| 为了证实利用超临界二氧化碳(CO2)流体进行喷射压裂的可行性,利用Span-Wagner气体状态方程建立超临界CO2流场的计算流体力学模型,模拟超临界CO2喷射压裂过程中的孔内流场。结果表明:在喷嘴压降相同的条件下,与水射流相比,超临界CO2射流的射流速度更高,射流核心区更长;超临界CO2喷射压裂具有比水力喷射压裂更强的射流增压效果,更容易压开地层;超临界CO2射流具有显著的焦耳-汤姆逊效应,会导致温度下降,在压裂施工中应合理控制喷嘴压降,以防发生冰堵事故;超临界CO2的密度主要受压力影响,通过调节压力就能有效控制,可适应不同的地层温度条件。 |
| 关键词: 超临界二氧化碳 射流 压裂 流场 数值模拟 |
| DOI：10.3969/j.issn.1673-5005.2014.04.011 |
| 分类号::TE 357 |
| 基金项目:国家自然科学基金重点项目(51034007);国家自然科学基金重大国际(地区)合作项目(51210006) |
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| Flow field character in cavity during supercritical carbon dioxide jet fracturing |
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CHENG Yuxiong, LI Gensheng, WANG Haizhu, SHEN Zhonghou, TIAN Shouceng, CAI Chengzheng
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(State Key Laboratory of Petroleum Resources and Prospecting in China University of Petroleum, Beijing 102249, China)
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| Abstract: |
| To verify the feasibility of supercritical carbon dioxide (SC-CO2) jet fracturing, a computational fluid dynamic model was established based on Span-Wagner state equation to simulate the flow field in the cavity during SC-CO2 jet fracturing. The results show that in comparison with water jet, the SC-CO2 jet has higher jet energy and experiences less energy attenuation. It also has higher pressure boosting effect than water jet fracturing. Joule-Thomson effect can happen during SC-CO2 jet and lead to temperature decrease. Therefore nozzle pressure drop should be reasonably controlled during the jet fracturing process to avoid ice block. The density of SC-CO2 is mainly influenced by pressure instead of temperature. So it can be controlled by adjusting pressure for it to work under different formation temperatures. |
| Key words: supercritical carbon dioxide jet fracturing flow field numerical simulation |
