Acta Petrolei Sinica ›› 2016, Vol. 37 ›› Issue (8): 1061-1068.DOI: 10.7623/syxb201608013

• Petroleum Engineering • Previous Articles     Next Articles

Calculation on the following performance of proppant in supercritical carbon dioxide

Hou Lei1,2, Sun Baojiang1, Jiang Tingxue2, Geng Xueyu1, Wang Zhiyuan1   

  1. 1. School of Petroleum Engineering, China University of Petroleum, Shandong Qingdao 266580, China;
    2. Sinopec Research Institute of Petroleum Engineering, Beijing 100101, China;
    3. The University of Warwick, Coventry CV4 7AL, UK
  • Received:2016-01-11 Revised:2016-06-02 Online:2016-08-25 Published:2016-09-02

支撑剂在超临界二氧化碳中的跟随性计算

侯磊1,2, 孙宝江1, 蒋廷学2, Geng Xueyu1, 王志远1   

  1. 1. 中国石油大学石油工程学院 山东青岛 266580;
    2. 中国石油化工股份有限公司石油工程技术研究院 北京 100101;
    3. The University of Warwick Coventry CV4 7AL UK
  • 通讯作者: 孙宝江,男,1963年11月生,1985年获华东石油学院钻井工程专业学士学位,1999年获北京大学流体力学专业博士学位,现为中国石油大学(华东)博士生导师、长江学者特聘教授,主要从事油气井工程、海洋石油工程、多相流理论及应用等方面的研究。Email:sunbj1128@126.com
  • 作者简介:侯磊,男,1987年6月生,2009年获中国石油大学(华东)石油工程专业学士学位,2015年获中国石油大学(华东)油气井工程专业博士学位,现为中国石油化工股份有限公司石油工程技术研究院博士后,主要从事非常规油气、超临界CO2压裂技术和支撑剂输送的研究工作。Email:wto511@126.com
  • 基金资助:

    国家自然科学基金联合基金重点项目“非常规天然气储层超临界二氧化碳压裂工程基础研究”(No.U1262202)和国家自然科学基金国际合作重点项目“页岩气藏水平井完井与多级压裂增产的基础研究”(No.5121006)资助。

Abstract:

As a new type of fracturing fluid, supercritical carbon dioxide (SC-CO2) has now become the research hotspot in domestic and foreign academia. However, the relevant technique is limited by the unclear sand-carrying mechanism. In this study, the concept of following performance is introduced to investigate the sand-carrying performances of fracturing fluid; the following performance of proppant and the sand-carrying performance of fracturing fluid are characterized by the ratio of the proppant horizontal velocity to the fracturing-fluid horizontal flow velocity. Then the following performance of proppant is used as the criteria for evaluating the horizontal sand-carrying performances of SC-CO2. Based on the classic BBO equation, the expression of drag force has been modified; in combination with the auxiliary equations of drag force coefficients, a calculation model has also been established to analyze the following performance of proppant in SC-CO2, which provides the theoretical foundation for evaluating and optimizing the transportation of proppant in SC-CO2. To verify the correctness of the model, an experiment is conducted on the following performance of proppant using the self-developed equipment, and then the factors that affect the following performance of proppant in SC-CO2 are analyzed. The results show that the following perfomance of proppant is slightly affected within the common range of density, which is consistent with the previous experimental results. In addition, a comparative analysis is performed on the following performance of sands in SC-CO2, slickwater and air. The analysis results indicate that the sand-carrying performance of SC-CO2 is more affected by its high-density property but less affected by its low viscosity. Because of high-density and low-viscosity properties, SC-CO2 is far better than air but worse than or approximately equal with slickwater in terms of sand-carrying performances. Especially at a high flow velocity, the horizontal sand-carrying performance of SC-CO2 is comparable to that of slickwater.

Key words: supercritical carbon dioxide, sand-carrying performance of fracturing fluid, following performance of proppant, numerical calculation, BBO equation

摘要:

超临界二氧化碳作为一种新型压裂液,是目前国内外的研究热点,但其携砂机理尚不明确,成为制约该项技术的关键问题之一。将跟随性的概念引入压裂液携砂研究,以支撑剂水平速度和压裂液水平流速的比值来表征支撑剂的跟随性或压裂液的携砂性能,并以跟随性为标准,对超临界二氧化碳的水平携砂性能进行了评价。在经典BBO方程的基础上,改进了拖曳力的表达式,联立拖曳力系数辅助方程组,建立了支撑剂在超临界二氧化碳中的跟随性计算模型,为评价和优化超临界二氧化碳输送支撑剂提供了理论依据。采用自主研发的实验设备,通过跟随性实验对该模型进行了检验,并采用模型进行了支撑剂在超临界二氧化碳中跟随性的影响因素分析。研究结果表明,在常用密度范围内,支撑剂密度对跟随性的影响不大,该数值分析结论与以往学者的实验研究结果相一致。此外,对比了砂粒在超临界二氧化碳、滑溜水以及空气中的跟随性,超临界二氧化碳的高密度特性对其携砂性能的影响大于低黏度特性对其携砂性能的影响,两者综合作用导致其携砂性能远高于空气,小于并接近滑溜水的携砂性能,特别是在较高流速下,超临界二氧化碳的水平携砂性能与滑溜水相当。

关键词: 超临界二氧化碳, 压裂液携砂, 支撑剂跟随性, 数值计算, BBO方程

CLC Number: