固井注水泥浆顶替效率评估的新模型
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摘要
提高固井注水泥浆顶替效率是保障水泥环密封性能的前提,已有的理论和实验室方法多集中于两相流(钻井液/隔离液、隔离液/水泥浆、钻井液/水泥浆)顶替模拟,而与实际工况下钻井液与隔离液先掺混、再被水泥浆顶替的动态过程特征相距甚远。为此,基于流体顶替过程中掺混与扩散机理,建立流体动态顶替过程数学模型,借助流动仿真软件探讨隔离液性能变化对顶替钻井液和被水泥浆顶替的内在演变机理,结合仿真数据,建立了水泥浆顶替效率评估的新计算模型。研究结果表明:①在顶替初期,低黏度、低密度隔离液体系与钻井液混浆严重,但有利于降低壁面钻井液黏滞力,清除滞留钻井液,进而改善水泥浆顶替效率;②高密度、低黏度隔离液虽然能快速清洗井筒钻井液,但也容易产生指进现象,进而导致水泥浆提前返出井口,容易被误认为顶替效率较好;③隔离液密度处于钻井液和水泥浆之间时,低黏度隔离液有助于清除壁面钻井液和被水泥浆顶替;④隔离液排量高于临界值时,顶替效果改善明显;⑤所建立的注水泥浆顶替效率评价新模型与数值仿真结果吻合度高,误差仅为4.6%。结论认为,该新模型有助于更好地认识与解释复杂流动机理,为改善注水泥井筒浆柱结构、浆体性能及提高顶替效率奠定了理论基础。
The precondition for ensuring the sealing property of cement sheath is to improve the displacement efficiency of cement slurry.Existing theories and laboratory methods focus on the displacement simulation of two-phase flows(drilling fluid/spacer fluid, spacer fluid/cement slurry, drilling fluid/cement slurry). However, such simulations are far different from the characteristics of the actual dynamic process of first mixing drilling fluids with spacer fluids and then displacing the mixture with cement slurry. For this reason, a mathematical model for the dynamic displacement process of fluids was set up based on the mixing and diffusion mechanisms during the fluid displacement process; fluid emulation software was used to analyze the impact of spacer fluid property changes on the internal evolution mechanism of displacing drilling fluids and being displaced with cement slurry; based on the emulation data, a new calculation model for evaluating the displacement efficiency of cement slurry was set up. The study results show that:(1) at the initial stage of displacement, low-viscosity and low-density space fluids are mixed with drilling fluids, which are favorable for reducing the viscous force of drilling fluids on the borehole wall, clearing residual drilling fluids, and thereby improving the displacement efficiency of cement slurry;(2) high-density and low-viscosity spacer fluids can quickly flush drilling fluids in the borehole, but they may easily cause fingering, thereby causing the cement slurry to return to the wellhead ahead of schedule. This may be mistakenly considered for better displacement efficiency;(3) when the spacer fluid density is between the density of drilling fluids and that of cement slurry, low-viscosity spacer fluids are favorable for clearing drilling fluids on the borehole wall and being displaced by cement slurry;(4) when the spacer fluid pump rate is higher than the critical pump rate,the displacement efficiency is significantly improved;(5) the new model for evaluating the displacement efficiency of cement slurry is well matched with the numerical emulation result, and the error is only 4.6%. It is concluded that the new model facilitates the understanding and interpretation of the complex flow mechanism and lays a theoretical foundation for improving the slurry column structures, slurry properties, and displacement efficiency.
The precondition for ensuring the sealing property of cement sheath is to improve the displacement efficiency of cement slurry.Existing theories and laboratory methods focus on the displacement simulation of two-phase flows(drilling fluid/spacer fluid, spacer fluid/cement slurry, drilling fluid/cement slurry). However, such simulations are far different from the characteristics of the actual dynamic process of first mixing drilling fluids with spacer fluids and then displacing the mixture with cement slurry. For this reason, a mathematical model for the dynamic displacement process of fluids was set up based on the mixing and diffusion mechanisms during the fluid displacement process; fluid emulation software was used to analyze the impact of spacer fluid property changes on the internal evolution mechanism of displacing drilling fluids and being displaced with cement slurry; based on the emulation data, a new calculation model for evaluating the displacement efficiency of cement slurry was set up. The study results show that:(1) at the initial stage of displacement, low-viscosity and low-density space fluids are mixed with drilling fluids, which are favorable for reducing the viscous force of drilling fluids on the borehole wall, clearing residual drilling fluids, and thereby improving the displacement efficiency of cement slurry;(2) high-density and low-viscosity spacer fluids can quickly flush drilling fluids in the borehole, but they may easily cause fingering, thereby causing the cement slurry to return to the wellhead ahead of schedule. This may be mistakenly considered for better displacement efficiency;(3) when the spacer fluid density is between the density of drilling fluids and that of cement slurry, low-viscosity spacer fluids are favorable for clearing drilling fluids on the borehole wall and being displaced by cement slurry;(4) when the spacer fluid pump rate is higher than the critical pump rate,the displacement efficiency is significantly improved;(5) the new model for evaluating the displacement efficiency of cement slurry is well matched with the numerical emulation result, and the error is only 4.6%. It is concluded that the new model facilitates the understanding and interpretation of the complex flow mechanism and lays a theoretical foundation for improving the slurry column structures, slurry properties, and displacement efficiency.
引文
[1]刘崇建,黄柏宗,徐同台,刘孝良.油气井注水泥理论与应用[M].北京:石油工业出版社,2001.Liu Chongjian,Huang Baizong,Xu Tongtai&Liu Xiaoliang.Theory and application of cementing in oil and gas wells[M].Beijing:Petroleum Industry Press,2001.
[2]Zulqarnain M&Tyagi M.Development of simulations based correlations to predict the cement volume fraction in annular geometries after fluid displacements during primary cementing[J].Journal of Petroleum Science and Engineering,2016(145):1-10.
[3]冯福平,宋杰,艾池,陈顶峰,于法浩,徐海粟,等.固井顶替界面研究方法分析[J].断块油气田,2014,21(4):540-544.Feng Fuping,Song Jie,Ai Chi,Chen Dingfeng,Yu Fahao,Xu Haisu,et al.Analysis on displacement interface research method in cementing[J].Fault-Block Oil and Gas Field,2014,21(4):540-544.
[4]孙劲飞,李早元,罗平亚,张刚刚,焦少卿.水平井偏心环空低速顶替运移机制研究[J].西南石油大学学报(自然科学版),2019,41(1):111-118.Sun Jinfei,Li Zaoyuan,Luo Pingya,Zhang Ganggang&Jiao Shaoqing.Study of the transport mechanism of low-speed displacement in eccentric annulus of horizontal wells[J].Journal of Southwest Petroleum University(Science&Technology Edition),2019,41(1):111-118.
[5]王金堂,孙宝江,李昊,曹成章,彭志刚,徐渴望.大位移井旋转套管固井顶替模拟分析[J].中国石油大学学报(自然科学版),2015,39(3):89-97.Wang Jintang,Sun Baojiang,Li Hao,Cao Chengzhang,Peng Zhigang&Xu Kewang.Simulation analysis of rotating-casing cementing displacement in extended reach well[J].Journal of China University of Petroleum(Edition of Natural Science),2015,39(3):89-97.
[6]Bu YH,Tian LJ,Li ZB,Zhang R,Wang CY&Yang XC.Effect of casing rotation on displacement efficiency of cement slurry in highly deviated wells[J].Journal of Natural Gas Science and Engineering,2018,52:317-324.
[7]罗恒荣,张晋凯,周仕明,陶谦,方春飞.偏心度和密度差耦合条件下水平井顶替界面特征研究[J].石油钻探技术,2016,44(4):65-71.Luo Hengrong,Zhang Jinkai,Zhou Shiming,Tao Qian&Fang Chunfei.Horizontal well cement displacement interface features under the coupling of eccentricity and density difference[J].Petroleum Drilling Techniques,2016,44(4):65-71.
[8]冯福平,艾池,杨丰宇,孟翔,钟鑫.偏心环空层流顶替滞留层边界位置研究[J].石油学报,2010,31(5):858-862.Feng Fuping,Ai Chi,Yang Fengyu,Meng Xiang&Zhong Xin.Astudy on the replacement position of laminar flow in eccentric annulus at retention layer boundaries[J].Acta Petrolei Sinica,2010,31(5):858-862.
[9]李明忠,王瑞和,王成文,方群.层流顶替钻井液滞留层厚度研究[J].水动力学研究与进展(A辑),2013,28(5):531-537.Li Mingzhong,Wang Ruihe,Wang Chengwen&Fang Qun.Astudy on drilling mud stagnant layer thickness under the condition of laminar displacement[J].Journal of Hydrodynamics,2013,28(5):531-537.
[10]Bittleston SH,Ferguson J&Frigaard IA.Mud removal and cement placement during primary cementing of an oil well--Laminar non-Newtonian displacements in an eccentric annular Hele-Shaw cell[J].Journal of Engineering Mathematics,2002,43(2-4):229-253.
[11]王瑞和,李明忠,王成文,方群.油气井注水泥顶替机理研究进展[J].天然气工业,2013,33(5):69-76.Wang Ruihe,Li Mingzhong,Wang Chengwen&Fang Qun.Research progress in the cementing displacement mechanism[J].Natural Gas Industry,2013,33(5):69-76.
[12]李早元,柳洪华,郭小阳,辜涛,欧红娟.油基钻井液组分对水泥浆性能的影响及其机理[J].天然气工业,2016,36(3):63-68.Li Zaoyuan,Liu Honghua,Guo Xiaoyang,Gu Tao&Ou Hongjuan.Impact of the oil-based drilling fluid components on cement slurry performances and its mechanism[J].Natural Gas Industry,2016,36(3):63-68.
[2]Zulqarnain M&Tyagi M.Development of simulations based correlations to predict the cement volume fraction in annular geometries after fluid displacements during primary cementing[J].Journal of Petroleum Science and Engineering,2016(145):1-10.
[3]冯福平,宋杰,艾池,陈顶峰,于法浩,徐海粟,等.固井顶替界面研究方法分析[J].断块油气田,2014,21(4):540-544.Feng Fuping,Song Jie,Ai Chi,Chen Dingfeng,Yu Fahao,Xu Haisu,et al.Analysis on displacement interface research method in cementing[J].Fault-Block Oil and Gas Field,2014,21(4):540-544.
[4]孙劲飞,李早元,罗平亚,张刚刚,焦少卿.水平井偏心环空低速顶替运移机制研究[J].西南石油大学学报(自然科学版),2019,41(1):111-118.Sun Jinfei,Li Zaoyuan,Luo Pingya,Zhang Ganggang&Jiao Shaoqing.Study of the transport mechanism of low-speed displacement in eccentric annulus of horizontal wells[J].Journal of Southwest Petroleum University(Science&Technology Edition),2019,41(1):111-118.
[5]王金堂,孙宝江,李昊,曹成章,彭志刚,徐渴望.大位移井旋转套管固井顶替模拟分析[J].中国石油大学学报(自然科学版),2015,39(3):89-97.Wang Jintang,Sun Baojiang,Li Hao,Cao Chengzhang,Peng Zhigang&Xu Kewang.Simulation analysis of rotating-casing cementing displacement in extended reach well[J].Journal of China University of Petroleum(Edition of Natural Science),2015,39(3):89-97.
[6]Bu YH,Tian LJ,Li ZB,Zhang R,Wang CY&Yang XC.Effect of casing rotation on displacement efficiency of cement slurry in highly deviated wells[J].Journal of Natural Gas Science and Engineering,2018,52:317-324.
[7]罗恒荣,张晋凯,周仕明,陶谦,方春飞.偏心度和密度差耦合条件下水平井顶替界面特征研究[J].石油钻探技术,2016,44(4):65-71.Luo Hengrong,Zhang Jinkai,Zhou Shiming,Tao Qian&Fang Chunfei.Horizontal well cement displacement interface features under the coupling of eccentricity and density difference[J].Petroleum Drilling Techniques,2016,44(4):65-71.
[8]冯福平,艾池,杨丰宇,孟翔,钟鑫.偏心环空层流顶替滞留层边界位置研究[J].石油学报,2010,31(5):858-862.Feng Fuping,Ai Chi,Yang Fengyu,Meng Xiang&Zhong Xin.Astudy on the replacement position of laminar flow in eccentric annulus at retention layer boundaries[J].Acta Petrolei Sinica,2010,31(5):858-862.
[9]李明忠,王瑞和,王成文,方群.层流顶替钻井液滞留层厚度研究[J].水动力学研究与进展(A辑),2013,28(5):531-537.Li Mingzhong,Wang Ruihe,Wang Chengwen&Fang Qun.Astudy on drilling mud stagnant layer thickness under the condition of laminar displacement[J].Journal of Hydrodynamics,2013,28(5):531-537.
[10]Bittleston SH,Ferguson J&Frigaard IA.Mud removal and cement placement during primary cementing of an oil well--Laminar non-Newtonian displacements in an eccentric annular Hele-Shaw cell[J].Journal of Engineering Mathematics,2002,43(2-4):229-253.
[11]王瑞和,李明忠,王成文,方群.油气井注水泥顶替机理研究进展[J].天然气工业,2013,33(5):69-76.Wang Ruihe,Li Mingzhong,Wang Chengwen&Fang Qun.Research progress in the cementing displacement mechanism[J].Natural Gas Industry,2013,33(5):69-76.
[12]李早元,柳洪华,郭小阳,辜涛,欧红娟.油基钻井液组分对水泥浆性能的影响及其机理[J].天然气工业,2016,36(3):63-68.Li Zaoyuan,Liu Honghua,Guo Xiaoyang,Gu Tao&Ou Hongjuan.Impact of the oil-based drilling fluid components on cement slurry performances and its mechanism[J].Natural Gas Industry,2016,36(3):63-68.
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