水平井CO_2吞吐增油机理及影响因素
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摘要
为了探究底水稠油油藏水平井注CO_2吞吐机理及影响因素,针对M油田G104-5油藏,开展了注CO_2膨胀实验并建立了单井注CO_2吞吐数值模拟模型,研究了G104-5油藏稠油注CO_2膨胀后的相态变化和注气工艺参数、油藏参数对水平井注CO_2吞吐的影响,并在此基础上进行了G104-5油藏7口水平井的注CO_2吞吐效果试验。结果表明,注入35 mol%CO_2后,M油田G104-5油藏稠油的黏度降低了45%,体积膨胀系数为1.13,饱和压力升高了200%,原油中C_9~C_(22)的摩尔分数下降了14.4 mol%。薄层底水油藏注CO_2吞吐增油时,效果最好的直井(射开1~3层)措施后平均含水率降至87%,累计增油313.17 t,水平井措施后平均含水率降至75%,累计增油679.91 t,水平井增油控水效果较好;在所有的影响参数中,注气量、油层厚度、含油饱和度、孔隙度是影响水平井注CO_2吞吐效果的主控因素,注入速度、焖井时间、采液速度、地层压力和渗透率对水平井CO_2吞吐效果的影响不大。M油田G104-5油藏7口吞吐井中G104-5P101井孔隙度最大(45%),注气量最大(412 t),累计增油量最多(1412.27 t)。
In order to research the enhanced oil recovery mechanism and influence factors of CO_2 puff and huff in horizontal well in heavy oil reservoir with bottom water,the CO_2 swell experiments was carried out and CO_2 puff and huff single well simulation model was built in view of G104-5 reservoir of M oilfield.The phase changing after CO_2 swell,and the influence of technological parameters of gas injection and reservoir parameters were studied,and the CO_2 puff and huff of 7 horizontal wells from G104-5 was conducted.It is concluded that after injected 35 mol% CO_2,the viscosity of heavy oil decreased by 45% and the coefficient of cubic expansion was 1.13,and saturation pressure increased by 200% and mole fraction of C_9—C_(22) in oil decreased by 14.4 mol%.After CO_2 puff and huff in the thin bottom water reservoir,the water cut of vertical well(shoot layer from 1 to 3),which had 313.17 t cumulative incremental oil,decreased to 87%,while the water cut of the horizon well,the cumulative incremental oil being of679.91 t,decreased to 75%,which indicted that the latter had better oil-increment and water-control effect.Among all of the effect parameters,the gas volume,reservoir thickness,oil saturation,porosity was the most important parameters;while the injection speed,formation pressure,shut time,exploit speed and permeability had little effect in CO_2 huff and puff with horizon well.In the7 CO_2 huff and puff wells of G104-5 reservoir,G104-5 P101 had the biggest porosity(45%),the maximum injected gas volume(412 t),and the most cumulative incremental oil(1412.3 t).
In order to research the enhanced oil recovery mechanism and influence factors of CO_2 puff and huff in horizontal well in heavy oil reservoir with bottom water,the CO_2 swell experiments was carried out and CO_2 puff and huff single well simulation model was built in view of G104-5 reservoir of M oilfield.The phase changing after CO_2 swell,and the influence of technological parameters of gas injection and reservoir parameters were studied,and the CO_2 puff and huff of 7 horizontal wells from G104-5 was conducted.It is concluded that after injected 35 mol% CO_2,the viscosity of heavy oil decreased by 45% and the coefficient of cubic expansion was 1.13,and saturation pressure increased by 200% and mole fraction of C_9—C_(22) in oil decreased by 14.4 mol%.After CO_2 puff and huff in the thin bottom water reservoir,the water cut of vertical well(shoot layer from 1 to 3),which had 313.17 t cumulative incremental oil,decreased to 87%,while the water cut of the horizon well,the cumulative incremental oil being of679.91 t,decreased to 75%,which indicted that the latter had better oil-increment and water-control effect.Among all of the effect parameters,the gas volume,reservoir thickness,oil saturation,porosity was the most important parameters;while the injection speed,formation pressure,shut time,exploit speed and permeability had little effect in CO_2 huff and puff with horizon well.In the7 CO_2 huff and puff wells of G104-5 reservoir,G104-5 P101 had the biggest porosity(45%),the maximum injected gas volume(412 t),and the most cumulative incremental oil(1412.3 t).
引文
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[2]D.KARAOGUZ,K.ISSEVER,N.PAMIR,et al.Performance of a heavy-oil recovery process by an immiscible CO2application,Bati Raman field[R].SPE 18002,1989.
[3]孙雷,庞辉,孙扬,等.浅层稠油油藏CO2吞吐控水增油机理研究[J].西南石油大学学报(自然科学版),2014,36(6):88-94.
[4]张娟.浅薄稠油油藏水平井二氧化碳吞吐数值模拟研究[D].成都:西南石油大学,2012:1-7.
[5]吴光焕,夏志增,时凤霞,等.CO2对超稠油物性影响的实验研究[J].油田化学,2015,32(1):67-71.
[6]李士伦,张正卿,冉新权,等.注气提高石油采收率技术[M].四川:四川科学技术出版社,2001.
[7]谢宏琴.烃源岩中有机质的超临界CO2萃取研究[D].兰州:中国科学院兰州地质研究所,2001:3-11.
[8]李赵,杜国勇,朱盟翔,等.超临界二氧化碳萃取废弃油基钻屑的实验研究[J].石油与天然气化工,2016,45(3):93-96.
[9]邢晓凯,秦臻伟,孙锐艳,等.CO2在黑59稠油中的溶解特性[J].油气田地面工程,2011,30(12):9-11.
[10]王舒华.超临界CO2对稠油性质影响规律研究[D].北京:中国石油大学,2014.