草舍泰州组油藏CO_2混相驱效果及二次气驱可行性研究
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摘要
草舍泰州组油藏CO_2混相驱提高采收率项目是国内较为成功的项目之一。针对一次混相驱后剩余油分布复杂、后期气窜严重等问题,开展二次混相驱的可行性研究。金相显微镜下观测真实岩心CO_2混相驱的流动过程具有微观分维的特征,剩余油以薄膜状、孤立点珠状附着在岩石孔隙表面,CO_2二次混相驱油效率为93.40%,比一次混相驱油效率提高9.73%;密闭取心显示平均残余油饱和度为30.8%,Ⅲ油组潜力较大。设计二次混相驱油可行性方案,采用分层系开发动用底部油藏,高部位注气抑制重力超覆,水气交替减缓气窜,全过程防窜调整剖面等方式,预计可进一步提高采收率8%～10%。
The CO_2 miscible flooding project in the Taizhou formation of Caoshe oilfield is one of the most successful CO_2 EOR projects in China. The feasibility study on the secondary miscible flooding was carried out to settle the issues of complex remaining oil distribution and severe gas channeling in the later stage after first miscible flooding. The characteristic of microscopic fractal dimension in the CO_2 miscible flooding process of real core sample was observed through metalloscope. The remaining oil types attaching to the pore surface of rock took on the forms of thin film and isolated beads. The displacement efficiency of the secondary CO_2 miscible flooding was 93.4 %, which was 9.73 % higher than that of the first CO_2 miscible flooding. The average residual oil saturation was 30.8 % in sealed coring test, indicating great potential of III formation. A feasible development plan for secondary miscible-phases flooding was proposed to develop the stratified reservoirs at the bottom position. The CO_2 injection on the higher position was adopt to suppress gas gravity overlap, and the water alternating gas was applied to slow down the gas channeling. Furthermore, the injection profile was adjusted during the whole process of gas injection. The incremental recovery ratio was estimated to be 8 % ～ 10 %.
The CO_2 miscible flooding project in the Taizhou formation of Caoshe oilfield is one of the most successful CO_2 EOR projects in China. The feasibility study on the secondary miscible flooding was carried out to settle the issues of complex remaining oil distribution and severe gas channeling in the later stage after first miscible flooding. The characteristic of microscopic fractal dimension in the CO_2 miscible flooding process of real core sample was observed through metalloscope. The remaining oil types attaching to the pore surface of rock took on the forms of thin film and isolated beads. The displacement efficiency of the secondary CO_2 miscible flooding was 93.4 %, which was 9.73 % higher than that of the first CO_2 miscible flooding. The average residual oil saturation was 30.8 % in sealed coring test, indicating great potential of III formation. A feasible development plan for secondary miscible-phases flooding was proposed to develop the stratified reservoirs at the bottom position. The CO_2 injection on the higher position was adopt to suppress gas gravity overlap, and the water alternating gas was applied to slow down the gas channeling. Furthermore, the injection profile was adjusted during the whole process of gas injection. The incremental recovery ratio was estimated to be 8 % ～ 10 %.
引文
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[13]汤勇,赵雪梅,汪洋. CO2驱最小混相压力影响因素研究[J].油气藏评价与开发,2018,8(4):42-45.
[14]王健,吴松芸,余恒.CO2泡沫改善吸水剖面实验评价研究[J].油气藏评价与开发,2018,8(4):22-25.
[2]王永兰. CO2混相驱优化决策与效果评价方法研究[D].成都:西南石油大学,2008.
[3]邓波,李鸿,曹建,等.注CO2驱油藏先导性筛选评价方法[J].西南石油大学学报:自然科学版,2009,31(2):105-108.
[4]陈祖华.低渗透油藏CO2驱油开发方式与应用[J].现代地质,2015,29(4):950-957.
[5]陈文,汤勇,梁涛,等.超临界CO2动态混相驱过程机理研究[J].钻采工艺,2011,34(3):77-80.
[6]计秉玉,王凤兰,何应付.对CO2驱油过程中油气混相特征的再认识[J].大庆石油地质与开发,2009,28(3):103-109.
[7]陈祖华,汤勇,王海妹,等.CO2驱开发后期防气窜综合治理方法研究[J].岩性油气藏,2014,26(5):102-106.
[8]赵辉,王传飞,侯健,等.倾斜油藏水气交替驱提高采收率机理研究[J].石油天然气学报,2009,31(5):135-138
[9] Jeschke P A, Schoeling, L H. CO2 flood potential of California oil reservoirs and possible CO2sources[C]//paper SPE-63305-MS presented at the SPE Annual Technical Conference and Exhibition, 1-4 October 2000, Dallas, Texas, USA.
[10] Chen Hsiu-Kuo. Gas injection in the Safah Field, Oman[C]//paper SPE-29805-MS presented at the Middle East Oil Show,11-14 March 1995, Bahrain.
[11]陈祖华,蒲敏,杨春红,等.CS油田CT复杂断块低渗透油藏CO2驱动态调整研究[J].石油天然气学报,2012,34(1):118-122.
[12]李士伦,张正卿,冉新权,等.注气提高石油采收率技术[M].成都:四川科学技术出版社,2001.
[13]汤勇,赵雪梅,汪洋. CO2驱最小混相压力影响因素研究[J].油气藏评价与开发,2018,8(4):42-45.
[14]王健,吴松芸,余恒.CO2泡沫改善吸水剖面实验评价研究[J].油气藏评价与开发,2018,8(4):22-25.