稠油热采水平井分段完井技术研究

Research on Segregated Completion Technology Applied in the Horizontal Wells with Thermal Recovery in the Heavy Oil Reservoirs

作为中国最大的稠油生产基地,截至2012年底,辽河油田水平井已超过1200口,形成了年产油250×104t以上的生产能力,为辽河油田千万吨稳产提供了强有力的支持。其中,热采稠油水平井有800余口,这部分水平井大多采用筛管完井,且没有管外封隔器,筛管与地层之间无法实现有效分隔,注汽时只能采用笼统注汽或筛管内分段注汽,由于油藏在平面及纵向上的非均质作用,使水平井段存在动用不均现象。经统计,水平井动用不均井数占全部热采水平井数的80%,水平井段动用较好的井段仅占水平段长度的1/2～1/3,严重影响了油井产能。为此,在管内分段注汽基础上,研发了稠油热采水平井分段完井、分段注汽工艺技术,通过水平井分段完井工艺研究,以及高温管外封隔器和套管热力扶正器等关键工具的研制,形成了稠油热采水平井分段完井、分段注汽技术。该技术已累计应用6井次,平均周期汽油比提高0.1以上,水平段均匀动用程度明显改善,油田开发效果显著提升。

Liaohe oilfield is the biggest production base of the heavy oil in China.There have been more than 1200 horizontal wells in Liaohe Oilfield by the end of 2012 with building up more than 250xlO4t production capacity,which provides a vigorous support for stable 10 million ton production of Liaohe oilfield.And there are more than 800 horizontal wells with thermal recovery in the heavy oil reservoirs.Most of them adopt screen to complete the wells without packer outside of the casing ,which results in packoff annulus space be- tween the screen and layer and only commingled steam injection or step steam injection inside the screen. Because of areal and vertical anisotropy of the reservoirs,the horizontal sections are exploited unequally.Ac- cording to statistics ,the horizontal wells with nonuniform exploitation are 80 percent of all the horizontal wells with thermal recovery,and only 1/3 to 1/2 of the horizontal sections are well produced.The oil well produc- tivity is seriously affected.So based on step steam injection inside the screen,we have developed the segre- gated completion and segregated steam injection technology applied to the horizontal wells with thermal recov- ery in the heavy oil reservoirs.By means of the research on the segregated completion technology and devel- opment of high-temperature packoff outside screen and casing thermal centralizer,the corresponding technology applied in the horizontal wells with thermal recovery is formed.Till now this technology has been applied in 6 wells ,and average cyclic steam/oil ratio rises by more than 0.1 ,and the uniform development level of the horizontal section have been improved and the oilfield development has advanced obviously.