泡沫体系改善草20区块多轮次吞吐热采开发效果技术研究

Improving Multiple Steam Stimulation Effects with Foam Fluids in the Cao-20 Block

针对草20区块存在产油量低、油气比低、含水高、开发经济效益差以及蒸汽在高渗透带无效窜流的问题,开展了高温泡沫改善多轮次吞吐稠油热采油藏开发效果的技术研究,在室内研制出了适用于310℃的FCY复合泡沫体系,分析了影响FCY复合泡沫体系性能的因素,确定了该泡沫体系的适用范围。通过管式模型和二维模型评价了不同注入时机、注入方式提高多轮次吞吐采收率的程度,确定氮气发泡剂混注为最佳现场注入方式。胜利油田草 20区块实施氮气泡沫辅助蒸汽吞吐试验8井次,单井日增油0．8-6．2 t,截至2005年5月,8口生产井累计增油 3 843 t。室内研究和现场试验表明,高温复合泡沫体系可有效改善热采稠油油藏吞吐开发效果,是进一步提高稠油热采油藏采收率的有效手段。

Technology researches on improving multiple steam stimulation effects via high temperature foams are conducted to solve problems existing in the Cao-20 Block, such as low oil yields, low oil/gas ratio, high water contents, bad economic benefits, and ineffective steam channeling in high permeability zones, etc. the FCY compound foaha system suitable for up to 310℃ environments is developed in lab. This paper analyzes factors affecting properties of the FCY compound foam system and confirms its applicable scopes. Degrees the recovery of multiple steam stimulation can be increased by different injection time and injection measures are evaluated via the pipe model and the two dimensional model. Finally, the foaming agent injection mixed with nb trogen is determined to be the best one. The auxiliary steam injection mixed with nitrogen is done 8 times in the Cao-20 Block in Shengli Oilfield, individual well yields are increased by 0.8 - 6.2 t/d. The accumulative increased oil outputs of these 8 wells have been up to 3843t by May 2005. Lab researches and field tests indicate that the high temperature compound foam system can effectively improve recovery effects of steam stimulations for thick oil and is an effective measure to further improve thick oil recovery .