渤海块状底水稠油油藏蒸汽吞吐参数设计

Design of steam huff and puff parameters for Bohai Sea heavy oil reservoirs with massive bottom water

渤海X油田底水普二类稠油油藏埋藏深、烃柱高度大,底水能量强,降低了热力采油的能量利用率,开发效果较差。在有限的注入热量下,为有效利用原始地层能量,实现原油降黏,提高流动能力,采用蒸汽吞吐热采方式开发。以DST测试资料为基础,利用数值模拟方法对蒸汽温度、干度、注汽速度、焖井时间及周期注汽量等参数进行优化分析。研究认为,该区最佳注汽温度340~350℃,注汽干度0.4,注汽速度300 m^3/d,焖井时间3~5 d,推荐周期注入量递增,第一个吞吐周期蒸汽注入量为3900 m^3,第二个周期开始,注入量逐周期递增10%左右,预测蒸汽吞吐4轮次平均单井累产油6.6×10^4 m^3。研究方法和结果对渤海同类油藏开发具有一定的指导意义。

The second class heavy oil reservoir with bottom water in Bohai X oilfield is deep buried with high hydrocarbon column height and strong bottom water energy,which causes low energy utilization rate of thermal oil recovery and poor development effect.In order to effectively utilize the original formation energy,reduce the viscosity of crude oil and improve the mobility,the steam huff and puff thermal recovery method is used for development under the limited injection heat.This paper optimized the parameters of steam temperature,dryness,steam injection speed,soak time and periodic steam injection by numerical simulation based on the DST test data.The results show that the optimal steam injection temperature is 340-350℃,the steam injection dryness is 0.4,the steam injection speed is 300 m^3/d,and the well shut-in time is 3-5 days.The injection rate is recommended to gradually increase.The steam injection volume in the first cycle is 3900 m^3.From the second cycle,the injection volume is increasing by 10%one by one.It is predicted that the average cumulative oil production of single well after four cycles is 6.6×10^4 m^3.The research methods and results have certain guiding significance for the development of similar reservoirs in the Bohai Sea.