海上稠油油田水平井多轮蒸汽吞吐生产规律研究

Study on development law of horizontal well multiple cyclic steam stimulation for offshore heavy oilfields

旅大油田是渤海油田首个循环蒸汽吞吐先导试验区,其中2口水平井已累计实施9轮次蒸汽吞吐。海上稠油循环蒸汽吞吐开发仍处于探索与试验阶段,针对海上多轮次吞吐开发规律的研究尚属空白。为摸清海上水平井多轮次吞吐开发规律,改善中后期热采开发效果,以旅大油田注采动态数据为基础,运用油藏工程方法,对水平井多轮次蒸汽吞吐生产特征、递减规律及开发效果评价等进行了研究。结果表明:1)蒸汽吞吐是开发海上稠油的有效手段之一,能大幅提高单井产能,第1周期高峰产能相对于冷采增产4.3倍,多轮次平均增产1.8倍。海上水平井蒸汽吞吐油汽比高,累积油汽比为2.34;2)在一个蒸汽吞吐周期内的产油量变化呈现先上升、再递减、后低产稳产的变化规律,可划分为放喷吐水期、高产期、递减期和低产稳定期4个阶段;3)单个周期内及周期间递减规律为指数递减,旅大油田第1~第5周期内递减率为15.5%~5.5%,不同周期间递减率为22.0%~24.8%。以上成果认识对海上相似稠油油田热采开发具有一定的指导意义。

Lvda Oilfield is the first cyclic steam stimulation pilot test area in Bohai Oilfield, two horizontal wells have carried out nine cycles of steam stimulation. The development of offshore heavy oil cyclic steam stimulation is still at the stage of exploration and experiment, and the research on the development law is still blank. In order to find out the development law of offshore horizontal wells multiple cyclic steam stimulation and improve the thermal production effect of the middle and late stage, based on the injection and production dynamic data of Lvda Oilfield, reservoir engineering methods were used to carry out research on the production characteristics, decline law and development effect evaluation of horizontal wells multiple cyclic steam stimulation. The results show that: 1)Steam stimulation is one of the effective means to develop offshore heavy oil, which can greatly improve the productivity of single well. Compared with cold production, the peak production of the first cycle is 4.3 times, and the average production of multiple cycles is 1.8 times. The oil-steam ratio of offshore horizontal wells cyclic steam stimulation is high, and the cumulative oil-steam ratio is 2.34;2)The oil production in a cycle of steam stimulation presented a change rule of first increases, then decreases, and finally low-level stable produce. It can be divided into four periods: water production period, peak oil production period, decline period and low stabilized oil production period;3)The decline law in a single cycle and between cycles is exponential decline. The decline rate in the first to fifth cycles of Lvda Oilfield is 15.5%~5.5%, and the decline rate between different cycles is 22.0%~24.8%. The above studies have a certain guiding significance for the thermal recovery of similar offshore heavy oil field.