无基础地震观测的时移地震油藏监测技术

20世纪90年代前,中国主要油田均无基础地震观测数据。如何解决老油田面临的油藏监测和剩余油气预测问题成为了地震油藏监测技术的难点。为此,本次研究选择中国辽河拗陷稠油热采油田,开展无基础观测条件下的时移地震油藏监测技术研究。该油田开发始于1997年,第一次三维地震观测是在2009年,尔后在2011年进行了第二次地震观测。通过两期时移地震数据的处理获得了较好的2009~2011年间的油藏监测结果,但无法获得2009年以前的油藏监测结果。针对这一问题,基于2009年地震数据的储层构造和沉积解释、地震与测井的储层静态建模和油藏模拟,通过综合3.5维地震解释获得了2009年以前油藏监测结果,在此基础上,结合2009~2011年的时移地震监测结果,最终给出了无基础地震观测条件下的油藏监测和剩余油气预测结果。该研究成果得到了油田实际温度监测和油藏开发等信息的验证。

3.5D+4D seismic reservoir surveillance without baseline survey

Before ninetieth last century the major oilfields in China were discovered using low-fold large-cell-size 3Dseismic or even 2Dseismic acquired by recording systems with the capacity of several hundred channels.Obviously these kinds of seismic data could neither satisfy the needs of reservoir monitoring nor be used as the baseline survey of the time lapse seismic.The reservoir monitoring and remaining oil prediction for these oilfields thus becomes a difficult subject.A heavy oilfield in Northeast China was chosen for the seismic reservoir monitoring study with no baseline survey available.Production of this oilfield started in 1997,and two monitor seismic surveys were acquired in 2009and 2011respectively.Obvious time lapse seismic difference which reflecting the reservoir change in the time period of two observations can be evaluated from the final processed results. But the reservoir changes before 2009could not be estimated.To solve the reservoir monitoring problem,reservoir structural interpretation and depositional interpretation of the 2009seismic,integrated reservoir modeling of seismic and well logs as well as reservoir simulation were carried out.And final 3.5Dseismic interpretation based on these studies gives us the reservoir monitoring results before 2009.Combining the 3.5Dseismic results and the time lapse seismic between 2009and 2011, reservoir changes was evaluated and remaining oil was predicted in despite of no baseline seismic measurement.The prediction is verified by the temperature measurement and production information in the field.