开发地震反演可行性研究及应用--以大庆长垣北部油田为例

Feasibility study and application of development seismic inversion-a case study from northern Changyuan oilfield of Daqing area

李占东 赵伟 李阳 彭政 张海翔

Li Zhandong Zhao Wei Li Yang Peng Zheng Zhang Haixiang

为解决开发地震反演可行性和精细储层刻画的难题,提出了一种基于分频补偿的曲线重构方法。根据测井曲线不同频率尺度反映不同砂岩特征的特点,利用高频恢复、低频补偿方法重构"拟波阻抗"曲线。反演可行性分析实验表明,通过曲线重构反演、模拟退火算法引入以及密井网反演等关键技术,能够加强结果稳定性的优化,提高薄储层预测精度;同时,正演模拟和反演实践证明,在大套泥岩中含有薄砂层的地质条件下,开发地震对刻画2 m薄层砂岩是可行的。而对于小于2 m以下的薄砂层,仅当泥岩围岩在2 m以上的泥包砂型薄砂层能够进行分辨。井-震联合沉积相研究主要修正了河道侧积体识别、河道连通关系、河道规模变化、河道组合关系和河道期次划分等5个方面。规模较大的分流河道含油性好,形成较好的注采不完善型剩余油;小型分流河道局部含油性好,但河道窄小,以井网控制不住型剩余油为主。

In order to make development seismic inversion and fine reservoir description feasible,we proposed a curve reconstruction method based on frequency division compensation.As logs with different frequency can reflect features of different sandstones,we reconstructed "quasi-wave impedance" curves through high frequency restoration and low frequency compensation.Inversion feasibility analysis experiments showed that result stability could be optimized and reservoir prediction accuracy could be improved through introducing curve reconstruction inversion,simulated annealing algorithm and high well-dense inversion.Meanwhile,forward modeling and inversion proved that 2 meters thin sandstone layer interbeded in thick mudstone could be recognized through development seismic inversion.But for sandstone layers with thickness less than 2 meters,they can be recognized only when interbeded within mudstone layers greater than 2 meters thick.Well-tied seismic sedimentary facies study was also carried out to refine prediction of sandbody volume on sides of channel,channel sand connectivity,channel sand scale change,channel combination and timing of channels.Large distributary channel sandbodies are high in oil potential and remaining oil is commonly caused by imperfect injection-production well pattern.Small distributary channel sandbodies locally have high oil potential,and remaining oil is commonly caused by limited control area of well patterns.

10.11743/ogg20110520