委内瑞拉水平井资料在地质统计反演中的应用

Application of Horizontal Wells in Geological statistical inversion

M区块位于委内瑞拉奥里诺科重油带,其砂岩储层埋藏浅,厚度大,胶结疏松,内部泥岩隔夹层发育.该区块地震资料品质差,缺少声波测井资料,无法实现常规的地震反演,并且区块内大部分井是水平井,如何利用水平井资料难度大.针对以上问题,本文创新性地提出了综合应用直井和水平井资料进行地震反演,利用GR和电阻率曲线重构出拟声波曲线,在已有声波做速度趋势的约束下,利用倾角叠加技术对水平井进行层位标定,采用稀疏脉冲反演和地质统计模拟进行地震反演.研究表明,重构的拟声波波阻抗能够很好地区分岩性,水平井信息参与反演大大提高了储层和隔夹层的预测精度,从而实现了在缺少声波和密度资料的情况下的直井和水平井约束的地震反演.

The M block locates in the Orinoco heavy oil belt of Venezuela. The sandstone reservoirs of this block characterized by shallow burial depth,great thickness,poor cementation and interbedded/intercalated mudstone. The quality of seismic data here is poor and most wells are horizontal without sonic and density curves. In such cases, it is difficult to perform seismic inversion. Therefore, this paper puts forward a new approach to seismic inversion using both vertical and horizontal well data. First, pseudo-DT curves were reconstructed based on both GR and resistivity logs. Second, with constraint of velocity trends by existing DT data, synthetic record of horizontal wells was generated to calibrate horizons through slant stack, and seismic inversion was carried on by CSSI and geo- statistical simulation. The results show that pseudo-DT curve can be used to distinguish lithology, and predictive accuracy of reservoir can be greatly improved with the contribution of information from horizontal well to inversion. This method realizes vertical and horizontal wells constrained seismic inversion in the area lack of DT and density logs.