塔河油田奥陶系碳酸盐岩缝洞型储层预测技术

塔河油田奥陶系碳酸盐岩油藏埋深在5300 m以上,基质不具储集性,储集类型以裂缝、溶洞为主,油气受控于古岩溶缝洞,储层纵、横向非均质性强,地震信噪比、分辨率低,预测难度大。寻找和预测奥陶系缝洞发育带是塔河油田增储上产的关键。在储层成因机理研究的基础上,建立了碳酸盐岩缝洞型储层的成因预测模式,为储层预测奠定了地质基础。针对塔河油田奥陶系储层的特点,建立了以叠前时间偏移和目标精细处理技术为核心的碳酸盐岩缝洞型储层精细成像技术,为储层预测提供了扎实的基础资料。通过储层标定和正演模拟分析,建立了碳酸盐岩缝洞型储层的地球物理识别模式,包括测井识别模式和地震识别模式,为储层识别和预测提供了依据。应用振幅变化率、相干体分析、波阻抗反演等技术,有效地预测了碳酸盐岩缝洞发育带。

Prediction of the Ordovician fractured-vuggy carbonate reservoirs in Tahe oilfield

The Ordovician fractured-vuggy carbonate reservoirs in Tahe oilfield have a burial depth of more than 5 300 m.Their matrix has no storage capacity and their reservoir spaces are dominated by fractures and vugs,which control the accumulation of oil and gas.The reservoirs have a strong heterogeneity both vertically and horizontally.The reservoir prediction is very difficult due to its low seismic SNR and poor resolution.Predicting and locating the highly fractured-vuggy zones in the Ordovician thus becomes the key factor for increasing of the growth of reserves and production in Tahe oilfield.Based on the strudy of genetic mechanism of the reservoirs,a genetic prediction mode is established for the fractured-vuggy carbonate reservoirs to lay a geological foundation for the reservoir prediction.In view of the characteristics of the Ordovician reservoirs,the fine imaging technology(cored with pre-stack time migration and object fine processing) of fractured-vuggy carbonate reservoir is developed.Through reservoir calibration and forward modeling analysis,a geophysical recognition mode(including logging recognition mode and seismic recognition mode) for carbonate fractured-vuggy reservoir is established and it provides evidences for reservoir recognition and prediction.To effectively predict the carbonate zones with highly developed fractures and vugs,technologies,such as amplitude variation,coherent cube analysis,and wave impedance and inversion,are also adopted.