塔里木盆地轮古西地区奥陶系碳酸盐岩储层的地震识别
SEISMIC IDENTIFICATION OF ORDOVICIAN CARBONATE RESERVOIRS IN WESTERN LUNGU AREA,TARIM BASIN
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摘要: 塔里木盆地轮古西地区奥陶系风化壳潜山油气资源丰富,但储层分布特征复杂,且储层类型主要有孔洞型、裂缝孔洞型及裂缝型,不同类型储层的地球物理响应特征差异较大。孔洞型储层由于储层内部与围岩的波阻抗差异非常巨大且高频衰减明显,地震剖面上表现为串珠状反射;裂缝型储主要表现为片状不连续的低振幅反射特征。针对其不同的地球物理响应特征,对孔洞型储层采用了分频技术和吸收衰减属性进行预测;对裂缝性储层分别采用了常规的相干技术和SEA3D特色裂缝检测技术,对裂缝的方向及强度开展精细研究,研究结果与单井的成像测井成果基本一致。引入的属性融合和三维可视化展示技术,进一步提高了针对缝洞型储层预测技术的预测精度和效率,对今后的勘探布井工作具有重要的参考意义。Abstract: The buried hills upon the Ordovician weathering crust in the western Lungu area of the Tarim Basin are rich in hydrocarbon resources. However, the distribution of reservoirs is rather complex. There are many types of carbonate reservoirs, such as pore-cave, crack-hole and fracture controlled reservoirs. Each of them has different geophysical reflection features. For example, due to the large wave impedance difference between the internal and surrounding rocks and the frequency attenuation, the pore-cave type reservoir exhibits a beaded reflex in seismic profiles, and the fractured reservoir mainly shows a plate discontinuous reflection with low amplitude. In this paper, different methods were used to deal with the seismic data. For the type of pore-cave reservoir we used frequency division technology and absorption attenuation attributes for forecast, and for the fractured reservoirs, conventional coherence technology was adopted. SEA3D characteristic crack detection technology was used for crack reservoir detecting. Our results fit well with the single well imaging logging and drilling data.