松辽盆地北部中央古隆起带基底储层AVO特征模拟及时频特征分析研究  

Simulation of AVO features and analysis of the time-frequency characteristics of the basement reservoir of the ancient central uplift zone in the northern Songliao Basin

作　　者：姜传金[1] 戴世立[1] 张广颖[1] 陈鸿安 李本彬 王海娇 JIANG Chuanjin;DAI Shili;ZHANG Guangying;CHEN Hongan;LI Benbin;WANG Haijiao(Exploration and Development Research Institute of Daqing Oilfield Company Ltd.,Daqing 163712,China)

机构地区：[1]中国石油大庆油田有限责任公司勘探开发研究院,大庆163712

出　　处：《石油科学通报》2022年第4期505-514,共10页Petroleum Science Bulletin

摘　　要：中央古隆起带位于徐家围子断陷和古龙断陷之间,是长期继承性发育的古隆起。由于中央古隆起带基岩潜山勘探面积大,油气成藏条件好,是目前风险勘探探索的重点领域之一。中央古隆起带基底的岩性主要为花岗岩和变质岩,但由于储集层复杂,储层物性较低,以裂缝为主,勘探程度低,对裂缝型储层地震响应的研究较少。本文针对中央古隆起带基底风化壳地层结构,利用岩石物理、测井、地震解释等成果,明确基底风化壳地层地球物理参数特征,建立基底地层地质模型,利用粘弹性波动方程模拟不同含气饱和度地层的AVO响应和地震波场,明确中央古隆起带基底盖层—风化淋滤层界面、风化淋滤层—裂缝层界面、裂缝层—内幕界面的AVO曲线都基本表现为反射振幅与偏移距成负相关关系,含水饱和度为100%时,反射振幅是最大的,当含水饱和度变为50%和0%时,振幅明显下降,说明当风化淋滤层中含气时,振幅会发生相对明显的下降。基于基底风化壳地质模型正演模拟地震记录并时频分析,明确当地层100%含气时,T_(5)强时频谱之下出现的弱时频谱相比100%含水的要强。整体上,基底风化壳储层含水和含气的AVO特征和时频特征存在差异,可以作为流体识别的可能指标。The paleo central uplift belt is located between the Xujiaweizi and Gulong fault depressions, as a long-term inherited palaeouplift. Due to the large exploration area and well conditions for hydrocarbon accumulation in the bedrock buried-hill, the paleo central uplift belt has become one of the major areas of risk exploration at present. The lithology of the basement of the paleo central uplift belt is mainly granite and metamorphic rocks. However, because of the complexity of the reservoirs and low physical characteristics of reservoirs with fractures as the major reservoir space, research into the seismic response of fractured reservoirs is not enough as there is a low degree of exploration. In this paper, based on the formation structure of the basement weathering crust in the paleo central uplift belt, the characteristics of geophysical parameters of basement weathering crust formation are defined by the results of rock physics, logging and seismic interpretation, and the geological model of the basement is established. The AVO response and seismic wave field of strata with different gas saturation are simulated by viscoelastic wave equations, the AVO curves of caprocks of the paleo central uplift belt–weathering leaching layer interface, the AVO curves of the weathering leaching layer–fracture layer interface, and the AVO curves of the fracture layer–inner layer interface all reflect that the reflection amplitude is negatively correlated with the offset. When the water saturation is 100%, the reflection amplitude is the biggest, when water saturation changes to 50% and 0%, the amplitude obviously decreases. This indicates that the amplitude will decrease significantly when the weathering leaching layer contains gas. Based on the forward modeling of seismic records and time-frequency analysis of the basement weathering crust geological model, it is clear that when the local layer contains 100% gas, the weak time spectrum under the T_(5) strong time spectrum is stronger than that with 100% water content.

关 键 词：AVO响应 时频分析 风化壳 裂缝型储层 

分 类 号：P618.13[天文地球—矿床学] P631.4[天文地球—地质学]