钙质砂岩强轴影响下的深水扇储层预测技术  

Deep-water fan reservoir prediction technology under the influence of strong amplitude of calcareous sandstone

作　　者：黄饶 侯昕晔 牛聪 纪沫 叶云飞 王志红 HUANG Rao;HOU Xinye;NIU Cong;JI Mo;YE Yunfei;WANG Zhihong(CNOOC Research Institute Co.,Ltd.,Beijing 100028,China)

机构地区：[1]中海油研究总院有限责任公司勘探地球物理研究室,北京100028 [2]中海油研究总院有限责任公司,北京100028

出　　处：《石油地球物理勘探》2023年第1期170-177,共8页Oil Geophysical Prospecting

基　　金：国家自然科学基金项目“莺琼盆地超高温压跨频段地震岩石物理响应机理研究”(U20B2015);中海油“十四五”重大科技项目“高精度地震勘探技术”(KJGG2022-0304)联合资助。

摘　　要：珠江口盆地白云深水区构造珠江组储层为陆坡重力流水道—朵叶复合体沉积,油气勘探潜力巨大,储层分布和圈闭条件是该构造研究需要解决的主要问题。由于研究区珠江组L砂岩上方普遍发育钙质砂岩,砂岩顶界面对应的地震波谷具有连续强反射的特点,致使深水扇储层预测及岩性圈闭落实难度大。针对上述问题,从地震正演出发综合分析了珠江组储层地震响应特征,证实了波谷连续反射是受到钙质砂岩的影响,下波峰反射是储层的真实反映。钙质砂岩的存在改变了含气砂岩AVO曲线的变化规律,并因此降低了纵、横波速度比(VP/VS)的岩性识别能力。基于叠前反演得到的纵波阻抗IP和VP/VS构建了一种新的岩性指示因子,实现了对珠江组深水扇砂体的精确识别,为岩性圈闭评价奠定了基础。实际应用表明,所提方法能够有效提高研究区岩性识别能力和岩性边界刻画效果,预测结果与钻井数据吻合,为研究区下一步探井部署提供了可靠依据。Zhujiang Formation reservoir in structure of Baiyun deep-water area of Pearl River Mouth Basin is a slope gravity flow channel-lobe complex deposition,which has great exploration potential.The reservoir distribution and trap conditions in this structure are the main problems to be solved.As calcareous sandstone is gene-rally developed above the sandstone L of the Zhujiang Formation in this area,the trough at the top interface of the sandstone features continuous reflection,and it is difficult to predict deep-water fan reservoirs and identify litho-logic traps.In view of these problems,this paper comprehensively analyzes the seismic response characteristics of Zhujiang Formation reservoir via seismic forward modeling and proves that the continuous reflection of the trough is affected by the calcareous sandstone,and the lower peak is the real reflection of the reservoir.In addition,it is found that the existence of calcareous sandstone changes the variation law of AVO curves of gas-bearing sandstone,which thus reduces the lithology identification ability of VP/VS(P_and S_wave velocity ratio).Based on the P-wave impedance(IP)and VP/VSresults obtained by pre-stack inversion,the paper constructs a new lithologic indicator and realizes the accurate identification of deep-water fan sand bodies of Zhujiang Formation,which thus lays a solid foundation for lithologic trap evaluation.The application results show that the proposed method can effectively improve the lithology identification ability and lithology boundary description effect in the study area.The prediction results are consistent with the drilling data,which provides a reliable basis for subsequent exploratory well deployment in the area.

关 键 词：深水扇 钙质砂岩 地震正演 AVO叠前反演 岩性指示因子 

分 类 号：P631[天文地球—地质矿产勘探]