孟加拉湾浅层气发育区地震资料处理关键技术

Key technologies of seismic data processing for shallow gas developed area in Bay of Bengal

王兆旗 范国章 杨存 王宗仁 邵萌珠

中国石油杭州地质研究院，浙江 杭州 310023

PetroChina Hangzhou Research Institute of Geology, Hangzhou 310023, China

孟加拉湾处于深水油气勘探前沿领域，近年来备受国际油公司关注。针对该区地震资料中存在的受鬼波影响产生虚假同相轴、浅层气影响下伏地层速度场求取、储层地震波振幅弱和频率低影响目的层成像精度等问题，采取了针对性的处理策略。首先，通过基于波场分离的自适应鬼波衰减技术实现对震源端和电缆端鬼波的压制；其次，采用基于倾角约束的网格层析速度建模技术，精细刻画速度场；最后，应用Q层析实现空间Q场的最终建立，开展基于射线追踪理论的克希霍夫法Q叠前深度偏移补偿资料吸收衰减。通过运用这些技术手段，较好地解决了浅层气造成的能量吸收现象，明显改善了弱能量区的成像质量，为孟加拉湾深水油气勘探奠定了良好的基础。

The Bay of Bengal is a frontier in deepwater oil and gas exploration and has received much attention from international oil companies in recent years. High?鄄quality seismic data is an important basis for oil and gas exploration. Considering the seismic data problems in this area, such as the false seismic event affected by ghost waves, the difficulty of obtaining the underlying strata velocity due to the influence of shallow gas, and the weak amplitude of the deep seismic wave and the reduced frequency, that seriously affect the imaging precision of the target layer, a targeted processing strategy is adopted. First of all, the source and cable ghost wave are suppressed by data?鄄adaptive deghosting technology based on wave field separation. Secondly, the velocity field is depicted by the dip constraint grid tomography velocity modeling. Thirdly, Q tomography is used to establish the Q field, and then Kirchhoff Q depth migration based on ray tracing theory is carried out, which are used to compensate for the attenuation of data absorption. The phenomenon of energy absorption caused by shallow gas has got a better solution. The imaging quality of weak energy area has also been obviously improved, which has laid a good foundation for deep sea oil and gas exploration in the Bay of Bengal.

10.6056/dkyqt201905010