Title

Seismic underwater reception experiment based on distributed helical optical cable

作者

颜晓霞刘斌朱静包洪刚蔡存军王海峰段伟伟

Authors

Xiaoxia YAN Bin LIU Jing ZHU Honggang BAO Cunjun CAI Haifeng WANG Weiwei DUAN

单位

1. 中石化石油工程地球物理有限公司科技研发中心, 江苏南京 211112 2. 中石化石油工程地球物理有限公司国际业务发展中心, 北京 100020

Organization

1. R&D Center of Science and Technology, Sinopec Geophysical Corporation, Nanjing 211112, China 2. International Department, Sinopec Geophysical Corporation, Beijing 100020, China

摘要

由于传统直光纤DAS存在侧向灵敏度较低的局限性, 因此将分布式声波传感应用于地面地震勘探中接收射线方向几乎与光纤轴向垂直的地震反射信号的案例较少。螺旋缠绕光缆(HWC)可以增强分布式光纤对侧向的灵敏度, 使DAS在地面地震勘探中推广应用成为可能。基于对光纤相对应变与缠绕角度和入射角关系的分析优选, 并考虑目前分布式螺旋光缆生产工艺的难易程度和造价情况下, 将一条部分段缠绕角度为30°, 另一部分段缠绕角度为60°, 总长2km的分布式螺旋光缆布设在江苏某地震采集工区内的河中进行了HWC地面地震采集探索试验。经过对分布式螺旋光缆采集数据与附近地面布设的节点采集地震数据及不同缠绕角度光缆采集的单炮和剖面的对比分析, 发现30°缠绕角度的分布式螺旋光缆能采集到地面地震反射波信号, 而且有效波波组特征清晰连续。试验采取了水中接收的方式, 试验结果为采用分布式螺旋光缆开展地震勘探提供了参考和依据。

Abstract

Due to low broadside sensitivity of conventional straight DAS, distributed acoustic sensing has seldom been applied to surface seismic acquisition to receive reflected signals with the ray direction almost perpendicular to the fiber axis.As an upgrade, the helical wound cable (HWC) with enhanced broadside sensitivity makes it possible to popularize DAS in surface seismic acquisition.Based on the analysis of the relationship between the relative strain of an optical fiber and its winding angle and incident angle as well as the technical difficulties and production cost of current distributed HWCs, a pilot test is performed using a distributed HWC of 2km long with two winding angles of 30° and 60° laid in a river in Jiangsu Province.Through the comparative analysis of HWC and nearby node data as well as shot gathers and stacked sections of HWC data at different winding angles, distributed HWCs with winding angle 30° can receive seismic reflections with clear continuous wavetrain features.The underwater experiment provides technical support for seismic exploration using distributed HWCs.

关键词：

分布式螺旋光缆; 地面地震勘探; 缠绕角度; 反射波;

Keywords:

distributed helical wound optical cable; surface seismic exploration; winding angle; reflection wave;

基金项目

中石化地球物理公司科研项目“分布式螺旋光缆地震勘探采集技术研究及装备研制”(SGC-2022-14)

DOI

10.12431/issn.1000-1441.2024.63.05.002

基于分布式螺旋光缆的地震勘探水中接收试验