天然气水合物地球物理勘探技术的应用及发展

Application and development of geophysical technology in gas hydrate exploration

天然气水合物是一种广泛分布于全球、能量密度高、具有极高资源价值的新型清洁能源,因而成为油气勘探界长期研究的热点.本文基于ICGH-9(第九届国际天然气水合物会),结合相关文献资料对天然气水合物地球物理方法及其取得的进展进行综述.内容主要包括地震勘探、海底地震仪(OBS)、地球物理测井、海洋电磁法、地质雷达以及室内声学研究在水合物相关的地质构造(麻坑、泥火山、底辟构造、气烟囱、大型海底滑坡及地质体)、地震识别和处理、地震属性分析与提取技术、天然气水合物及游离气饱和度计算、水合物模拟实验等方面取得的进展.提出地震勘探、地球物理测井技术目前在水合物地球物理勘探中具有勘探精度高、分辨率高等优势,海洋电磁技术因对烃类气体、薄层及薄互层识别困难而逐渐成为了辅助手段,建议在下一步勘探中:①在当前集中于近海底研究的基础上,开展对海底表面、海水甚至海面都进行有效的系统性调查;②建立海洋地震勘探、可控源电磁法、地球物理测井、数据采集、数据处理、数值模拟、异常分析、成像技术等一体化系统;③结合地震、地质、岩性等资料对水合物生产动态进行数值模拟计算,带入储层岩性及地质结构特征参数、储层温压状态参数、水合物藏的储量等参数,结合岩石物理模型、地温梯度参数、水合物相平衡条件以及常规产气速率等,对不同开采方式或者多种方式联合使用情况下,模拟生产对天然气水合物储层的物性影响、引起的环境效应以及最高产气量等多种响应.

Natural Gas hydrate(NGH) is a widely distributed new clean energy around the world. It has become a long-term research focus among the oil and gas exploration industry by reason of high energy density and resource value. The article combines the ICGH-9(the 9 th International Conference on Gas Hydrates) with related literatures to elaborate on the geophysical methods of the hydrate field and its progress. The content mainly involves advances of seismic exploration, Ocean Bottom Seismograph(OBS), geophysical well logging, electromagnetic research, geological radar and laboratorial acoustics research made in hydrate-related geological structures(pockmark,mud volcanoes,diapir structure, gas chimney, large-scale submarine landslide and geologic body), seismic identification and processing, analysis and extraction of seismic attributes, hydrates and free gas saturation calculations, hydrate simulation experiments etc. Proposing that seismic exploration, geophysical well logging technology in the geophysical prospecting in hydrate has high exploration precision and high resolution advantages, by reason of difficulting to identifying hydrocarbon gases,thin layer and thin interbed, marine electromagnetic technique has gradually becomes an auxiliary tool, suggest that in the next exploration :①On the basis of the current research on the bottom of the sea, effective systematic investigations should be carried out on the seabed surface, sea water and even the sea surface;②To establish an integrated system of marine seismic exploration, controlled-source-electromagnetic method, geophysical well logging, data acquisition, data processing, numerical simulation, abnormal analysis, imaging technology;③Combing with seismic, geology, lithology data to carry out dynamic numerical simulation calculation of hydrate production, taking the reservoir lithology and geological structure characteristic parameters, the reservoir temperature, pressure state parameters and the amount of hydrate resources into account, combing with rock physics models, the parameters of the geothermal gradient, hydrate phase equilibrium condition, and the conventional gas rate etc. According to different production methods or synthetic methods to simulate the effects of production on the physical properties of natural gas hydrate reservoirs, the environmental effects and the most high yield.