应用烃类直接检测技术预测天然气藏

柴达木盆地位于青藏高原北部，是中国大型含油气盆地之一，历经４０年的勘探，发现了丰富的油气资源。柴达木盆地东部地区是第四纪沉降与沉积中心，区内第二系生储气岩厚度大、分布广、第四纪新构造运动形成的同生沉积构造发育、保存完整、具有形成大中型天然气田的地质条件。此外，由于该地区含气地层时代新、埋藏浅、成岩与胶结作用差、含气层厚度大、孔渗性好，加之构造条件简单，人文干扰小、是应用烃直接检测技术寻找天然气的有

Natural gas prediction using direct hydrocarbon detection technique

The cast part of Caidamu Basin is the center of subsidences and sediments of the Quaternary Period in thc area. Over there the Quaternary rocks in huge thickness which are promising for gas generation and storage are widely distributed and the syndepositional structures generated during the late Quaternary tectonic movement are well-developed and intactly preserved. Those provide the area with favouritc circumstances for the formation of large/moderate scale gas reservoirs.Furthermore, the potential gas-bearing formations are featured by their younger age, shallower buried depth, larger thicknes,better permeability,poorer diagenesis and cementation added in their simpler structure and weaker local artificial interferences, which make it posssible to explore natural gas fields by mcans of direct hydrocarbon detcction.This paper details the role that the direct hydrocarbon detection technique has played in the process of the discovery of thc Tainan gas field. As the first step we found some seismic anomalies,an direct indication for hydrocarbon concerning natural gas. An analysis was then made for the anomalies' seismic features to account for the mechanism of which the anomalies is generated. Via an integrated application of the indication and a seismie forward modeling approach we have affirmed the presence of natural gas, defined its stretching extent,roughly evaluated the geological rescrve and submited the locations of discovery well and the wells for evaluaton. The prediction was confirmed by well-drilling. As a result of applying the direct hydrocarbon detection technique, the Tainan gas field was found at high hitting accuracy of well drilling and expedited exploration process and consequently the significant economic and geological benefits.