影响CSEM勘探效果因素分析

海洋可控源电磁勘探技术(Marine Controlled-Source Electromagnetic Methods,mCSEM)通过探测地层电阻率的分布情况,并与地震资料结合来确定构造中是否含有油气,可以大大降低勘探风险。深水油气勘探开发的成本非常高,采用CSEM进行油气勘探已被世界各大石油公司认可。虽然CSEM勘探在深水油气勘探中取得了较好的效果,但其最终的勘探效果受水深及海底地形、目标层埋深、目标层与围岩电阻率差异、目标层厚度与侧向规模、浅部高阻层以及目标层附近非油气高阻异常体等因素的影响。通过对CSEM勘探影响因素的分析认为,在进行CSEM勘探前须对各种因素进行分析,并结合地质资料进行模拟。只有在各种条件满足CSEM勘探的前提下,才能取得令人满意的效果。

FACTORS AFFECTING CSEM PERFORMANCE

Marine Controlled-Source Electromagnetic Methods (mCSEM)are used to measure sub- surface resistivity from seabed. The resistivity information can be integrated with seismic data to define whether a structure contains hydrocarbon or not. Deepwater drilling is very expensive, so CSEM is widely used by large oil companies in deepwater petroleum exploration. The performance of CSEM on a specific block is affected by many factors, including water depth, seabed topography, burial depth of the target, resistivity contrast between the target and surrounding rocks, thickness of the target, target's lateral scale, and other non-hydrocarbon high-resistivity anomalies near the target or in sallow burial depth. This paper analyzed all these factors and their affects to CSEM. Before CSEM data acquisition, it is crucial to evaluate all these factors with mathematic modeling. Once all these factors are fit for CSEM, the results shall be maximized.