3.5D地震勘探实例研究

3D和随时间推移（TL）地震是油田评价与开发阶段重要的地震勘探方法。近年来，TL地震正逐步成为油藏开发和管理中的重要手段之一。但TL地震受到储层条件、开采方式、TL地震勘探过程中非重复性噪声以及一些油田在开发早期未开展基础3D地震观测等诸因素的影响，这些因素使得这一技术在陆上油田开发中的应用受到了制约。为此，提出了3．5D地震勘探方法。3．5D地震勘探方法应用油田开发中、晚期的高精度3D地震数据，结合油田开发动态信息解决油田开发中存在的问题，寻找剩余油气分布区域。通过对中国西部某油田的开发实例研究，认为：3．5D地震可以较有效地解决油田开发中的问题，发现剩余油气的分布，不但解决了一些油田早期没有3D地震或早期3D地震数据质量存在严重非重复性噪声影响的问题，同时还可降低TL地震勘探的风险，提高油田开发的经济效益。

Case study for 3.5-D seismic exploration

3-D and 4-D(or time-lapse)seismic are important exploration techniques for field evaluation and development phase.Increasing- ly,time-lapse seismic is becoming a most popular tool for reservoir development and management.However,its application is con- strained by reservoir conditions,production mechanism,non-re- peatability noise in time-lapse seismic,and even the availability of basic 3-D seismic survey.This constrains the application of time- lapse seismic in onshore fields.Therefore,a 3.5-D seismic tech- nique was proposed.The high quality 3-D seismic data obtained in the middle and later stage for reservoir development is used in the technique,combined with the production history to solve the prob- lems in reservoir development and identify the distribution of resid- ual hydrocarbon.The application to an onshore field in West China shows that 3.5-D seismic can effectively solve the problems in res- ervoir development,identify the distribution of residual hydrocar- bon,and overcome the problem of the shortage of 3-D seismic or the impact of non-repeatability noise in the early stage of field.At the same time,the technique can decrease the risk of time-lapse ex- ploration and improve the economic benefit of reservoir develop- ment.