蠡县斜坡岩性油气藏提高分辨率采集技术

Acquisition Technology for Improving Resolution of Lithologic Reservoir in Lixian Slope

饶阳凹陷蠡县斜坡是典型的岩性油气藏富集区,该区地表地下地震地质条件复杂,断距小、储层厚度薄、地层岩性圈闭落实难度大。以往的地震资料频带窄,信噪比低,岩性识别难度大。针对这一难题,本文提出基于层序地层模型正演的观测系统设计技术、基于属性均匀的炮点设计技术、高保真拓频接收技术、安全环保井震联合施工技术等解决方案,按照地层沉积层序的关系,在大层内建立薄砂体,有利于薄互层、小砂体地质体的观测系统设计,根据工区资料品质系数、外部环境系数、信噪比计算单支接收覆盖次数,能够确保低频信息的接收,基于“炮点贡献率”的炮点设计及井震联合施工有效保证了资料的完整性、属性均匀性。实施上述采集技术后,有效识别了薄砂体的厚度及横向展布规律,识别了3~5 m厚度的尾砂岩,对比测井资料最大相对误差0.7%。利用新采集的三维地震资料,在蠡县斜坡外带新发现12个有利目标。该方法为类似地区岩性油气藏的高分辨率地震采集提供了经验。

Lixian slope in Raoyang depression is a typical rich lithologic reservoir area,with complex surface and underground seismic geological conditions,the small fault distance,thin reservoir thickness and difficulty in implemeting stratigraphic and lithological traps.The previous seismic data have narrow frequency band,low signal-to-noise ratio and great difficulty in lithology identification.To solve this problem,this paper proposes safe,environment-friendly well seismic joint construction technology solutions.based on the sequence stratigraphy modeling observation system design technology the properties of uniform shotpoint design technology and high fidelity extension frequency receiving technology.Establishing thin sand bodies in large layers according to the relationship of stratigraphic sedimentary sequence,is conducive to the design of observation system for thin interbeds and small sand bodies.The calculation of single point reception coverage times based on the data quality coefficient,external environment coefficient and signal to noise ratio in the work area can ensure the reception of low-frequency information.Shot point design based on “shot point contribution rate” and well seismic joint construction effectively ensures the integrity and attribute uniformity of the data.After application of acquisition technology,the thickness and lateral distribution of thin sand body are effectively identified.This technology can identify the tail sandstone with a thickness of 3~5 m,with a maximum relative error of 0.7 % for well data.Using the newly collected 3D seismic data,12 new favorable targets have been discovered in the outer zone of Lixian slope.This method provides experience for high-resolution seismic acquisition of lithologic reservoirs in similar areas.