东沙隆起区灰岩强振幅影响下储层识别与流体检测研究及应用

Research and application of reservoir identification and oil-gas prediction underthe influence of the strong amplitude of limestone in the Dongsha uplift area

H1S地区位于珠江口盆地珠一坳陷东沙隆起边缘,发育两套呈条带状展布的岩性砂体K08和K22,由于邻近生烃洼陷,成藏条件极佳。该砂体超覆于东沙隆起台地碳酸盐地层之上,且横向变化大,因受到灰岩强反射界面的干扰,该区域储层识别和流体预测一直未得到较好解决。这里首先利用匹配追踪算法理论,对强反射进行压制,恢复原有储层应有的反射特征,通过对工区内典型探井进行分析,建立高精度的岩石物理模型,优选弹性阻抗和固液解耦等效流体体积模量为敏感参数,为储层描述和流体识别工作提供有力支撑。利用贝叶斯弹性阻抗反演方法获取部分角度叠加的弹性阻抗数据体,对固液解耦等效流体体积模量进行直接提取,获取含气性分布。实际反演结果与实测测井解释结果吻合率达到83.4%,证明了反演精度较高,明确了H1S地区的含油气的潜在目的层系的展布范围和储层情况。

H1s area is located at the East Sand uplift edge of Zhuyi depression in the Pearl River Mouth Basin.Two sets of lithologic sand bodies K08 and K22,distributed in strips are developed.Due to its proximity to hydrocarbon generating depression,the reservoir forming conditions are excellent.The sand body overlaps the carbonate formation of the Dongsha uplift platform and changes significantly in the transverse direction.Due to the interference of limestone,robust reflection interface,reservoir identification,and fluid prediction in this area have not been solved well.Firstly,this paper is conducive to the matching tracking algorithm theory to suppress the strong reflection and restore the reflection characteristics of the original reservoir.A high-precision petrophysical model is established by analyzing typical exploration wells in the work area,and the elastic impedance and solid-liquid decoupling equivalent fluid bulk modulus are selected as sensitive parameters to provide strong support for reservoir description and fluid identification.The Bayesian elastic impedance inversion method is used to obtain the elastic impedance data volume with partial angle superposition.The solid-liquid decoupling equivalent fluid bulk modulus is extracted to obtain the gas-bearing distribution.The coincidence rate between the actual inversion results and the measured logging interpretation results is 83.4%,which proves that the inversion accuracy is high and defines the distribution range and reservoir of potential target strata of oil and gas in H1s area.