饶阳凹陷虎8北潜山重力三维松约束反演

Part-constrained 3D gravity inversion for the Hubabei buried hill in Raoyang Sag

饶阳凹陷前古近系古潜山是油气勘探的重要目标,为了清楚认识虎8北古潜山的结构特征,对该地区的大比例尺重力资料进行了处理和三维反演计算。首先采用二次趋势面最小二乘法剔除区域异常后,得到剩余重力异常;然后以地震解释的前古近系顶界面数据和该区的密度数据为基础,建立基于层面的三维模型,采用Parker算法对剩余重力异常进行三维密度界面松约束反演;最后采用松约束三维重力资料反演方法,得到了与重力异常吻合的前古近系顶界面三维模型,为认识虎8北古潜山的规模和幅度等结构特征提供了依据。研究表明,利用地震资料对重力资料进行松约束三维反演是一种比较有效的方法,能充分发挥地震资料和重力资料各自的优势,提高认识的可靠性。

Buried hills of the pre-Tertiary are important targets for oil and gas exploration. In order to recognize structural features of the Hubabei buried hills, large-scale gravity data is processed and inverted. First residual gravity anomaly is calculated by removing regional trend through the least squares method. Then a quadric surface is used as a trend. Residual gravity anomaly is transformed to the frequency domain from the spatial domain using two-dimensional Fourier transformation. A three-dimensional initial model is built based on seismic interpretation data of the pre-Tertiary top boundary, and the density data based on the logging data. Three-dimensional structure inversion is applied to the residual gravity data by Parker algorithm. A constrain grid is also created based on the quality of the seismic data to confine the inversion. The final model of the buried hill is obtained by the inversion. Result shows that the proposed 3D inversion is an effective method to recognize structural features of buried hills. © 2016, Editorial Department OIL GEOPHYSICAL PROSPECTING. All right reserved.