基于生物启发算法的地震双极性变换拟声波测井约束反演方法应用——以塔河油田S9702井区石炭系超深薄砂层为例

Application of pseudo-acoustic wave log constraint inversion method with seismic bipolarity transform based on bioinspired algorithm:A case study of carboniferous ultradeep thin sand layer of Well S9702 area in Tahe Oilfield

塔河油田石炭系超深薄砂层地震响应复杂,声波时差、密度测井曲线对储层敏感性差,地震属性和现有反演方法对储层的预测精度不能满足油气藏精细开发的要求。提出基于生物启发算法的地震双极性变换拟声波测井约束反演方法,首先利用生物启发算法对不同相位地震资料进行双极性变换,使其具有双极性特征,提高了地震资料的视分辨率,绝大部分薄砂层有地震反射同相轴与其对应,改善了薄砂层与地震响应之间的关系;其次开展自然电位、自然伽马测井曲线拟声波重构,增强了反演参数的储层敏感性,因此反演过程仅需较低程度的测井约束,反演结果与地震资料相关性好,降低了多解性,提高了储层预测的可信度。利用该方法在塔河油田S9702井区可以识别埋深达5 000 m、厚度大于3 m的石炭系超深薄砂层,且误差较小,窄河道形态较清楚,砂体展布符合地质规律。

The seismic response of the carboniferous ultra-deep thin sand layer in Tahe Oilfield is complex. The interval transit time and density logging curve are less sensitive to reservoirs,and the seismic attribute and the existing inversion methods cannot meet the requirements of fine development of oil and gas reservoirs in terms of reservoir prediction accuracy. Therefore,this paper proposes a pseudo-acoustic wave log constraint inversion method with seismic bipolarity transform based on bio-inspired algorithm. Specifically,the paper uses the bio-inspired algorithm to perform bipolarity transform on seismic data with different phases to make the date bipolar,which enhances the visual resolution of the data. In addition,most of the thin sand layers have corresponding seismic reflection events,which improves the relationships between thin sand layers and seismic responses. Then,the paper reconstructs pseudo-acoustic wave by self potential and natural gamma log curves to strengthen the reservoir sensitivity of inversion parameters. As a result,the inversion process only requires low-level log constraint,and the inversion results have a positive correlation with seismic data,which decreases the ambiguity and increases the reliability of reservoir prediction. The carboniferous ultra-deep thin sand layer,with a depth of 5 000m and a thickness of more than 3 meters of Well S9702 area in Tahe Oilfield,can be identified by the proposed method and the error is small. The narrow channel morphology is relatively clear,with the distribution of sand bodies in line with the geological law.