大庆油田长垣地区萨零组横波速度预测方法研究

Study on the Prediction Method of Shear Wave Velocity in the Saling Formation

萨零组是大庆油田萨尔图油层组顶部发育的一个沉积单元,含油面积广,油气资源丰富。萨零组储层致密、物性差、一直未动用,为了对大庆油田长垣地区萨零组进行高质量勘探开发,急需开展萨零组储层横波速度预测方法的研究。根据萨零组在平面上的分布特征,将长垣地区由南到北分5个区块,以67口井Xmac测井曲线和全波声波测井资料为基础,采用最小二乘法,分别进行线性关系和二次多项式关系拟合,得到长垣地区不同区块的纵横波速度经验公式。线性关系拟合的相关指数比二次多项式关系拟合的相关指数小,二次多项式关系预测值更接近实测值,应用不同区块的经验公式可以预测出横波速度,弥补了萨零组横波速度资料少的问题,对于提高垂向应力解释精度、判断压后裂缝形态等方面具有参考价值。

Saling Formation is a sedimentary unit developed at the top of the Sartu oil layer in the Songliao Basin of Daqing Oilfield,with a wide oil bearing area and abundant oil and gas resources.The Saling Formation reservoir is tight,with poor physical properties and has not been utilized.In order to provide a good guidance for its the high-quality exploration and development,it is urgent to study the prediction method of shear wave velocity in Saling Formation.According to the distribution characteristics on the plane,Changyuan area is divided into 5 blocks from south to north.Based on the Xmac log and full-wave acoustic log data of 67 wells,the linear relationship and quadratic polynomial relationship are fitted by the least square method,and the empirical formulas of the P-S wave velocity in different blocks are obtained.The correlation index of linear relationship fitting is smaller than that of quadratic polynomial relationship fitting,and the predicted value of quadratic polynomial relationship is closer to the measured value.The shear wave velocity can be predicted by applying the empirical formula of different fields,which compensates for the insufficient shear wave velocity data.Besides,it is meaningful to improve the interpretation accuracy of vertical stress and judge the fracture morphology after compression.