致密油水平井双甜点评价及产能预测技术

Double Sweet Spots Evaluation and Productivity Prediction Technology of Horizontal Wells in Tight Reservoirs

以乾安地区扶余油藏致密油水平井为研究对象进行水平井双甜点评价产能预测。利用测井资料求取储层脆性、应力差、裂缝指数,构建储层的工程甜点指数I_(A)。通过I_(A)指数建立储层工程甜点评价标准,优化射孔簇,对I_(A)相当的层选取射孔簇,保证设置的射孔簇能够压开,减少了无效、低效射孔簇。利用孔隙度、渗透率、电阻率、含油饱和度、自然伽马、渗透性砂岩厚度等测井曲线,构建地质甜点指数RA,将储层分为4类。建立储层类别和水平井中期产能的相关性,创建了基于有效厚度指数的产能预测评价方法。在水平井评价中,先划分工程甜点优化射孔段,再划分储层类别,求取储层有效厚度指数,对水平井产能进行预测。应用该方法对乾安地区100口水平井进行产能预测,准确率达82%。该项技术减少了无效射孔簇,提高了水平井采收率,在砂泥岩剖面水平井中具有推广应用价值。

Taking tight oil horizontal wells in Fuyu reservoir in Qian’an area as the research object,the double sweet spots evaluation and productivity prediction of horizontal wells are carried out.Based on the brittleness,horizontal stress difference and fracture characteristic parameters obtained from logging data,the reservoir engineering sweet spots evaluation index I_(A)is constructed.Through index I_(A),the evaluation standard of reservoir engineering sweet spots is established,the perforation cluster is optimized,and the perforation cluster is selected for the layer with equivalent I_(A)value,so as to ensure that the set perforation cluster can be opened and the ineffective and inefficient perforation clusters can be reduced.Using the logging curves of porosity,permeability,resistivity,oil saturation,natural gamma and permeable sandstone thickness,the geological sweet spots evaluation index R A is constructed,and the reservoir is divided into four categories.The correlation between reservoir type and productivity of horizontal wells is established,and the productivity prediction and evaluation method of effective length index is established.In the evaluation of horizontal wells,we first identify the engineering sweet spots and optimize the perforation section,then identify the reservoir type,calculate the effective length index of the reservoir,and predict the productivity of horizontal wells.In the application of 100 horizontal wells in Qian’an area,the accuracy of productivity prediction is as high as 82%.These two technologies reduce the ineffective perforation clusters and improve the recovery of horizontal wells.They have the value of popularization and application in horizontal wells with sand shale profile.