A New Method for Identifing Abnormal Neutron and Density Logging Curves:An Example from Mishrif Reservoir in the Middle East W Oilfield

Quality inspection of logging curve is a necessary part in the reservoir evaluation.The peak frequencies of sonic cures are approximately consistent,but the density value is on the high side and neutron curve is on the low during the evaluation of the Mishrif reservoir of the Middle East W Oilfield.However,to check the quality of the curves in the case of more wells is a huge time consuming project.Hence,a quick method that checks abnormal density and neutron logging curve is proposed to reconstruct a new curve by combining density and neutron logging curve,then calculating the distance between new curve and the sonic curve to automatically identify abnormal curves.The result shows that when the value is equal to or greater than 0.4,the curve is normal,abnormal conversely.A new calibration method is proposed and a new correction formular is introduced because of the inadequacies of the previous calibritions combining the scale and response characteristics of the logging curve after the automatic identification of abnormal curves.In this way the abnormal neutron and density logging curve is adjusted to the normal position and the reasonable total porosity is obtained.