Fuzzy Comprehensive Evaluation Model for Estimating Casing Damage in Heavy Oil Reservoir

Abstract

A new method for estimating casing damage with fuzzy comprehensive evaluation method is developed on the basis of a comprehensive analysis on development factors affecting casing failure. The six leading factors affecting casing damage are steam injection cycle, sanding, shooting density, bore diameter, phase angle, and cement job quality. How to ascertain the weigh of all factors attaches directly to the evaluation preciseness of casing damage. The authors introduce the Delphin method and expert inquiry method. Then the fuzzy comprehensive evaluation is used to ascertain the weighing for all factors affecting casing damage. With the data coming from actual heavy oil reservoir, the casing damage is predicted. The calculated results fit well with the field observations, indicating the reliability of the model. The model overcomes the shortcoming of the single element limitation evaluation and can be widely used in the prediction of casing damage in heavy oil reservoir.