Identification of leak zone pre-drilling based on fuzzy control

The key factor of plugging operation is how to identify leak zone as well as the difficult point for drilling operation in complex formation. Drilling fluids leakage and reservoir contamination frequently occurred due to the traditional method of identification of leak zone that lost circulation had already happened before detected. In this paper, the difficult problem of technology in identification of leak zone before drilling is solved by using fuzzy control theory. According to analyzing relevant parameters of lost circulation, the relationship between Euclid approach degree and lost circulation is established by using fuzzy relationship of lost circulation parameters. The field application indicated that this method is more accurate and workable in forecasting and practicing whereas the cost is effective. Above all, good results have been achieved in predicting the risk of leak zone by introducing this method.