Mud Loss Prediction in Realtime Through Hydromechanical Efficiency

Abstract

Abstract Improving drilling efficiency is more of a concern as we prepare for fully autonomous drilling. It is evident that increasing the rate of penetration for minimum cost is not always the best solution, as the drilling problems encountered may negate the benefits. One of the significant drilling problems to be considered is mud loss. This study presents a method to evaluate and quantify circulation loss with a specific energy concept. The methodology is used to compare different wells with and without mud loss conditions using real-time data from two wells. Mechanical specific energy and hydraulic mechanical specific energy (HMSE) using the pressure component were calculated. The unconfined compressive strength pressure, UCS, is also calculated from log data to calculate drilling efficiency. The Realtime loss circulation depths are pointed as the digit [1] for no loss circulation event and digit [0] for loss circulation event. An equation is suggested to relate the loss circulation event to the amount of energy applied to the loss zones. For the present study, several cases with Realtime data were analyzed. The drillability is calculated and modified to account for the differential pressure effect on the ROP. The drilling efficiency, defined by using UCS to HMSE, is modified to reflect the differential pressure effect showed the mud loss conditions in the wells where the mud loss was observed. Also, the impact of the differential pressure between the bottom hole pressure and the formation pressure is presented in this study. The results show a big difference between the amount of energy applied in the loss formation and the required energy to excavate the formation in the analyzed wells. The calculated loss circulation severity was fingerprinted to estimate the amount of mud loss from daily drilling reports. The method developed also predicted the severity of loss circulation using the HMSE and UCS. The effect of the differential pressure can be estimated in real-time and quantified between the high-pressure depth interval and the low-pressure zones. The proposed workflow was tested on historical wells; the results are compared against the proposed analytical model. The results were also verified with the daily drilling reports from the field to confirm the predictions of the algorithm presented. The results predicted were synchronous. A new modified approach of using pressure in the mechanical specific energy is conducted. The study suggests monitoring the ratio of the ROP over the modified drilling efficiency. The drilling crew now has the whole picture about all contributed drilling parameters to manage the drilling parameters to improve the drilling efficiency.