Method and apparatus for early detection of kicks

Abstract

The present disclosure relates to a method for early kick detection in a drilling system with a drilling fluid loop, comprising: collecting flow-in rate and flow-out rate of a drilling fluid; calibrating the flow-out rate to obtain a calibrated flow-out rate of the drilling fluid; determining a flow rate difference between the flow-in rate and the calibrated flow-out rate of the drilling fluid; and identifying the kicks based on the flow rate difference. The present disclosure also relates to an apparatus for early kick detection in a drilling system with a drilling fluid loop.

What is claimed is: 
     
         1 . A method for early kick detection in a drilling system with a drilling fluid loop, comprising:
 collecting flow-in rate (VFR in ) and flow-out rate (VFR out ) of a drilling fluid;   calibrating the flow-out rate (VFR out ) to obtain a calibrated flow-out rate (   out ) of the drilling fluid;   determining a flow rate difference (Δflow) between the flow-in rate (VFR in ) and the calibrated flow-out rate (   out ) of the drilling fluid; and   identifying the kicks based on the flow rate difference (Δflow).   
     
     
         2 . The method of  claim 1 , wherein calibrating the flow-out rate (VFR out ) to obtain the calibrated flow-out rate (   out ) of the drilling fluid comprises:
 monitoring an evaluation of the flow-in rate (VFR in ) and the flow-out rate (VFR out ) over time;   obtaining a reference pattern based on the evaluation of the flow-in rate (VFR in ) and the flow-out rate (VFR out ) over time; and   determining the calibrated flow-out rate (   out ) based on the reference pattern.   
     
     
         3 . The method of  claim 2 , wherein the reference pattern comprises at least one time-varying parameter (K, T 0 ) for calibrating the flow-out rate. 
     
     
         4 . The method of  claim 1 , further comprising:
 pre-processing the flow-in rate (VFR in ) and the flow-out rate (VFR out ) of the drilling fluid to filter out fluctuations.   
     
     
         5 . The method of  claim 1 , further comprising:
 collecting a drilling parameter (S, drillingbitvelocity) of drilling bit motion; and   estimating a drilling flow-out rate (VFR out     drillingbit   ) based on the drilling parameter (S, drillingbitvelocity) to calibrate the flow-out rate (VFR out ).   
     
     
         6 . An apparatus for early kick detection in a drilling system with a drilling fluid loop, comprising:
 a first sensor, positioned in a onshore input flow section of the drilling fluid loop, for detecting flow-in rate (VFR in ) of a drilling fluid;   a second sensor, positioned in an undersea return flow section of the drilling fluid loop, for detecting flow-out rate (VFR out ) of the drilling fluid; and   a controller communicated with the first sensor and the second sensor and comprising:
 a parameter collecting unit configured for collecting the flow-in rate (VFR in ) and the flow-out rate (VFR out ) of the drilling fluid; 
 a calculating unit configured for calibrating the flow-out rate (VFR out ) to obtain a calibrated flow-out rate (   out ) of the drilling fluid and determining a flow rate difference (Δflow) between the flow-in rate (VFR in ) and the calibrated flow-out rate (   out ) of the drilling fluid; and 
 a kick detection unit configured for identifying the kicks based on the flow rate difference (Δflow). 
   
     
     
         7 . The apparatus of  claim 6 , wherein the calculating unit comprises:
 a modeling element for monitoring an evaluation of the flow-in rate (VFR in ) and the flow-out rate (VFR out ) over time, obtaining a reference pattern based on the evaluation of the flow-in rate (VFR in ) and the flow-out rate (VFR out ) over time; and   a calibrating element for determining the calibrated flow-out rate (   out ) based on the reference pattern.   
     
     
         8 . The apparatus of  claim 7 , wherein the reference pattern comprises at least one time-varying parameter (K, T 0 ) for calibrating the flow-out rate. 
     
     
         9 . The apparatus of  claim 6 , further comprises:
 a pre-processing unit configured for pre-processing the flow-in rate (VFR in ) and the flow-out rate (VFR out ) of the drilling fluid to filter out fluctuations.   
     
     
         10 . The apparatus of  claim 6 , wherein the parameter collecting unit is further configured for collecting a drilling parameter (S, drillingbitvelocity) of drilling bit motion from a third sensor; and the calculating unit is further configured for estimating a drilling flow-out rate (VFR out     drillingbit   ) based on the drilling parameter (S, drillingbitvelocity) to calibrate the flow-out rate (VFR out ).