Understanding Real-Time Job Signatures on Deepwater Cementing Jobs with Dynamic Losses

摘要

Two of the most important parameters to monitor during a primary cementing job are the flow rate in and return flow rate measurements.To achieve optimum quality control of a primary cementing job,measuring annular return rates and comparing them with simulated data in real-time will provide better understanding of job signatures and result in the best possible top-of-cement estimation prior to running any cement evaluation log or taking decision to continue drilling the next section of the well.The return rate job signature along with the wellhead pressure is essential to understand the behavior and discrepancies between simulated and acquired surface data.Therefore,to assess the risk of job issues,such as unsuspected washout and lost circulation among others,accurate measurements of the return rate are critical.Historically,cement job evaluation has been limited by the fact that most drilling rigs do not have an accurate flow meter installed on the annulus return line,and a simple verification of mud tanks volumes versus pumped volume,as reported by drillers or mud loggers,more than often results in an unreliable assessment of the volume lost downhole,due to the unfamiliarity with the U-tubing effect and lack of data consolidation from the cement unit(flow rate in)and the rig(flow rate in & flow rate out).This paper will review a solution developed to mitigate the lack of a direct flow rate measurement by computing and displaying the return rate using either a paddle meter measurement or the derivative over time of the volume observed in the rig tanks.