Methods for determining a position of a droppable object in a wellbore

Abstract

The position of a droppable object (e.g., a cementing plug or drillpipe dart) in a cased wellbore may be determined in real time during a cementing operation. A pressure data acquisition system is installed at a wellsite, a pressure transducer is installed at the wellhead and a flowmeter is placed to measure fluid displacement rate. The fluid displacement causes the droppable object to travel through the casing towards a target position. During displacement the pressure data and flow-rate data are transmitted to a pressure data acquisition system and a flowmeter, respectively. The pressure and flow-rate data are processed mathematically to obtain pressure pulses, pulse reflections or both. The fluid flow rate data and pressure data are processed by generating a pressure spectrogram converted to pulses. The pulses are then matched with casing tally pulses, thus allowing correction of the droppable object depth.

Dependencies are inferred from the claim text.