DRILLING A WELL WITH PREDICTING SAGGED FLUID COMPOSITION AND MUD WEIGHT

摘要

Methods of drilling or treating a well including the steps of: designing a fluid with high-gravity solids (e.g., barite); calculating the sagged fluid mud weight after allowing for sag according to formulas; forming a fluid according to the sagged fluid mud weight; and introducing the fluid into the well. The methods can be used to help control the well or to avoid excessive drilling torque or pressure, kick, or lost circulation due to sag of high-gravity solids such as barite.

主权项

1. A method of managing or controlling a drilling operation in a well, the method comprising the steps of:
(A) obtaining composition and initially uniform mud weight of a drilling fluid; (B) obtaining wellbore flow conditions in the well operation, including trip-in and trip-out timings, rate of drill pipe rotation, and drilling fluid circulation rate; (C) estimating an initial equivalent circulation density for the drilling fluid based on the initial uniform mud weight of the drilling fluid; (D) estimating or experimentally determining a sagged fluid mud weight (MWs) for the drilling fluid; (E) re-evaluating a later equivalent circulation density based on the estimated MWs; and (F) modifying the drilling fluid or the wellbore flow conditions to manage or control the well or avoid an equivalent circulation density difference greater than 0.05 ppg in the well.