How to Keep Mud Properties within Design Scope

May 04, 2014

READ: Drilling operations need certain amount of agents whose available content and ratio, especially that of anti-sloughing agents, should be well preserved, and adequate anti-high-temperature materials to avoid high temperature thickening or thinning and other agent failures.

Drilling operations need certain amount of agents whose available content and ratio, especially that of anti-sloughing agents, should be well preserved, and adequate anti-high-temperature materials to avoid high temperature thickening or thinning and other agent failures, as well as larger amount of lubricating materials to keep frictional resistance within limits and to impart property characteristics needed for drilling fields.

Proper mud density is of high necessity since only it can well control formation pressures, maintain well bore stability and ensure successful electrical logging.

Notably, we can get our first crack at strict control of mud properties within limits rather than substantial adjustments and formation of fine, thin but strong cake rather instead of thick but fragile one by following the steps below:

1. Drill by low plastic viscosity, large yield point and yield point & plastic viscosity ratio well beyond 0.5mPa.s.

2. Make short trips, especially at the lower wall of slant hole interval, to not form cuttings bed.

3. Remove harmful solids from drilling fluids by quality mud purification equipment.

4. Maintain well bore stability with proper amount of asphalt additives.

Drilling operations demand high rheology and thixotropy in the mud. Guantao Formation is drilled with mud of standard shear viscosity rather than low shear viscosity and with well borehole cleaning.