Mechanical, Chemical, and Dynamic Equilibrium of Fluids Disturbed

Wireline tools measure the physical properties of the rock, but in fact, their interpretation relies on the understanding of processes happening during and after drilling. Desired and undesired logging responses are captured by the logged tools, and we as interpreter need to distinguish and interpret them.

One of the most useful features is the disturbance of the equilibrium of fluids.

Mud filtrate invasion, its restriction by the build-up of mud cake and no invasion in impermeable zones is one of the most important signature to look for when reviewing subsurface properties for geothermal assets. The ancient electrical tools can identify tight and permeable zones, even the borehole wall is not in perfect shape.

Surprisingly, one of the ancient electrical logs, the spontaneous potential, does not exist before drilling and shows such disturbances quite well as it is associated with physical and electro-chemical invasion processes.

Ancient log suits may show less vertical resolution, but they capture the freshly created equilibrium of physical forces. How practical. 😊

About the Author

• Dr Claudia Steiner-Luckabauer is the Principal Petrophysicist and geothermal expert at the HOT Energy Group. She has been working in a leading role on numerous integrated reservoir characterisation and field development projects, focussing on integrated petrophysical evaluation and formation evaluation.
• As HOT’s subject matter expert, Claudia has extensive experience assessing mature oil fields, heavy oil fields, gas condensate fields, gas fields, underground gas storage, clastic and carbonate settings, low-salinity environments, unconsolidated reservoirs, and fractured reservoirs (chalk, carbonate, granite basement, sandstone). She is also an experienced instructor of academic and industry workshops on various topics in geosciences and has authored numerous papers.