CPG Drilling Operations & Well Logging 4

Question 1

Measurement-while-drilling (MWD) tools transmit data to surface primarily via:

Accepted Answer

Pressure pulses (mud pulse telemetry) through the drilling fluid column

Answer

Most MWD systems use mud pulse telemetry, encoding data as pressure variations in the mud column that are detected by surface pressure transducers.

Question 2

The sonic log measures which property of formations?

Accepted Answer

Compressional wave travel time (interval transit time, Δt) through the formation

Answer

The sonic log records the time required for compressional (and sometimes shear) acoustic waves to travel one foot through the formation, which reflects lithology, porosity, and fluid content.

Question 3

In well logging, 'invasion' refers to:

Accepted Answer

Penetration of drilling fluid filtrate into the permeable formation surrounding the borehole

Answer

Invasion is the displacement of native formation fluids by mud filtrate that penetrates the porous, permeable formation near the borehole, creating flushed and transition zones.

Question 4

Which well control method involves allowing formation fluids to enter while simultaneously bleeding pressure to keep bottomhole pressure constant?

Accepted Answer

Volumetric method

Answer

The volumetric method controls bottomhole pressure by bleeding small fluid volumes at the surface to allow gas migration while maintaining constant BHP through careful pressure management.

Question 5

What is 'equivalent circulating density' (ECD) and why is it significant?

Accepted Answer

The effective mud density including annular friction pressure losses; it increases effective BHP during circulation

Answer

ECD represents the hydrostatic head plus annular friction losses expressed as an equivalent fluid density; it can exceed the fracture gradient and cause lost circulation during drilling.

(CPG) Certified Petroleum Geologist Practice Test

(CPG) Certified Petroleum Geologist Practice Test

CPG Drilling Operations & Well Logging 4