Geomechanics · Module G1
Geomechanics and the 1D Mechanical Earth Model
An introduction to geomechanics for well planning. The module explains effective stress, the vertical and two horizontal principal stresses and the faulting regimes their order defines, then sets out the sequence a one-dimensional model follows: elastic properties, overburden, pore pressure, rock strength, horizontal stresses and finally the range of mud weights that keeps the hole stable.
- Level
- Intermediate
- Position
- Module 1 of 8
- Video
- About 15 minutes, narrated
- Format
- Narrated video lesson with captions and slide reading view; with the certified option, a quiz whose pass unlocks the next module.
What the module covers
- Why wells kick, lose mud, collapse or get stuck
- Total stress, pore pressure and effective stress
- The vertical and the two horizontal principal stresses
- Normal, strike-slip and reverse faulting regimes
- The log, survey and test data a model needs
- Pressure and mud weight units side by side
Learning outcomes
After the module you should be able to:
- Name the chain from logs to mud weight window and what each link needs.
- Explain effective stress and the role of the Biot coefficient
- Identify the faulting regime from the order of the three stresses
A short preview
Effective stress is the share of the load the rock framework carries. At 9,000 ft true vertical depth with an overburden gradient of 1.0 psi/ft and a normal pore pressure gradient of 0.465 psi/ft, the vertical stress is 9,000 psi and the pore pressure about 4,185 psi, so with a Biot coefficient of one the grains carry about 4,815 psi. Overpressure the same depth to 0.7 psi/ft and pore pressure becomes 6,300 psi while effective stress falls to 2,700 psi, which changes every later result: horizontal stress, usable strength and the mud weight the hole needs.
Who it is for
Drilling, completion and reservoir engineers, petrophysicists and geoscientists who build or review pore pressure and wellbore stability predictions for well planning.
Prerequisites: None required; working familiarity with well logs helps. The hands-on steps use the Geomechanics workspace, available from the Professional plan.
Take the module in the Learning Hub
Geomechanics: Specialty course, sold separately: eight modules that build a calibrated 1D mechanical earth model from logs, from elastic properties and pore pressure to the mud weight window and its range. The lesson opens in the Learning Hub once the track is purchased; graded quizzes and the certificate come with the certified option.