When the Earth Lies: An Atlas of Pitfalls
Every dry hole was drilled on data that looked convincing. This path collects the classic deceptions, fizz water posing as gas, cemented sand posing as pay, gas clouds faking structure, multiples faking geology, migration and 2D shortcuts lying by construction, and pairs each with the discriminating test that catches it. Learn the earth's tricks the cheap way: before the well.
You can name the pitfall a suspicious anomaly most resembles and run the test that separates it from the real thing: Vp/Vs and AVO against fizz water, the template against cement, flatness-in-time against velocity pushdown, moveout and periodicity against multiples, aperture and crossline checks against 2D and migration artifacts, and the statics QC that stops the near surface from writing fake structure at depth.
How data deceives
The cleanest way to be deceived is to test a method on the same assumptions that built it; the inverse crime is the house rule against believing your own synthetic too much.
Below tuning, thickness becomes amplitude and two beds become one; half of stratigraphic interpretation's false confidence is forgetting where the wavelength floor sits.
Fluids and rocks that lie
Ten percent gas makes almost the whole impedance anomaly of full gas; amplitude proves gas is present, never that it is abundant, and fizz water has drilled more dry holes than bad luck ever did.
A few percent of quartz cement stiffens a sand until it looks like low-porosity pay on impedance alone; the template's second axis is what unmasks it.
Both drop velocity, both dim the stack, and they demand opposite drilling decisions; the discriminator is which velocities move and how density behaves.
An azimuthal anisotropy signal can be aligned cracks or an unequal stress field closing cracks preferentially; the two stories predict different drilling and different frac jobs from the same map.
Waves that lie
A slow anomaly writes fake structure on everything beneath it: the gas-cloud sag that mimics a syncline is a velocity artifact wearing a structural costume.
The classic full-scale deception: a shallow gas chimney pushes the deep reflector down in time, and depth conversion either fixes or immortalizes the lie.
A strong interface plays its reflection twice, and the echo arrives with believable geometry; periodicity and moveout are the tells that the deeper event never existed.
Unmigrated data lies about position by construction, and migration with the wrong velocity lies with more confidence: smiles, swings, and mispositioned faults are the artifact vocabulary every interpreter needs.
A 2D line through 3D geology records sideswipe it cannot place and out-of-plane energy it cannot name; the convolutional shortcut adds its own fibs on top.
The weathered layer delays every trace by a different amount, and uncorrected statics write fake structure on every reflector below; the shallowest hundred meters can forge the deepest picture.
The discipline of doubt
The final defense is procedural, not technical: loop ties, well ties, and the QC habits that catch an interpretation drifting from evidence into wish.