Abstract: In methods according to the invention, subsurface formations below the surface of the earth are detected by introducing a condensable material in vapor form into the subsurface formation, measuring radiation of the condensable material, increasing the concentration of the condensable material through condensation, measuring radiation of the condensable material of increased concentration, and comparing the radiation of the condensable material of increased concentration to the radiation of the condensable material in vapor form to identity the presence of the condensable material.

Abstract: In methods according to the invention, subsurface formations below the surface of the earth are detected by introducing a condensable material in vapor form into the subsurface formation, measuring radiation of the condensable material, increasing the concentration of the condensable material through condensation, measuring radiation of the condensable material of increased concentration, and comparing the radiation of the condensable material of increased concentration to the radiation of the condensable material in vapor form to identity the presence of the condensable material.

Abstract: A differential analysis method can be used to determine the presence or absence of a fluid in contact with a tubing string within a wellbore. The method uses a signal generator and detects tubing-perturbed signals, searches for an initial interfacial indicator within a window, axially aligns indicators within a data series as the detector traverses the tubing, discerns an adjacent interfacial indicator known to be incrementally changed by the presence of the fluid, and compares the adjacent indicators to the known incremental change. Even if the absolute location or condition of the interface is uncertain, the relative change indicates the presence or absence of fluid. A prior condition indicator can also be used to determine a second window for detecting an adjacent surface signal indicators.

Abstract: A log analysis method can be used to determine a relative condition of a lined casing within a geothermal well from logged instrument data. Uncertain conditions, such as an unknown scale layer thickness, may perturb the indicators of a casing condition within the logged signals. The method can be used to detect the perturbed signals, discern a perturbed reference interfacial indicator in the data, searches for an adjacent interfacial indicator within a window, and axially aligns the adjacent indicator by shifting the data signal towards the reference indicator. The baseline indicator may be an arbitrarily selected signal indicator or a prior (non-scaled/non-eroded) condition indicator. A prior condition indicator can also be used to determine a second window for detecting an adjacent surface signal indicators.