Definition: Downhole Techniques
Downhole techniques are measurements collected from a borehole environment which provide information regarding the character of formations and fluids intersected by a well. These petrophysical data are fundamental to developing the understanding of a geothermal reservoir.
- Petrophysics (from the Greek πέτρα, petra, "rock" and φύσις, physis, "nature") is the study of physical and chemical rock properties and their interactions with fluids.A major application of petrophysics is in studying reservoirs for the hydrocarbon industry. Petrophysicists are employed to help reservoir engineers and geoscientists understand the rock properties of the reservoir, particularly how pores in the subsurface are interconnected, controlling the accumulation and migration of hydrocarbons. Some of the key properties studied in petrophysics are lithology, porosity, water saturation, permeability and density. A key aspect of petrophysics is measuring and evaluating these rock properties by acquiring well log measurements - in which a string of measurement tools are inserted in the borehole, core measurements - in which rock samples are retrieved from subsurface, and seismic measurements. These studies are then combined with geological and geophysical studies and reservoir engineering to give a complete picture of the reservoir.While most petrophysicists work in the hydrocarbon industry, some also work in the mining and water resource industries. The properties measured or computed fall into three broad categories: conventional petrophysical properties, rock mechanical properties, and ore quality.Petrophysical studies are used by petroleum engineering, geology, mineralogy, exploration geophysics and other related studies.