Abstract: A device for evaluating the density of protons present in a given body with the possibility of identifying the material forming part of the constitution of the body and to which the protons belong. The device includes a permanent magnet having north and south poles, the magnet presenting a longitudinal axis of symmetry and a plane of symmetry perpendicular to the axis; two coils disposed at opposite ends of the magnet, centered on the axis, and symmetrical about the plane; a radio frequency electricity generator connected to the two coils in such a manner that the radio frequency electric current feeds the two cols so that the faces of the two coils respectively facing the two poles of the permanent magnet are of the same magnetic kind; and a receiver connected to the two cols to analyze the electrical signals delivered at the output of the two coils when the generator is disconnected from the two coils.

Abstract: Methods and devices for determining the quality of an oil well reserve or the like delivering a given fluid derived from a productive layer, by measuring the response R of the well. The method implemented by the device comprises modulating the fluid flow rate (4) in the well (1) by a sinusoidal function with a controllable preventer (5), and measuring the variations in flow rate and pressure of the fluid respectively with a flow meter (7) and a pressure sensor (9), the response Rc of the well (1); if the productive layer comprises a damaged zone having a positive formation damage of non-null thickness, is obtained by the equation (I), and the response Rf of the well; if the productive layer comprises a fracture having a negative formation damage, is obtained by the equation (II). The invention is applicable to oil prospecting.