Subsoil part, e.g. rock, magnetic imaging device, for e.g. gas reserve determination, has connecting unit mounting sensors in cooperation with shoes and arranged such that plane is constantly parallel to axis when tool moves in well

摘要

#CMT# #/CMT# An imaging device has a connecting unit (105) connecting shoes (101, 102) to a tool (103) such that the shoes move in proximity to a wall (Pa) of an oil well (Pp) when the tool moves in the well along a determined longitudinal axis (104). The connecting unit mounts magnetic field sensors (C1, C2) in cooperation with the shoes and is arranged such that a plane (Pn) is constantly parallel to the axis when the tool moves in the well. Each sensor has a transmitter coil (13) for creating a transmission magnetic field in a magnetic core (10) and a receiving coil (20) with two windings. #CMT#USE : #/CMT# Used for carrying out magnetic imagery of a subsoil part such as rock, bordering a wall of an oil well (claimed) for determining accumulation and reserve of oil and gas in the rock. #CMT#ADVANTAGE : #/CMT# The device ensures that the response of the sensors is not based on an intrinsic physical parameter of the rock formation, permitting carrying out of the magnetic imagery of the subsoil part without excitation of the rock formation in the border of the wall in a simple manner, while ensuring a sufficient sensibility which is in the order of ten nano-Tesla. The device has reduced encumbrance, while considering reduced temperature drift. The device permits determination of the magnetization fraction related to the magnetic susceptibility of the formation in order to determine dating of the layers of the sub-soil and to make an interpretation in terms of magnetic stratigraphy of the layers surrounding the wall of the well. The movement of the tool in the well allows a complete image of all the useful parts of the well to be obtained. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The drawing shows a block diagram of a subsoil part magnetic imaging device. C1, C2 : Magnetic field sensors Cct : Control and processing electronic circuit Pa : Wall Pn : Plane Pp : Oil well 10 : Magnetic core 13 : Transmitter coil 20 : Receiving coil 101, 102 : Shoes 103 : Tool 104 : Determined longitudinal axis 105 : Connecting unit.