Borehole to Surface Electromagnetic Transmitter
AssigneesBGP Arabia Co., Ltd., Saudi Arabian Oil Company
InventorsAlberto Marsala, Zhanxiang He, Tang Biyan, Muhammad H. Al-Buali
Life of this patent
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Abstract
An electromagnetic energy transmitter is provided for borehole to surface electromagnetic (BSEM) surveying. The transmitter is lowered into a well borehole to a desired location in a well borehole to emit electromagnetic energy for the surveys. The transmitter affords more accurate measurements of its position in the well borehole. The transmitter also senses pressure and temperature conditions at its borehole location to provide indications of detected potential problems in the well from the survey or other sources, and to reduce risks and enhance safety and quality of the operations.
Claims11
An electromagnetic energy transmitter mounted with a wireline for electromagnetic surveys of subsurface earth formations from a well borehole which has a casing installed along its extent into the earth to a location near a formation of interest, the casing being formed of lengths of tubular members connected at end portions to adjacent tubular members by casing collars, the transmitter comprising:
- an electromagnetic energy source emitting electromagnetic energy in the form of electric current when activated;
- a control circuit activating the conductive bar to emit electromagnetic energy for a selected time and duration;
- a sonde body housing the control circuit and being lowered by the wireline in the well borehole to the location near the formation of interest;
- an upper connector subassembly mounted above the sonde body connecting the control circuit to the wireline and permitting the flow of electrical current to the electromagnetic energy source;
- a lower connector subassembly below the sonde body connecting the electromagnetic energy source to the control circuit;
- a casing collar locator mounted in the sonde body and providing indications of the movement of the sonde body past casing collar in the casing during movement of the transmitter through the well borehole;
- a fluid pressure sensor mounted in the sonde body for measuring fluid pressure in the well borehole at the location of the sonde body;
- and
- a temperature sensor mounted in the sonde body for measuring temperature in the well borehole at the location of the sonde body.
A method of electromagnetic surveying subsurface earth formations from a well borehole which has a casing installed along its extent into the earth to a location of interest near a formation of interest, the casing being formed of lengths of tubular members connected at end portions to adjacent tubular members by casing collars, the method comprising the steps of:
- lowering an electromagnetic energy source with a sonde body connected therewith to the location of interest in the borehole below the casing;
- forming a measure with the casing collar locator of the number of casing collars past which the source and sonde body travel during the step of lowering to determine the depth of the source and sonde body in the borehole based on the measured number of casing collars;
- deactivating the casing collar locator when the source and the sonde body are at the location of interest;
- and
- emitting electromagnetic energy with the source at the location of interest to travel through the subsurface formations for electromagnetic energy surveying of the subsurface earth formations.
Dependencies are inferred from the claim text.