GRID-MODEL CONSTRUCTION FOR NEUTRON GAMMA LOG
The application of a grid-model technique for the solution of problems in neutron gamma logging is proposed. The model must be of the same kind as that used in solving the problems of resistivity logging with some changes introduced. Instead of the source of current placed on the axis of the drill hole, sources are introduced into the centers of the cells. To this end, the nodes of the grid are connected through resistors to the source of current. In this way the spatial distribution of the sources of high-velocity neutrons is represented. A resistor is attached to each node of thegrid, and each resistor is then grounded. The force of current passing a resistor should correspond to the quantity of neutrons absorbed by the volume element of the medium, represented by the cell of the grid. A relationship was determined between the equation expressfng Kirchoff's first law--for a node of any grid cell--and the differential equation for the distribution of high-velocity neutrons, in the case when the diffusion coefficient for the entire medium is constant. It is shown that in order to depict the excitation of a uniform medium in any particular zone of space, one must similarly change the resistivities of the grid cells associated with this zone of space. It is proposed that, in order to determine the intensity of gamma radiation at the point of observation, the total I = SIGMA a/sub i/n/sub i/, where n/sub i/ is the neutron density obtained in the model for the pofnt of space corresponding to the i-node of the grid; a/sub i/ is a factor determined by calculations. (TCO)
- Research Organization:
- Originating Research Org. not identified
- NSA Number:
- NSA-13-022223
- OSTI ID:
- 4231831
- Journal Information:
- Priklad. Geofiz. Sbornik Statei, Vol. Vol: No. 15; Other Information: Orig. Receipt Date: 31-DEC-59; Related Information: Translated from Referat. Zhur. Geol. No. 10, 1957, p.208-9
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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