Systems and methods using tandem gravimeter

摘要

Systems and methods are provided for determining a property, e.g., density, of a geological formation based on Einstein's theory of gravitation. A tandem-structured gravimeter uses two gamma radiations emitted to two directions to determine a gravitational potential difference between two positions of the geological formation. The gravimeter can be a part of a downhole tool. The gravitational potential difference determined can be used to determine the property of the geological formation.

主权项

1. A system for obtaining a property of a geological formation, the system comprising:
a component including a first portion and a second portion, the first portion extending from a first position to a second position and the second portion extending from the second position to a third position, the first portion including a first source, a first absorber, and a first detector, the first portion to measure a first frequency shift of gamma radiation travelling between the first position and the second position, the first frequency shift resulted from a gravitational potential difference between the first and second positions, the second portion including a second source, a second absorber, and a second detector, the second portion to measure a second frequency shift of gamma radiation travelling between the second position and the third position, the second frequency shift resulted from a gravitational potential difference between the second and third positions, the first and second sources to respectively emit a first gamma radiation and a second gamma radiation to the first and second absorbers, the first and second absorbers to absorb at least a portion of the gamma radiation emitted from the respective source, the first and second detectors operatively connected to the first and second absorbers respectively to detect the absorption and to respectively generate first one or more signals associated with the first frequency shift and second one or more signals associated with the second frequency shift; and one or more processors operatively connected to the first and second detectors, the processors to receive the first signals associated with the first frequency shift and the second signals associated with the second frequency shift from the first and second detectors respectively, determine a gravitational potential difference between the first position and the third position from the signals received, and determine the property of the geological formation between the first and third positions from the gravitational potential difference determined.