In oil and gas exploration and development, formation resistivity is a key parameter reflecting formation lithology and pore fluid properties, while the dual laterolog tool is the core equipment for accurately acquiring this parameter. Through its special electrode structure and measurement mode, it effectively overcomes borehole environment interference and provides high-resolution resistivity data for reservoir evaluation.
The basic structure of the dual laterolog tool consists of a main electrode, shielding electrodes, measuring electrodes, and a current transmitting and receiving system. The main electrode is responsible for emitting a stable current into the formation, while the shielding electrodes form a focused electric field by emitting shielding currents, confining the main current within a specific radial range and reducing the influence of borehole mud and surrounding rock. The measuring electrodes, distributed on both sides of the shielding electrodes, are used to monitor the characteristics of electric field distribution, and the formation resistivity is derived by calculating the relationship between current and potential.
Its working principle is based on Ohm's law and electrostatic field theory. After the tool emits current into the formation, the current exhibits differential distribution in formations with different resistivities. Formations with high resistivity have a strong blocking effect on the current, resulting in a narrow current distribution range; formations with low resistivity, on the other hand, allow the current to diffuse more widely. The potential difference signals captured by the measuring electrodes are converted into dual laterolog curves reflecting the radial resistivity changes of the formation through circuit conversion and algorithm processing.
The dual laterolog tool includes two measurement modes: deep laterolog and shallow laterolog. In deep laterolog measurement, the current penetration depth is large, mainly reflecting the resistivity characteristics of deep formations (far from the borehole), and is suitable for identifying distant oil and gas layers; the shallow laterolog, focusing on formations near the borehole, is sensitive to the permeability and contamination status of the near-wellbore area. The combined application of the two modes can not only distinguish reservoir fluid properties but also determine the degree of formation damage around the borehole.
In practical applications, dual laterolog data serve as an important basis for reservoir evaluation. Through comprehensive analysis with logging curves such as acoustic and density logs, key parameters such as formation porosity and oil saturation can be calculated, providing reliable support for oil and gas reserve estimation and development plan formulation. Meanwhile, its high-resolution feature enables it to maintain good measurement accuracy under complex geological conditions such as thin layer identification and fracture evaluation.
As an important part of modern logging technology, the dual laterolog tool, with its advantages of strong anti-interference ability, high measurement accuracy, and wide applicability, has become an indispensable key equipment in oil and gas exploration and development. For a deeper understanding of relevant technologies or product information, please contact sales@celestep.com, which continuously provides accurate geological basis for the efficient development of underground resources.
