Geophysical investigation of wells: varieties and application

One of the main issues in hydrogeology is the well logging. This is an important process. Many companies are currently solving this issue by common methods of logging or geological prospecting. However, in some cases they can use other modern technical means.

Varieties of the process

During a long period of work on wells, specialists developed various logging methods, including geophysical and radioactive ones. When deciding on the choice of a particular method of exploration, as well as on its conduct, it is necessary to ensure the reliability, efficiency of the research in understanding the necessity and expediency of its implementation and maintaining its profitability. Therefore, when doing geophysical exploration of wells, traditional methods of logging in our time are used in conjunction with innovative methods. Their purpose is to study the section and find out in it the water-bearing intervals. This concerns wells both without protection of the trunk, and protected by metal or plastic.

There are various geophysical methods for studying wells, but the main ones are:

• High-frequency induction;
• Gamma-ray logging;
• electric;
• A video gateway;
• Method of potentials of spontaneous polarization.

The most effective is gamma-ray logging. It allows us to separate the layer into lithographic elements and to distinguish aquifers and clay intervals. Nowadays, wells are often plastered with plastic pipes. They protect the structure from deformation during the movement of rocks. This increases the need to apply such a geophysical study of wells, which will allow to study the electrical properties of the rocks through the obstruction. However, traditional logging methods based on the use of conduction currents are unacceptable in this case. The best option is to use methods of working with high-frequency induction. In the technical analysis of wells, a video gateway and a magnetic location are used. A method such as cavernometry can also be used. When applying a video gateway, carrying out geophysical exploration of wells, basically, they use a color video camera of the latest design. It gives a higher resolution when displaying the side walls of the inspected object.

Tip

If the work is carried out in a carbonate rock with a different tendency to crack, it is very important to properly cement the well. This process should be approached with special attention. Quality control of cementing is achieved using acoustic scanning methods. This method is important in this case. As a result of acoustic scanning, cementing defects are identified that can disrupt the integrity of the skin, and the technical condition of the profile and walls of the column is determined.

The result

All these methods allow us to provide high-quality geophysical well studies. They are the most effective in this process. At the same time, operative solution of such questions as lithographic study (dismemberment) of the rocks through which the well passes, assessment of the technical equipment of the well itself, the capacity of the water-bearing intervals and the filtration qualities of the rocks are achieved, and the quality of the extracted water is determined.