This refers to retrieving logging measurements through well casing or pipes of metals inserted into the well when the operations are completed. Though performed rarely, there is valuable information about the well that is gained when the operation is done. A cased hole logging determines what has obstructed flow, therefore very necessary to have such an operation.
- It’s importance
This operation is important to evaluate, how a well was formed and completed. It is a detailed operation to determine the state of perforation and corrosion, and the cement used to build the well. Regardless of the hole depth, there are small modern tools that are used to run through the tubing to correlate the perforation depth. Through relative porosity and log lithology, the neutron logs and gamma rays have made it possible to locate liquid-gas contacts through the casing. This is also way easier, as the casing collars for perforating are also located, to remove what’s hampering the flow.
- It’s objective
In a quest to improve cost and time performance, and reduce exposure from risks while maintaining the data quality, a company may result in this operation. The main objectives of this; are to access the integrity of mechanical workers, to allocate production and identify problems in production, and to monitor the reservoir fluid contacts. A depth reference is given when the measurements and services of a cased hole operation are done. Once the operation is done, there are changes in the saturation of pores and the formation properties, and this should be checked to evaluate the nature of the changes.
- Safety Measures
Several logging tools use high voltage and radioactive sources. In this field, one needs a lot of caution when dealing with both gas and oil, as they are hazardous. The aftermath of an accident from either gas or oil is very fatal. During lightning or thunderstorm weather conditions, logging should not be carried out. The operation workers should adhere to the general precautions as written out by the company. A firefighter should be stationed at the site and smoking or having an open flame should be prohibited in an area where logging is going on. Radiology, is the method used to carry out logging and maintaining a safe distance from the source, reducing the time of exposure, and shielding the source of harm are the ways to prevent the radiation hazard.
The operation is necessary to be undertaken by the oil and gas industries. However, caution should be paramount as any negligence or ignorance could cause greater harm.