Three-component geo-acoustic logging (TCGL)
TCGL is used for carrying out the geo-acoustic logging. It indicates anomalous values in respect to the background of the acceleration vector components under the conditions of dynamic processes in a well (for example: movement of water, oil, gas etc.). Data logging is implemented at a gage point when a device is in a fixed position in a well.
The edge water, hydrocarbon fluid, gas or their mixture produce typical vibration in the course of their movement through the hollow space behind the casing columns, perforations or through the leak-off connection in the underground well equipment. The equipment register vibrations in a frequency range of 100-5000 Hz, so called geo-acoustic noise. These vibrations are generated depending on the volume of fluid, pressure difference in a borehole and the pathway of the flow.
Working frequency range
|100 - 500 Hz||Movement of water, noise of rock|
|500 - 5000 Hz||Movement of hydrocarbon mixture (gas, oil, condensate)|
|500 - 1500 Hz||Movement of oil|
|2500 - 5000 Hz||Movement of gas|
Resources of the device
- identification of presence and direction of the intercasing flows;
- study of a flow profile at perforation intervals;
- determination of leaks in structural elements of the well;
- identification of manmade vein;
- the type of fluid flow identification;
- identification of intraformational movement of the fluid;
- determination of the intensive absorption areas in an open hole and behind casing columns;
- determination of active reservoirs at the blank nonperforated pipe in a well;
The advantage of TCGL is that it makes possible to survey a greater radial transmission distance in contrast to standard methods. For example, movement of water is pointed by TCGL in borehole environment in a radius of 70-100 m, movement of oil is shown in a radius of 50-70 m, movement of gas – in a radius of 30-50 m. While tracing these quantities by standard methods the detection distance is just 0.5 m. The casing columns in observable wells are not a barrier for TCGL.