is used for inspection of casing, tubing and annular space technical conditions during expertise of industrial safety of unkilled wells inside of tubing not removing them from operation.
The complex allows:
- running cement bond logging of flowing gas wells;
- detecting industry-related caverns in active gas reservoirs;
- detecting gas accumulations in annular space;
- identifying coefficient of gas saturation;
- constructing lithologic well model.
Application field
Cased wells with external diameter max. 180 mm, inside of tubings with internal diameter min. 60 mm, cumulative thickness of strings up to 30 mm, maximum operating temperature on borehole bottom 120°C and maximum hydrostatic pressure 80 MPa.
OTSK-OSZP downhole tool consists of two modules, having possibility of separated as well as cooperative operations. The top module of logging tool includes sondes of spectrometric gamma ray logging (SGR), scanning magnetic impulse defectoscope, and thermometer and pressure indicator. The bottom module of logging tool includes two sondes of Neuron-Neuron logging (NNL), being placed lower than closed radioactive source of fast neutrons and three sondes of wide-range spectrometric neutron gamma ray logging (SNGR-WR) placed higher than source of fast neutrons.
During the process of operation in wells, the tool is centralized with three centralisers. The tool is stocked with fourth centralizer (no-go) for possibility of separated operation of every module.
The small-sized apparatus was tested on gas and oil fields in Russia, Germany, and Kazakhstan etc.
OTSK module
|
Number of investigated pipes |
1; 2 |
|
Minimum internal diameter of investigated pipes, mm |
59 |
|
Maximum external diameter of investigated pipes, mm under logging of a single pipe under logging of casing through tubing |
180 324 |
|
Minimally defined thickness of a single pipe, mm |
3 |
|
Maximally defined thickness of a single pipe, mm |
19 |
|
Maximally total thickness of two pipes, mm |
30 |
|
Basic error of pipe wall thickness measurement, mm under logging of single pipe 2.5” under logging of single pipe 5” |
±0.3 ±0.4 |
|
Basic error of pipe wall thickness measurement in double casing string well program, mm: for tubing 2.5” inside of casing 5” for casing 5” inside of tubing 2.5” for casing 5” inside of casing 10” |
± 0.4 ± 0.7 ± 0.5 |
|
Minimum length of detectable defect “longitudinal crack” along pipe, mm under logging tubing 2.5” under logging casing 5” under logging casing inside tubing 2.5” |
20 30 70 |
|
Minimum length of detectable defect “hole” along pipe, mm under logging tubing 2.5” under logging casing 5” under logging casing inside tubing 2.5” |
14 30 70 |
|
Minimum length of detectable defect “cross crack”, mm under logging tubing 2.5” under logging casing 5” |
40 80 |
|
Energy resolution of SGR sonde, % |
up to 15 |
|
Lower range limit of gamma quantum detection of SGR sonde, MeV |
up to 0.1 |
|
Upper range limit of gamma quantum detection of SGR sonde, MeV |
no less 3 |
|
Basic relative error of energy reconversion of gamma quantum to pulse amplitude (non-linearity of spectrum energy scales, SNGR), % |
up to ±3 |
|
Resolution of thermometer, °С |
0.01 |
|
Time constant of thermometer, s |
0.5 |
|
Range of pressure indication, |
1 – 800 |
|
Nominal diameter, mm |
48 |
|
Length without centralizer, mm max. |
up to 2600 |
|
Weight, kg |
up to 12 |
OSZP module
|
Identification gradation number of cement stone filling degree of annular space and interstring space through tubings |
4 |
|
Detection of technological caverns in operative collectors and estimation of their dimensions: minimum local augmentation of nominal well radius, cm minimum height of cavern, cm |
5 depth sampling interval |
|
Basic relative error of identification of gas saturation formation, % |
±10 |
|
Number of sonde detectors: SNGR-WR NNL |
3 2 |
|
Measurement range of water-filled rock porosity according to the method of 2NNL, % |
1-40 |
|
Basic relative error of porosity factor (Pf) measurement in range 1-40 % does not increase, % |
4.2+2.3 (40/Pf-1) |
|
Energy resolution of SNGR sondes, being measured against the peak Cs 137 % |
up to 15 |
|
Lower range limit of gamma quantum detection of all sondes SNGR-WR, MeV |
up to 0.1 |
|
Upper range limit of gamma quantum detection of low-energy part of all sondes spectrums SNGR-WR, MeV |
no less than 0.6 |
|
Upper range limit of full spectrums detection of all sondes SNGR-WR, MeV, |
up to 8 |
|
Basic relative error of energy reconversion of gamma quantum to pulse amplitude (non-linearity of spectrum energy scales, SNGR), % |
up to ±3 |
|
Nominal diameter, mm |
48 |
|
Length with centralizers, mm |
up to 3700 |
|
Weight of tool lower module with centralizes, kg |
up to 25 |
Exploitation conditions
|
Maximum operating pressure, MPa |
80 MPa |
|
Range of operating temperatures, °C |
from +5 up to +120°C |
|
Usable borehole cable, the number of conductors |
1-3 |
|
Maximum length of solid-conductor cable |
up to 5 km |
Interface block of apparatus
|
Format of data transmission |
Manchester- 2 |
|
Rate of data transmission, Mbaud |
1/48 |
|
Supply current of tool, ma |
up to 250 |
|
Supply |
180-260 V, 50 Hz |
|
Power consumption, W |
up to 30 |
|
Overall dimensions, length × thickness × height, mm: |
330×270×75 |
|
Weight, kg |
4 |
|
Relative air humidity, % |
up to 98 |
|
Atmospheric pressure, MPa |
60-106 (450- 800) |
Estimation of collector saturation character and degree of annular space filling with cement stone by apparatus OTSK-OSZP
Example of interval identification of cumulative perforation