Self-contained neutron-neutron logging tool APNNK-90
Designed to carry out geological well logging using the method of compensated three-probe neutron-neutron logging of thermal neutrons 2NNKt (2ННКт) and gamma-ray logging of geological material natural activity using one independent detector unit (gamma-ray logging).
Designed to explore very pitching and horizontal sections of oil- and gas-well bores filled with oil- and water based circulation fluid with NaCl content up to 300 g/l.
Active tasks:
- correlation of well logs and lithologic changes;
- detailed lithologic differentiation;
- stratigraphic studies;
- determination of gas-bearing formations, gas-liquid and oil-water contact;
- determination of gas saturation factor.
Tool is designed to operate with a plutonium-beryllium neutron source, type IBN-8-5 (ИБН-8-5) with neutron flux between 5×106 and 2×107 s-1. Neutron detector units – helium counter tubes. Gamma-quantum detector scintillation crystal with a photo-electronic multiplier.
| Measured parameters | Range | Accuracy |
| Natural gamma-ray EDR of geological materials | 0÷250 μR/h | 15 % |
| Porosity measurement range | 0÷40 % | 4.2+2.3(40/ КA-1) % |
| Gamma-ray logging channel sensitivity | at least 750 pulses/min per 1 μR/h | |
| General technical specifications | ||
| Tool overall length, mm | 3720 | max. |
| Tool diameter, mm | 90 | max. |
| Total tool weight, kg | 110 | max. |
| Maximum ambient temperature, °C | 90 (120) | see Note |
| Maximum hydrostatic pressure, MPa | 80 | |
| Logging speed, m/h | 800 | |
| Diameter of the hole, mm | от 120 до 350 | |
| Standalone downtime, hours in recording mode | 10 | |
| Record frequency, (samples per second) | 2 | |
| Sitting | on drill tool | |
Note: during logging in wells with temperature over +90ºC it is necessary to use either special heat-resisting power supply elements or thermostat control device for rechargeable battery pack.