High Resolution Array Induction Tool (HRAI)
| The HRAI
tool is an electric wireline logging tool that measures
apparent conductivity of the formations at a high
sampling density of 50 ms per sample. Signal processing
based on electromagnetic principles converts the
conductivities into apparent resistivities of the
formations drilled in boreholes filled with water-, air-
or oil-based muds. Standard HRAI tool logs present
resistivities at vertical resolutions of 4-ft, 2-ft, and
1-ft, and their radial distribution around the borehole
at six depths of investigation (10-in., 20-in., 30-in.,
60-in., 90-in. and 120-in.). The resistivities are
inverted to yield true resistivities of the formation in
the virgin zone (Rt) and in the invaded zone
(Rxo) in the vicinity of the borehole. Invasion
diameters (Di) corresponding with
Rt and Rxo are also presented.
HRAI tool answer products are available real-time while
logging. |
| » HRAI Tool Features |
| The HRAI
tool contains the following features: |
|
| The HRAI
tool array design is an improvement upon the 3-coil
structure of the receiver arrays used in Halliburton’s
first array induction tool—HRI™. The HRAI tool has a
single transmitter operating at two frequencies (8 KHz
and 32 KHz) and an array of ten receivers positioned in
a symmetrical manner around the transmitter coil. Each
receiver array provides an independent focused
measurement and has the same vertical resolution as the
other arrays. The standard signal processing consists of
sophisticated software to correct the effects of (1)
irregular tool motion in the borehole, (2) rugosity of
the hole, (3) borehole fluid conductivity (4) conductive
skins and (5) shoulder beds. The software also achieves
2-D focusing of the conductivity data. |
| The HRAI™
tool sonde includes an SP electrode, a Z accelerometer
to correct for tool motion and a borehole mud
resistivity measurement for the purposes of
environmental correction of the conductivity
measurements. A temperature sensor in the sonde provides
for real-time temperature corrections. |
|
| The HRAI
device is a bottom-only tool. It can be logged at speeds
up to 6,000 ft/hr. |
|
| The
following toolstring configurations are available with
this service: |
- HRAI/SDLT/DSN II/D2TS or D4TG
- HRAI/FIAC/FWS
- HRAI/WSTT
- HRAI/EMI
|
| » HRAI Tool Benefits |
| The HRAI
tool provides the following benefits: |
|
- Reliable Rt and Rxo in a
variety of geological and borehole environments,
thereby helping to estimate the pore fluid saturations
and hydrocarbon reserves
- Provides picture of the radial fluid distribution around the borehole that aids in qualitatively assessing permeability of the reservoirs
- Since the HRAI tool resolves beds as thin as 1-ft,
it is ideally suited for integration with EMI borehole
image logs. This can significantly enhance oil and gas
reserves estimation and stratigraphic
correlation
|
| » Associated Answer Products |
| The HRAI
tool provides the following answer products real-time
while logging: |
|
- Six radial resistivities at 10-in., 20-in.,
30-in., 60- in., 90-, and 120-in. with matched
vertical resolutions of 1-ft, 2-ft and 4-ft.
- Rt-Rxo and corresponding invasion diameters
- Array coherency and resistivity maps
- Rw and Sw maps with porosity log in the
string
|
|
|
 |
| Standard
HRAI-X tool log presentation. Six radial resistivities
at vertical resolutions of 4-ft, 2-ft and 1-ft are
respectively shown in Tracks 2, 3 and 4. |
|
 |
| Real-time
answer product of HRAI-X exhibits the results of radial
inversion of the logs in Figure 1. Invasion map is
displayed in Track 2 while the Rt and
Rxo are presented in Track 3. |
|
 |
| Thin bed
resolution capability of HRAI-X is demonstrated by this
comparison of 1-ft vertical resolution radial
resistivities (Track 3) with the EMI borehole image
(Track 2). |
|
|
| Model |
Length |
Diameter |
Maximum
Pressure |
Maximum
Temperature |
Weight |
| (ft) |
(m) |
(in) |
(mm) |
(psi) |
(Mpa) |
(°F) |
(°C) |
(lb) |
(kg) |
| HRAI-X |
35.03 |
10.7 |
3.625 |
92.7 |
20,000 |
137.9 |
300 |
150 |
586 |
266.5 |
| HRAI-Polaris |
28 |
8.5 |
3.625 |
92.7 |
20,000 |
137.9 |
300 |
150 |
586 |
266.5 |
|
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