Product Name:NDSL DIPOLE CROSS SONIC LOGGING TOOL
Type:
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NDSL
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producer:
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Huanding Energy Services
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Description:
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Dipole cross sonic logging tool is a new generation of sonic logging tool. It is mainly used for measurements in soft formation, direct shear wave logging, parameter measurements of formation stress for drilling reference. This tool can acquire plenty of strata information in one trip, the survey method includes all present open hole sonic logging ways, and solve shear wave measurement in soft formation.
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INTRODUCTIONFUNCTIONSPECIFICATIONSPROCESSED REPORT
Dipole cross sonic logging tool is a new generation of sonic logging tool.
It ismainly used for measurements in soft formation, direct
shear wave logging, parameter measurements of formation stress for drilling
reference. This tool can acquire plenty of formation information in one trip, the
survey method includes all present open hole sonic logging ways, and solve
shear wave measurement in soft formation.
It is composed of five sections, they are: electronic
circuits, receiver sub, sonic isolator, transmitter sub and transmitter control
circuit sub, shown in the following figure.
It is configured
as lower transmitters and upper receivers, the toolsring sequence from top to
bottom as: main electronic circuits, receiver sub, sonic isolator, transmitter
sub and transmitter control circuit sub
1. The monopole full wave logging:acquiring the speed of compress wave ,
shear wave, and stoneley wave to calculate the porosity of target formation.
2. Identify
gas reservoir :Δt of compress wave will
change dramatically in the gas reservoir, while that of shear wave will change
a little, so that the gas reservoir can be discovered by the ratio of compress wave speed and shear wave speed
VP/VS.
3. Investigation and evaluation
of natural fracture.
4. Indication of
permeable bed.
5. Determination of the formation
anisotropy: the crossed dipole transmitter emits pressure bending wave into the
formation ,received by crossed receivers ,If the formation is homogeneous,
waveforms of X-X and Y-Y will arrive in
receiver simultaneously, namely, they have the same transmitting time and
phase. Otherwise, there should be some time and phase differences, so the
formation anisotropism can be determined..
6. Evaluation of rock mechanic
properties: rock young’s module, bulk module and poisson ratio, which are the
three important parameters of rock mechanic property.
The sonic system applies the structure of single
transmitter and 8 receivers.
Total
length:9.7 meter
Sonic
source:
There are two kinds of sonic sources: monopole sonic
source and two
dipole sonic sources that are cross arranged. The monopole transmitting
source is a piezoelectric ceramics ring transducer. X
and Y dipole transmitting source are at the same depth point. They are
piezoelectric ceramics three pieces pileup bender vibration transducer. Both X dipole
and Y dipole sonic sources are composed of 2 transducers that are arranged at
angle of 180°.
Receiving array:
For receivers: there are 8 receiving rings, each of
which is composed of the 4 dipole receivers that are arranged at 90° in the
circumferential direction. Both sonic source signals of monopole and dipole use
all the 8 receiving rings as receivers. The distance between two adjacent
receiving rings is 6 inches.
Monopole
spacing:8 feet
Dipole
spacing:9 feet
Transmitting
source:Both monopole and dipole transmitting transducers are
activated in way of power driving on the transmit excitation source. That enables
the transmitting transducer work under forced vibrating mode to control the
transmitting frequency. The main operation frequency of the monopole
transmitting source is 8kHz. The dipole transmitting source has three operation
frequencies: 1.2kHz,1.5kHz and 2.2kHz, they are selected by program to be
applicable soft formation (Δt>120us/ft),
medium formation (100us/ft <Δt < 120us/ft) and hard formation(Δt<
120us/ft).
Receiving
circuit:There are 32 independent receiver acquisition channels on
circuits. Signals of each receiver channel are digitalized acquired.
Working mode:A basic acquiring period is 1s. During an acquiring period, monopole , dipole
X and dipole Y acquisitions will be executed once for each. The acquisition sequence
is monopole, dipole X and dipole Y.
Max. temperature:150℃(IB) OR175℃(IC)
Max.
pressure: 100MPa (IB) OR 140MPa(IC)
Borehole
range:5”~12”
Max
vertical resolution:6”
Max depth
of investigation:1~3ft
Providing
logs in real time:Monopole compress wave slowness,
X dipole shear wave slowness and Y dipole shear wave slowness, quality monitor
picture of these three logging curves in real time.
Providing logs after
precise processing:speed of monopole compressive wave, attenuation analyze,
Poisson ratio, rock mechanic properties, anisotropism of formation strains, fracturing height, stoneley
wave field separation and permeability calculation more curves.