calcite). It requires careful processing and analysis as diagnostic
spectral feature of oil and gas hydrocarbons extracted, at
diagnostic absorption features is weaker at 1720-1750nm. In
order to effectively detect, we need high performance hyper
spectral remote sensing instruments. Combing with the
hydrocarbon alteration minerals (e.g.: kaolinite, illite, etc.)
hyper spectral extraction models, we can also indirectly identify
the target filed of land oil and gas reservoirs by using hyper
spectral remote sensing technology. After hydrocarbons that
naturally leaked from the undersea oil and gas reservoirs rise
above the water, it will form a thin film in the sea surface, and
then gradually spread to a thinner film layer. At present, the
description of oil film is based on a series of changes of oil film
in shape and hue, such as strip (Streamer), silver (Silver sheen)
(Foudan et al., 2003) and so on, but it also need to distinguish
oil films according to the variation of the spectrum of the film
to facilitate the hyper spectral remote sensing exploration of oil
slicks.
U.S. West Virginia University successfully detected oil and gas
microleakage of California, Santa Barbara coast, and found
several oil and gas fields between 1998 and 1999 by delineating
the distribution of the hydrocarbon leakage of mineral alteration
on surface through the AVIRIS Airborne Hyperspectral Imager
with 224 bands (Heather, 2003). U.S. Geosat Committee
detected the process of hydrocarbon leakage and migration on
Australia's Northwest Ocean basins in 2001 by utilizing Probe-1
Hyperspectral Imager with 128 bands, then found several sea
thin films with the length about 5-30 meters long sea thin films,
and interpreted the distribution and transport of the oil
film(Ellis et al, 2001) The GEOSCIENCE Company in
Australia detected the process of hydrocarbon leakage and
migration on Australia's Northwest Ocean basins in 2001 by
utilizing HYMAP airborne hyperspectral remote sensing
technology with 128 bands, then found several very thin oil
films distribution areas on sea which were formed by the
hydrocarbon microleakage of oil and gas undersea, and
interpreted the distribution and transport of the oil film
(William et al., 2002). After that, they successfully detected the
surface hydrocarbon leakage and three undersea hydrocarbon
microleakage reservoirs at offshore waters of USA California,
Santa Barbara In 2003 by utilizing HYMAP Airborne
Hyperspectral Imager with 128 bands which was developed by
Hyvist Company in Australian, and combining with the
effective identification and semi-quantitative analysis of
components of hydrocarbon leakage oil and gas (Horig et al.,
2001).
This article mainly researched the land and offshore oil and gas
exploration of Qaidam Basin and the Liaodong Bay marine in
China by combining with the spectrum of indoor and outdoor
observation experiments and using of satellite HYPERION
hyperspectral remote sensing technology.
2. REMOTE SENSING DETECTION METHOD OF
QAIDAM BASIN RESERVOIS
2.1 Study Area and Hyperion Image Description
SeBei gas filed in the eastern of Qaidam Basin, which located
in northeastern of Tibetan Plateau, was chosen as study area.
The Geological condition is Saline Lake, saline soil and salt
rock. In addition, the district structure is quaternary. The mainly
lithology is dark grey sandy shale, with a small part of clay
siltstone and brown carbonaceous mudstone. Most of the
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B7, 2012
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia
surface is covered with floury soil and salty sand soil.
Groundwater is shallow, the content of salt easy to dissolve is
high, much of that is ultra chlorine saline soil, and part salty soil
(Palmer et al., 1999; Palmer et al., 1994). Accordingly, the
vegetation in this area is sparse, and has less community
composition, simple structure and low coverage. It is very
suitable to explore oil and gas using hyperspectral remote
sensing images for this area. A sight of Hyperion hyperspectral
image acquired on August 11, 2005 was selected in the study,
and its coverage was shown in Figure 1(O Hyperion Image
Copyright 2005). The image coverage is within the scope in
favour of developing gas, and the lower image covers most
SeBei-2 gas field, lower of which is marsh, while the upper
image is Hump mountain anticline structural belt. Hump
Mountain and SeBei-1 gas field are respectively located in the
upper and lower image. Meanwhile, we can identify clearly a
small amount of cloud and cloud shadows.
2.2 Spectrum Experiment and Analysis of Petroleum
Hydrocarbon in Soil
We measure the reflectance spectrum of soil with different
content of oil in the lab, and analyses the sensibility to spectral
response and spectral feature of crude oil in soil. Spectrometric
instrument is Field Spec ASD field spectrometer produced in
American spectrum Device Company. Spectral range from 350
to 2500nm, with a spectral resolution of 3nm(350-1000nm)and
10nm(1000-2500nm).Putting dry Qaidam soil samples weight
of 100g into plastic disc with diameter of 10cm and depth of
2cm, floating with glass bar, and measuring soil spectra without
oil and water. Pouring the soil whose spectra had been
measured into glass bottle, taking crude soil at a volume of
0.5ml into the bottle using injector, putting the cap on the bottle,
shake hardly until crude oil and soil fully mixing, and then
putting the soil back the disc and floating, and measure the
spectra. Determine repeatedly spectra of soil whose volume
dose are respectively 1ml, 1.5ml, 2ml, 2.5ml, 3ml, 3.5ml, 4ml,
4.5ml, 5ml, 5.5ml, 6ml, 6.5ml, 7ml, 7.5ml, 8ml, 8.5ml and 9ml .
Measuring the spectrum of soil with different content of crude
oil for five times, taking the average to mapping, and then
comparative analyzing. As shown in Figure 1, with the
increasing of the content of crude oil in soil, reflectance spectra
curve present the following features: (1) the reflectance of
whole spectrum curve is lower and lower; (2) the decrease of
reflectance value of overall spectrum curve is more and more
slowly; (3) gradually increased the double absorption peak
feature occur around 1748nm, the primary peak around 1726nm,
and the secondary around 1761nm, and their feature are more
and more obvious; (4) gradually increased the double
absorption peak feature occur around 2330nm, and their
absorption depth increased gradually, primary and secondary
peak feature is not obvious.
Double absorption peak feature around 1748nm and 2330nm
diagnosing that whether the soil contains oil hydrocarbons
(Cloutis et al., 1989; Ellis et al., 2001). As shown in Figure 1,
the peaks are located at 1670nm and 1748nm, around 1748nm.
The primary absorption of the valley at 1726nm begins to occur
when the content of crude oil in soil is up to 1.5ml/100g. As
COs’ in soil at 2350nm generates the absorption feature that
wide at left but narrow at night (Foudan et al., 2003), the
absorption peak composing of three bands at 2330nm, 2348nm
and 2348nm has already existed before adding crude oil.
Moreover, with the increasing of the content of crude oil in soil,
the reflectance values at 2308nm and 2349nm tend to be equal.