Liaodong Bay Research Articles

Electrochemical measurement of steel corrosion in seabottom sediment with “MD” method

The through one year corrosion potential and polarization resistance for 3 kinds of steels in seabottom sediment of Liaodong Bay were measured with the “MD” method.

Integrated Geochemical and Basin Modeling Approach to Hydrocarbon Systems Analysis, Bohai Basin, Peoples Republic of China: ABSTRACT

An integrated hydrocarbon systems evaluation was undertaken in the Bozhong and Liaodong Bay areas of the Bohai Basin in an effort to delineate trends and clarify risks for value-based bid decisions. The Bohai Basin is part of the North China Basin (currently producing >1.2 MMBO/D), which is an intracontinental rift basin 200,000 km[sup 2] in size and contains up to 11 km of Tertiary continental to lacustrine rocks. Geochemical analyses of biomarker data (GC/MS) from 43 oils and rock extracts from 41 wells indicate that two main types of lacustrine oils, both generated from the Shahejie 3 Formation, can be distinguished. One type, from the Upper Shahejie 3, has algal affinities, high relative gammacerane content, and is generated and expelled at vitrinite reflectance equivalents (VRE) of 0.5 to 0.6 %, based on sterane isomer ratios. The other oil type, from the Lower Shahejie 3, has higher bacterial relative to algal input, lower relative gammacerane content, and is generated and expelled at 0.8 to 0.9 % VRE. Basin modeling studies and migration pathway analyses were integrated with results from the geochemical work to calibrate the thermal model, estimate timing of generation and expulsion, and calculate potential resources available for migration tomore » traps. A rifting heat flow thermal model was calibrated to measured maturity data (Ro, Tmax, and VRE from sterane ratios) and corrected bottom hole temperature data for 30 wells throughout the basin. The time of major Tertiary rifting was estimated at 55-38 mybp, and beta stretching factors of 1.6 to 2.0 were used. Continuous down-well estimates of hydrocarbon yields for resource estimates were calculated from an empirical relationship between measured TOC and Hydrogen Indices (HI) from well samples and[Delta] log R calculations of TOC and HI.« less

Coatal salt marshes and mangrove swamps in China

Based on plant specimen data, sediment samples, photos, and sketches from 45 coastal crosssections, and materials from two recent countrywide comprehensive investigations on Chinese coasts and islands, this paper deals with China’s vegetative tidal-flats: salt marshes and mangrove swamps. There are now 141700 acres of salt marshes and 51000 acres of mangrove swamps which together cover about 30% of the mud-coast area of the country and distribute between 18°N (Southern Hainan Island) and 41 °N (Liaodong Bay). Over the past 45 years, about 1750000 acres of salt marshes and 49400 acres of mangrove swamps have been reclaimed. The 2.0×109 tons of fine sediments input by rivers into the Chinese seas form extensive tidal flats, the soil basis of coastal helophytes. Different climates result in the diversity of vegetation. The 3∼8 m tidal range favors intertidal zone development. Of over 20 plant species in the salt marshes, nativeSuaeda salsa, Phragmites australis, Aeluropus littoralis, Zoysia maerostachys, Imperata cylindrica and introducedSpartina anglica are the most extensive in distribution. Of the 41 mangrove swamps species,Kandelia candel, Bruguiera gymnorrhiza, Excoecaria agallocha andAvicennia marina are much wider in latitudinal distribution than the others. Developing stages of marshes originally relevant to the evolution of tidal flats are given out. The roles of pioneer plants in decreasing flood water energy and increasing accretion rate in the Changjiang River delta are discussed.

The Coastal Zone Loess of the Liaodong Peninsula, Liaoning Province

Abstract This Paper discusses the origin of the Coastal Zone Loess on the Liaodong Peninsula, Liaoning Province. The loess is composed mainly of proximal materials transported by low‐altitude air flow and less commonly of inland distal materials carried by high‐altitude air flow. The main provenance is the Liaodong Bay. When the sea level declined during glacial period, the bottoms of the Liaodong Bay and Bohai Sea emerged, where desertization occurred. As a result, submarine sediments were transported by strong northwesterly winds to the eastern coastal zone of the peninsula and deposited there. These materials mixed with the windblown dust carried by atmospheric circulation from the interior of the continent, forming the loess. Key words: Liaodong Peninsula, coastal zone, loess.

A tidal model of Bohai

We computed the tides in Bohai using the Crean (1983) model, with open boundary sea level forcing from five constituents (M 2, S 2, N 2, K 1 and O 1). A fine mesh (3 km × 3 km) was chosen with islands included. The model output was analysed with the Foreman (1978) harmonic analysis program. The largest tidal elevations occurred in Liaodong Bay to the northeast with a maximum amplitude of 146 cm for M 2, 37 cm for S 2, 32 cm for N 2, 35 cm for K 2, 22 cm for O 1 and 32 cm for the shallow water constituent M 4. The strongest tidal curents were found near the northern part of Bohai Strait, reaching a maximum of 86 cm s −1 for M 2 and 45 cm s −1 for K 1. Residual tidal currents and tidal energy flux density were also computed.

Reservoir Delineation by Geophysical Methods in the Suizhong 36-1 Oil Field, Bohai Gulf, China: ABSTRACT

The Suizhong 36-1 oil field is located in Liaodong Bay, People's Republic of China. Oligocene fluviodeltaic and lacustrine sandstones contain over 1 billion bbl of oil in place in a combination structural-stratigraphic trap. An international effort to delineate the reservoirs by geophysical methods was completed in June 1989. Three hundred and fifty kilometers of seismic data were reprocessed and interpreted. An attempt was made to reprocess vertical seismic profile data to better relate seismic data to subsurface reservoir parameters. Unfortunately, incomplete field data and/or documentation made such an effort infeasible. Synthetic seismograms were used for correlation and for wavelet processing of the seismic data. Seismic-petrophysical analyses were done to relate the measurable seismic parameters to the subsurface rock and fluid parameters. Seismic data processing comprised conventional reprocessing, special processing primarily for hydrocarbon indicators, and three-dimensional velocity analysis. The reprocessing of the seismic data improved data quality over that of the original processing. Amplitude vs. offset processing revealed no obvious hydrocarbon indicators in the main reservoir zones. Velocity analysis produced a three-dimensional velocity field that was the key to the interpretation and engineering work that followed. Stratigraphic and structural interpretation was done on a GeoQuest workstation and iterated several times to more » obtain a consistent match with the wells. Seismic attribute generation and analysis were used primarily to reveal patterns associated with the depositional environments. Two kinds of seismic trace inversion processes were used to obtain quantitative estimates of the subsurface acoustic impedance distribution. One, the approximate or pseudoinversion method developed by Lindseth was applied to 300 km of seismic data and was the basis for all the reservoir parameter estimates. « less

The character and genesis of condensate in the north of Liaodong Bay, China

The JZ20-2 structure located in the north of Liaodong Bay is a great offshore condensate field. The composition of light fraction (carbon number < 10) of oil consists of 56% alkanes, 36% cycloalkanes and 8% aromatics, GC-MS analysis shows that sesquiterpanes and tricyclic diterpanes are more abundant than hopanes in the condensate. The steroids have more rearranged steranes (C 27–C 29) and 4-methyl steranes (C 28–C 30). The high maturity of the condensate is indicated by biomarker parameters and light HC index. C 29-sterane has ββ/αα + ββ 0.47, S/S + R 0.50. Its paraffin index is 1.2, heptane value is 26. The associated gas δ 13C 1 value −36% PDB. According to the correlation of oil and source rock, the condensate was derived from the high mature mudstone in the Liaozhong depression, east of this structure. The type of the organic matter may be lacustrine sapropelic-humics.