Guided by the theory of petroleum system, we analyzed the Lower Palaeozoic hydrocarbon accumulation elements and conditions of the Middle uplift of Southern Yellow Sea Basin and concluded the hydrocarbon accumulation pattern. The results showed that: the source rock of lower Palaeozoic in the Middle uplift of Southern Yellow Sea Basin consists of the dark mudstone and carbonate rock; carbonate rock is the main favorable reservoir followed by clastic rock; there are three source-reservoir-cap assemblages; the source rock of Lower Palaeozoic has experienced two hydrocarbon generation stages which are late Silurian and late Middle Triassic; hydrocarbon generated by Lower Palaeozoic source rock can only migrate to the traps near the center of hydrocarbon generation by sandbody and cracks in a short distance; lithologic trap and broad anticlinal trap are the main types in the study area. Through the above analysis, we conclude two accumulation patterns of Lower Palaeozoic in the Middle uplift of Southern Yellow Sea Basin.

Guided by the theory of petroleum system, we analyzed hydrocarbon accumulation elements and conditions of the Shahejie Formation in Tangzhuang area and concluded the hydrocarbon accumulation model based on the geological and geophysical data. Hydrocarbon comes from the source rock of Es3 in Linyi sub-sag located to the southeast of Tangzhuang area. Reservoir mainly is clastic, followed by carbonate. There are 4 source-reservoir-cap assemblages in the Shahejie Formation. The Es3 source rock of different tectonic units in Linnan sub-sag has experienced different hydrocarbon generation stages. The central region experienced two hydrocarbon generation stages while the edge only experienced one stage. The hydrocarbon generated by the source rock of Es3 in Linnan sub-sag mainly migrated to Tangzhuang area along fault and sand body. The structural trap is the dominant type followed by structure-lithologic trap and lithologic trap. Based on the analysis of hydrocarbon accumulation condition, we concluded the lower generating and upper reserving model of the study area. The findings will play an important role in guiding Tangzhuang oil and gas exploration.

The geological environments in the western of the North Yellow Sea(NYS) are comparatively complicated and pregnant with various geo-hazards. High-resolution sub-bottom seismic data and previous research progress have been used to examine marine geo-hazards’ types, acoustic reflection features, origins and disaster mechanisms. The results indicate that the hazardous types are complicated and multiple in the western of the NYS, including tidal sand ridge, sand wave, tidal erosion gutter, underwater shoal, shallow gas, buried paleo-channel, active fault, irregular bedrock and so on. They have some connections as well as differentiations in their distribution and genesis. This paper can provide the theoretical basis on marine engineering, disaster prevention and mitigation in the western of the NYS . More attention should be given to severe geo-hazards that can constitute direct or potential hazards to the economic development and engineering construction.

The energy situation of China has been very tough. Our country’s oil is heavily dependent on imports and lack of oil and gas reserve. The shortage of oil and gas resource has become an important factor which restricts our national economy health and sustainable development. Guided by the theory of petroleum system, we analyzed the Mesozoic-Palaeozoic marine strata hydrocarbon accumulation elements and conditions of the sourthern depression in Southern Yellow Sea Basin and concluded the hydrocarbon accumulation pattern in order to find the reserving oil and gas. There are seven source-reservoir-cap assemblages. Different tectonic units experienced different tectonic evolution history. The source rock of Lower Palaeozoic, Upper Palaeozoic and Lower Triassic have experienced four, three and two hydrocarbon generation stages separately in the depression. But the source rock of Lower Palaeozoic and Upper Palaeozoic in the salient have only experienced two and one hydrocarbon generation stages separately. Hydrocarbon generated by Mesozoic-Palaeozoic source rock migrated to the traps by fault, crack and unconformity. Lithologic trap, broad anticlinal trap and fault-lithologic trap are the main types in the study area. By the analysis of Mesozoic-Palaeozoic marine hydrocarbon accumulation in the sourthern depresssion, we concluded two accumulation patterns which are the original lithologic reservoir in the Mesozoic-Palaeozoic marine strata and fault-lithologic reservoir in the Mesozoic-Cenozoic terrestrial strata. These results will help to predict the oil and gas resources.

Surveying the damaged site on anticorrosion coating of Underground metal pipeline is currently a realistic problem in pipe network construction projects, They are detected through artificial field source method (DC method), including Person method,potential test method,Close interval pipe-to-soil potential survey and Direct Current Voltage Gradient method, but the principle of detecting about electrical method rare mentioned, the article discusses the forward modeling and inversion method of Surveying the specific damaged site on anticorrosion coating of Underground metal pipeline by DC method in great detail, Through calculation and analysis, The authors believe that the DC method is effective in detecting the damaged site on anticorrosion coating of Underground metal pipeline.