The understandings for sedimentary environment of Paleogene Huangxian Formation in Huangxian basin are different, or suggesting it as inland freshwater lacus, or considering it as coastal lagoon.
The formationwater in L area, M Basin is fresh. The natures of drilling mud vary with different drilling depth. There is a complicated relationship between electric properties of water and oil.
盆地L区地层水为淡水类型，各井随埋深的不同及钻井泥浆性能的不同，油、水电性识别极为困难。
3
The causes for creation of black floccules in the mixture of produced water and fresh injection water (shallow formation water) at offshore oil field SZ36-1, Bohai, are investigated.