Study On Generation Mechanism And Effect Factors Of Hydrogen Sulphide In Dongsheng Oildom

Dongsheng oildom is one of major oil exploration in Shengli oil field. In recent years H2S has been found in many blocks of Dongsheng oildom within the well drilling, testing and exploring history, especially in Dawangzhuang region. Hydrogen sulphide is a highly toxic and highly corrosive gases, The existence of hydrogen sulphide has been a threat to the security of oil production. Therefore, toresearch the distribution of hydrogen sulphide, to study the generation mechanism of hydrogen sulphide, to conclusion the effect factors of hydrogen sulphide, and to draw up self-contained safety guide procedure, it can provide geological basis for the next phase of oil damh gas erploration and development.At first, we investigate the distribution situation of hydrogen sulphide in Dongsheng oildom, the statistical results show that hydrogen sulphide is detected in seven blocks, among these blocks, the high and medium concentration of hydrogen sulphide distribues in the limestone reservoir the fourth member of Shahejie Formation of Dawangzhuang region intensively, the rest blocks and intervals are all detected low concentration of hydrogen sulphide.We have analyzed the generation mechanism of every blocks in Dongsheng oildom which based on counting the hydrogen sulphide concentration of every blocks and the document of lithic facies, character of the farmation water , ancient geothermal, and the recover methods of the hydrogen sulphide dieplay layer segment. The results shows that: the generation mechanism of hydrogen sulphide in Da 18 block, Da 6 block, Yi 37 block and He 122 block is thermochemical sulfate reduction, the generation mechanism of hydrogen sulphide in Wang 91 block is thermal decomposition of the destabilization sulfides and thermochemical sulfate reduction, the generation mechanism of hydrogen sulphide in Chegu 56 block and Shang 4 block is bacterial sulfate reduction. Among these, the mainly effect agents of hydrogen sulphide concentration in the thermochemical sulfate reduction blocks are temperature, hydrocarbons, anointed rock, the content of the sulfate ion in formation water and exploiting measures, the mainly effect agents of hydrogen sulphide concentration in the thermal decomposition of the destabilization sulfides blocks are production time, the sulfur source and temperature, the mainly effect agents of hydrogen sulphide concentration in the bacterial sulfate reduction blocks are the content of the sulfate ion in formation water, ph value and temperature.In view of the problems exsiting in the hydrogen sulphide proctective work of Dosheng oildom, and combined with different hydrogen sulphide concentration,formation mechanism and influncing factors between the seven blocks, we have established four diffirent hydrogen sulphide protective measures, and these will point out the direction of the next protective work.