Hydrochemistry Characteristics and Origin of Formation Water of Paleogene and Neogene in the Western Qaidam Basin(PDF)
《地球科学与环境学报》[ISSN:1672-6561/CN:61-1423/P]
- Issue:
- 2016年第04期
- Page:
- 558-568
- Research Field:
- 水资源与环境
- Publishing date:
Info
- Title:
- Hydrochemistry Characteristics and Origin of Formation Water of Paleogene and Neogene in the Western Qaidam Basin
- Author(s):
- ZHANG Wang-ming; ZENG Jian-hui; LI Fei; ZHAO Yun-li; ZHANG Yi-dan
- 1. State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Beijing 102249, China; 2. College of Geosciences, China University of Petroleum, Beijing 102249, China; 3. College of Mechanical and Transportation Engineering, China University of Petroleum, Beijing 102249, China
- Keywords:
- geochemistry; formation water; hydrochemistry; origin; water-rock interaction; dolomitization; chloritization; Qaidam Basin
- PACS:
- TE122；TE133；P641.4+62
- DOI:
- -
- Abstract:
- The chemical data collected from oilfield water of Paleogene and Neogene in the western Qaidam Basin were analyzed and summarized, and the characteristics and origin of formation water were discussed. The results show that the type of formation water is mainly CaCl2composed of Na++K+the salinity is high with the average of 166 g?L-1, and the lowest reaches 3.90 g?L-1; the formation water is highly concentrated, belonging to brine level; the main ions present increase-decrease alternately trends, and salinity firstly decreases and then increases with the increase of depth, which is significantly different from the eastern basins of China; various major ion ratios including Na-Cl coefficient, metamorphic coefficient and desulphidation coefficient all reflect that the formation of western Qaidam Basin overall are closed well; the Ca2+ accumulation at Upper and Lower Youshashan Formations is caused by dolomitization, which results in the poor of Mg2+,followed by calcite dissolution; there are only a few data points at Upper and Lower Ganchaigou Formations showing Ca2+ accumulation, which is caused by calcite dissolution and chloritization, is the main reason for the lack of Mg2+;the precipitation of a lot of gypsum and the reduction of large amounts of sulfate reducing bacteria result in a loss of SO42-; besides the HCO3-produced by the reduction of SO42-, CO2 and organic acids can be added to cause an increase of HCO3- of formation water in the process of organic maturation.
Last Update: 2016-07-19