Characteristics and formation mechanisms of silicified carbonate reservoirs in well SN4 of the Tarim Basin
| Autor: | Hongqiang Ma, Binbin Xi, You Donghua, Jun Han, Qianglu Chen, Yixiong Qian, Wenxuan Hu |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
010504 meteorology & atmospheric sciences
Renewable Energy Sustainability and the Environment business.industry lcsh:TJ807-830 lcsh:Renewable energy sources Geochemistry Energy Engineering and Power Technology Tarim basin 010502 geochemistry & geophysics Strike-slip tectonics 01 natural sciences Degree (temperature) lcsh:Production of electric energy or power. Powerplants. Central stations chemistry.chemical_compound Fuel Technology Nuclear Energy and Engineering chemistry Natural gas lcsh:TK1001-1841 Ordovician Carbonate business Geology 0105 earth and related environmental sciences |
| Zdroj: | Energy Exploration & Exploitation, Vol 36 (2018) |
| ISSN: | 2048-4054 0144-5987 |
| DOI: | 10.1177/0144598718757515 |
| Popis: | High-yield natural gas was discovered in well SN4 in the Ordovician Yingshan Formation in the Tarim Basin. The gas is found in unusual, silicified, carbonate reservoirs. According to the degree of silicification, the silicified reservoirs can be divided into a lower section of silicified carbonates, a middle section of limestone, and an upper section of silicified carbonates. The silicified carbonates are mainly composed of quartz and calcite, in which the reservoir space mostly occurs as vugs, inter-crystalline pores of quartz, and partial fractures. Porosity varies widely, ranging from 3 to 20.5% with strong heterogeneity. The homogenization temperatures of fluid inclusions in quartz and calcite show that the silicification temperatures were 150–190°C, with characteristics of high temperature/low salinity and low temperature/high salinity. The 87Sr/86Sr ratios of secondary calcite are 0.709336–0.709732, which are significantly higher than that of concurrent seawater, indicating that the hydrothermal fluid originated from the deep clastic strata or the basement (sialic rock). The δ13C values of the secondary calcite are similar to that of the surrounding limestone, indicating that the carbon in the secondary calcite is derived from the limestone strata, and that the secondary calcite is the product of dissolution and re-precipitation resulting from interaction between the silica-bearing hydrothermal fluids and surrounding limestones. The silicification of silica-bearing hydrothermal fluid was significantly controlled by strike-slip faults. The fluids ascending along the fault zone and branch faults interacted with the surrounding limestone in the Yingshan Formation. As a result, a large amount of quartz and secondary calcite were formed together with various types of secondary pores, resulting in excellent reservoirs. |
| Databáze: | OpenAIRE |
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