DICKITE AND ITS SIGNIFICANCE IN ORDOVICIAN CARBONATE RESERVOIR OF SHAANGANNING BASIN
Huang Sijing;Pei Xigu;Xie Qingbang
There are a number of kaolinite subgroup clay minerals in the Ordovician carbonate sediments of Shaanganning Basin. They were studied by scannins electron microscopy, X-ray powderdiffraction,infrared absorption spectroscopy and differential thermogram analysis and comfirmed thatthiS kind of mineral is dickite and not kaolinite. Since depth-dependent transformation of kaolinite todickite needs acidic diagenetic agent,the present dickite indicates the activity of relatively acidic porefluid during diagenesis. Under this condition,calcite and dolomite rich in iron and manganese sealingoff most of the porosity could not precipitate. So,dickite is an indicator of good reservoirs. In addition,the maximum palaeotemperature of Ordovician carbonate reservoir underwent was approximately140-160℃ by means of the geothermometer of dickite.
【CateGory Index】： P536