Impact analysis of coal source rock on sandstone tight development

In order to make sure the relationship between the coal source rock and the tight sandstone development,based on the rock section,cathodeluminescence and some other experiments,the research results found that on the condition of the cathodeluminescence,a large quantity of quartz shining brown can be observed in the He 8 of lower Shihezi formation,Yichuan,Ordos basin.And the light brown quartz secondary enlargement also can be observed.The cathodeluminescence analysis demonstrates that at least 10%～20%feldspars are dissolved by the acidic fluid related with the coal measure strata in the process of the burial diagenesis.In the coal measure strata,the early plant remains oxygenolysis generate humic acid and a large amount of organic acid from oxygenic clusters collapsing in the type Ⅲ kerabitumen of the coal source rock.These acidic fluids dissolute quartz,feldspar and some other instable minerals,then these mineralsgenerate SiO2 and form the quartz secondary enlargement. It causes the reservoir porosity decrease greatly.So the coal source rock and the sand tight development is bonded greatly.