The Dabei gas field as a tight sand reservoir is controlled by the fracture development which directly affects the discovery and deliverability of the natural gas.The appropriate way to describe the fracture is very important.At present,the fracture spacing is a general method to describe the fracture degree,but its shortage is only suitable for the description of outcrop,core and FIM.A few of drill cores and Door representativeness can not illustrate the fracture distribution in well bore.The fracture analysis by image data requires the skillful analyst and the image data,with the random interpreted conclusion,the high expense of the image data,and absence of image data.So,the concept of fractal is proposed in the research of fractured reservoir.According to fractal concept,the data of conventional logging suite were used,in combination with the logging feature of fracture in the Dabei gas field.The fracture in the goal layer of Dabei area is quantitatively described by the method of R/S.The result which was tested by the data of cores and drilling available,suggests that the method of R/S is feasible to quantitatively describe the fractures in the Dabei gas field.

Because of the great change in thickness of the overlying gyprock and the high density drilling fluid in Kuqa depression,it is very difficult to define the boundary stratotype.TDC are used in exploration wells and the temperature at the bottom of well can be measured continuously and the natural gas reservoirs of Eogene-Cretaceous are high pressure reservoirs.Based on this situation and according to the cause and feature of the abnormal high temperature in the natural gas reservoir,we inspected the formation temperature continuously and predicted correctly the change of the formation,defined the boundary stratotype,found the trace of gas and solved the difficulty in work.