Logging Rock Mechanics Analysis And Application Of Tight Fractured Sandstone Reservoir

The exploration and development of unconventional oil and gas reservoirs can be regarded as an important link to solve the current energy problem in China,and the deep tight sandstone gas reservoir is one of the main fields in the unconventional oil and gas development stage in China.Keshen area in Tarim Basin is one of the main producing areas of tight sandstone gas reservoir,and its target layer is the Cretaceous Bashijiqike formation.The formation is characterized by deep burial,high temperature,high pressure,complex lithology,diverse reservoir types,great changes in physical properties,strong heterogeneity,and widespread fractures.Due to the complex stratigraphic environment,the conventional oil and gas exploitation methods will result in the failure of exploitation or extremely low recovery rate in Keshen area.In order to improve the recovery rate and reduce the difficulty of exploration engineering,it is of great significance to study the rock mechanical parameters,in-situ stress and fracture pressure in Keshen area before oil and gas exploitation.The main work and achievements of this paper are as follows:(1)The core data of Keshen area are sorted out to obtain the formation characteristics,and the porosity and permeability are analyzed from the perspective of logging.According to the relationship between porosity and lithology,physical property and electrical property,fine interpretation of sandstone reservoir in Keshen area is carried out.(2)Static and dynamic parameters of rock mechanics are obtained through triaxial rock mechanics experiments and logging data.In view of the fact that the static rock mechanics characteristics are closer to the actual rock mechanics characteristics in the actual production process,the dynamic static conversion relationship between Young's modulus and P.oisson ratio is established.(3)According to the experimental results and related rock mechanics foundation,the reasonable calculation model is selected to calculate the in-situ stress,fracture pressure and formation pressure in Keshen area.Through the establishment of rock mechanics profile,the rock mechanics parameters are comprehensively analyzed.Through the above research,a set of research models for rock mechanics parameters,in-situ stress and fracture pressure of oil and gas reservoirs in Keshen area are formed.A method for predicting borehole stability and identifying fracture characteristics is established from three aspects:borehole stability,influence of in-situ stress on resistivity and fracture identification by using rock mechanics parameters.Combined with the actual well data and the final production test results,the method has a good effect in the prediction of borehole stability and identification of fracture characteristics.