STUDY ON LOGGING INTERPRETATION FOR SHALE GAS RESERVOIRS

Compared with conventional reservoir, the exploration target of shale reservoir is the high quality of organic matter and the content of the high silicon content and the brittle source rocks of the fracture development. There is usually a very complex lithology and mineral composition; not only has a different response characteristics of the log, but also the evaluation of the means and objectives are also different. A case study was performed on three shale gas wells in a basin in China. Based on core experiments, logging interpretation was applied to predict the gas content of the Q1 shale with the integration of the correlativity model and experimental formula. The results matched well with the experimental test results, verifying the rationality of this presented model. The following conclusions were drawn: (1) the gas content logging interpretation model built based on the adsorption isotherm and volume model is applicable to shale reservoirs and its major parameters can be obtained by use of the correlativity model between core experimental results and logging data or empirical formula; (2) the gas content obtained by use of the adsorption isotherm and volume model matches well with the measured values, especially for the shale with relatively low gas content. When applied in different areas, the correlativity model should be modified according to core experiment results and logging data. Finally, it is pointed out that separate calculation of free gas content and adsorbed gas content via logging data is the most rational method for shale gas content description.