A Study On Measurements Of Shale Gas Key Geochemistry Parameters

Shale gas as an alternative fossil energy is of great significance to develop, China has the advantage of shale gas geology and reserves, but the weak testing technology limits its development and application, it is necessary to set up new test method for shale gas evaluation. Organic geochemistry parameter is the foundation of air-content evaluation, its important contents of the determination of total organic carbon(TOC), the extraction of matrix kerogen and determination of kerogen maturity are studied in this paper, the concluded results are showed below:(1) The best temperature and time of loss on ignition(LOI) method were deternined by condition experiments with Erdos Basin shales and the conversion relationship of organic matter and TOC under this condition was linear fit to establish a fast and accurate LOI method which can apply to the determination of shale TOC. The two concluded conversion relationships reflected a better accuracy with relative error, detection limit and relativity are 1.691 %, 0.41 %, 91.17 % and 0.486 %, 1.60 %, 97.72 %, respectively, what means a simple, efficient and accurate method has been built. Compared with the traditional LOI method, the built method is simple and easy, has solved the important issue in traditional method that loss on ignition is under-representation to organic matters for the decomposition of mineral salt in high temperature, which expand the sample applicability.(2) The best extraction condition and process of kerogen were obtained by the conditions and the orthogonal experiments, the specific processing conditions to the key steps(acid treatment, soluble organic matter, refractory mineral processing) are shown in the text. Compared to the traditional process, the reaction time, kerogen yield, purity of the new designed process increased by respectively 60 %, 70 %, 7 %. Infrared spectrum, SEM analysis showed that the minerals, soluble organic matter, refractory minerals had been removed thoroughly, conveys a good enrichment of kerogen. Microscopic parameter of new process kerogen was better than the original ones, what means a consistency of two processes components. Vitrinite reflectance correlation reached 99.28 % and indicated a new method for fast extracting high quality kerogen.(3) Micro-photometer, solid nuclear magnetic resonance(NMR), laser Raman technique were applied to the test of Ro. After comparing, found that the SNMR and laser Raman method without complex pretreatment and test operation, less subjective factors and high detection efficiency. NMR and Raman technique has wide applicability to Ro detection and no organic matter type limit. A relevance of 91.54 % obtained by applied an experiential ratio 38 % with SNMR what pointed out a simplify to the complexity test of solid dipole phase transfer. Laser Raman parameters reflect good Ro correlation, and the D and G peak respectively reflect the lower and high maturity of Ro with the highest correlation of 91.654 %. In conclusion, SNMR and laser Raman method show a prospect compared with optical method.