Experimental Research Of Shale Gas Bearing

Shale gas experimental researches are important supports to geological theory development, resource potential evaluation, imputes to shale gas development, avoiding risk in exploration and development.Based on Shale gas enrichment mechanism and the evaluation of the gas bearing particularity:shale, both as source rocks and as a reservoir rock, on the same sample for hydrocarbon reservoir capacity and gas special aspects of the experimental test, the experimental test system shale gas assessment and evaluation process involved in the experimental tests carried out to determine the need; summary of shale gas gas evaluation process involved geological problems, according to its corresponding determine parameters listed in the experimental analysis method for determination of these parameters can be used.There are direct and in direct ways to test absorbed gas amount. Field desorption is the direct way. Nowadays, domestic instruments are well designed, small, well sealed, incisive, portable, apt to be used in field, heated evenly and easy to operate. Isothermal adsorption, logging interpretation, and chemical parameter deduce are considered to be indirect ways. TOC and maturity of the organic carbon are two factors taken into consideration in absorption gas content calculation which is very close to field measured value. However, the outcrop samples shows different result, which means it's more proper to take TOC as the only controlling factor. The reason is considered as the weathering has influenced the maturity greatly, and caused a misleading result.Geochemical parameter deduce way is more close to the measured value which can be well applied in practice.Free gas content is got through logging interpretation or physical parameter calculation. These methods are applied in Longmaxi shale of well YY1, the free gas is tested as 1.67 m3/t, which match the measured value.According to the experimental data analysis of Longmaxi shales, lower Silurian in Southeast of Chongqing area, there are exist a certain correlation among shale gas, shale geochemistry and reservoir physical parameters,Organic carbon content and gas content have a good positive correlation, the higher of the Organic carbon content, the higher of the gas content, adsorbed gas content can be calculated indirectly; The relationship between maturity and adsorpbed gas is more complex,Overall, the adsorbed gas is highest when maturity is 1.5-3.0%,both too high or too low maturity are not good to be a reservoir. There are negative correlation between shale porosity, permeability and adsorbed gas, with the increasing of the permeability, the absorbed gas desorpted as free gas existed in the reservoir, the adsorbed gas content in shale become lower; with the increasing of the quartz content, the adsorbed gas content in the black shale is increased; total clay minerals and the adsorption volume are positively correlated; the carbonates of Longmaxi shales in the Southeast of Chongqing areas including calcite and dolomite, the carbonate content and the adsorbed gas content showed a slight negative correlation; with the increasing of the shale density, the adsorbed gas content is decreased, there are negative correlation between them.