Adsorption characteristics of moist shale in Niutitang Formation,Northwest Hunan
PENG Xuehong;WANG Tao;XU Shaoxuan;WANG Zhiqiang;No.2 Oil Production Plant,Xinjiang Oilfield Company,PetroChina;Heavy Oil Development Company,Xinjiang Oilfield Company,PetroChina;
In this work, water vapor adsorption experiments were performed on shale samples sourced from Northwest Hunan, then,the main controlling factor were analyzed in detail; subsequently, the moisture-equilibrated samples were used to conduct the methane adsorption experiments to investigate the effect of moisture on methane adsorption and the contribution of clay minerals to shale gas content. The results indicate that water vapor adsorption of shale with over-high maturity are mainly controlled by clay minerals, monolayer absorption occurs under low humidity condition while capillary condensation takes place under higher humidity environment; with the increasing of water content, the methane adsorption capacity of shale samples gradually decreases and then tends to be stabilized. Further analysis shows that: under the dry condition, the contribution of clay minerals to the methane adsorption capacity of two shale samples is 37% and 53%, respectively; however, when water content approaches to the actual reservoir condition(3.5%), the contribution will decline to 12% and 13%. Therefore, the experiments under dry condition mainly overstate the contribution of clay minerals to shale gas content, which will further influence the reserve assessments.
【CateGory Index】： P618.13