doiSerbia

Measurement of shale gas in place based on different approaches and their comparison study

Memon Asadullah (School of Petroleum Engineering, China University of Petroleum (East China), Huangdao district, Qingdao, Shangdong Province, P.R. China)
Li Aifen (School of Petroleum Engineering, China University of Petroleum (East China), Huangdao district, Qingdao, Shangdong Province, P.R. China), aifenli@upc.edu.cn
Ren Xiaoxia (School of Petroleum Engineering, China University of Petroleum (East China), Huangdao district, Qingdao, Shangdong Province, P.R. China + School of Science, Qingdao University of Technology, Jialingjiang road, Qingdao, Shangdong Province, P.R. China)
Mehmood Asif (School of Petroleum Engineering, China University of Petroleum (East China), Huangdao district, Qingdao, Shangdong Province, P.R. China)
Fang Qi (School of Petroleum Engineering, China University of Petroleum (East China), Huangdao district, Qingdao, Shangdong Province, P.R. China)
Han Wencheng (School of Petroleum Engineering, China University of Petroleum (East China), Huangdao district, Qingdao, Shangdong Province, P.R. China)
Ma Min (School of Petroleum Engineering, China University of Petroleum (East China), Huangdao district, Qingdao, Shangdong Province, P.R. China)

The understanding of gas sorption mechanism is essential to characterize the original gas-in-place for shale gas reservoirs. In this study, experimental data of five shale samples have been used to estimate the shale gas-in-place with new sights. Langmuir model is commonly used to measure the amount of adsorbed gas but this model does not include the amount of absorbed gas and its behavior. However, such gas usually contributes about 22% in respect to total gas storage even though its input remains undefined. Sorption model used in this study includes adsorbed and absorbed gas. Good results are obtained from sorption model as compared to Langmuir model. Variable range of total gas storage is observed using different approaches in all shale samples. Initially at low pressure, total gas storage is observed to be higher because of gas absorption contribution in new proposed approach when compared to approach-2. When pressure increases, total gas storage is altered in keeping with characteristics of adsorption and absorption of gas. Adsorbed and sorbed porosity is estimated at two different approaches and where total gas storages capacity is affected due to adsorbed or sorbed porosity. Further, the contribution of absorbed gas amount is found at about 19-22% in respect to total gas storage in all shale samples and that is in same range as mentioned in literature. The sorption model and new proposed approach includes adsorption and absorption of gases and provides new insights to understand the gas storage mechanisms and estimation of shale gas-in-place.

Keywords: free gas, adsorbed gas, absorbed gas, adsorbed porosity, sorbed porosity, gas-in-place