摘要
页岩的吸附特征是评价页岩气是否具有开采价值的一个重要标准,是研究页岩气富集规律的一个核心内容。为此,以四川盆地南部地区下志留统龙马溪组取心页岩为研究对象,开展页岩等温吸附实验研究。实验发现龙马溪组泥页岩的Langmuir体积较大,平均为1.33m3/t,Langmuir压力平均为1.66 MPa,反映了龙马溪组页岩的吸附能力较强,具有良好的储气能力,但不利于解吸。结合页岩矿物特征及孔隙结构特征,研究发现温度、有机碳含量、湿度、比表面积等是影响龙马溪组页岩吸附能力的主要因素;页岩气的吸附过程属于放热反应,随温度升高吸附气量减少;由于水分占据了一定原本被气体吸附的孔隙表面,因而湿度越大,吸附气量越小;中孔和宏孔体积与页岩饱和吸附气量具有较好的正相关性;有机碳含量越高,饱和吸附气气量就越大;比表面积更是饱和吸附气量的控制因素,二者具有极高的相关性。
As an important factor influencing the exploration value of a shale gas play,the adsorption capacity is the research focus of shale gas accumulation mechanism.Therefore,isothermal adsorption tests were conducted to study the core shale rocks taken from the Longmaxi Shale Play in southern Sichuan Basin.According to the test results,the Langmuir volume of the Longmaxi Shale Play was relatively large,about 1.33 ms/t on average and average Langmuir pressure was 1.66 MPa,indicating that the adsorption capacity of the Longmaxi Shale Play was huge,conducive to gas preservation,but adverse to desorption.In combination with shale mineral and pore structure characteristics of the Longmaxi Shale Play,a study showed that the adsorption capacity of the Longmaxi Shale Play was mainly controlled by temperature,organic carbon content,humidity,and specific surface area.Shale gas adsorption is an exothermie reaction,so the adsorption capacity decreases with a temperature rise.Water covers a part of pore surface where gas is originally adsorbed,thus the greater the humidity is,the less gas is adsorbed.The volumes of mesopores and macropores are in positive correlation with saturated adsorption capacity,namely,the greater the organic carbon content is,the higher the saturated adsorption capacity will be.Specific surface area is a major controlling factor of saturated adsorption capacity,both of which are closely correlated.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2014年第12期63-69,共7页
Natural Gas Industry
基金
国家杰出青年科学基金"油气藏渗流力学"(编号:51125019)
青年科学基金项目(编号:51404206)
博士点基金项目(编号:20135121110001)
