页岩气解吸规律可间接反映其富集程度和保存条件。基于变温解吸实验及解吸气成分测试，划分南方海相页岩气解吸类型，并对其成因进行了探讨。南方海相页岩气有4种解吸类型: ①常温解吸型。在地表温度条件下即大量解吸页岩气，解吸气以甲烷为主，良好的生气物质基础和保存条件、较发育的裂缝系统是其形成的主要原因。②地温解吸型。在地层温度条件下开始大量解吸，解吸气以甲烷为主，弱盖层封闭和侧向散失所导致压力封闭条件的缺失是其形成的主要原因。③高温解吸型。在90 ℃以上高温条件下开始大量解吸，解吸气中O₂和N₂含量较高，浅埋藏作用和破坏的保存条件是其形成的主要原因。④高温低气型。在高温条件下解吸气含量较低，解吸气中基本不含烃类气体，长期深埋藏作用和破坏的保存条件是其形成的主要原因。常温解吸型页岩气具有较好的勘探开发条件，地温解吸型目前不具备经济开发条件，高温解吸型和高温低气型无勘探价值。

Desorption characteristics reflect shale gas enrichment and its preservation conditions indirectly. Marine shale gas desorption types and their genesis in southern China have been divided and evaluated by thermal variation desorption test and gas constitution test. There are four marine shale gas desorption types. The atmospheric temperature desorption shale gas desorbed greatly under atmospheric temperature, the desorbed gas was mainly methane. Its main causes are ascribed to a good gas generation material base and preservation conditions, as well as well-developed fracture system. The reservoir temperature desorption shale gas desorbed greatly under reservoir temperature, the desorbed gas was also mainly methane. Its cause is ascribed to the absence of pressure sealing conditions formed mainly by weak caprock sealing and lateral dissipation. The high temperature desorption shale gas desorbed greatly under a high temperature above 90 ℃, the desorbed gas had relatively high O₂ and N₂ contents. Its causes are ascribed to shallow burial condition and destroyed preservation condition. High temperature-low content desorption shale gas desorbed a little gas under a high temperature above 90 ℃, the desorbed gas had little hydrocarbon. Its causes are ascribed to long time deep burial history and destroyed preservation condition. The atmospheric temperature desorption shale gas had better exploration and development condition, however, the reservoir temperature desorption shale gas maybe lack of economical development conditions at present. The other two types of shale gas are not worth further exploration.