三塘湖盆地条湖-马朗凹陷煤层气甜点预测

Sweet Spot Prediction of Coalbed Methane in Tiaohu-Malang Depression,Santanghu Basin

三塘湖盆地煤层气勘探开发工作仍处于初期阶段,通过建立煤层气资源地质工程一体化评价方法,预测煤层气开发甜点区。结果表明,条湖-马朗凹陷煤层气赋存条件优越,9^(#)煤层主体埋深600~2600 m,含气量1.3~4.5 m^(3)/t,煤层厚度5.0~60.9 m,构造较为简单,顶底板岩性均以泥岩为主。优选煤层厚度、埋藏深度、顶底板岩性、构造、沉积相带、孔隙度、渗透率、脆性指数、破裂压力、泥质含量10个参数作为评价指标,预测煤层气甜点区(Ⅰ类区)主要分布于条湖凹陷东北部和马朗凹陷西部。

The CBM exploration and development in Santanghu basin is still in the early stage,and the sweet spot of CBM development can be predicted by establishing the integrated evaluation method of CBM resources geological engineering.The results show that the occurrence conditions of coalbed methane in Tiaohu-Malang depression are superior,the main buried depth of No.9 coal seam is 600-2600 m,the gas content is 1.3-4.5 m^(3)/t,the thickness of coal seam is 5.0-60.9 m,the structure is relatively simple,and the lithology of the roof and floor are mainly mudstone.The 10 parameters of coal seam thickness,burial depth,lithology of the roof and floor,structure,sedimentary facies zone,porosity,permeability,brittleness index,rupture pressure and mud content are selected as evaluation indexes,and it is predicted that the sweet spot area(Class I area)is mainly distributed in the northeast of Tiaohu depression and the west of Malang depression.