黔北下石炭统祥摆组是一套海相煤系沉积地层，是页岩气勘探开发的重要层系之一。以黔北威宁龙街向斜龙参1井为例，评价了其煤系气成藏特征及其有利开发层段。结果显示:海相煤系地层祥摆组储层空间展布具有分段性:下段薄煤层发育，煤层层数较多，煤-泥岩-砂岩互层发育;上段泥页岩发育，单层连续厚度大。泥页岩 TOC含量在0.77%~8.94%，平均2.01%，随层位埋深增大而增大。祥摆组上段有机质类型主要为Ⅱ1型，下段主要为Ⅱ2型,Ro,max平均为 2.54%。矿物组分主要以黏土矿物和石英为主，石英平均质量分数38.52%，黏土平均质量分数48.99%，脆性指数高，平均为48.02%，整体上随层位埋深增大而增大;泥页岩孔隙度平均为4.77%，渗透率平均为0.002×10-15 m2，属于低渗储层;泥页岩储层物性接近于非含煤海相地层，优于含煤海陆过渡相地层。泥页岩含气量介于0.27~1.48 m3/t，平均0.57 m3/t。气体组分结果显示860 m以浅仍处于风化带。薄煤层变质程度高，Ro,max平均为2.92%，但含气量平均为5.88 m3/t，含气饱和度低。整体显示海相煤系气资源潜力具有以页岩气为主，煤层气为补充的特征，推测深部区域更具有勘探前景。以煤系页岩气为评价主体，选取泥页岩单层厚度、TOC含量、含气量、脆性指数等关键参数，采用主成分分析法，评价了祥摆组煤系气有利开发层段。综合研究认为:有利开发层段主要位于祥摆组上段中部和下段的下部。

The Lower Carboniferous Xiangbai Formation in Northern Guizhou is a set of marine coal-measure sedimentary strata,which is one of the important strata for shale gas (SG) exploration and development.In this paper,the Longcan test well 1 from Weining Longjie syncline in the north of Guizhou Province is taken as an example to evaluate the coal-measure gas (CMG) accumulation characteristic and favorable development segments.The results show that the spatial distribution of Xiangbai Formation reservoirs has segmented feature.The thin coal seams are developed in the lower section,with a large number of coal seams,and interbedded coal-shale-sandstones.The shale are developed in the upper section,with a large continuous thickness of a single layer.The TOC content ranges from 0.77% to 8.94%,with an average of 2.01%,which increases with the increasing depth of the layer.The upper member of Xiangbai Formation is mainly type II1,and the lower member is mainly type II2.The average Ro,max of shale is 2.54%.The mineral components of shale are mainly clay minerals and quartz.The average content of quartz is 38.52%,the average content of clay is 48.99%,and the average brittleness index is 48.02%.The brittleness index generally increases with the increasing depth of the layer.The shale reservoir has an average porosity of 4.77% and an average permeability of 0.002×10-15 m2,which is a low-permeability reservoir.The physical properties of shale reservoirs are close to those of non-coal-bearing marine facies,and are better than coal-bearing marine-continent transitional facies.The SG content ranges from 0.27 to 1.48 m3/t,with an average of 0.57 m3/t.The SG composition results show that it is still in the weathered zone below 860 m.The average Ro,max of the coal seam is 2.92%.The coalbed methane (CBM) content of coal seams ranges from 3.34 to 10.66 m3/t,the average CBM content is 5.88 m3/t,and the CBM saturation is low.Overall,it shows that the potential of marine CMG resources is mainly characterized by SG,supplemented by CBM,and it is speculated that deep areas have more exploration prospects.Furthermore,using coal-measure SG as the main body of evaluation,based on the key parameters of single layer thickness,TOC,gas content,brittleness index,etc.,the principal component analysis method is used to evaluate the favorable development segment of CMG in the upper and lower member of the Xiangbai Formation.The comprehensive research suggests that the favorable development segments are mainly located in the middle parts of the upper member and lower parts of lower member in the Xiangbai Formation.

1 地质背景

2 实验测试

   2.1 基础测试

   2.2 物性测试

   2.3 含气性测试

3 煤系储层物性

   3.1 煤层

   3.2 泥页岩

4 煤系含气性特征

   4.1 煤层含气性

   4.2 泥页岩含气性

5 煤系气开发有利层段评价

6 结论