塔里木盆地顺北地区一间房组台地碳酸盐岩异常泥质含量与断裂带距离及裂缝发育关系

Relationship between argillaceous content and distance to main faulted zone and fractures development in the platform carbonate rocks of Yijianfang Formation in Shunbei area,Tarim Basin

在塔里木盆地顺北地区奥陶系走滑断裂带寻找碳酸盐岩“断溶体”型油气藏成为近年来油气勘探的热点。多口钻井显示顺北1号主走滑断裂带“断溶体”裂缝发育部位普遍具有异常高的自然伽马测井值。因此,可以根据异常高泥质含量参数来反映裂缝发育程度,进而指示含泥“断溶体”储层的发育位置。首先利用GeoEast软件提取了顺北1号走滑断裂带T74界面(一间房组顶)相干体属性并进行了断裂解释。根据5口井一间房组自然伽马测井数据,探讨了台地碳酸盐岩走滑断裂带断核和损伤带异常高泥质含量值与主干断裂带距离和裂缝发育程度之间的关系。结果表明:顺北地区奥陶系一间房组台地碳酸盐岩沉积环境稳定,背景泥质含量较低;NE向主走滑断裂带核部和裂缝发育部位的泥质含量远高于台地碳酸盐岩背景值,具有随着离主干断裂带距离增大和裂缝发育程度下降而降低的变化趋势,最终接近其背景值。由此表明,可利用自然伽马测井计算泥质含量,间接指示走滑断裂带“断溶体”储层发育程度。该研究为深层-超深层走滑断裂带储层评价提供了一种新的思路。

The exploration of carbonate"fault-karst"reservoirs in Ordovician strike-slip fault zone in Shunbei area of Tarim basin has become a hot spot recently.Multiple drilling wells in Shunbei area of Tarim Basin show that the fault zone and fracture development site generally have unusually high natural gamma logging values.Therefore,according to the parameters of abnormally high shale content,reflect the degree of fracture development,so as to indicate the development location of the reservoir containing mud fault solution.In this paper,the coherent properties of the T47 interface of Shunbei 1 strike-slip fault zone were extracted and interpreted by GeoEast software.Then,according to the natural gamma ray logging data of Yijianfang Formation in 5 Wells,the relationship between the abnormal high shale content of strike-slip fault zone and damage zone of platform carbonate rocks and the distance of main fracture zone and the degree of fracture development was discussed.The results show that the sedimentary environment of carbonate platform in Yijianfang Formation of Ordovician in Shunbei area is stable and the background argillaceous content is low.The argillaceous content at the core and fracture development site of the NE main fault is much higher than the background value of platform carbonate rocks,which decreases with the increase of distance from the PDZ and the decrease of fracture development,and finally approaches its background value.This indicates that the shale content can be calculated by natural gamma ray logging,which indirectly indicates the development degree of"fault-karst"reservoir in strike-slip fault zone.It provides a new thinking for reservoir evaluation of deep and super deep strike-slip fault zone.