Classification of compaction degree in shallowly buried extremely thick gravel layers and analysis of geological influencing factors

The Cretaceous Formation in Kuqa Depression is the main battlefield for increasing natural gas storage during "the 14th Five-Year Plan" period in Tarim Basin. Engineering problems occur frequently when drilling into very thick gravel layers. In order to clarify the compaction of shallow gravel layer, this paper takes the Bozi-Dabei area as an example, and puts forward the method of "classification of compaction degree based on quadratic clustering". The results show that the method consists of four steps: the selection of characteristic parameters, the clustering effect of single cluster analysis, the classification standard of quadratic cluster construction, and the construction and verification of the classification standard of compaction degree. In the vertical direction, affected by Tianshan uplift and Tuzimazha Salt Wall, the compaction degree of three fan bodies in the study area is significantly different, and the compaction degree of Bozi fan body is stronger than that of Dabei fan body. On the plane, with the increase of source distance, the compaction degree of Bozi 3 fan body decreases due to the influence of gravel composition. The compaction degree of Bozi 1 fan body first increased and then decreased. The compaction degree of Dabei fan body is weak.