物探化探计算技术2025，Vol.47Issue(5)：731-741,11.DOI:10.12474/wthtjs.20240701-0002
柴达木盆地英雄岭坳陷干柴沟组页岩岩石物理弹性特征
Rock physical elastic characteristics of Ganchaigou Formation shale in Yingxiongling Depression,Qaidam Basin
摘要
Abstract
A set of high-quality source rocks is developed in the Ganchaigou Formation of the Chaixi Depression.It is the key to predicting the reservoir"sweet spot"and determining the variation rule and influencing factors of its rock physical parameters.In this paper,the shale of the Ganchaigou Formation is taken as an example.Based on systematic rock physical experiments,the velocities of shale samples in different bedding directions are obtained under normal temperature and pressure and variable confining pressure.The changes of seismic rock physical elastic characteristics of the Ganchaigou Formation are analyzed by means of microstructure observation(whole rock analysis by X-ray diffraction and scanning electron microscope).The results show that the whole shale of the Qianchaigou Formation can be divided into gray dolomite,dolomitic limestone,argillaceous shale,and intercalated sandstone,and the content of carbonate minerals is relatively high.As pressure increases from 0 MPa to 40 MPa,the microfissure in shale gradually closes.Concurrently,both vertical and horizontal wave velocities increase,with the vertical bedding velocity rising more significantly than the parallel bedding velocity.Furthermore,the microfissure in shale rock becomes more pronounced,and its anisotropy becomes more pronounced.Because the pores of calcareous dolomite and dolomitic limestone are dominated by intergranular pores and dissolution pores,respectively,the velocity variation trend is weak under the action of compaction.The velocity of rock increases during the process from clay mineral as rock skeleton to calcite as rock skeleton and then to dolomite skeleton.The shale of the Ganchaigou Formation is affected by the higher content of carbonate rock minerals and has higher compressibility than shale in other areas.The results can provide a basis for the seismic"sweet spot"prediction of the shale oil reservoir in the Ganchaigou Formation.关键词
干柴沟组/岩石物理特征/超声波速度/变围压/脆性指数Key words
ganchaigou formation/rock physical characteristics/ultrasonic speed/variable confining pressure/brittleness index分类
天文与地球科学引用本文复制引用
黄雯悦,刘丽江,张文帅,夏辉..柴达木盆地英雄岭坳陷干柴沟组页岩岩石物理弹性特征[J].物探化探计算技术,2025,47(5):731-741,11.基金项目
国家自然科学基金面上项目(41774136,42474149) （41774136,42474149）
