Sandstones are, as a rule , interbedded with shales.砂岩通常都与页岩互层.This paper presents the PDC bits with the satisfactory testing result in the multi - interbedded formation.介绍了一种复合式PDC钻头,该钻头在多夹层地层钻井施工中取得了较好的试验效果.A shale for...
孩子生病时我陷入了绝望的深渊之中。I was in the depths of despair when the baby was sick.他们常常陷入孤独、屈辱和绝望的深渊。They frequently plumb the depths of loneliness, humiliation and despair.她发出了绝望的叫声。She uttered a cry of despair....