Timely treatment of photocoagulation and (or) cryotherapy for prethreshold type 1 and threshold disease of ROP may lead to famous prognosis.

对值前病变1值期ROP进行及时的激光（或）冷冻治疗具有比较满的疗效。

The deep formation has a high degree of hardness and abrasivity;the bit type selection is difficult and the ROP is low especially under the high density mud.

深部井段地层的硬度高、研磨性强，钻头选，特别是在高密度条件下机械钻速低。