However, the accident of drill string damage happened easily in the overthrustnappe belt of these regions in the drilling.
但是，在其逆掩推覆带钻井作业中，极易发生钻具失效事故。
2
In present gravity exploration of overthrustnappe, people usually use gravity continuation method, forward gravity modelling method and integrated gravity-seismic interpretation method.
目前，应用重力资料研究逆冲推覆构造，多采用重力延拓法、重力模型正演法和重力、地震综合解释法。
3
The structural system of nappe consists of several overthrust fracture belts, thrust sheets and thrust slices, and master fault and secondary fault form an imbricate structure.