The Research of Underbalance Drilling Technology Applying in Daqing Oil Field;

When the sandstone gas reservoir is drilled open by the underbalanced drilling using water based mud (WBM), the underbalance pressure normally can hardly offset the imbibition capillary force of the rock, which may result in backwash imbibition.

With application of underbalanced drilling technology, how compound logging adapts the development and challenge of the new technology as soon as possible has become an important study tasks in the logging field.

Application of comprehensive mud logging parameters in interpretation & evaluation of the under-balanced well gas layers;

There are 4 big difficult problems in perforations under balanced well: perforation under wellhead pressure,snubbing operation throughout perforating process,low confining pressure perforating operation and the fullbore string convenient for the following operations.

Under balance drilling is paid great attention to by people for it is favourable for discovering and protecting oil and gas reservoirs,raising drilling speed,reducing cost and lessening drilling lost circulation and differential pressure sticking.

Gas acquisition and interpretation & evaluation under under-balanced drilling;

Effect of annular cuttings on negative pressure in under-balanced drilling process;

Practical drilling fluid technology for under-balanced drilling;

Bottomhole pressure control technology in underbalanced drilling;

The prediction technology of hole enlargement ratio in the condition of underbalanced drilling;

The new well control device for underbalanced drilling process;