In the course of drilling,many problems occurred such as well falling down,gas invasion,and difficulty to control well deviation,and affected drilling speed.

The gas invasion will result in tremendous loss and serious threat for the safe production in oil and gas fields, therefore, how to rapidly and accurately test the gas invasion is a problem in oil and gas drilling operation.

Source of cement gas cut and current industry handling methods;

4-Phase separation for drilling fluid recovered from ground during drilling process was studied,and the focuses were emphasized on the separation system of drilling fluid with high density and high viscosity that could cause gas cut at high-pressure,ultra high-pressure gas layer and well control.

Based on the theory of two-phase flow pattern of gas and liquid, gas cut change can be detected with acoustic wave after gas flowing into wellbore.

Simulation study on two-phase gas-liquid flow during gas kick;

The paper constructs two-phase gas-liquid flowing finite differential equation group which considers different permeability and exposed length of gas reservoir during gas kick and acquires the solution of the equation group.

In order to illustrate the gas volume variation characteristics correctly,the gas kick process is simulated under the condition, and is almost the onsite drilling process.