The Optimization Research On High Gas Underbalanced Drilling Mud Security Separator

The proportion of low permeability oil reservoir is gradually increased with the development of oil exploration technology, which leads to constantly developing of the under-balanced drilling technology. Removing the gas from drilling mud during the mud circulation to the ground is very important in the under-balanced drilling process. A variety of gases will be swapped into drilling mud for reducing the density of drilling mud in the process of under-balanced drilling. If the gas can not be effectively removed in the ground degassing, it will be bright a great security risk, and affected the drilling process parameters and measurement accuracy of the data, made the situation underground to determine more complex; on the other hand, it will affect the efficiency of drilling fluid circulation and mud pump, and lead to the wearing of parts. It may also cause an explosion or malignant poisoning incidents. At present, degassing under-balanced drilling mud on the ground is mainly using gravity-type gas-liquid separator at home and abroad. Gravity-type gas-liquid separator has some defects, which handling of small amount, low separation efficiency, operation complex, not easy to demolition and maintain. Therefore, using of gas-liquid cyclone separation technology to separation of the gas from under-balanced drilling mud is this paper's main task.The key component of harmless proceeding is the separation of the gas from under-balanced drilling mud, and this is also the main contents of this article: optimization of drilling mud gas-liquid cylindrical cyclone separator. The flow field in drilling mud gas-liquid cylindrical cyclone separator was studied using the computational fluent dynamics (CFD) method. The stress distribution, axial velocity and tangential velocity were simulated, and the flow field feature of the drilling mud gas-liquid cylindrical cyclone separator was also obtained. The relationships between some factors, which affect the separation efficiency of drilling mud gas-liquid cylindrical cyclone separator, and the separation efficiency of this cyclone separator were obtained. These factors include: the entrance speed, aspect ratio, the liquid containing gas, import position, drilling fluid viscosity, separator diameter, bubble diameter, etc., and made the results compared to the reality test to verify the correctness of simulation using the CFD software. This result provides guide lines for drilling mud gas-liquid cylindrical cyclone separator technical designing.