The Ground Metering Technology Research Of Oil-gas-water Three-phase Flow In The Case Of High Water Content Based On The Separation Of The Gas Liquid

It is an important work of oil-field development that is the measure of oil-gas-waterthree-phase flow in the ground. The core of the work is the precise metering of the flow andthe liquid moisture content. In the late1980s, the ground metering system was improved byDaqing oil-field. Now the development of Daqing oil-field is in the period of high water-cut,and it makes that the metering difficulty is promoted greatly with the addition of gas phase, soit urgently needs a device that can meter the important technical indicators e.g. the flow andmoisture content and so on continuously, reliably and accurately.Based on the summary of the oil well metering method, the devices and the experienceand achievement of multiphase flow measurement technique at home and abroad, it designs adevice that can measure the multiphase accurately under the condition of high water content.The device adopts the gas-liquid separation technique that gas phase is detached and notmeasured, and just measures the oil and water two-phase, meanwhile it adopts a diffluent wayfor the oil field high water content environment. The way means that a part of water phase isseparated, then use turbine flowmeter and impedance water-cut meter to measure the flow andmoisture content of the remainder oil water two-phase. The way not only makes thethree-phase metering simplify two-phase, but also it can improve the metering resolution andprecision.It contains that the design of gas-liquid separator and the size establishment of gas-liquidseparator and the design of automatic exhaust valve and the shunt and the design ofmeasuring tube and so on, and finally it gives the general assembly drawing of the devicedesign. Because the split-flow effect directly concerns the final metering result, it adopts theflow field simulation software of Fluent to simulate the split-flow effect of the groundmetering device when the length of the shunts is three different. The target is to determine theoptimal structure of the device that is the perfect place of the shunt. Through the comparisonanalysis of simulation results, the split-flow effect is the best when the length of the shunt is1100mm.Based on the general design and simulation, it manufactures the ground metering deviceand does dynamic experiments using the multiphase flow experiment. The results shows thatit is correct and viable, by mean of turbine flowmeter and impedance moisture content, toapply to the measure of ground multiphase flow; and the addition of the shunt has a bettersplit-flow effect, and it improves the resolution and precision of liquid-phase moisture contentmetering when the range of moisture content is80%~100%and the range of the flow is20~150m3/d that is the condition of high water content. The addition of the shunt canimprove the metering resolution by39.99%via the calculation, thereby, realize the precisemeasure under the condition of high water content.