The Limit Confirming And Hydraulic/Thermodynamic Calculation Method Research For Oil-gas-water Mixing Transportation Safe In Pipeline During Oil Producing With Supper High Water Cut

UOGGT (unheated oil-gas gathering and transfering) is one of the main measures thatreduce the energy consuming in domestic and overseas oil field. Some oil fields have doneUOGGT technics experiment since 1970s, such as Shengli oil field, Zhongyuan oil field, Liaoheoil field, Changqing oil field, Fuyu oil field, Huabei oil field, Jiangsu oil field, Henan oil fieldand Daqing oil field etc. But basic theory and influential factors of UOGGT haven't beenperfect yet. The method to define limit and to do hydraulic/ thermodynamic calculation ofoil-gas-water three-phase pipelines haven't been studied by the systemic experiment and theoryresearch. The output of oil well produced liquid and the oil-gas-water tempareure ofoil-well-head icrease continuously with supper high wather cut so that the oil-gas-water threephase flow pattern and hydro/ thermo speciality change greatly. In order to provide technic helpfor UOGGT and advance the total economic benefit of oil fields, it need urgently to reestablishstudy on thermodynamic calculation method of oil-gas-water pipelines, and develepmanagement software.We sdudy on the new technical thermodynamic calculating method of oil-gas-watermixing pipelines for UOGGT system, and make assistant running management software in thispaper. the followings are done:1. In order to sdudy thermodynamics calculation method of oil-gas-water three-phaseburied pipelines by testing datas, temperature drop are tested under different temperature,water-cut, liquid production ouput and gas production output in oil gathering pipeline.2. Different kinds of soil are collected from everglade, infield and badlands in severe coldregion. We measured their water-containing rate, dry density, thermal conductivity, temperaturediffusivity and volumetric specific heat capacity with both states of frozen and thaw. Sometemperature sensors are buried in soil in different depth of high and low hypsography in severechilliness region.The soil natural temperature field is measured. These temperature datas arebase of verifying the calculation method of the soil natural temperature field. We analyzed therunning method of oil-gas-water gathering pipes when atmosphere environment temperaurechanged suddenly.3. The changes of soil's natural temperature have been sdudied with the changes of soil'sheat physical characters. The calculating program of soil temperature field is made with theannual periodic variety. The soil natural temperature field is computed by the physicalparameters tested in the severe cold region. The mathematics model of periodic non-steady soiltemperature field is satisfied thought contrasting analysis between calculation result andexperiment result. We draw a conclusion that the soil natural temperature changes very littlewith the frozen and thaw soil heat physical characters.4. The temperature drop calculating mathematics model of oil-gas-water three-phase buriedpipeline is established. We considered the effect of Tom-Joules effect, pipeline slope, the annualperiodicity change of soil temperature field and time delay when the model was developed. Thecontrasting result indicates that the average relative error between the calculation well headtemperature and test result is smaller than ±9%. So the thermodynamic calculation method isfit for the mixture transportation pipeline with supper high water cut.5. Factors influencing on the temperature drop of the oil-gas-water collection buried pipeare analyzed. We draw a conclusion that the temperature drop changes very little with gasoutput , water-cut, soil's coefficient of thermal diffusivity and the highest air temperature, on heother side, the temperature drop changes serious with liquid output, length of pipe, heatresistance of pipe and the average air temperature.6. The case that buried pipe is bare is considered in the temperature drop computation. Andthe minimum's computation model of added hot water is builed. They make a convenience forthe temperature drop computation model's application in oil field.7. Based on the research of the limit of oil-gas-water and hydraulic/ thermodynamiccalculation method of oil-gas-water mixture transportation pipeline gathering and transferringwithout heating, the software named "Assistant operating software for the run and managementof UOGGT during supper highly-watery stage" is developed. This software can calculate thetemperature drop and pressure drop in transportation pipeline of the water-containing ascends85% and simulate numerically the operating chart of the pressure on well head and the returningoil temperature in measuring space. The software also provides an advice for the whole year'soperation of UOGGT for every well.The achievement of this paper is that provide academic reference and scientific means forthe operating and management of the no heating oil-gas-water gatering and delivering withsupper high water cut, the paper is helpful to the development of multiphase flow and itsacademic and applied value is momentous.