| At present,Mishrif Reservoir in Hafaya oilfield keeps the oil layer pressure higher than the saturated pressure mining,the wellbore is mainly oil-water two-phase flow,the crude oil is heavy 19-25°API,less than the formation water density,the water phase slips in the process of the wellbore rising flow,and the lifting pressure drop increases,resulting in the oil well stopping and spraying early.Aiming at the above problems,this paper uses the method of physical simulation,theoretical research and engineering application to study the phenomenon of water phase slip in horizontal well oil-water two-phase rising pipe.Complete the following main tasks:(1)Based on the well structure and production data of 51 production wells in Mishrif Reservoir,the apparent velocity range of wellbore oil and water two-phase is calculated,and the range of experimental parameters is further clarified based on the principle of velocity equivalence,which in order to prepare for the simulation experiment of oil-water two-phase pipe flow slip.(2)Designed and established a set of visual wellbore oil-water two-phase flow phase slip simulation experimental device with inner diameter 20mm,high 4m and variable well angle(0?90°),and is equipped with related experimental equipment and data acquisition system.It provides experimental conditions for the evaluation and optimization of flow pattern prediction method and the establishment of pressure drop model considering flow pattern.(3)Taking white oil and water as experimental medium,a total of 120 two phase pipe flow slip experiments under 6 inclination angles and different oil-water velocity were carried out,and 5 types of flow patterns were summarized according to the distribution pattern of interface and the flow characteristics of each phase,and the prediction methods of 5 kinds of flow patterns,such as Govier,Zavareh and Flores,are analyzed and evaluated,and it is recommended that the vertical pipe section Flores flow pattern+Inclined pipe segment Flores flow pattern+Horizontal pipe segment Trallero flow pattern diagram.(4)In this paper,the influence law of oil and water flow rate and tube bevel on the moisture content of experimental test is analyzed,and based on the evaluation of the optimized Mukherjee&Brill model,considering the influence of liquid flow rate,water content,pipe inclination and flow pattern on the water holding rate,the prediction model of wellbore water holding rate suitable for Mishrif Reservoir is established and calculation method of pressure drop is proposed.The average absolute error 5.58%of the flow pressure is calculated by using the test data of 23 well secondary field flow pressure in Mishrif Reservoir.(5)The simulation program of oil-water two-phase flow pressure drop is compiled by using Visual Basic6.0,which can calculate the pressure and temperature profile of the production well,comparing the slip and non-slip pressure drop and analyse the effect of the oil yield,water yield,pipe diameter and oil pressure on the pressure drop.It is a good auxiliary tool for the simulation and analysis of oil and water two-phase flow pressure drop in Mishrif Reservoir.(6)Calculated using X well as an example show that the difference between the same condition slip and non-slip bottom flow pressure is 2.01 MPa,the oil production quantity,water yield and wellhead oil pressure are positively correlated with pressure drop loss,the tubing diameter and the bottom hole temperature are negatively correlated,and pressure drop loss is sensitive to the water yield,tubing diameter and wellhead oil pressure.The research in this paper provides important theoretical and technical support for the wellbore condition diagnosis and optimization of the late lifting proces in Mishrif Reservoir production well.They also have certain significance for the development of Mishrif Reservoir production well. |
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