Reconstruction Of Sealing Process And Design Of Oil Stability Technology For Crude Oil Treatment Station In Xinjiang Oil Field

This subject comes from the reconstruction and extension project of a combined station of Xinjiang Oil Field.The crude oil dehydration in the old area of the station adopts the process of the large and open tank,which causes oil-gas evaporation loss and environmental pollution,and which does also not conform to the requirements for fully-sealed oil treatment;meanwhile,crude oil in the newly-developed M well area shall be piped to the combined station for processing,but the treatment scale of crude oil in the station cannot meet the production requirement.Therefore,this paper designs and improves the crude oil dehydration process in the old area and builds a new crude oil dehydration and stabilization process to treat the crude oil in well M.Main design requirements are:the treatment scale of crude oil is 210×10~4t/a,the water cut of the crude oil after the dehydration shall not be larger than 0.5%,the saturated vapor pressure of crude oil after the stabilization shall not be higher than 0.7times the local atmospheric pressure at storage temperature,and the transmission temperature shall be 50?.Through analyzing the experimental data of crude oil dehydration and combining the practical experience and specification requirements,this paper confirmed that the crude oil dehydration in the old area adopted the joint dehydration process of“thermo-chemical dehydration+electro-chemical dehydration”,with dehydration temperature of50?,requiring 2 sets of newly-built three-phase separators,2 sets of phase-change heating furnaces,2 sets of pressure dehydration tanks;and confirmed that the produced liquid in well M adopted the joint dehydration process of“thermo-chemical dehydration+electro-chemical dehydration”,with dehydration temperature of 60?.And in order to achieve the rolling production of the oil field,it adopted 3-line device in parallel,and the single-line device equipped with 1 set of pressure surge tank,3 sets of lift pump,1 set of phase-change heating furnace,1 set of pressure dehydrator and 1 set of electric dehydrator.This paper designed,calculated and selected the equipment mentioned above.According to the nature of crude oil and specification requirements,as well as the overall consideration of crude oil dehydration process in Well M,this paper designed negative flash stabilization and micro-positive pressure flash stabilization these two sets of crude oil stabilization processes,and applied the software of Hysys to simulate the process,and determined that the feeding temperature of negative flash stabilization ranged from 55?to 60?,and the operating pressure was 0.07MPa(a);while the feeding temperature of micro-positive pressure flash stabilization ranged from 85?to 90?,and the operating pressure was 0.15MPa(a).According to the results of process comparison and selection,the vacuum flash evaporation had easy and short process,needed fewer equipment and had lower energy consumption;in addition,the vacuum flash evaporation project could save the investment of 18,296,100 yuan.Therefore,the vacuum flash evaporation was selected as the stabilization process.The single-line devices included 1set of vacuum flash tower,1 set of oil-free screw compressor,2 sets of top gas heat exchangers,2 sets of stable oil heat exchangers and 1 set of three-phase separator.This paper designed,calculated and selected the equipment mentioned above.And finally,according to the design technology and the combination of requirements of Design specification of general plan for petroleum and natural gas engineering SY/T0048-2016,this paper completed the general layout of the station and proposed the corresponding measures to control the pollution sources produced by the process and dangerous and harmful factors and ensure the safety and environmental protection of the process operation.