Optimization On Cooling Gathering & Transportation Processing Parameters In Songfangtun Oilfield

With the development of oilfields entering the middle and high water-cut stages and peripheral scattered oilfields was developed, the oil gathering & transportation system widely experienced a series of inconsistent situations, such as the drop in load rate, decline of operation efficiency and rise of energy consumption, which leads to the increasing production cost of crude oil. Therefore, the implementation of energy-saving and consumption-reducing measures, deep optimization research and technology simplification for the gathering and transportation system have fallen within the key projects in the overall surface plan of oilfield. The Songfangtun oilfield is one of Daqing peripheral oilfields, it is of low well production rate, low gas-oil ratio, low wellhead fluid temperature and poor crude oil properties, in addition, its gathering radius of single-tube ring watering cooling gathering & transportation system is long, so that the unit consumption of natural gas has been higher than the production control requirements. Therefore, it is necessary to fully study the technical limits and characteristics of cooling gathering and transportation, optimize the water mixing process parameters and make the energy-saving transportation program to make use of the oil gathering energy reducing the crude oil production cost and ensure the safe and smooth operation of oilfield surface production system.In this paper, based on the full consideration of operating conditions, such as the pipeline gages, edatope temperature, water injection rate, water injection temperature and medium velocity, a set of watering gathering process simulation test device was designed and experimental techniques was developed to meet the necessary accuracy of process parameter optimization experiment in cooling gathering and transportation. According to indoor simulation test under different conditions, the oil-water flow patterns of low-temperature oil gathering and transportation pipelines were classified, the mobile medium temperature, water content and flow rate were considered as the main factors affecting the flow patterns, the characteristics of temperature drop and pressure drop along the pipeline were given, and combined with the characteristics of typical oil gathering ring and production process in Songfangtun oilfield, the processing parameters, such as the safe oil arrival temperature limits, the water injection rate and temperature, were established on the basis of flow pressure gradient. And based on the economic evaluation of the oil gathering programs, the wall deposition situation in low temperature oil gathering techniques and the best hot wash period were studied.The cooling gathering & transportation field tests were carried out in new and old blocks of Songfangtun oilfield, which is in accordance with the indoor simulation experiments. The results showed that the safe oil arrival temperature was 32℃, the water injection temperature in valve group room was 45℃and average water injection rate was 0.63m3/h corresponding to maximum soil temperature, and the water injection temperature in valve group room was 55℃and average water injection rate was 0.81m3/h corresponding to minimum soil temperature. Based on a test result that the oil arrival temperature was lower 5℃than the crude oil freezing point, take SongⅡ-4 oil transfer station as an example, the yearly gas-saving amount can reach 38.6 X 104m3, which means 355,000 Yuan of operating costs was saved.