Study On Dehydration Technology Of Crude Oil From Yushulin Oilfield

As major oilfields in Daqing enter high water-containing stage one after another, the development of peripheral oilfields plays an important role in offsetting the reduction in production in the old area of Oilfield. However, due to limited production of peripheral oilfields, oil recovery methods include mechanical recovery by pumping unit and bailing recovery, and oil collection involves transport by pipe, and regular unloading and transporting. In responding to this, the property of ground production fluids becomes more and more complex, significant oil-water emulsification occurs due to return of chemical agent, or emulsion stability increases due to long time storage and aging, leading to problems that limit production, such as increased energy consumption of ground processing system, unstable operation of processing facilities, increased consumption of treating chemical, increased treating difficulty, and poor treatment effect. Aiming at unstable operation of ground crude oil dehydration system in Yushulin Oilfield, this paper analyzes, through theory and test research, the physical properties of the crude oil from the Yushulin Oilfield, such as the density, wax content, colloidal asphalt content, freezing point, mechanical impurities and iron content, and defines the impact of dehydration temperature, returns of acid well, ground oil, bailing oil, water content of crude oil, etc. on the stability of dehydrating electric field. Demulsifier and dehydrating techniques that suit the crude oil from Yushulin Oilfield are provided in this paper, and appropriate dehydrating process is formulated, with economic evaluation being conducted.The results show that the typical features of fluid produced from bailing well are accumulation of many gelatine, a lot of mechanical admixture, high-content inorganic sulfide and zoogloea formed due to the successive growing and reproduction of bacteria; of which, various impurities more easily gather on the oil-water interface and form the thick interfacial film, which, together with the unavoidable long-term aging of oxygen exposure, can further improve the emulsion stability;In addition to the appropriate water content, proper temperature conditions and dosage fitting, the key points to solve the frequent"field transverse"of electric dehydrator are to prevent the failed oil with high content of mechanical impurity and acidulated returns rich in iron from entering the dehydration system;The HCMP can form large transient power with the advantage to damage the high-strength emulsion without generating the electrodispersion; the HCMP, can remarkably reduce the consumption of demulsifying agent and improve the effect of purifying treatment for crude oil.;Study and specify the dehydration technology parameters for dehydration process flow suitable to the Yushulin Oilfield: for the phase-I dehydration of free water and phase-II HCMP electrical-chemical dehydration, the dehydration temperature shall be about 60℃, water content of incoming fluid not more than 30%, treatment amount 30~60m3/h, operating pressure 0.2~0.3MPa, water content of oil after dehydration not more than 0.3%, oil content of sewage not more than 1,000mg/L.