Research On Viscosity Reduction Technology Of Heavy Oil Wells In Santanghu Mabei Block

The heavy oil in Mabei block of Santang Lake has the characteristics of high density,high viscosity,high freezing point,high non hydrocarbon content and medium wax content.In the process of production,the viscosity of crude oil increases rapidly due to the influence of temperature drop and degassing in wellbore,which makes the flow resistance of heavy oil in wellbore high.Therefore,viscosity reduction technology is needed to ensure the crude oil is lifted to the wellhead.According to the properties of heavy oil in Mabei block of Santang Lake,the viscosity reduction technology is studied in this paper.The methods of viscosity reduction by electric heating,oil blending,chemical emulsion viscosity reducer and oil soluble chemical viscosity reducer were evaluated and optimized.Based on the development experience of Lukeqin heavy oil field,a series of laboratory studies were carried out and field experiments were carried out.In the experiment of viscosity reduction with thin oil,the thin oil from Niudong 89-11 well is selected for viscosity reduction experiment.The viscosity of oil sample with different temperature and different blending ratio is tested.The viscosity of oil sample can be reduced to less than 300 m Pa?s under the condition of thick to thin ratio of 1:1 and temperature of 33℃,which can meet the requirements of wellbore viscosity reduction and lifting.However,the heavy oil has a high wax content and wax deposition problem in the later stage.In the experiment of mixing chemical emulsified viscosity reducer,the experiments of compatibility of viscosity reducer,emulsification viscosity reduction,optimization of oil-water ratio and concentration of chemicals were carried out.The results showed that the viscosity of crude oil can be reduced to less than 300 m Pa?s when the oil-water ratio is 5:5 and the dosage of chemical viscosity reducer HY2-1 and TS-1 is 500 mg/L,and the effect of chemical viscosity reducer HY2-1 is better than that of TS-1.According to the production data,fluid velocity characteristics and emulsion viscosity reducer characteristics of oil wells,combined with process adaptability and benefit calculation analysis,the blending technology on annular pump is optimized.This study formed a viscosity reduction lifting technology and chemical agent viscosity reduction formula system suitable for Santang Lake heavy oil wells.The test well load is reduced by 27%,the electricity cost is saved by 150,000 yuan per year,the average daily production is increased by 1.1 t,and the well opening time rate is increased from 64% to 100%.The purpose of stable production is achieved.This paper provides technical support for the economic and reasonable development of Santang Lake heavy oil wells.