Study On Water Invasion Law And Protection Countermeasures Of Edge And Top Water In SAGD

With the increasing improvement of oil production technology,SAGD technology has been widely used in the development of heavy oil reservoir.However,there is no specific research on the problems of the decrease of steam chamber temperature drop and ineffective heat loss caused by edge and top water in non cap rock of heavy oil reservoir with edge and top water.Therefore,studying the influence of edge and top water invasion on the SAGD development of edge and top water reservoir and carrying out protection countermeasures has become the key research content to ensure the further effective development of edge and top water reservoir.Aiming at the research problems of the intrusion law of side and top water in SAGD and its prevention countermeasures,this paper uses the high temperature and high pressure reactor to carry out experimental analysis and numerical calculation to study the thermodynamic relationship of the temperature difference between the steam chamber and the water body.It is concluded that when the water intrusion of the steam chamber at 260℃is 10%,the temperature drops to 163℃ and the pressure of the steam chamber decreases by more than 4MPa;Visual experiment and three-dimensional experiment are used to study the invasion law of edge and top water,and summarize the migration law of breaking through the formation when one water invasion channel is developed in edge water and multiple water invasion channels are developed in top water,and the results that edge and top water will reduce the overall recovery of SAGD and end the stable period of oil production ahead of schedule;The physical simulation displacement device of heavy oil composite flooding is used to obtain the flow characteristics of heavy oil in porous media at different temperatures of crude oil,establish steady-state and unsteady state experimental methods,study the starting pressure gradient of heavy oil varying with temperature,determine the fluidity of different types of heavy oil in porous media,and obtain the temperature distribution of temperature seal layer by using energy conservation,Thus,the calculation method of the limit sealing layer thickness between the steam chamber and the edge and top water is established,and the operating pressure of the steam chamber is deduced;Then,using the calculation methods of remaining oil layer thickness,temperature distribution and seal layer thickness,the edge and top water treatment scheme is established,in which nitrogen injection is the best to inhibit edge water invasion and opening skylight and reducing steam injection are the best to inhibit top water invasion.This paper studies the water invasion law of SAGD development in edge and top water reservoir,and discusses the prevention and control countermeasures.The research results play a guiding role in judging the damage degree of water invasion in the development of edge and top water reservoir SAGD with water invasion,and play a positive role in avoiding water invasion and carrying out prevention and control after water invasion in the development of edge and top water reservoir SAGD without water invasion.It ensures the efficient development of SAGD technology in edge and top water reservoirs without caprock.