| SAGD(Steam Assisted Gravity Drainage)is the international leading technology in heavy oil development and is widely used all over the world currently.It was widely used in the world since it was put forward by Butler in 1970 s.The oil recovery mechanism of this technology is to inject the high temperature and high dry steam continuously into the injection well so that the steam cavity is formed in the upper part of the reservoir firstly.Then the oil in the upper oil layer will be heated so that its viscosity reduces to the easy-flowing degree,and after that the crude oil and hot water are drainaged to the bottom production well by gravity,and the oil and water are produced through the lifting system of the production well.Therefore,the effect of SAGD cycle preheating will directly affect the production of SAGD production.In order to ensure a good preheating effect,it is necessary to get to know the mechanism and operation norms of each stage in the preheating process,and make a scientific and rational judgment on the connectivity degree of the horizontal segment in the SAGD horizontal well pairs.With the problems existing in the M well area of SAGD pilot test block,this paper studies mainly on the heat connectivity judgement.Firstly,the status of SAGD thermal connectivity judgment technology at home and abroad is investigated,and the advantages and disadvantages of foreign related technologies are studied.On the basis of foreign methods,the influence of the main factors such as static / dynamic parameters,operation mode and tubular structure on thermal connectivity during the process of cyclic preheating is clarified,and two methods for judging thermal connectivity of SAGD and braised wells and the mechanism of judging the connectivity degree are made clear.Finnally,the key parameters in the process of self operation were further optimized.Comparing the data returned from the oil field,the feasibility of the research results is confirmed.The method can be used for scientific and effective judgement of the thermal connectivity of circular preheating in actual production. |
