Study On Blocking Mechanism Of Gravel Pack Sand Control Well

At present,gravel packing completion is one of the sand control methods,which has the best sand control effect.However,the gravel packed process is complicated,and it is prone to sand control failure.In addition,when the gravel type,the degree of compaction and the production speed are different,the sand control effect is also different.However,there is no relevant literature for these studies,and the understanding of the blocking mechanism is not clear enough.For this purpose,this paper uses small-sized sand control equipment.An indoor study is conducted on the influence of gravel type,the compaction degree of gravel layer and production speed on the blockage of gravel layer.Experimental results show:a)when the packed gravel has high sphericity and high roundness,solid particles such as clay in the formation fluid are not easily retained in the gravel layer,and it helps to relieve plugging in the gravel layer.b)When the compaction degree of gravel layer is more than 90%,the gravel layer can effectively stop the formation sand from entering the wellbore.c)There is a critical production speed.Below the critical speed,it is easily caused sand production;above the critical speed,the amount of produced sand is minimal,but production capacity will decrease.This paper also uses finite difference method and MATLAB software to simulate the blocking of the gravel layer in the production process.The simulation results show that with the increase of time,the degree of blocking increases,and the blocking becomes stable after reaching a certain time.When the gravel layer has a large porosity,blocking is more likely to occur in the gravel layer.In addition,when pore throat size in gravel layer is unevenly distributed,the fluid flow is not uniform and the gravel layer is likely to be partially blocked and eroded so that the sand control fails.