Research Of Intermittent Pumping Law On Low Production And Inefficient Oil Wells Of A Block In Yanchang Oilfield

During the development of oilfield,as production time goes by,there have been a large number of low production and inefficient oil wells.Due to insufficient liquid supply,low production and inefficient oil wells are led to be always an unbalanced state of production and supply.The intermittent pumping law against the low production and inefficient oil wells is studies to determine the reasonable intermittent pumping work system.Thus,the phenomenon of "dry pumping" can be effectively avoided to emerge,and the pump efficiency can be effectively improved.The mechanical wear can be effectively reduced,and energy can be saved up to the hilt.Therefore,this study is proved to have important practical significance.In this paper,the low production and inefficient oil wells of Qilicun oil production plant in Yanchang oilfield are taken as the research object.By the integrated use of means and methods of geology,fluid mechanics through porous medium,reservoir engineering,production engineering,reasonable working system is determined among intermittent pumping oil wells.The main contents are as follows:(1)The oil wells of Qilicun oil production plant in Yanchang oilfield are investigated.The average permeability of chang 6 reservoir is 0.82 × 10-3um2,and the average porosity of chang6 reservoir is 8.71%.Thus,chang 6 reservoir is a low porosity and ultra-low permeability reservoir.(2)Based on linear seepage theory of conventional reservoir,the three-phase inflow performance model of low permeability reservoir is established.Furthermore,the mathematical model of the relationship between inflow volume and liquid level in the wellbore is established.The relationship between submergence depth and pump efficiency is summarized.The mathematical model of the relationship between output and liquid level in the wellbore is established.Being used MATLAB software,the curve of the relationship between inflow volume and liquid level and the curve of the relationship between output and liquid level are superimposed to determine reasonable intermittent pumping interval of liquid level.(3)Based on the GM(1,1)model of gray system theory,the mathematical model of the relationship between liquid level and productive time and the relationship between liquid level and idling time is established,which is proved to meet exponential law.The intermittentpumping cycle of the oil wells can be determined by software.(4)The different control techniques are selected to carry out intermittent pumping system.Furthermore,the rate of fluid loss,economic benefit and dynamometer card are regarded as evaluation index to evaluate field test effect of intermittent pumping system.