The Integral Optimization Technology Of Oil Well Production Based On Block Benefit

With the development of oilfields during the medium-high water cut stage,oil production rate keeps falling down,causing a significant rising of exploitation difficulties and developing costs.The optimization of oil production for single oil well can no longer assure the minimum energy cost and maximum economic benefits for the whole oilfield under the original production plan.To slove the above mentioned problem,fully considering the most frequently used parameters for the evaluation of the overall benefit of oilfield block and production effectiveness for single well(Technical parameters such as system efficiency,pump efficiency,production rate and total input power,and economic indicators such as block-ton-oil power consumption,ton-oil operation cost,ton-oil total cost,etc.),a calculation model of comprehensive evaluation index is established.Take an oilfield block containing 21 beam-pumping wells and 10 progressive cavity pumping(PCP)wells as an example,evaluating the production effectiveness of the oil wells,the average system efficiency is 41.25%,the ton-oil total cost is 1628.33 RMB/t(less than oil price deduction),16 oil wells belong to marginal-efficiency-area and the other 15 are of high-efficiency-area.The overall production level of the block stays profitable.Taking the physical system of beam pumping wells as research object and using nodal system analysis,a dynamic simulation and production optimization method for beam pumping wells is established based on Petrobras inflow performance relationship calculating model(modified),Beggs-Brill wellbore-multiphase flow calculating model(modified),fluid-physical-parameter calculation models as well as the real-time monitoring data from the oil field.After dynamic simulation,error testing and correction based on field production data,the average calculating errors of parameters including production rate,working load,torque,power,and efficiency are all lower than 15%,which show an improved result of the dynamic simulation for beam pumping wells.Under different single oil well production rate,a regression model of the minimum ton-liquid total cost is established referring to the aim of minimum single well ton-oil total cost.An equality constraint model of block-overall-benefit optimization is established based on minimum integral block ton-oil total cost.The optimal oil production rate for fulfilling block overall production rate is calculated using Lagrange multiplier method,base on which oil well production rates are distributed and the optimal set of swabbing parameters are determined.Under constant-rate-production,the maximum block-overall-benefit is reached choosing minimum ton-oil total cost mothod for single wells.Among the 13 beam-pumping wells and 18 PCP wells,the total production rate of the block is 50.14 t/d,ton-oil total cost is 1609.79 RMB/t and ton-oil production profit is 69.53 RMB/t,bringing an economic profit of 3486.23 RMB/d,which are respectively 18.54 t/d and 969.37 RMB/d higher than previous.The above research followed the aim of minimum integral block operation cost and achieved the reduction of energy consumption and oil well production optimization maintaining the task of production distribution accomplished.The study achievements show great practical significance to improve the overall block economic benefit.