No abstract

The high temperature reservoir is in the high water cut stage after long-term development, and the inefficiency or invalid circulation caused by injected water is aggravated. With a long development history, the well pattern has been adjusted many times, and the remaining oil distribution is highly dispersed. Based on the high-temperature reservoir conditions of the target block, the influence analysis of different key parameters on EOR effect of LB- block was carried out. The gas flooding and chemical flooding potential were evaluated by numerical simulation method, and the EOR effect of different oil flooding systems was defined. The gas flooding and binary flooding numerical models were established according to the well pattern, reservoir and fluid physical parameters. The development effect is predicted under different formation dip, reservoir permeability, oil viscosity, oil saturation, effective thickness and reservoir temperature. The simulation results show that the key factors of EOR in gas flooding and binary flooding are formation dip.

Current methods for the analysis of channeling-path phenomena in reservoirs cannot account for the influence of time and space on the actual seepage behavior. In the present study, this problem is addressed considering actual production data and dynamic characteristic parameters quantitatively determined in the near wellbore area by fitting the water-cut curve of the well. Starting from the dynamic relationship between injection and production data, the average permeability is determined and used to obtain a real-time quantitative characterization of the seepage behavior of the channeling-path in the far wellbore area. For the considered case study (Jidong oilfield), it is found that the seepage capacity of the channeling-path in the far wellbore area is far less (10 times smaller) than that of the channeling-path in the near wellbore area. The present study and the proposed model (combining near wellbore area and far wellbore area real-time data) have been implemented to support the definition of relevant adjustment measures to ultimately improve oil recovery.

Jidong oilfield belongs to complex fault block reservoir, and the development has now entered into high water-cut stage. when using Well pattern encryption technology to stabilize production, it is necessary to study the feasibility of Well pattern encryption to ensure a better economic benefit. In this paper, we use theoretical analysis method, consider the influence of oil price on the calculation, improve the economic limit Well pattern density calculation formula, calculate the economic limit Well pattern density under different recovery rates, make recovery rate prediction for different Well pattern density scenarios by combining with Sherkachov's formula, and use the curve intersection method to determine the Well pattern density at the break-even point, so as to determine the economic feasibility of Well pattern encryption. The example calculations show that the use of well network encryption alone does not meet the development requirements of the Liu 90 South block and has no significant economic benefits, so a combination of two-three methods is needed to further improve the recovery rate. Numerical simulation prediction results show that the two-three combination method can improve the recovery rate by 14.54%, accumulate 28.88×104t of oil increase and increase revenue by 678,245,000 yuan.