Abstract:

It is an important way to improve discharge capability of an injection-production system by increasing drawdown pressure in old wells. By analyzing water injectivity and production capacity in main microfacies sandbodies, it is concluded that the distributary channel and the mouth bar have more production capability than the front sheet sand has at the late stage of oilfield development. The sheet sand has too poor water injectivity to make up the shortage of pressure caused by raising withdrawal rate, while the distributary channel and the mouth bar have enough water injectivity to reach injection-production balance and to ensure oil well’s sustainable discharge. According to the drilling status, numerical simulation and water-drive performance curve of new wells, residual oil distribution is studied at the late stage of oilfield development. It is concluded that residual oil produced by hydrodynamic methods is rich in distributary channel. So the wells for raising withdrawal rates should be chosen in the distributary channel at the late stage of development in Shuanghe oilfield. Practical result also shows that wells in distributary channel chosen for raising withdrawal rates have an apparent effect on stabilizing oil output and controlling water.

Key words: raising withdrawal rate, microfacies sandbody, production capacity, water injectivity, residual oil, the late stage of oilfield development