Abstract
Discrete reservoirs are commonly seen in fractured-caved carbonate reservoirs. The effect of cyclic huff-n-puff in single well and water flooding in well group is varied for different wells. Some wells fail in water injection stimulation due to unforeseen high water cut. Therefore, it is necessary to estimate the displacing potential of water injection after its start and adjust the development strategy in time. The oil volume and water volume an required to be distinguished from the drainage pore volume of an isolated reservoir besides the conventional dynamic reserve evaluation. Based on the material balance principle, a mathematical model for dynamic reserve evaluation is established considering the volume ratio of oil and water. Then controlling equation describing the relationship between pressure recovery and water volume ratio in reservoir is combined with boundary conditions at time nodes before and after water injection to numerically solve the model. The dynamic reserve of crude oil and water can be accurately concluded to deepen the understanding of oil-water distribution characteristic in fractured-caved reservoirs. The method has been proved to meet the actual production after the application in Halahatang Oilfield in Tarim Basin, providing a reliable potential estimation for subsequent recovery enhancement measures.
NSTL