| dc.description.abstract | Water injection is arguably the most widely used technology in maintaining reservoir pressure and enhanced oil recovery. However, the water injectivity always declines as water injection process continuing due to the injection water quality and changes in formation condition. When the injection pressure is above the formation parting pressure, the formation will be fractured, whether inadvertently or purposely. The parting pressure for a depleted reservoir is affected by many parameters including reservoir pore pressure, injection fluid temperature, and rock geomechanics, etc.
In this study, a stochastic modeling is used to determine the parting pressure for water injection. The reason of using Monte Carlo simulation is because petrophysical parameters in the subsurface environment are of a high level of uncertainty, and operator usually knows the range of them to a certain level, but does not know them accurately with high precision. Therefore, Monte Carlo simulation can take the possible distribution into consideration and give the range of possible parting pressure and possibility of occurrence.
Once the formation parting pressure is determined, the operation profile between the injection rate and injection pressure can be established. This project proposes a procedure to determine the injection profile by considering the dynamic well injectivity and injection pressure. The determined profile can be used in injection operation and reservoir management.
The proposed models and procedure are applied in a case study for a water injection well in a producing asset in the Gulf of Mexico (GoM). The comparison results showed that the determined parting pressure matches the field measurements very well and thus the determined injection profile can be used as injection guideline to injecting water through formation matrix or purposely fracturing the matrix.
The work is practically important and scientifically challenging. Operators can use the program to operate water injection wells together with other surveillance tools to well manage the asset. Additionally, the formation parting pressure during water injection is affected by many parameters inherently and many of them have the high level of uncertainties. Therefore, the project also proposes some future work to extend the scope of the work. | en_US |
