A Mathematical Model for the Prediction of Injectivity Decline
Injectivity impairment due to invasion of solid suspensions has been studied by several investigators and some modelling approaches have also been reported. Worthy of note is the development of analytical models for internal and external filtration coupled with transition time concept for predicting the overall decline in injectivity.
This study presents a new mathematical model which is based on mass balance of particles flowing through the porous media by coupling rate changes in injection pressure within the reservoir due to formation damage with rate changes in porosity within the invaded region. This model when fully validated will ensure the reliability of injectivity decline prediction from a well injectivity index history which will further pave way for an effective planning of water treatment whereby creating a new frontier in the management of produced water in oil and gas technology.
Keywords: Injectivity impairment; internal filtration; External filtration; water injection; filter cake; porosity reduction; formation damage; injection decline