Mohsen Mohammadi Meymand - Department of Petroleum Engineering, Petroleum University of Technology, Ahwaz, Iran
S.R Shadizadeh - Ph.D., PE, Department of Petroleum Engineering, Petroleum University of Technology, Ahwaz, Iran
Reza Nakhaei Kohani - Department of Petroleum Engineering, Petroleum University of Technology, Ahwaz, Iran
Morteza Salehi - Department of Mechanical Engineering, Petroleum University of Technology, Ahwaz, Iran

When drilling the producing interval, drilling mud filtrate and colloidal particles in the drilling mud will inevitably invade the formation adjacent to the wellbore. Any alteration to the virgin reservoir rock wettability, intrinsic permeability, water saturation, and oil viscosity can be detrimental to the reservoir productivity. It is called skin effect. The wettability of a crude oil/brine/rock system affects its flow behavior and relative permeability because it is a major factor controlling the location and distribution of fluids, especially residual oil, in a porous medium. In this work the effect of Chamomile hydroglycolic extract on wettability alteration of carbonate reservoir rock has been experimentally investigated. The glycolic drilling mud, as a new-developed mud in the oil and gas industry, is used for the tests. Degree of alteration is determined by contact angle measurement. The results show that the presence of Chamomile extract in the mud will cause wettability alteration of oil-wet carbonate reservoir rock to neutral-wet condition. Due to its low cost and availability, this extract can be used as a natural surfactant in Iranian oil fields

Mud filtrate, Wettability, Skin effect, Chamomile hydroglycolic extract, Contact angle measurement