Rise in core wettability characterization method

摘要

The various embodiments herein provide a method for determining core wettability characteristics of reservoir rock samples based on modified form of Washburn equation. The method involves saturating a core sample with a first reservoir fluid such as water and imbibing with a second reservoir fluid such as oil. The change in square of the core mass with respect to time is monitored during an imbibition process to acquire a data to calculate a contact angle to determine the wettability of the sample. The contact angle is calculated by using the modified form of Washburn equation. A single or twin core sample is used to calculate the wettability characteristics. The method measures wettability characteristics in terms of contact angle and not in terms of wettability index.

主权项

1. A method for determining Reservoir Rock wettability comprising steps of:
generating and utilizing core samples, wherein a core sample is generated by dividing a core plug into a plurality of core samples of a preset size and wherein the preset size of each core sample in the plurality of core samples is an average diameter of 3.8 cm and a length of 1.5 cm; sealing a side of the core sample with an epoxy resin, wherein the side of the core sample is sealed to ensure a one-dimensional liquid penetration into the core sample; mounting a hook on a top side of the core sample; saturating the core sample with a first reservoir fluid; connecting the saturated core sample to a high precision balance, wherein the saturated core sample is connected using a thin rope; taking a second reservoir fluid in an imbibition beaker; hanging the saturated core sample over the second reservoir fluid contained in the imbibition beaker, wherein the saturated core sample is hanged using a thread and wherein the saturated core sample is hanged in a way such that a bottom part of the saturated core sample barely touches the second reservoir fluid; commencing an imbibition process for the hanged and saturated core sample; monitoring a change in a mass of the hanged and saturated core sample over a period of time as imbibitions taking place to obtain a data and wherein the data is a square of the change in the mass of the hanged and saturated core sample over a period of time; generating a curve using the obtained data by plotting a square of the change in the mass of the hanged and saturated core sample with respect to time; calculating a slope of the generated curve; computing a value of a rock constant for the core sample; and applying the calculated slope of the generated curve and the computed value of a rock constant for the core sample in a modified form of Washburn equation to compute a value of a contact angle; wherein the computed value of contact angle represents a wettability of the core sample and in turn represents the wettability of a reservoir rock from which the core plug is generated.