Abstract

The Dual Drop Method is a new hightech wettability measurement method developed based on direct contact angle and spontaneous imbibition measurements performed on rock samples from conventional or unconventional reservoirs. This technique can be used to optimize drilling, completion and stimulation fluid chemistries. The method can be used on rock or drilling cuttings and works well with water based and oil based fluids. It addresses some of the limitations of the widely used CST (capillary suction time) and roller oven methods. This method is a lot faster than any other wettability measurement method available such us Amott, USBM Wettability methods, capillary rise imbibition method (CRM).

Knowing how strong a fluid wets the formation is the key to fluid optimization in drilling, completion and stimulation. During drilling the wellbore wettability can be modified using surface active chemicals making the water based drilling fluids less likely to wet the shale therefore reducing the wellbore stability and other drilling problems.

For hydraulic fracturing, it is possible to select the least damaging fluid chemistry that will maximize the after fracturing load recovery. A reduction in the shale water saturation can have a significant increase in the relative permeability to hydrocarbons.

The Dual Drop Method uses drop shape analysis to compare the contact angles, sessile volumes and wetting tensions (surface tension multiplied by the cosine of the contact angle) between a rock sample, oil and water.