A predictive model for the wettability of chalk

Abstract

Wettability is usually measured in special core analyses of limited plug samples according to typically costly and time-consuming procedures. For comparative purposes, wettability is considered an index. The two most frequently used wettability indices are the Amott–Harvey wettability index and the U.S. Bureau of Mines (USBM) index. The Amott–Harvey wettability index is linked to imbibition characteristics and the USBM index is associated with the area under capillary pressure curves. To provide a fast analytical method, a mathematical model for predicting the wettability of chalk is presented. The model is calibrated using experimental wettability data and subsequently applied to two wells in Danish chalk oil fields in the North Sea and to outcrop chalk samples. The model supplements traditional labor-intensive laboratory measurements and predicts water wettability variations with depth by modeling both depth and porosity dependencies; in addition, it provides estimates of the effects of the aging time and displacement temperature of chalk wettability measurements in the laboratory.

Comparison of machine learning techniques for predicting porosity of chalk

“…According to RReliefF algorithm analysis, calcium and aluminum are the second and third significant elements contributing in prediction of chalk porosity, respectively. Aluminum, calcium and silicon are the main elements present in clay, calcite and silica, respectively [24,25]. Therefore, the quantities of these elements are proportional to the corresponding chemical compounds, such as clay, calcite and silica, which are present in chalk samples.…”

“…Nourani et al (2019) reported that the chalk porosity can be effectively controlled by aluminum, Fe, K, calcium and silicon. Aluminum, calcium and silicon contents of chalk emanate from clay, calcite and silica, respectively [24,25]. Chakraborty et.…”

Standardization of Particle Size for Floating Particle Wettability Measurement for Carbonate Rocks

“…The A–H index, I AH , is related to the imbibition characteristics of the rock, and the USBM index is related to the area under the capillary pressure curves. Though these two are internationally accepted standard methods, both are very time-consuming, require a high level of expertise, and require expensive equipment setup …”

“…Though these two are internationally accepted standard methods, both are very time-consuming, require a high level of expertise, and require expensive equipment setup. 18 Another major limitation of the Amott−Harvey index is that a neutral wetting state cannot be measured as either water or oil can be freely imbibed into the rock. Other disadvantages include the long period of time it requires to imbibe and drain fluids out of the core, in addition to the contamination and wettability alteration that the core might be exposed to during the coring process.…”

“…Though these two are internationally accepted standard methods, both are very time-consuming, require a high level of expertise, and require expensive equipment setup. 18 …”