Impact of Iron Minerals in Promoting Wettability Alterations in Reservoir Formations

Abstract

Asphaltene adsorption and deposition onto rock surfaces are predominantly the cause of wettability and permeability alterations which result in well productivity losses. These alterations can be induced by rock−fluid interactions which are affected by well operations such as acidizing, stimulation, gas injections, and so forth. Iron minerals are found abundantly in sandstone reservoir formations and pose a problem by precipitation and adsorption of polar crude components. This is due to rock−fluid interactions, which are dependent on reservoir pH; thus, this research work studied the surface charge development of pyrite, magnetite, and hematite. To ascertain conditions that will result in iron mineral precipitation and adsorption of asphaltene on iron mineral surfaces, zeta potential measurement was carried out. This is to determine the charge and colloidal stability of the iron mineral samples across wide pH values. Experimental results show that the charge development of iron minerals is controlled by mineral dissolution, the formation of complexes, adsorption of ions on the mineral surface, and the collapse of the double layer. The findings provide insights into the implications of iron mineral contacting crude oil in reservoir formations and how they contribute to wettability alterations due to different well operations.

A Surface Charge Approach to Investigating the Influence of Oil Contacting Clay Minerals on Wettability Alteration

“…Reservoir rock mineral surface charges are significantly affected by the presence of ionic species that adsorb on their surfaces . These ionic species are from the reservoir brine, which has a varying concentration of ions with the propensity to adsorb on the clay mineral surface.…”

“…Asphaltene deposition and adsorption due to fluid–fluid interaction are well documented in the literature; ,− however, scarce in the literature is the clay mineral effect on asphaltene molecule adsorption. The influence of rock minerals on asphaltene adsorption is a subject in another publication of ours; however, of concern in this paper are the contributions and influence of clay minerals in asphaltene adsorption. Sandstone is said to be predominantly quartz, and often, when researchers address sandstone, reference is made to quartz.…”

Wettability Changes Due to Nanomaterials and Alkali—A Proposed Formulation for EOR

“…The authors attributed that to the proportionality between ultimate oil recovery to the square root of dimensionless time, where wettability is highly dependent on IFT and the mobility ratio. Clay content in Keuper samples: Core plugs with large mineralogical heterogeneity like the Keuper cores containing goethite are believed to be more oil wet [ 65 , 66 ]. Sayyouh et al [ 65 ] suggested that under low to moderate salinity the tendency towards oil-wet increases with increasing clay content.…”

“…Clay content in Keuper samples: Core plugs with large mineralogical heterogeneity like the Keuper cores containing goethite are believed to be more oil wet [ 65 , 66 ]. Sayyouh et al [ 65 ] suggested that under low to moderate salinity the tendency towards oil-wet increases with increasing clay content.…”

Feature Ranking and Modeling of Mineral Effects on Reservoir Rock Surface Chemistry Using Smart Algorithms

“…The importance of the reservoir rock mineral constituents cannot be over-emphasized in the determination of rock mineralogy, as 0.01% of a particular mineral can cover the pore surface and control the behavior of interactions. 25 Induced pH change is due to different well operations implemented which affect the constituent mineral surface charge. The impact of these well operations such as nanoparticle injection, 36 low salinity water flooding, 37 viscoelastic surfactant injection 38 etc.…”