Investigation of Permeability Deformation of Class G Cement During Acidizing Treatment

Class G cement is widely used in oil and gas industry for well cementing. When the well cannot produce the hydrocarbon as per demand due to positive skin, the well stimulation is carried out. One of the popular well stimulation is acidizing treatment. Previous studies have shown that acidizing treatment was affected the cementing of the wellbore which led to the zonal isolation problem. Even though the main purpose of applying the acidizing treatment is to enhance or improve the productivity of producing hydrocarbon unfortunately it also gives the bad impact to the oil and gas industry as well. The objective of this study is to investigate the permeability deformation of Class G cement during acidizing treatment. Throughout the project, a comparison study between before and after the analysis was carried out. The aims of analysis are to find out the mass loss and also to investigate the permeability deformation upon acid stimulation. The first step was to cure the cement slurries under condition of 3000 Psia and 90°C based on average well condition in Malay basin for eight (8) hours. Then, the samples were immersed in three (3) different concentrations of hydrochloric acid (HCL) / hydrofluoric (HF) acid solution or known as mud acid for 40 minutes.