WPŁYW KWAŚNYCH GAZÓW ZATŁACZANYCH DO OTWORÓW NA ODPORNOŚĆ CEMENTÓW WIERTNICZYCH – STAN BADAŃ

Abstract

DRILLING CEMENTS RESISTANCE TO THE INFLUENCE OF ACID GAS INJECTED INTO THE WELLBORES – STATE OF THE ART

Abstract. This paper presents specific nature of the deterioration of sealing materials, as well as an overview of recent experimental studies on the problem of wellbore cement behavior in case of acid gas injection. The problem, which now is given a lot of attention, is the well integrity in the boreholes which could serve the purposes of the waste gas injection. In order to examine the degradation mechanisms of drilling cement there are carried out a number of laboratory tests, which can be divided into two groups: static and dynamic ones. In the case of the static experiments, migration of fluids and acidic reaction products is limited to diffusion in the cement mass. The dynamic experiments include pore fluid movement, but it also may be limited in an intact sample of cement, due to its low permeability. Despite extensive research, reporting the geochemical and mineralogical alteration of well cement by acid gases (mostly CO₂) under geologic sequestration conditions, the pore structure and permeability change of cement is still poorly understood. There are also poorly recognized the changes within the cement-formation interface, especially in dynamic experiments.