Assessment of Foamed Cement Used in Deep Offshore Wells

Abstract

The use of foamed cement systems for deepwater applications has been increasing and is often the system of choice for shallow hazard mitigation as in the Gulf of Mexico. However, there is little information regarding foamed cement behavior under wellbore conditions. Research is being conducted to develop a predictive relationship between the mesostructure and physical properties of foamed cements used in offshore applications. Samples of foamed cement have been generated using both atmospheric laboratory and high-pressure field preparation methods. Field-generated foamed cement samples were collected in constant pressure (CP) sample cylinders using the same full-scale field equipment used to generate foamed cements in a well. These samples were scanned while inside the CP cylinders using X-ray Computed Tomography with a scan resolution of approximately 35 m.Results of the laboratory testing indicate a correlation between foam quality, bubble size distribution and physical properties such as strength and permeability. Initial results also highlight key differences in laboratory and field-generated foamed cements. The variations in cement structure within the fieldgenerated foamed cement samples appear to indicate a strong relationship between the flow of the cement into the sample vessel and the final porosity and properties of the in-place hardened cement. This research will provide a better understanding of the effects that foam cement production, transport downhole, and delivery to the wellbore annulus has on the overall sealing process.

An Assessment of the Dynamic Moduli of Atmospherically Generated Foam Cements

“…With the results presented here, we now have a foundation for future foam cement research, particularly with foam cements generated under wellbore pressures (Kutchko et al 2014). With the results presented here, we now have a foundation for future foam cement research, particularly with foam cements generated under wellbore pressures (Kutchko et al 2014).…”

“…It is also our goal to subject cements generated in the field (Kutchko et al 2014) to similar dynamic and static testing. It is also our goal to subject cements generated in the field (Kutchko et al 2014) to similar dynamic and static testing.…”

“…In addition, industry can use these results as a baseline for comparison with previous, current, or future work including recently acquired field-generated foamed cement samples (Kutchko et al, 2014). Mechanical properties of the hardened foamed cement samples, such as Young's modulus (YM) and Poisson's ratio (PR) will be discussed, as well as permeability.…”

A novel self-generating nitrogen foamed cement: The preparation, evaluation and field application

“…It is significant to find out the density variation law of SNFC slurry with pressure and temperature in order to rationally adjust the SNFC slurry density based on the bottom hole temperature and pressure (Kutchko et al, 2015). The SNFC slurry with 1.25 g/cm 3 was heated and pressurized for curing following the method of De Rozieres and Ferrlere (1991).…”

Digital Cement Integrity: A Methodology for 3D Visualization of Cracks and Microannuli in Well Cement

“…X-ray computed tomography (CT) is a powerful, non-destructive characterization method that allows visualization and quantification of defects inside material samples and is therefore well-suited to study cement failure mechanisms as well. Several authors have therefore used CT to study defects, cracks, and porosity inside cement samples [22,[28][29][30][31][32], as well as to study cement carbonation and subsequent leak path alteration during CO 2 exposure [33][34][35][36][37][38][39][40]. In our group, we have recently developed an experimental characterization procedure where we use CT for 3D digital visualization of well cement in realistic annular geometries.…”