Enhancing the Cement Quality Using Polypropylene Fibers

Abstract

With the high global demand of oil and gas, oilfield companies are seeking resources in the unexplored areas by drilling wells to explore the potential reserves of oil and gas. The drilling process has become more challenging in these unexplored areas, especially at the high pressure and high temperature conditions (HPHT). A strong cement sheath is highly desired to ensure the durability and integrity of the wells to overcome these challenges. The cement slurry design and cementing job become more challenging especially when the process is carried out at the high pressure and high temperature conditions. Industry is always looking for the new material which can be stable at these extreme conditions and meet the requirement effectively and economically. Polymer fibers are being used in the petroleum industry lately to assist in meeting these tough requirements. In this research, the usage of polypropylene fibers (PPF) on enhancing the oilwell cements properties at high pressure and high temperature (HPHT) were evaluated. The polypropylene fibers were added into cement admixture with discrete amount to evaluate its influence on enhancing the performance of cements especially those relate to the toughness. Experiments were performed using distinct cement slurry characteristics such as rheological properties, thickening time, compressive strength, density, porosity and permeability. The Scanning Electron Microscope (SEM), and X-ray powder diffraction (XRD) was also performed for analyzing the microstructure of the cement. The experimental tests showed that addition of fibers improves the mechanical properties, accelerates the thickening time, reduces the porosity and permeability and helps in designing a new cement slurry which withstands the HPHT conditions. Polypropylene fiber has a significant effect on reducing the porosity and the permeability of the base cement. Microstructural analysis showed that polypropylene fiber particles block the capillaries by filling the pores in the cement, so a dense cement structure is achieved.