Iranian experts have achieved a new combination of cement that can be used in oil well drilling following a research project conducted by the research and technology department of the National Iranian South Oilfields Company at the Research Institute of Petroleum Industry, IRIB reported. When it comes to oil well drilling, the compressive strength of cement is a fundamental factor in well casing, as a poor cement bond may allow unwanted fluids to enter the well. Particle-size distribution is a key issue, as the empty spaces between the cement particles should be practically diminished. One approach is to fill the empty space between the particles by non-uniform grains, Bagher Ghasempour, head of the research and technology department of the National Iranian South Oilfields Company told IRIB.