This book is about enhancing the rheological properties of oil well cement by using Nanomaterials, Nano specifically silica. Nanotechnology can offer revolutionary changes in drilling, cementation, oil, and gas production. its structure can produce materials with interesting properties, so it is an important material to improve the oil well cement properties. This paper aims to demonstrate the effects of Nano Silica on the rheological properties and compressive strength of cement in the oil well drilling field.