A Laboratory Investigation of Cementing Horizontal Wells

Summary Obtaining a successful cement job will remain one of the most important factors to the productive life of any well and will be especially critical for horizontal-well completions. Achieving a high mud-displacement efficiency under highly deviated or horizontal-well conditions requires that special attention be given to the many aspects of drilling/completion practices—e.g., drill-fluid systems and properties and casing and hole sizes—to obtain optimum mud displacement and cementing results. A study of factors affecting mud-displacement efficiency focused on cementing an ultralow-permeability formation that is being evaluated as a subject for horizontal completion. Realistic laboratory testing was conducted on a large-scale test model that has been used for many years to evaluate factors influencing drilling-fluid-displacement efficiency. Factors evaluated for this study included influence of hole and pipe sizes, pipe centralization, displacement rates, and spacer systems. Findings from this study provided specific recommendations for low-permeability reservoirs that also can be applied to horizontally drilled wells. Various techniques for cementing horizontal wells will be discussed and general recommendations will be given.