Roughness analysis within flexible water injection pipes in petroleum production projects

•We use field data to evaluate the roughness of flexible pipes utilized in oil fields.•There are macroscopic elements on the surface of flexible lines and exposed to the flow.•The API standard overestimates the roughness in corrugated pipes.•We compared roughness of flexible lines with field data, laboratory and standard API.•More accurate in the roughness can reduce the cost of projects of water injection wells.

In petroleum production projects it is important to consider injection wells in order to promote the mass balance of the porous environment and increase the recovery factor of petroleum. Some of the injection wells are utilized to inject water, especially in the Brazilian scenario of petroleum production. There are some uncertainties regarding the flow modeling, mainly associated with the inner wall roughness determination of flexible pipes whose manufacturing process can originate a corrugated surface or surfaces that are not informed by the manufacturer or are hard to determine. This study takes an approach to water injection well modeling in petroleum production systems and how, through the flow data measured in the field, the pipe inner wall roughness is determined. These results are analyzed with other values of roughness that are normally utilized at wells of water injection in flexible flowlines and numerical–experimental results recently observed in Brazil. The results show that an accurate consideration of the roughness value can bring significant benefits to reducing the costs of injection well projects.