Abstract: One example of a gerotor pump includes an inner rotor comprising multiple teeth, the inner rotor configured to rotate about a first longitudinal gerotor pump axis. The gerotor pump also includes a hollow outer rotor including an outer surface and an inner surface having substantially identical contours, the inner surface configured to engage with the multiple teeth and to rotate about a second longitudinal gerotor pump axis. The pump includes a pump housing within which the inner rotor and the outer rotor are disposed, wherein the outer surface of the outer rotor defines gaps between the pump housing and the outer rotor.

Abstract: A flow meter well tool includes a volumetric well flow meter to be positioned in a wellbore. The volumetric well flow meter includes a hollow cylindrical tubing to be positioned in the wellbore. The tubing splits well fluid through the wellbore into an internal fluid through the volumetric well flow meter and an external fluid through an annulus between the wellbore and the volumetric well flow meter. The hollow cylindrical tubing includes an internal portion, where an internal cross-sectional area of the internal portion is less than an internal cross-sectional area of the hollow cylindrical tubing.