Intakes and gas separators for downhole pumps, and related apparatuses and methods

A multi-stage intake of a downhole rotary pump:

• defines a fluid flowpath and comprises two or more intake stages arranged in parallel, with two or more of the intake stages each having one or more impellers;
• in which for one or more intake stages of the two or more intake stages:
• the intake stage comprises an outer housing and an inner housing, the inner housing defining a fluid flowpath and an inlet hole to the fluid flowpath;
• an annular plenum is defined between the inner housing and outer housing;
• the inlet hole comprises an inner inlet hole and an outer inlet hole;
• the inner housing defines the inner inlet hole;
• and
• the outer housing defines the outer inlet hole to permit entry of fluid into the annular plenum.