A set of manifold string members usable to selectively control separate flowing fluid streams of varying velocities for operations of well construction, injection or production of fluid mixtures of liquids, gases and/or solids, that can be injected into, or taken from, one or more proximal regions of a subterranean passageway, underground cavern, hydrocarbon or geothermal reservoir. Fluid communicated through a manifold string radial passageway of a manifold crossover, between conduit strings and at least one other conduit, can be controlled with at least one flow controlling member, communicating with a passageway member from an innermost, concentric, and/or annular passageway. Fluid communication can be selectively controlled for various configurations of one or more substantially hydrocarbon and/or substantially water wells, below a single main bore and wellhead.