Use of autonomous (self-adjusting) valves in injectors in oil production

1. A method for injecting a fluid into an oil and/or gas reservoir or formation, comprising the steps of:

flowing the fluid into the reservoir or formation through a plurality of autonomous valves provided along an injector, each valve of the plurality of autonomous valves comprising a freely moveable controlling body in a flow path through the valve such that the freely moveable controlling body moves by exploiting forces generated by the Bernoulli effect to provide a substantially constant flow-through volume above a given differential pressure for autonomously adjusting the flow of the fluid in order to ensure a substantially constant volume rate from the injector to the reservoir or formation along an injector length.

2. The method according to claim 1 , further comprising the steps of:

including the freely movable controlling body in a recess of the injector wall or in a separate housing body in the wall, the controlling body facing an outlet of an aperture or hole in the center of the recess or housing body and being held in place in the recess or housing body by a holder device or arrangement, thereby forming a flow path where the fluid enters the valve through the aperture or inlet flowing towards and along the body and out of the recess or housing.

3. The method according to claim 1 , wherein the fluid is water, steam, hydrocarbon gas and/or CO 2 .

4. The method according to claim 2 , wherein the fluid is water, steam, hydrocarbon gas and/or CO 2 .