This paper discusses a new generation of inflow control devices (ICDs), which are known as autonomous inflow control devices (AICDs) that can balance production flow and restrict the unwanted fluid. This paper describes the functional testing conducted to evaluate the performance of the fluidic diode type AICD for oil conditions of less than or equal to 1.5 cP and the restriction of unwanted gas in field-like conditions. It will also compare flow performance curves to those of a traditional nozzle-type ICD. Unbalanced inflow from a reservoir can result in water or gas breakthrough, and unless this situation can be addressed satisfactorily, valuable reserves may be lost. When oil is producing from all zones, the AICD will behave as a passive ICD, thereby balancing flow. However, when lower-viscosity fluids break through, the AICD provides a choking effect, significantly reducing flow from the zone responsible for producing these undesirable fluids. Such autonomous characteristics enable a higher recovery rate of oil and also reduce the cost for processing the unwanted fluids. The AICD creates this change in production performance without control lines, moving parts, or electronics. The AICD presented in this paper, also known as Range 1, has an innovative fluidic sensor that is highly sensitive to the fluid properties and is currently best suited for oil viscosities of 0.3–1.5 cP. The Range 1 AICD uses an autonomous on/off type switching function upon gas breakthrough to control gas inflow instead of a gradual change in total flow performance as provided by other inflow control device types. Oil flow is fed directly to the exit port of the AICD, while gas is "switched" to a highly restrictive, spinning path that limits gas production through the tool. Results from single-phase experimental flow testing with oil and nitrogen are presented and discussed. The test results demonstrate that the AICD is an effective tool for restricting gas production. The discussion further shows that if technology, such as the new AICD, is applied to a well-completion design, total oil recovery can be enhanced by increasing the life of the well and reducing the production of undesirable fluids.

Applying proven technology to control the production of water and gas has become necessary to extend the life of very light-oil reservoirs while optimizing economics. Traditional inflow control devices (ICDs) can help balance the flow of oil, but are not helpful once water and gas breakthrough occurs. Multiphase data and field-evaluation applications show that low-viscosity, fluidic-diode, autonomous ICDs (AICDs) support the production of very light oil while restricting gas and water. Testing has proven that the low-viscosity, fluidic-diode AICD can differentiate oil from water and gas, even very light oils. Tool performance was characterized by measuring the pressure differential vs. the flow rate of diverse oil viscosities representing very light-oil formations in Canada, Russia, Malaysia, and Brazil. The AICD was flow tested with very light oils, water, and gas, as well as multiphase testing simulating mixtures of oil/water for different water cuts and oil/gas at diverse gas-volume fractions. The characterization of flow performance was embedded into sophisticated reservoir simulators for steady and transient evaluations. The multiphase condition of the test fluids was achieved by increasing water cuts and gas-volume fractions. The flow performance tests indicated that the highly sensitive fluidic sensor of the low-viscosity AICD enhances the production of very light oil and restricts water and gas as the water cut and gas-volume fraction increase. The restriction process gradually increases as per the water and gas ratio in the mixture and is reversible if water and gas production recede. Comparisons of the low-viscosity, fluidic-diode AICD vs. a traditional ICD show approximately 25% less water production and 40% less gas production with the AICD. The ability of the low-viscosity AICD to produce very light oils while restricting the flow of gas and water extends the life of light-oil reservoirs by increasing the production of hydrocarbons while helping to lower costs. For optimum reliability, this unique fluidic-sensor technology has no moving parts or control lines, but uses fluid dynamics to distinguish fluids. Multiphase-flow performance testing and field simulation of light-oil reservoirs indicate that the low-viscosity, fluidic-diode AICD favors the production of light oil (0.3 cP–1.5 cP) and restricts the flow of gas and/or water in a multiphase production-flow environment.

No abstract

Light-oil reservoirs are affected by the undesired production of water and gas. After breakthrough, these undesired fluids decrease the life of the well, leaving valuable reserves downhole. Inflow control devices (ICDs) delay the production of these undesired fluids; however, they become ineffective after water and gas production begins. Multiphase data and production installation history show how the Autonomous ICD (AICD) with fluidic dynamic technology favors the production of light oil while restricting gas and water. The fluidic diode AICD completions have been successfully installed since 2011 in carbonate, sandstone reservoirs, as well as standalone screens and gravel pack completions. The fluidic diode AICD responds to changing well conditions with no action from the operator. When water and/or gas reach the wellbore, the AICD changes (with no moving parts) the flow path of the fluid and restricts its production. The flow through the device has been validated with extensive testing for single-phase oil, water, and gas. To characterize its performance with the mixture of oil and undesired fluids, multiphase testing has been performed simulating various water cuts (WCs) and gas volume fractions (GVFs). The AICD was characterized by measuring the pressure drop vs. the flow rate at various oil viscosities that represent the light-oil formations in the Middle East. The WC and GVF of the test fluids were altered by increasing the water and gas ratio. This ratio increase enables representative testing of downhole conditions for Middle East reservoirs. The flow performance tests show that the fluidic diode AICD enhances the production of light oil and restricts water and gas as the ratio in the mixture of the undesired fluid increases. When comparing the AICD to a traditional ICD, the AICD exhibits at least 40% more flow of oil than water and approximately 50% less production of gas. Reduced water and gas flow helps reduce operating costs and represents more revenue from the oil production as a result of extending the life of the well. The fluidic diode AICD is a reliable solution to increase the ultimate recovery with no intervention or moving parts. It has been proven that it can promote hydrocarbon production and restrict the production of gas and/or water. The AICD flow performance is predictable in single and multiphase flow. The fluidic diode AICD has been successfully installed in light-oil reservoirs in the Middle East and the North Sea.

In heavy oil fields, well longevity is limited by water inflow. Passive inflow control devices (ICDs) are effective in terms of balancing production flow and delaying the onset of water production. Nevertheless, when gas and/or water breakthrough occurs, a passive ICD enables production of the unwanted fluid. Autonomous ICDs can provide additional restriction to the unwanted fluids and can further enhance the production of oil. The fluidic diode autonomous ICD is functionally based on fluid dynamics technology in which internal geometry directs flow movement based on the viscosity of the fluid. The autonomous ICD enhances oil production while restricting water and gas influx, without the requirement of intervention or moving parts within the device. The result is improved sweep efficiency, which can extend well life and thereby assist in reducing operating costs. Effective design of an autonomous ICD completion is aided with an accurate prediction of the flow behavior through the device. This paper describes flow testing and field performance of a fluidic diode autonomous ICD optimized for the production of very heavy oils with a viscosity above 150 centipoise (cp), while restricting water and gas production. The test results of the autonomous ICD demonstrate that the fluidic diode can produce more oil while restricting water. In fact, heavy oil can flow at a higher rate with less pressure drop than water. Flow performance of this device has been characterized by measuring the pressure drop versus the flow rate at differing viscosities, confirming that the autonomous ICD effectively restricts undesired fluids, while enhancing the production of oil. Numerical simulations demonstrate an improvement of water reduction by more than 50% compared to standalone screen completions. This technology has been used to promote oil production and restrict water influx in fields where the oil viscosity is greater than 700 cp. This paper also demonstrates the appropriate design philosophy when determining the suitable application of the technology to help maximize oil recovery and minimize water production. Fluid flow performance is what truly distinguishes the autonomous ICD from other devices. This fluidic diode autonomous ICD is a robust, reliable solution with no moving parts, nor the requirement of intervention of any kind. Its predictable flow performance has been proven through testing, modeling, and field application.