In recent years, the application envelope for inflow control devices (ICDs) has significantly shifted toward harsher environments, for example, to high temperature changes for SAGD, high production pressure differentials in wells with high reservoir permeability contrast, and extreme pressure differentials during short-duration acid stimulation. To confirm whether ICDs are able to withstand these extreme conditions, representative and reproducible equipment testing must be performed. The objective of this paper is to describe testing methods and results for a new type of design validation test related to mechanical integrity of production ICDs when operated at high pressure differentials with both injection and production flow as might be observed during either short-duration acid treatments or initial clean-up operations.
A method is presented for validating multiple ICD designs via full-scale testing at high pressure differentials. The first part of this test consists of a flow-to-failure test where the flow rate is incrementally increased until the ICD design flow characteristics are altered (permanently or temporarily). ICD performance may change due to shifting, deformation, and/or loss of sealing surface contact of critical internal components under the loading condition, causing an increase in flow area. A notable change in the ICD flow characteristics is considered to represent the critical upper differential pressure limit. A separate endurance test is also performed with a new ICD at a safety factor adjusted burst rating to determine the integrity of the ICD design over an extended flow period.
This new test method has been applied to several ICD designs over the past few years. Testing outcomes range from unexpected changes in performance characteristics of some ICD designs (cracking of internals, ballooning of the ICD housing, and failure of critical seals) to no apparent failure up to the pressure limit of the flow loop. Lessons learned from testing via this protocol have encouraged service companies to improve their ICD designs, thereby providing more reliable and robust products to the industry.
When these testing programs were initiated, there wasn't an industry-wide accepted best practice for testing ICDs. To build a base of accepted test procedures and methods for ICDs, this paper describes the fundamentals of a new method involving flow-to-failure and endurance validation testing. The methods represent a specific procedure that can be used by oil-field operators as guidelines for specifying validation techniques for untested ICD designs. These methods have now been incorporated into the AWES RP 3362-78 Annex F (2017).