Autonomous Inflow-Control Technology Reduces Water in Gas Wells

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This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 229970, “Reducing Water in Gas Wells With Autonomous Inflow Control Technology,” by Tarjei T. Larsen, SPE, InflowControl; Kåre Langaas, SPE, Aker BP; and Tilak C. Dhital, SPE, InflowControl, et al. The paper has not been peer-reviewed.

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An autonomous inflow-control technology for gas wells (gas AICT) has been developed to autonomously detect and choke unwanted water production while allowing gas and condensate production, improving both economic and sustainability measures of gas wells. To the authors’ knowledge, this is the first published flow performance test of an AICT that autonomously detects and chokes water while allowing gas and light condensate at downhole conditions.

Introduction

Autonomous inflow-control technology (AICT), which operates without the need for electronics or other means of communication or control, has demonstrated its market value by efficiently choking back unwanted fluids in oil wells. Currently, no proven autonomous technology exists for gas wells with potential water problems, although it has been discussed as a potential application for density-based AICT. Using the same principles as the proven AICT concept for oil wells, this paper presents the development and testing of a novel AICT for gas wells. Hereafter, the featured technology will be referred to as gas AICT, or simply “the valve.”

The valve’s autonomy is regulated by a secondary flow path, known as the pilot flow, that runs parallel to the main flow within the valve. The pilot flow comprises two constant flow resistances in series: the turbulent flow element (TFE) and the laminar flow element (LFE), as illustrated in Fig. 1. Depending on the viscosity and density of the incoming fluid, the pilot branch generates an intermediate pressure level between the two flow elements (P2), which is used to control the choking level in the valve. This effect is entirely based on fluid mechanical principles and is fully reversible. The valve can be adjusted to match the specific fluid conditions in a well.

Test Rigs and Conditions

Initial valve development used a dedicated test loop with model fluids such as water and compressed air. The facility is designed to closely replicate downhole fluid conditions by precisely controlling pressure and temperature. Configured for both single- and multiphase testing, the open-loop rig includes fluid mixing before the test section, which simulates a screen joint to capture realistic inflow conditions. Advanced instrumentation—Coriolis flowmeters, temperature and pressure sensors, and high-accuracy differential pressure transmitters—ensures comprehensive monitoring of all relevant parameters.

The fluid properties of the model fluids were compared with the density and viscosity of the actual fluids used in the multiphase flow loop tests. The results indicated that model fluids can be adjusted by varying pressure and temperature to closely replicate the properties of real fluids.