Remote-Controlled Automated Foam Injection: A Digital Solution to Liquid Loading in a China Unconventional Gas Development

Abstract

Abstract Gas field C is an unconventional tight gas reservoir located in the central of China which has prominent characteristics, including thin formation, low permeability and poor reservoir connectivity which significantly impact on the field development. Horizontal wells multistage hydraulic fracturing has been proven to be an effective technique to recover the hydrocarbons from this gas field. However, with continuous production overtime, reservoir pressure declines which results in a decrease in gas production rate below the critical gas velocity, leading to accumulation of liquid in the wellbore (liquid loading), which further results in back pressure and damage to the formation. Currently, gas field C loses up to 1500 mmscf/year in gas production and associated revenue due to liquid loading. Some other factors which hinders effective deliquification of the gas wells include remote well pad locations, poor road conditions during harsh weather conditions, friction with local communities, limited manpower to daily effectively analyze over 200 wells for liquid loading diagnostics and operational risks during well intervention. To tackle these challenges, a new versatile intelligent dosing technology has been piloted to reduce liquid loading. This remote-control dosing unit is located at the well pad and is equipped with automatic valves that can dispense two different chemicals (soap and methanol) in one unit. A key new feature of this system is the ability to receive and implement instructions that optimizes the dosing rate and frequency. This remote-control functionality eliminates on-site operator intervention and HSE risks especially in winter when the well pads could be inaccessible with poor road conditions.