Why are companies looking to bring old gas wells back online?
“We’re in the midst of an energy crisis, with a real drive to make sure production of hydrocarbons is maximised wherever possible. The value of hydrocarbons, plus the challenge of getting them in some markets in the past year, has led to the industry looking at existing assets to determine if more hydrocarbons can be viably recovered - this may also reduce some the urgency to drill new wells and can enable a more efficient and safer abandonment of this infrastructure in the future.
“If you can find a low cost and low risk route for recovering hydrocarbons that have previously been hard to recover, it is definitely the time to try this - and that’s why foamers are of such great interest in gas well deliquification.”
Why are foamers a logical first-step to trying to recover hydrocarbons from a mature or offline well?
“In short, trialing a chemical foamer in your well is typically low cost and simple to execute, and could generate significant return on investment.
“If your well is set-up to easily inject fluids, then it is definitely worth trying a foamer before any other solution. I would say the key benefits are:
Chemical foamers are significantly lower cost than most mechanical methods
They are very easy to apply and determine if they’ll be successful - you can very quickly run a trial application
A chemical foamer won’t introduce integrity risk, unlike many mechanical options
Foamers also don’t restrict what you do going forward. If you can’t get the well online, and decide to abandon, there are no issues doing this. You could even try a mechanical option afterwards.
“From my perspective, trying a chemical foamer first is a no-brainer, and we have seen fantastic results from clients who have done this.”
How do chemical foamers work in re-starting the flow of hydrocarbons?
“Our chemical foamers are formulated with a variety of components, but the key ingredient is always a surfactant. Depending on the conditions, the nature of this surfactant may be changed to better suit the conditions in the well, and the fluids in which the foamer is being introduced. Functionally, the surfactant acts a little like the eggs in a cake mixture - where it traps the gas at the centre of a mixture of water and hydrocarbon-based chemistries (okay in a cake you hopefully haven’t added hydrocarbon, but you will have fats and will trap air in the mixture of water and butter/vegetable oil, assisted by your eggs/egg-substitute). Depending on the ratio of water, hydrocarbon, salts and other materials present in the well, we recommend a specific foamer and have the option to assess some of the tendency to foam with simulated, lab-based testing. It should be noted that simulating downhole conditions for a foaming operation is a challenge, and we’re probably seen about a dozen variations in testing methodologies typically dictated by the operator or service companies.
“Once applied, the foam then helps to lift the liquid up the well, by reducing the hydrostatic head you typically have for that material - particularly if you have a reasonable pressure of gas at the bottom of the well.
“As the foam reaches higher depths, it expands and creates a greater lift - transferring less hydrostatic head to the material below, and encouraging more material to keep flowing up.”
How can chemical foamers be applied?
“Chemical foamers are typically bullheaded, where the liquid is injected through the wellhead, or a more targeted approach can be taken using coil tubing to achieve a spot application to a specific area within the well. Obviously some wells may also have existing chemical treatment lines that may be utilised as well.
“Once the method is selected, a decision is made around what type of application is required - a batch treatment, or continual treatment.
“A batch treatment is typically a one-off operation, and may involve anything from a 25L injection of chemical foamer up to several cubic metres, depending on the size of well, volume of fluids to remove, effectiveness of foamer in lab assessments and some other job-specifics. Quite often, the foamer is chased with some water and may also require an injection of nitrogen, as the pressure may not be high enough and a great lift would not be achieved without this boost.
“A continual injection of foamer is a better route if you know you’re going to constantly get condensate produced along with the gas. Many companies opt for a batch treatment initially to get the well back online, but once the recovery of gas dips, move to a continual injection.
“The best method will depend on your well and your targets - do you have a specific recovery target in mind, or are you looking to recover as much as possible from this well? Our team is here to help determine and plan the best approach to using chemical foamers."
Are there different chemical foamers available?
“We have a full range of environmentally-friendly foamers here at Italmatch, largely developed at different times over the last decade, and we can tailor these to meet our clients’ specific requirements. These are not created using general surfactants - they are made from biodegradable products that enable their use in offshore environments.
“We also work closely with our clients to select the best foamer for their well. Understanding the fluid make-up is critical during this recommendation phase. This allows us to select the best product, and if the actual well fluids are unavailable, we can set-up tests with simulated fluids, which can be agreed with the customer.
“Material compatibility has been a core focus for us in developing our chemical foamers; to date, we have treated wells that utilise a variety of corrosion, hydrate and scale inhibitors within their production systems, as well as many other injection chemicals. If required, we can run compatibility testing, or work with other third parties to run these tests, where more appropriate.
“We also have high performance foamers for use in high temperature environments. We are continually developing and improving our range from both a performance and environmental perspective.”
To learn more about the Aubin® range of chemical foamers, or to speak to Callum and his team, visit our Foamers web page by clicking here.
