Dissolvable Rubber Element vs. Conventional Rubber: Key Differences

A downhole instrument is sealed with a dissolvable rubber element part that will dissolve after a certain time. Conventional rubber remains intact and must be mechanically removed if the tool has to come out. That's the crucial distinction. A soluble rubber element is suitable for temporary isolation such as in multi-stage fracture when the expense and danger of retrieval is added. Standard rubber suits long term sealing and severe or unpredictable fluids. I prepared this guidance for procurement managers and material engineers who have to match the proper compound to each well. Below I compare service life, hardness, compression set, testing and supplier inspections in straightforward language.

How a Dissolvable Rubber Element Works

What Makes a Dissolvable Rubber Element Different

A designed elastomer part is a soluble rubber part. It holds pressure for a certain work and then degrades away losing its mechanical strength. Manufacturers make it from a polymer matrix, together with additives, fillers and curing chemicals that influence how the material responds to heat and fluid. Hardness, density, geometry and surface design also influence the outcome. This approach is followed by HAGRIEN dissolvable rubber elements. They are elastomer parts that accomplish the job of sealing during fracture and subsequently disintegrate, so workers don’t have to recover them. I constantly encourage customers to distinguish between real dissolution and swelling, hydrolysis, and mere mechanical breakdown.” Each modifies how debris acts in the wellbore, and each requires its own test evidence.

The Sealing-to-Degradation Sequence

The element operates in two steps. In the first step the tool sets and the rubber expands and contracts against the casing or tool body to create a pressure seal. This is when the pumping and stimulation occurs. In the second step, the material begins to alter with temperature, completion fluid, and time. Hardness, tensile strength and elasticity are progressively lowered. Then the element loses its sealing role and disperses or breaks down. Order is important. A seal that fails early damages the stage, a seal that is late hinders production. We formulate special rubbers with mechanical strength and controlled deterioration. The purpose is to provide dependable zonal isolation during pumping and on time removal thereafter.

Dissolution Time Is a Test Result

You won’t find a hard and fast time to dissolve on a datasheet. The exam is based on certain criteria. The outcome is affected by temperature, fluid chemistry, salinity, pressure, sample size, state of compression and thermal history. Even the term "dissolved" has to be defined. It might signify the first property change, loss of sealing, partial or total extinction. I ask four questions when I take a request for a dissolvable rubber element to a buyer: what temperature, what fluid, what shape and what endpoint. A thick piece with little surface exposed will often take longer than a thin one . Colder areas might delay the process down. Ask for dissolution curves conducted in fluids similar to your own and compare them to your treatment regimen.

Dissolvable Rubber Element vs. Conventional Rubber: Side-by-Side Comparison

Service Life and Removal Strategy

The engine of everything is the service life. The dissolvable rubber element is designed to provide temporary sealing and controlled breakdown, which may eliminate the need for drill-out, milling, fishing and retrieving activities. Conventional rubber is long-lasting. It is chemically resistant, maintains its suppleness for a long time and remains in place until removed or damaged by extreme circumstances. Neither decision is always winning. If your plug has to exit the well, typical rubber means you’re left with milling or drilling. If you want a seal that will endure months, a degradable compound is not the right instrument. I would recommend to write the isolation period first. List your intended actions of intervention and cost of delay. This basic activity typically reveals what material is appropriate for the purpose before any lab work is started.

Material Systems, Hardness, and Compression Set

Conventional downhole rubber is generally from established families. Nitrile (NBR) is good for oil. Hydrogenated nitrile (HNBR) provides higher heat and chemical resistance. Fluoroelastomer (FKM) is designed to resist greater temperatures and harsh fluids. EPDM is good for water and steam, but not hydrocarbons. Buyers weigh them on three metrics. Shore A hardness (ASTM D2240) is a measure of rigidity. Compression set is a measure of the residual flattening of a seal following loading, using standard procedures outlined in ASTM D395 and ISO 815-1. Strength. Tensile data, ASTM D412. Rubber elements from HAGRIEN are available with a hardness of 60 to 90 Shore A and can withstand temperatures of up to 200 °C. For every lot ask for measured values not catalog ranges. Tools that are similar might seal differently because of hardness drift within a lot.

Fast-Dissolving vs. Slow-Dissolving Formulations

The rate of dissolution is a design option. Fast dissolving formulations allow the wellbore to clean up rapidly after treatment and save waiting time. They still have to maintain strength via pumping. Slow dissolving formulations are suitable for extended treatment regimens, however they may impede access when the zone is colder or fluid contact is restricted. Premature failure means pressure is not isolated. Late or partial breakdown increases waiting time, debris danger and intervention expense. If I am talking to a client about a dissolvable rubber part I like to set a timeframe. A minimum seal-hold time and a maximum clearing time. Then ask the provider for test results against both limitations . More important than choosing a quick or slow grade by name is matching the window to your actual stage time.

Applications and Selection Criteria

Where a Dissolvable Rubber Element Fits Best

Temporary isolation is the best fit. The primary use is multi-stage fracturing using frac plugs and bridge plugs, since removing or grinding tools out of lengthy laterals increases expense and danger. Selective stimulation, temporary obstacles and completions requiring clean wellbore access following treatment are also suitable. The use of a degradable rubber seal eliminates a retrieval stage, so personnel spend less time on the well post-job. Our dissolvable rubber pieces are designed to target frac plugs, bridge plugs and dissolvable isolation tools. Some designs combine dissolvable and regular sealing pieces into one tool, allowing each material to execute the task it handles best. The following part addresses the scenarios when conventional rubber comes out on top.

When Conventional Rubber Is the Better Choice

If you want the seal to remain in place for a long period, go for traditional rubber. This includes permanent or semi permanent packers, retrievable tools and applications requiring long term elastic recovery. It also operates in harsh chemical conditions and in wells with an unclear temperature profile, which makes it challenging to predict when it will dissolve. The selection of materials must be carefully considered when used in sour service. ISO 23936-2 contains guidelines on elastomers in interaction with oil and gas media. Material engineers commonly want confirmation of resistance to hydrogen sulfide and quick gas decompression. Honesty does us all good here. Not every conventional seal can be replaced with a dissolvable rubber piece. I would rather win the correct order than win the wrong order.

Matching the Compound to Well Conditions

Begin with a defined operational profile. Record the kind of well, the completion design, bottom hole temperature, differential pressure, fluid chemistry, element size, compression ratio and isolation duration. Then compare the chemical to that profile. Fluid incompatibility may lead to early failure, hence soak testing with your real completion fluids are important. There must be a margin for temperature too. Our rubber elements can take temperatures up to 200 deg C. But I still urge you to advise your actual bottom hole circumstances before I recommend a grade. The result is not only a function of temperature, but also pressure, fluid and shape have a significant role. Storage counts. Heat, humidity, UV radiation and improper packing may affect the characteristics of the elastomer before the tool even gets to the rig, so make sure you verify storage and shelflife guidelines in writing.

Qualification, Testing, and Supplier Evaluation

Batch-Level Data Beats Catalog Data

A catalog tells what a chemical can perform in general . A batch report is a record of what your lot performed in the lab. That distinction matters to audits. For each lot request measured hardness (ASTM D2240), tensile strength and elongation (ASTM D412), compression set (ASTM D395 or ISO 815-1) and dimensional inspection. And when the work requires, provide dissolution-time results in fluids like yours, and pressure-hold and aging tests for each batch of dissolvable rubber elements. HAGRIEN offers rubber elements created in ISO certified plants, tested in CNAS authorized labs and with complete COA traceability, so every batch can be traced back to its records. Set acceptance limitations up front, before the order is placed, such as allowable hardness range so any deviation is seen immediately, not on the assembly line.

Small-Batch Trials Before Volume Orders

Few customers will commit to volume pre-field evidence. The standard route begins with submission of parameters and suggestion of compounds, then a small prototype lot, then bench and field testing, then approval of the provider, then an annual supply agreement. A first project might take a few months. When you reach the prototype stage, examine three things: minimum order quantity for trial pieces, sample pricing, and whether the trial lot is made by the same technique as production. A sample produced to a different spec than the actual item demonstrates nothing. Send us your designs and operating parameters and we will confirm trial numbers and price in the quote. Keep the field test simple. Same tool design, same fluids, reported results for hardness, seal hold, and clearance.

Delivery Coordination and Supplier Checks

Rubber and metal pieces need to come together, else assembly stops. If you have two suppliers, one for the elastomer and one for the metal body, the schedules might wander. HAGRIEN also produces dissolvable bridge plugs, setting tools, packers and associated components, and offers magnesium alloy and dissolvable magnesium alloy bars and machined parts. So we may design the dissolvable rubber part and the metal things in one session. We check technical requirements within 24 hours, and offer a formal estimate and delivery plan within one to three business days, however complicated projects need to be confirmed separately. We provide EXW, FOB and CIF terms, and we handle North American projects via our U.S. business. Supplier Review Check documentation, batch traceability, testing capability, lead time and technical assistance.

Conclusion

A dissolvable rubber element and traditional rubber tackle distinct challenges. First seals for a set task and then degrades which reduces retrieval or milling work in such applications as multi stage fracturing. The second maintains its form and suppleness for lengthy service and suits aggressive or unpredictable situations. The proper decision relies on the time of isolation, temperature, fluid chemistry, geometry and cost of delay. Dissolution time is a test result and so it requires specified circumstances and a distinct end point. Hardness, compression set and tensile data should be obtained from the actual batch, tested by established procedures, not from catalog ranges. Small-batch testing, stated acceptance limits and coordinated supply of rubber and metal mitigate risk ahead of large purchases. The customer who first establishes these parameters may confidently pick the proper material.

FAQ

1. How long does a dissolvable rubber element take to break down?

It is contingent upon the formulation, the temperature, the chemistry of the fluid, the pressure, the element size, the compression and how you define "dissolved". A thick element in a cold zone breaks down slower than a thin one in a hot zone. Get test curves from your provider that apply to your situation.

2. Can I use the same compound for every well?

No. Pressure, temperature and fluid chemistry affect the behavior of each substance, therefore hot or sour wells require product-specific validation, not broad promises. Our dissolvable rubber elements can withstand temperatures up to 200°C and are available in 60 to 90 Shore A hardness. We will look at your real circumstances before assigning a rating.

3. What documents should I request?

Request batch level data on hardness, tensile, compression-set and dissolution, safety data sheets and traceability records. HAGRIEN has complete COA traceability of its rubber constituents and COC and SDS papers are available on request. These sheets allow your audit team to track every lot.

Send Your Parameters to HAGRIEN for a Dissolvable Rubber Element Quote

Looking for a source of dissolvable rubber elements that can meet your well conditions? Please provide HAGRIEN your desired tool type, element size, temperature, pressure, fluid chemistry and quantity. We’ll evaluate your data, offer a compound and provide you with a quote with the documentation your team requires. To start your technical evaluation, email cyrus@us-hagrien.com or visit us-hagrien.com.

References

1. ASTM International, Standard Test Methods for Rubber Property—Compression Set (ASTM D395), 2018.

2. ASTM International, Standard Test Method for Rubber Property—Durometer Hardness (ASTM D2240), 2021.

3. ASTM International, Standard Test Methods for Vulcanized Rubber and Thermoplastic Elastomers—Tension (ASTM D412), 2016.

4. International Organization for Standardization, Rubber, Vulcanized or Thermoplastic—Determination of Compression Set—Part 1: At Ambient or Elevated Temperatures (ISO 815-1), 2019.

5. International Organization for Standardization, Petroleum and Natural Gas Industries—Downhole Equipment—Packers and Bridge Plugs (ISO 14310), 2008.

6. International Organization for Standardization, Petroleum, Petrochemical and Natural Gas Industries—Non-Metallic Materials in Contact with Media Related to Oil and Gas Production—Part 2: Elastomers (ISO 23936-2), 2011.