A unique breakthrough in material science

Technology is the backbone for the development of revolutionary solutions and remains at the center of innovation in the oil and gas industry. Material science is the study of a solid material’s structure and capability through physics, chemistry and metallurgy.

The expanding isolation system increases operational reliability.

By applying the knowledge of these sciences with the application defined by disciplined engineering, the Halliburton Completion Tools product service line transcended boundaries and realized a new realm of technical possibilities to pave the way into the future. Halliburton’s proprietary vision, The Future of Completions™, combines material science with sensors and telemetry while leveraging insights from digitalization to help operators address their complex reservoir challenges and maximize asset value.

Material science is integral to a robust technology development strategy, because it builds reliability into the foundation of solutions required in oilfield design. Through testing of materials, compounds and chemistries, as well as applied engineering, the service line’s innovation team created a unique type of zonal isolation technology: the proprietary Ovidius™ Expanding Isolation System.

Combining the simplicity of swellable elastomers with the robustness of non-elastomeric seals, the new expanding isolation system is an engineered metal alloy that transforms into an impermeable rock-like material. The non-elastomeric material expands, seals and interlocks between the base pipe and sealing inner diameter (ID).

The initial focus and application for the new system is zonal isolation, as there is a clear correlation between improved ultimate recovery and wellbore control, with effective isolation between zones and sections of the completion. Current zonal isolation systems have limits from temperature, operational complexity, shape conformance, and chemical resistance. The new isolation system enhances the operating envelope for operators, providing a non-elastomeric material that can expand, seal and anchor in a wide variety of brines at high temperatures/high pressures (HP/HT) and in different shapes. It is capable of withstanding high-differential pressures (up to 17,500 psi) and high-anchoring forces (up to 500,000 pounds)—all without moving parts.

MATERIAL SCIENCE INNOVATIONS

The Company’s technology team created the expanding isolation system by applying knowledge in material science to design a new non-elastomeric expanding metal alloy. The process began with an understanding of the fundamental physics and chemistry of reactive metal alloys and their reaction to engineered or naturally occurring environmental factors, such as fluid and temperatures. When studying the effects of these reactions, the team was able to define and control the interactive nature of the chemical bonds at a nanostructure level.

This engineered metal alloy forms the basis of the new expanding isolation system. The alloy bonds with the water in the wellbore, and a chemical reaction occurs, which causes the metal to expand into a rock-like material. This chemical reaction results in a new material that is larger than the original alloy, because part of the water is incorporated into the alloy, allowing it to transform into its final state.

A series of material science insights was necessary to force the reaction by-products to lock together. A key insight was that a specific alignment of the crystal structure significantly altered the alloy transformation process. Extensive study, testing and experimentation led to an alloy that can be controlled and transformed into a rock-like material.

The material science insight was to force the expanding metal alloy into a rock-like material with aligned crystal structure, as shown on the left in Fig. 1, rather than a poorly aligned crystal structure shown on the right in Fig. 1.

Fig. 1. Aligned crystal structure (left) and poorly aligned crystal structure (right).

An additional experiment used a sleeve of the engineered metal alloy in a controlled environment, representing the annular between the production tubing and an open-hole formation. Figure 2 shows the expansion and metamorphosis of the metal alloy into a rock-like material. During this test, the experiment was observed through a polycarbonate window, which provided clarity and definition of the process and resulting transformation.

As the metal alloy reacts with water, the chemical reaction causes the engineered alloy to expand and fill the annular region before transforming into the rock-like material that forms the seal and anchor for the isolation system (Fig. 2, right side).

Fig. 2. The metal alloy (left) transforms into a rock-like material, as it expands to seal the annular gap (right).

BUILDING ON A LEGACY OF SEALING TECHNOLOGIES

The advent of swellable elastomers in the early 2000s represented an innovative step in open-hole isolation. In 2005, Halliburton¹ installed the first Swellpacker® Isolation Systems in Norway, providing annular isolation with a swellable elastomer. Initially developed for open-hole isolation, swellable packer technology has since evolved, enabling cased-hole applications, as well as combinations with cementing operations.

Despite the widespread adoption of swellable elastomers, some applications require non-elastomeric zonal isolation. The new expanding isolation system demonstrates the Company’s engineered approach to develop a solution capable of extreme performance, while offering unmatched operational simplicity. Material science engineering provides a complex solution in an easy-to-use form that is robust, reliable, and capable of meeting current application needs. These solutions, as well as future applications of the expanding isolation material, are based on both engineering principles and extensive testing.

EXTENSIVE TESTING

Extensive testing and analysis of engineered alloys over several years enhanced the company’s knowledge of metals, elastomers and non-elastomers, providing the basis for the study of the engineered alloy that is at the center of the new expanding isolation system. Successive testing of the engineered metal alloy allowed for reliable and consistent mapping of the transformation from a metal alloy into a rock-like material. These tests covered a wide span, building from microscale tests, to small-scale testing in test rigs, through full-scale testing in flow loops and wellbore performance testing.

Microscale testing allowed for visualizing the transformation from a metal alloy into a rock-like material, as well as the effect of downhole chemicals. X-ray fluorescence analyzed the chemistry, X-ray diffraction analyzed the minerology, electron microscopy analyzed the structure of the materials, and thermographic analysis mapped the thermal stability. This provided greater insight into the crystallographic structures of the material and identified details about the crystal formation, quantifying the formation of the rock-like material. The testing provided the basis to analyze the resulting effects on the material from H₂S exposure, CO₂ exposure, and pressure-holding capability in a HCl acid-rich environment.

Small-scale laboratory testing allowed for rapid testing of multiple materials, heat treatments, designs, and brines. The smaller size allows for quickly obtained results and multiple iterations to verify the setting process, with sealing material created from ambient temperature through 570˚F. Seals were created in smooth cylinders, as well as irregular shapes, in a wide range of brine types and brine concentrations and at near-atmospheric pressure and high pressure. The result was an expanding engineered alloy that creates a robust seal and durable anchor across a wide range of temperature, pressure, and brine conditions.

The new expanding isolation system results in a rock-like material that creates a pressure seal while serving as a permanent anchor. The anchoring capabilities of the material were visually demonstrated, using a 4-in. section of the rock-like material to lift a truck of over 4,000 lbs.

In Fig. 3, the short red section of set packer material is loaded in shear. This demonstration illustrates the anchoring capability of the new material system and is not recommended for general truck lifting.

Fig. 3. Anchoring capabilities of the proprietary expanding isolation system visually demonstrated.

A ROBUST, COMPLIANT SEAL

Microscale and small-scale tests provide enhanced understanding of the material science behind expanding metal alloy, but operational performance was proven during full-scale testing. Differential pressure testing of the new system’s full-size set packers was performed using the testing approach previously optimized for the swellable packer systems. All tests were performed according to API 19OH specifications, with the addition of the anchoring force testing (not part of the specification).

A series of varied setting pressures, temperatures, and mechanical configurations were used throughout testing to best mimic actual downhole conditions, some of which were tailored to the specific customer needs for required applications. The test results proved successful at each step. The new isolation packer qualified and released for operational applications of up to 17,500 psi, with thermal stability noted at 570°F and anchoring loads in excess of 500,000 pounds.

In addition to the isolation application, the expanding isolation system was used during plug and abandonment (P&A) of a test well in Texas. With its highly conforming seal, the isolation system provided an effective barrier for the P&A of the well. Multiple variants of the expanding isolation system’s P&A prototype plugs were trialed during the decommissioning process (Fig. 4), and each of the plugs achieved the stated objective in the P&A test program.

Fig. 4. The expanding isolation system’s P&A prototype plug running into a well that was being decommissioned.

CONCLUSION

Simple, robust and flexible, the Ovidius™ Expanding Isolation System provides operators with the next generation of cased-hole and open-hole wellbore isolation completions technology while delivering unmatched versatility and superior anchoring performance. Operational reliability is increased by reducing the risks of in-hole, swab-off or wellbore geometry issues that can damage currently available technologies. Its configurable slip-on design offers operational flexibility while simplifying logistics.

When transformed from its metallic alloy state into its rock-like material state, the expanding isolation packer provides a long-lasting seal for improved well integrity in high-salinity brines and high-temperature environments. Continued perseverance and relevant breakthroughs in material science can lead to further industry advancements as we navigate The Future of Completions.

REFERENCES

1. In 2005, Halliburton’s Energy Services Group, through its affiliates Halliburton Energy Services, Inc. and HESI Norge Holdings, AS, signed an agreement to purchase Easy Well Solutions AS, a Norwegian based company, accredited for installing the first Swellpacker^® isolation system.