EXPLORATION AND PRODUCTION TECHNOLOGIES
 
“Nanite” for Better Well-Bore Integrity and Zonal Isolation Last Reviewed November 2016

DE-FE0014144

Goal
The project goal is to demonstrate how real-time sensing of Nanite™ can improve long-term wellbore integrity and zonal isolation in shale gas and applicable oil and gas operations. Nanite is a cementitious material that contains a proprietary formulation of functionalized nanomaterial additive to transform conventional cement into a smart material responsive to pressure (or stress), temperature, and any intrinsic changes in composition. Nanite’s electrical, radiometric, and acoustic properties; improved chemical and physical properties; and durability have the potential to ensure long-term wellbore integrity and zonal isolation.

Performers
Oceanit,  Honolulu, HI 96813

Background
Well integrity and performance failures occur for different reasons, one of which is poor cementing. Cementing is a crucial step in drilling safely for oil or natural gas; however, it is an inherently uncertain process and prone to frequent failures such as the one that led to the Deepwater Horizon disaster in the Gulf of Mexico. Environmental protection regulations generally require that cement extend to 150 ft. below the deepest water well in the area in order to protect aquifers from wellbore fluids. Thus, the fracturing process is not supposed to begin until the wellbore has been properly cased and cemented. However, contractors often rush the casing and cementing process and what may at first appear to be a good cement job or casing connection ends up being degraded by the pressure exerted during the fracking process, which causes the casing to fail at the connecting joints or cement cracks. The cracked cement or failed casing then allows wellbore fluids (including fracking fluids and natural gas) to contaminate aquifers or the surface.

Conventional techniques (such as sonic and ultrasonic) used by industry to inspect the integrity of cementing behind multiple casing strings have proven to be inaccurate, insufficient, and unreliable, and continuously monitoring the integrity of cement plugs throughout their lifetime using conventional approaches is not a viable option.  Hence, there is imminent need for new cement evaluation technologies and approaches to improve the effectiveness of existing technologies to assess cement integrity.  Oceanit’s Nanite will be tailored to address key challenges faced during oil and gas cementing.

Impact
The cementing process was developed well over a century ago and the cementing material currently being used has not undergone any significant improvement or innovation since that time. The proposed research utilizes nanotechnology to address persistent cementing issues such as wellbore integrity and zonal isolation. A smart, sensing, durable cementing material such as Nanite will significantly improve the economics of drilling by helping to prevent blowouts and resolving environmental concerns.

Accomplishments (most recent listed first)

  • Multiple modalities of sensor data communication from downhole to surface (electrical and acoustic with and without relays) were considered and down-selected for future field deployment with direction from a joint industry partner (JIP).
  • Full scale diameter pipe section hydraulic test fixture with cement annulus was fabricated and tested, demonstrating the immediate and sensitive response of Nanite to applied stress in a downhole configuration.
  • Explored optimal electrode configurations (annular, axial, and segmented) in hydraulic test fixture.
  • Performed proof-of-concept experiments with sub-scale hydraulic test fixture using control and Nanite test specimens that indicated greatly enhanced response from Nanite.
  • Designed hydraulic test fixtures at multiple size scales for applying and monitoring stress in an annular cement sheath.
  • Nanite cement formulation was evaluated according to API-recommended practices by a certified third-party lab service for rheology, fluid loss, thickening time, and ultrasonic compressive analysis, and the impact of Nanite admixture on cement properties was found to be minimal and within limits for field use.
  • Developed and tested an updated high-speed electrical resistivity tool for Nanite with faster sample rates, greater flexibility in the selection of calibration modes and direct connection to a single board computer.
  • Investigated different modified nanomaterial additives and processing methods for further improving admixture performance for Nanite load sensitivity.
  • Successfully tested the load response of Nanite in alternative form factors concluding that Nanite is scalable to various form factors.
  • Deployed an in-ground Nanite-based weigh-in-motion sensor system with multiple distributed Nanite sensors at a State of Hawaii Weigh Station for continuous monitoring of vehicle loads thus gaining valuable field deployment experience with remote detection operations.
  • Designed electrical and electromagnetic measurement systems for sub-scale testing of Nanite interrogation techniques.
  • Developed a reliable and repeatable electrical measurement technique to assess well cement stress and condition.
  • Optimized specimen preparation procedures resulting in substantially improved uniformity and yield.
  • Performed numerical modelling on the mechanical stress distribution in Nanite specimens under compressive loading.
  • Developed improved data analysis protocols enabling tracking of specimen performance over time and the use of data mining techniques to aid in development of electrical behavior models.
  • Oceanit has consulted a drilling and production technical advisor with a major international operating company regarding deployment opportunities for Nanite who confirmed that Nanite is appropriate for determining well cement integrity using a continuous monitoring system or downhole tool.
  • Received Budget Period II continuation authorization.
  • Hosted DOE program manager site visit in May 2015.
  • Demonstrated a pipe expansion test with impedance logging.
  • Development of high bandwidth impedance analyzer electronics.
  • Acoustic transmission loss comparison between Nanite and base cement.
  • Optimization of electrical impedance of electrode materials used for Nanite measurements.
  • Evaluated Nanite electrical impedance humidity dependence.
  • Refined lab-scale electrical impedance interrogation technique for Nanite.
  • Nanite electrical impedance measurements transitioned to concentric casing form factor.
  • A Nanite curing model was developed to predict hydration rate and level based on electrical impedance measurements.
  • Electrical impedance measurements have been used to reliably detect dynamic mechanical loading and fracture of Nanite.
  • A next generation Nanite electrical impedance analyzer module with small form factor and low energy requirement was designed, produced, and calibrated.
  • Assessed properties of Nanite slurries and cements according to API specifications and found the impact of Nanite admixtures on cement properties to be minimal.
  • Nanomaterials were qualified for initial vendor selection via chemical, thermal, and microscopic analysis.
  • Dissemination of results to communities of interest:
    • On December 5, 2016, Oceanit briefed a global technology advisor from a major international operating company (a JIP) on the current status of Nanite and demonstrated Nanite’s electrical response to radial pressures exerted on subscale concentric wellbore casing strings cemented with Nanite.
    • On January 21, 2016, Oceanit briefed DOE NETL, EPA, and USGSA on Nanite technology during a WebEx conference meeting.
    • On November 23, 2015 Oceanit hosted its 30th anniversary celebration providing technology demonstrations to hundreds of visitors from the business community and government.
    • On November 16, 2015 Oceanit briefed a deepwater technology advisor from a major international operating company (a joint industry partner) who recommended Nanite technology for a broad range of well cement monitoring applications.
    • Dr. Vinod Veedu visited the offices of a major national operating company (a joint industry partner) on November 6 - 9, 2015 to provide an in person briefing on the project status.
    • Oceanit hosted a senior executive from a major international operating company (a joint industry partner) in Honolulu on October 20, 2015 for a briefing on Nanite and Oceanit’s capabilities.
    • Oceanit attended the TechConnect World Innovation Conference and Expo 2014. TechConnect World is the world’s largest multi-disciplinary multi-sector conference and marketplace of vetted innovations, innovators and technology business developers, and funders. Oceanit presented on advanced materials and exhibited its latest innovations, including Nanite, in its exhibition booth.
    • Dr. Vinod Veedu delivered the keynote presentation at the International Association of Drilling Contractors Advanced Rig Technology Conference and Exhibition in Galveston, TX on September 16, 2014. The event was an opportunity to explore potential applications of Nanite for well cementing and showcase recent developments. This leading forum explores the state-of-the-art advances in rig technology and downhole operations and how to seamlessly integrate the two with minimal human intervention.
    • Early stage technology demonstration of Nanite at the Houston Technology Center in conjunction with the Offshore Technology Conference with over 60 oil and gas industry leaders attending.
  • Oceanit has successfully set up a Joint Industry Partnership with two leading international oil companies, one national oil company, and one independent oil company for this work. The active involvement of the oil operators underscores the importance of this work to the industry.

Current Status (November 2016)
Oceanit has been preparing to deploy Nanite for monitoring downhole cement conditions by having the formulation evaluated by a certified third-party cement evaluation company, testing the material and detection system in a sub-scale concentric wellbore casing test fixture, developing high-speed electrical interrogation hardware, optimizing electrode configurations for localized stress detection along the casing, and designing a system for communicating wellbore status data to the surface from downhole. Nanite was tested by a cement evaluation service according to API-recommended practices for properties relevant to use downhole and was found to be similar to base cement, indicating standard cementing practices can be used. A hydraulic test apparatus with a pressurized, cemented casing pipe was designed, constructed, and used to simulate downhole configuration and test the response of Nanite to radial loading. This fixture setup provides a platform for evaluating different electrode configurations, optimizing the detection system, and evaluating defect and contamination detection. Preliminary results indicated immediate and sensitive response of the electrical properties of Nanite to pipe pressurization. A live demonstration of the hydraulic pipe setup was performed for a JIP global technology advisor as part of a coordinated deployment planning effort. Based on this setup, Oceanit will perform key tests to enhance the technology transfer possibilities of the Nanite sensor system for industry applications.

Project Start: October 1, 2013
Project End: February 28, 2017

DOE Contribution: $1,132,074
Performer Contribution: $300,000

Contact Information:
NETL – William Fincham (william.fincham@netl.doe.gov or 304-285-4268)
Oceanit – Vinod Veedu (vveedu@OCEANIT.COM or 713-357-9622)

Additional Information:

Nanite For Better Well-bore Integrity and Zonal Isolation (Aug 2016)
Presented by Vinod Veedu, Oceanit Laboratories, 2016 Carbon Storage and Oil and Natural Gas Technologies Review Meeting, Pittsburgh, PA