Resource utilization from solid waste originated from oil-based shale drilling cutting during shale gas development

Area of Science:

• Materials Science
• Environmental Engineering
• Petroleum Engineering

Background:

• Shale gas development generates toxic oil-based shale drilling cuttings (OBSDC).
• Current OBSDC treatment methods are inadequate for oily sludge.
• Resource utilization of OBSDC is needed to address waste challenges.

Purpose of the Study:

• To investigate the pyrolysis of OBSDC for use as a cement slurry admixture.
• To evaluate the mechanical properties and cement sheath integrity of OBSDC-amended cement.
• To understand the role of pyrolyzed OBSDC in cement hydration and microstructure.

Main Methods:

• Pyrolysis of OBSDC.
• Preparation of cement slurries with varying OBSDC content.
• Mechanical property testing of cement samples.
• Cement sheath integrity evaluation under high internal pressure.
• Microstructural analysis using hydration and crystallization indicators.

Main Results:

• Cement with up to 35% pyrolyzed OBSDC showed favorable mechanical properties.
• The OBSDC-amended cement met production requirements for casing integrity at 50.01 MPa.
• Active SiO2 and feldspar in pyrolyzed OBSDC promoted cement hydration and C-S-H crystallization.
• Optimized pore structure and increased cement strength were observed within the effective OBSDC dosage range.

Conclusions:

• Pyrolysis offers a viable method for OBSDC resource utilization in cement production.
• OBSDC-amended cement provides a sustainable solution for well cementing in shale gas operations.
• The study highlights the potential of industrial solid waste to enhance construction material performance.