Wellbore stability enhanced through the use of glass technology, reducing non-productive time whilst increasing efficiency and extending equipment life

Project Summary

The failure of rock during oil and gas extraction is a major problem. Sand particles, under the flows required to extract hydrocarbons, can cause blockages in pumping equipment, reducing extraction efficiency shortening equipment life, and therefore increasing operational costs.

Glass Technology Services (GTS) has been working in the field of soluble glasses for many years. They are currently mainly used in the biomedical sector for the controlled release of minerals and nutrients to stimulate bone and tissue regeneration. Similar glasses have potential for the modification of rocks and cements in the oil and gas industry.

NZTC worked with GTS to identify glass products that have the potential to be deployed in oil and gas wells to enhance wellbore stability. These soluble glass materials react with fluids and formation to consolidate rock formations either allowing or preventing the flow of formation fluids.

Industry value:
Glass solutions can be used to stabilise sandstones whilst retaining permeability and sealing sandstone.

The NSTA estimates the average cost of a development well to be £23million with NPT accounting for approximately 25% (£5.75million) of these costs for platform wells, with equipment and casing, and cement and mud accounting for a further 18% of well costs.

Assuming the application of soluble glass treatment could save 10-20% of this time, the savings per deployment in NPT alone will be in the region of £0.5-1million per well. There would also be associated savings from reduced rig, equipment and cementing costs (approx. £0.8million, at 20% saving).

Other potential applications of soluble glass treatment are aimed at reducing production losses in existing wells through prevention of sand and water production. The 2018 OGA Insights Report states that 7% of production losses (2.3 mmboe) are due to sand and water production and that intervention is only successful in 50% of cases. Assuming that this technology could overcome these unsuccessful interventions caused by sand and water, this technology has potential to significantly increase this success rate with the potential to extract oil worth approximately £50million per year (assumes 1.15 mmboe restored at $56/bbl and 1GBP-1.3USD).

Key results:
Glass Technology Services have previously utilised their knowledge in high solubility glass chemistry to develop a preventative solution to particle generation and liquification in chalk hydrocarbon formations. This project aims to investigate the feasibility of developing this technology to produce a similar glass-based solution for use in sandstone formations.

Several glass solutions have been identified that stabilise sandstones whilst retaining permeability. As a by-product of the work GTS has also identified glasses capable of reducing permeability and sealing sandstones. All the glass developed contain raw materials that do not present an environmental or health and safety risk. A manufacturing route for scale up of production for trials has been established.

Lessons learned:
The literature review confirmed that there is no typical rock composition. Several different families of glass exist which interact with different rock to produce controllable levels of consolidation and sealing.

The project will now progress to phase two, which will examine optimisation of a glass system for composition, concentration and morphology for deployment. This will also include verification of results by a third-party laboratory to perform bench top test under simulated down well conditions. Once complete, phase three will see the manufacture of sufficient material for field trial with an appropriate partner.