Billingham-based Tracerco, an oil and gas services subsidiary of British chemical company and conglomerate Johnson Matthey, has patented technology that enables the measurement of individual gas, oil, and water stage production along the length of a wellbore, without well intervention.

This inexpensive technology provides confirmation that a wellbore is open to flow, identifies and quantifies stage (flow contribution) of each phase, and provides measurement of drainage area connectivity — simply by adding small amounts of unique chemical tracers to each stage’s stimulation fluid.

The accurate knowledge of individual stage production is vital, as it allows a correlation between zonal productivity and wellbore position within a formation, stimulation and production design.

Using this knowledge, future well development plans can be adjusted with confidence to ensure that any changes made, will result in enhanced ultimate hydrocarbon recovery.

A number of surveillance tools can be used to help gather information on how best to drill and stimulate a well. These include seismic, micro-seismic, core and multiple specialist log data sets.

Historically, it has been difficult to place faith in surveillance data to vary future drilling or stimulation activities.

At best, there was no confirmation that recovery would improve if the data was used to change the program design. Or worse still, one data set was inconsistent with another, leaving the operator unsure which to believe.

Tracerco technology offers a method to prove the accuracy of these measurements, providing operators with confidence when planning future well and field development.

Usually, Gamma Ray (GR) heat maps turn red when the well is drilled lower than the target zone (toe stages) and blue when above the target zone (middle stages). These GR observations support geological expectations (pictured).

Often, red bars provide a measure of the cumulative gas produced during the operation, whilst the blue bars present water production.

When organisations drill outside of zone low (toe stages), it commonly resulted in reduced gas production and increased water production. Drilling out of zone high (middle stages) was not detrimental.

These types of stages show effective hydrocarbon production without suffering from increased water. Armed with this knowledge and by incorporating real time GR monitoring during drilling, operators become better positioned to efficiently complete future wells in the field and remain in the more productive rock.

When referring to real life examples, higher hydrocarbon production was associated with sections of the offset wells that had been drilled above the parent well elevation.

Also note the increased production from stages in the centre section of the horizontals that was believed to result from accessing rock, not previously produced by the parent well.

Tracerco frac tracer technology has become the industries standard methodology to identify stage production of gas, oil, and water along the length of a wellbore.

Using this knowledge, the operator can evaluate drilling, stimulation, and production decisions and extract the full benefit of pre-completion seismic and geophysical diagnostics (seismic, log, micro seismic, landing zone, etc) to ensure enhanced ultimate hydrocarbon recovery.

If you would like to read a more in depth study with references to GR graphs, visit the Tracerco blog (www.blog.tracerco.com/marketing/tracing-a-path-to-better-oil-gas-shale-production)