Friday, 21 November 2014

Statement from the European Academies Science Advisory Council

This week the European Academies Science Advisory Council released a statement on shale gas in Europe. EASAC is formed from the national science academies of EU member states. You can read the full statement here, and an executive summary here

A spokesman for EASAC stated:
"While there is no scientific or technical reason to ban hydraulic fracturing, there are clear rules to be followed: Companies must work harder to obtain societal approval to operate, by engaging stakeholders in constructive dialogue and working towards agreed outcomes. Trust is critically important for public acceptance; requiring openness, a credible regulatory system and effective monitoring. Data on additives used and the results of monitoring to detect any water contamination or leakages of gas before, during and after shale gas operations should be submitted to the appropriate regulator and be accessible for the affected communities. The same openness to discuss on the basis of factual evidence must, however, also be expected from the other stakeholders." 
Key passages in the statement include the following:

  • This EASAC analysis provides no basis for a ban on shale gas exploration or extraction using hydraulic fracturing on scientific and technical grounds, although EASAC supports calls for effective regulations in the health, safety and environment fields highlighted by other science and engineering academies and in this statement. In particular, EASAC notes that many of the conflicts with communities and land use encountered in earlier drilling and hydraulic fracturing operations based on many single-hole wells have been substantially reduced by more modern technologies based on multiple well pads, which can drain up to 10 km2 or more of gas-bearing shale from a single pad. Other best practices, such as recycling of flow-back fluid and replacement of potentially harmful additives, have greatly reduced the environmental footprint of ‘fracking’. Europe’s regulatory systems and experience of conventional gas extraction already provide an appropriate framework for minimising disturbance and impacts on health, safety and the environment.
  • Overall, in Europe more than 1000 horizontal wells and several thousand hydraulic fracturing jobs have been executed in recent decades. None of these operations are known to have resulted in safety or environmental problems.
  • Regulations intended to ensure safe and environmentally sensitive drilling activities are already in force in those European countries with their own oil and gas industry.
  • The reservoir volume accessed from a single site has increased substantially through such multi-well pads and longer horizontal laterals, offering a potential extraction area of 10 km2 or more from one pad and reducing surface land use area accordingly. Unconventional gas fields thus no longer have significantly higher well pad densities than conventional fields. Technically, horizontal wells with a reach of up to 12 km are possible (although such wells would at present be uneconomic), but even with clusters of only 3 km radius, it becomes viable
  • to produce unconventional gas in heavily populated areas.
  • A recent meta-analysis (Heath et al. 2014) of the scientific publications on this issue [shale gas and CO2 emissions] came to two conclusions: (1) that emissions from shale gas extraction are similar to those from conventional gas extraction and (2) that both when used in power generation would probably emit less than half the CO2 emissions of coal.
  • Regarding potential sources of emissions from shale gas extraction, flaring and venting in conventional exploitation in Europe ceased during the 1990s (with the exception of initial flow tests in successful exploratory drilling); industry therefore possesses the necessary expertise to avoid this problem. ‘Green’ completion technologies are also widely used to capture and then sell (rather than vent or flare) methane and other gases emitted from flow-back water (they can be recovered at low cost by taking out the gas within a confined separator). This will be mandatory for hydraulic fracturing of all gas wells in the USA from 2015 onwards. Ensuring ‘green completion’ is fully applied in Europe is thus an essential prerequisite for maximising benefits from shale gas to climate change policies.
  • General industry practice in conventional wells (which typically have higher pressures and gas flow rates and longer lifetimes than shale gas wells) has solved the problems of gas migration. By pressure testing, the tightness of the well can be verified. Hydraulic fracturing also uses external casing packers to separate individual fracked zones from each other, creating mechanical barriers in the lowermost part of the well against gas migration outside of the casing.
Finally, I can only conclude that the EASAC are avid readers of Frackland, as they illustrate how lateral well drilling allows a substantial reduction of the surface footprint, as I have done numerous times on this blog. 
Figure 2 Innovation in well design and operation (source: Range Resources Ltd.). Left: old single well spacing (Texas); right: modern multi-well cluster configuration accessing gas from an area of up to 10 km2 (Pennsylvania).

Saturday, 1 November 2014

Image of the Day: Reclaimed Well Pads

A question I am often asked is what does a shale gas well pad look like. The answer can depend, because a pad will change over time. During operations, there will be lots of equipment on the pad, and it won't look particularly nice. However, well construction typically takes a few months, and once complete most of the infrastructure can be removed. Once this is done, much of the pad can be reclaimed and restored.

Of course, the pad in full action is the most dramatic, so this is what the media likes to show. This leaves people with the impression that a shale gas pad will always look that way, not that it's like this for a few months before being restored. 

To address this balance, here are a couple of images of well pads during construction, and then what they look like when finished. 

Firstly, this under-over image shows a pad with a single well being flow-tested, with the gas being flared, and then the same well once the pad has been reclaimed and restored. 

This next image shows a multi-well pad with a drilling rig on site. You can also see open flowback ponds storing water. It's not clear whether this is fresh water yet to be used, or waste flowback water. In the UK flowback water cannot be stored like this.

Underneath shows the same site once it has been completed. Most of the pad is grassed over, with only a small amount of infrastructure left on the pad.