Drilling into the world of petrophysics: a summer school in Leicester

In the midst of an unusual (and unexpectedly long) British heatwave, what better way to meet a group of aspiring Earth scientists than over some cold drinks in the wonderfully air conditioned King Richard III Visitor Centre on the last day of June. Hosted by the Department of Geology at the University of Leicester, we had all gathered to attend the 3rd Petrophysics Summer School. With 21 participants from ten countries it was sure to be a diverse week of culture, stories, accents, scientific interests and, of course, petrophysics. After the ice had been broken (or perhaps melted by the Leicester warmth) Professor Sarah Davies, the Head of School for Geography, Geology and the Environment, provided a warm welcome to all the participants. Having been sufficiently cooled down it was time to explore the King Richard III Visitor Centre before heading back to our respective accommodations, ready to properly start the course in the morning.

With wide and refreshed eyes, the cohort gathered in the Department of Geology where our instructors greeted us with tea and coffee, ready to hit the ground running. It started with talks from Dr Sally Morgan (who was our course saviour for the week) from the University of Leicester, Drs Angela Slagle and Gilles Guerin from the Lamont-Doherty Earth Observatory of Columbia University who spoke about the history of the IODP and drilling techniques. We then heard from Dr Erwan Le Ber from Leicester about some of the other work that has been done recently by the IODP.

During this time, we also put up our posters and were able to see the sorts of things that everyone was working on and start some interesting conversations. This ranged from research on fracture modelling, to seismology, and, of course, petrophysics. A diverse range of potentially disparate subjects that could easily be weaved and entwined together through the application of petrophysics. In the afternoon we undertook our “elevator pitches” – that is, a two minute (a hawk eye timed two minutes as well) talk from all the participants and tutors to learn about who they are, what they do, and why they were there. The take home message from that was that people were rather fond of ice cream… The weather may have had something to do with that and we consequently hit the nearest beer garden for some more in depth and free-flowing conversations.

On Monday morning Dr Peter Fitch from Imperial College London decided to put the fear into all of us by saying that he normally teaches his Petrophysics 101 class in four days, not three hours…. However, such was Peter’s excellent teaching skills and mastery of the topic, we flew through the slides (in perfect time) and were left with a proper understanding of the key concepts and methods in petrophysics, all supported with some back-to-school worked examples. It turned out that whilst petrophysics is complex, it is not quite as scary as it may have first seemed. This was then followed up by a short introduction into the use of statistics and petrophysics by Dr Tim Pritchard from the University of Leicester. Later that afternoon we put some of this knowledge to the test with exercises from Dr Sam Matthews of BP where we estimated the volume of in place hydrocarbons from a real example using well log data. In the evening we were treated to a special reception at the New Walk Museum where Dr Tom Harvey gave us a short lecture about some of the fossils on display and the history of palaeontology in Leicester.

Armed with new knowledge on the basic principles of petrophysics we headed out on a field trip. First, we went to Weatherford, one of the biggest downhole logging service companies in the world. We were given a detailed and thoroughly interesting tour around their site and learned all about how their equipment is made, tested and operated, how it works and what pitfalls can occur when on site. Rarely do early career scientists get to see the nuts and bolts of operations such as this, or meet the people that make it happen – so it was an extremely worthwhile and enjoyable excursion. After basking in the glorious sunshine with our packed lunches we then headed into the British Geological Survey Core Store at Keyworth. Here, we looked at a number of cores from a range of depositional environments and compared the fine detail sedimentology to the outputs of borehole logs. An important lesson to learn about the respective scales of different datasets and the potential caveats that are inherited. We finished off with a tour of the Core Store, the sort of place that makes geologists look like children in a sweet shop! Later that evening there was the small matter of an England World Cup game against Colombia…

On day four we were fortunate enough to receive a skype lecture by Dr Johanna Lofi from the University of Montpellier on the recent IODP Expedition 346 in the Japan Sea. Johanna’s lecture would provide an excellent context for us as we then moved onto a more technical part of the course and interpretation of petrophysical data. Later that afternoon we began work on Techlog, a software package from Schlumberger for the interpretation of borehole data. Rudi Mathers from Schlumberger, alongside the very helpful Jess Keeble (Schlumberger), Kieran Blacker and Laurence Phillpot (both Leicester), then guided us through the software. We used the IODP data from Johanna, which we had just heard about, and were shown how to implement the various logs in the software. We spent the afternoon learning how to view and edit the different logs, as well as other useful tools like cross-plotting the data. The technical sessions really helped to put all the theory we had worked on at the beginning of the week into perspective and we started to feel like real petrophysicists! Once 5pm hit we then retired for the day to Brewdog for some pizza and beer (we are still students after all) to celebrate the 4th of July with our American colleagues who had travelled over for the course.

After our previous night’s fill of pizza and beer we got stuck back into Techlog and learning some of the more complex operations, like how to interpret different facies-types using Techlog’s many advanced features. Later in the afternoon, Gilles then provided us with an insight into sonic data before a break for some well-earned ice lollies – despite the temperature, they did not completely melt immediately out of the ice cooler! To finish off the afternoon, Angela gave us a lecture on well-seismic integration from some fascinating data offshore New Zealand. Later that evening we had a big (a VERY BIG) dinner at Kayal’s Indian Restaurant for our final meal together as a cohort.

On Friday, the last day of the course, Gilles provided us with a lecture on how to use velocity data to tie borehole logs to seismic reflection data, before a talk from Erwan about physical properties, and a chance to try our hand at the lab equipment used to measure P-wave velocities and thermal conductivity. We spent a free afternoon session on Techlog with our own datasets.  This was really useful as we could finally use all the knowledge and skills we had gained on our own research, and with some (a lot of) help from the demonstrators, we were able to make a start on answering some of the questions we had presented on our posters earlier that week. After another break for ice lollies, the course was finished up with prizes being awarded for the best presentations and all the participants received their well-earned certificates. After a couple of hours of more chatting and laughing (somehow we still all had things to talk about) some had to begin to make their journeys home, bringing an end to an excellent week in glorious sunshine of Leicester.

By the end of the week, we had covered everything from the theory of petrophysics, to the tools used onboard IODP’s drilling vessels, to the data collection and how it is processed. The course tied everything together and we left with an overall understanding of how we, as newly inducted petrophysicists could use a variety of measurements, from small-scale grain analysis to large-scale seismic surveys to gain a deeper understanding of the Earth’s structure and subsurface processes.

The Petrophysics Summer School 2018 was a terrific experience with plenty of new knowledge, and, perhaps more importantly, new friends and colleagues (and an unofficial theme tune, which is still in our heads). A wonderful week with plenty of laughs spent in the sunshine of Leicester that was organised and carried off with total precision. A lot of thanks must go to Sally for all her hard work, sponsors, and of course the rest of the tutor team, several of whom travelled 1000s of miles to give us the benefit of their wisdom and knowledge. Suffice to say, the new contacts and friendships that have been forged have been solidified already with plans for future conference beers and even scientific collaborations already in the pipeline (geological pun intended).

***

This blog was written by 3 of the UK participants of the 2018 Petrophysics Summer School:

Andrew Newton Queen’s University Belfast: “My research currently focuses on exploring subsurface fluid flow and by using my new knowledge on petrophysics I hope to be able to use quantitative rock properties to make my interpretations more robust and geologically realistic.”

Melissa Gray Imperial College London: “I work on creating P-wave velocity models across the Hikurangi megathrust using Full-Waveform Inversion. As the area has just been the focus of two IODP expeditions, this course was really useful for my future research of integrating these drilling results into my models.”

Nathaniel Forbes Inskip Royal Holloway, University London: “My present research involves analysing how hydraulic fractures may propagate in unconventional oil and gas reservoirs. To do this I use a combination of experimental methods to measure the relevant rock properties, and numerical and analytical methods to then analyse how these rock properties may influence fracture propagation. The Petrophysics Summer School taught me the fundamentals of measuring petrophysical properties in the subsurface, which will help me relate my research to subsurface conditions.”

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