is anyone out there?, page-16

Further notes on the micro-seismic event diagram:

Well ...? What did you find? Yes, all of you. Did you look at the micro-seismic event diagram in the 10 Dec 12 announcement, enlarge it up to the max on your screen, pore over it, and make notes? It is surprising how much useful enlargement that particular diagram will allow. (Read also my comments in previous post of 16 Dec 12.)

I thought that there might have been at least a minor deluge of comment here, new observations and suggestions for possible explanations of the oddities. How do you think science progresses unless careful eyeballs, controlled by a sharp and patient mind, spots interesting patterns and makes inferences?

Did you try to visualise both the multicoloured pings and grey ones in 3-D? Did they look slightly staggered to you (i.e. one layer from HAB 4 slightly above or below that of HAB 1 and laterally displaced somewhat)? How might this matter?

After much staring at the very pretty colours and varied sizes of the ‘marbles’ in the diagram, one comes back to Earth and looks at the background grey dots. They are printed merely as points but their density and distribution is very telling. The areal extent appears to be greater than the new data recorded for the HAB 4 stimulation.

Notice that the (0,0) reference point is the location of the HAB 1 well, HAB 2 appears to be the black dot on the diagram at (-290m,-330m), while HAB 4 is at approx (+365m,+480m). The direct line distance between HAB 2 and HAB 4 is ~1077m.

Hence there are three overlapping micro-seismic event patch diagrams from HAB 2 in the South West, to HAB 1 in centre, to the new HAB 4 in the North East.

Now for some consideration of the rate of progress of the stimulation over time. Close inspection of the diagram suggests that the fracture front extends radially (roughly) from the well centre (dark blue) at (+365m, +480m) for about 600 m over 15 days where it appears to stop, but then suddenly generates an 800m spurt to the North (brown spheres) in only about 5 days. It is as if the pressurised water found a path of weakness into a new layer and was then rapidly able to expand further North.

Looking again carefully at the macro features of the diagram (besides the East and West limits mentioned in the previous post) there appears to be a fainter but definite geological intersection visible as a straight line running S-West to N-East, across which the fluid path has made the sudden transition. The (early) grey points on the left also help to define this line. Further inspection gives indications of a subtle similar geological intersection running S-E to N-W.

This leads to the general question of the project specifications for the stimulation crew: What were the pressures they were allowed or limited to using, was this constant during the whole of the test period, what determined the cut off time (end of test)? One would think that a few more days of stimulation might have extended the Northern progression significantly.

It might be instructive to inspect the event diagrams produced from each well separately to see if there is a trend of some kind. This means going through the GDY anns of several years ago. Since the pressurised water is free to find its own natural fracture of least resistance, these fractures need not be precisely identical at each well. It would be possible for one to be under another by some metres.

Note that the spatial resolution of the individual pings seems to be better than 10m. This means that if two pings occur 10 m or more apart they will appear as distinct points on the diagrams. It also means that if there were two sheet fractures less than 10m above one another this could not be seen as separate. [This might be important to know as it is hoped that each of these fractures do in fact interconnect.] The geophysicists at Geodynamics will have all the data in 3-D readily accessible on their computers so that they can rotate the images in all directions at a keystroke.

It is important to distinguish between the ‘ping’ and the fracture gap. Once the natural fine fracture has been prised open there is a permanent weakness that cannot be reversed . The fracture gap size could, in principle, vary under physical processes and thereby change the flow potential.

Based on this info what is GDY likely to do next? The stimulated area has not increased greatly as they were hoping. Even so the flow might increase if the fracture gap can be maintained.

The lack of new stimulation expected at the boundaries of the old areas is intriguing. Could it be that the fracture gaps from 5 years ago have significantly closed up? If so, due to what cause? Could it be that, if the key fractures from each well are just above one another, the stimulation of one could flex the rock layers adjacent to the earlier one sufficiently for a substantial closing up? This would be a minor disaster. The use of proppants could be preventative but their approximate uniform distribution becomes a new potential problem. GDY has not mentioned use of proppants for some time.

N.B. The website advert of Shanzi Tiani Ceramic Proppant Co (J. printed). They produce proppants ranging from 0.45 to 0.9 mm and stress their uniformity in size.

So what interesting things do you see and what interpretations would you make? I have no more data than you have. It is all there in the diagrams and in the previous ASX announcements. I have an enlarged printout hanging over my desk and, on fresh days, I ponder possible new interpretations.

Doone Wyborn’s retirement as Chief Scientific Officer leaves a vast gap of knowledge and experience for Geodynamics. I hope that there is some enterprise memory so that this experience is not entirely lost.

Juke