Geothermal Survey

Purpose continued by the client:

Electrical production starting from geothermal energy resulting from natural aqueous flows.

Particular Conditions:

There do not exist particular conditions compared to the general terms.

The surface of the concession to be explored must be, at least, of a few km², according to the area where it is located.

Nature of the swift service:

This service is typically swift in two times (we thus move twice):

1. Before exploratory drillings

Our intervention provides, for each point of exurgence (or leakage point) of a geothermal reservoir (i.e. of a water reservoir with very high enthalpy) being on the concession:

• precise positioning on site, except for the centimetre, of projection on the ground of the exurgence point identified,
• the precise GPS coordinates, possibly reproduced on a chart provided by the client, of this exurgence point,
• an estimate of drilling depth to 30 % closenecessary reaching this exurgence point,
  • this precision on the depth of collecting well is what we can reach of better in the actual position of the techniques put in work, but we work to improve this value,
  • this inaccuracy in the estimate depth requires a vertical drilling to reach with certainty the exurgence point (which is the only point “useful to know” of a geothermal reservoir).
• an estimate of mass flow from the geothermal reservoir with a margin of 30%; this estimate rests in particularon the determination:
  • amongst branches, i.e. of cone water arteries, directly resulting from the exurgence point; this number of branches is, according to the characteristics lithospheric with this depth, very revealing of the efferent mass throughput,
  • the length of the water arteries resulting from this exurgence point (only the main part of these water arteries is estimated, because these water arteries are suitable for be subdivided to form a tree structure); these water arteries typically feed one or more aquifers located at a depth of about 50 to 100 meters.

We cannot estimate the temperature of the geological fluid on the outlet side of the geothermal reservoir, but we can guarantee without reserve a higher temperature with 250°C for all the exurgence points which we specify.

Contrary to competition, exploratory drillings are not used to us to specify a locus of extraction, but to prove the existence of this locus of extraction (with respect to our clients) and to precisely measure what we can only estimate in the course of survey (the depth, the mass throughput, the temperature) or that we are straightforwardly unable to estimate in the actual position of our means like the chemical composition, the rate of suspended particles, the presence of non condensablees gas…

The drilling locations which we specify are points of which we guarantee the optimal character compared to hydrogeological criteria. In the contrary case (i.e. so of other drillings, that or those which we specified, is more productive), no fee is due.

2. After exploratory drillings revealed geothermal reservoirs which our client has the intention to exploit

The purpose of This second survey is to identify the optimal points of re-injection. Surprisingly (for many people), it is more difficult to locate the points of re-injection than the collecting locations. As one of the goals of the collecting well is to minimize the disturbance with the hydrogeological system, a very good at the same time total and local comprehension of this one is necessary to carry out the re-injections.

Compared to the common practices, this re-injection, given starting from angiogeological considerations, is accompanied by good and a bad news:

• The good news is that, as the exploitation of the geothermal reservoir amounts collecting ascending underground water flow, the re-injection can be done with much lower depth than the collecting well (typically with less than 50 meters deep whereas the collecting well is made with more than one kilometer of depth),
• The bad news is that several points of re-injection are necessary (typically as much as there are cone branches at the exurgence point) and that they are all the more far away from the well of collecting well which underground water flow from the geothermal reservoir is important.

For the perpetuation of the collecting well, we highly disadvise reinjecting anywhere and with any depth (as that was always done until now).

For each injection well to be drilled, we provide:

• precise positioning on site, except for the centimetre, of projection on the ground of the point of re-injection,
• the precise GPS coordinates, possibly reproduced on a chart provided by the client, of this point of re-injection,
• an estimate of drilling depth to 30 % close necessary reaching this point of re-injection.

There are quasi always several points of re-injection to envisage by collecting location (thus by exurgence point).

The respect of the locus of re-injection is to be regarded as a contractual constraint, except situation invalidated by drillings carried out.

Duration:

The duration of intervention is variable according to the circumstances and depends typically on:

• facility of displacement on the site (given that part of displacements is done on foot),
• visibility (the denser the vegetation is, the less it is easy),
• weather,
• the surface of the concession.

By way of an example, a complete survey of a concession of several km² can be done in one week in the most favorable cases.

Cost and conditions:

The cost of an angiogeoscopy is negotiated with the client. It is recurring and depends exclusively on the income generated by the wells of exploitation which we specified. It is not thus due:

• that as from the moment when our survey produced its fruits in terms of incomes actually generated by the wells of which we determined the site,
• that if no best locus of exploitation could be discovered on the site of the concession by our client or one of his subcontractors (apart from a radius of 50 meters around the point or drilling locations specified [S]).

This cost is directly proportional to the generated income following a coefficient prone to a negotiation which integrates all specificities the survey.

Alternatively and if a exploratory drilling already were carried out or is in progress, our fees can also be calculated proportionally with the increase in income rising from the best positioning of the wells of drilling than we would have specified compared to the drillings carried out within the framework of former or concomitant explorations. The proportionality factor is obviously not the same one as in the preceding case.

Deliverable:

For each angiogeoscopy carried out, we deliver:

• A data sheet by point of exurgence - corresponding to the precise place where to carry out exploratory drilling - taking again all the information collected within the framework of our service of survey (before exploratory drilling),
• A data sheet by point of re-injection - corresponding to the precise place where to carry out the drilling of the injection wells - taking again all the information collected within the framework of our second visit,

We make sign by our client each one of these data sheets for reception, because those have a contractual value and our fees - or the absence of those - rise from the data which appear in it.

Invoicing:

Our fees are invoicees quarterly on the basis of income generated during the quarter passed by the collecting well which we specified. We thus invoice only after the introduction of the power station (and in so far as all the conditions of garanteed result that we offer were met).

Reserves:

A exploratory drilling is necessary to specify the exact depth, flow and the enthalpy. It is also essential to determine:

• the chemical composition of the geological fluid present in the geothermal reservoir,
• the nature of the geological layers to cross during drilling,
• the proportion liquid-steamer which could be naturally gone up on the surface.