Water Vessels

In a nutshell…
All saturated underground water reservoirs “leak”. These leaks do not diffuse through a filtration area or through a slit but produce slender structures or conduits called water vessels. Their typology, characteristics, “demography” and genesis are outlined in this introductory page.

Definition

Water vessels are narrow natural conduits through which confined underground water flows upwards. They form a tree-like network interconnecting water reservoirs of various types (such as geothermal reservoirs, aquifers or the water table).

Underground water flows between various water reservoirs (or aquifers, or water table). These reservoirs are interconnected by water vessels. The pressure inside water reservoirs depends on their confinement capacity and on their incoming (or afferent) flow. The incoming flow produces an overpressure that causes those reservoirs to leak when their confinement capacity is exceeded. The hydrodynamics of those outgoing flows is such that those leaks are quite localized (i.e. they are point-like with respect to the reservoir surface) and are quite limited in number (they are not necessarily unique but almost). The efferent (outgoing) flow from the reservoir does not diffuse through a slit or through a filtration area but is concentrated in one – or slightly more than one – locations. Stable and slender structures – or conduits – called water vessels are produced from those leaks. The diameter of water vessels is typically measured in inches while their length is measured in miles for the deepest and longest ones or in tens of yards for the most shallow ones – which also happen to be the less useful ones. The flow through water vessels goes steadily upwards. It originates in geothermal reservoirs and rises to the surface through a water system made up of interconnected reservoirs (or aquifers or water table) and water vessels.

Typology

We distinguish two types of water vessels based on their origin:

  • water vessels produced by geothermal reservoirs are called water arteries: they are characterized by a high enthalpy (i.e. a high pressure and temperature) as well as by an important mineralization content. Geothermal reservoirs themselves have an afferent flow the origin of which is introduced in our explanation of the full water cycle.
  • water vessels produced by aquifers or by the water table (when saturated) are called water veins; these aquifers and water tables are themselves fed, either by one or more water arteries, or by water veins, as well as by the infiltration of water from the ground surface.

Water vessel” is the common name for water arteries and for water veins. Water vessels are the – often ignored – “heroes” of hydrogeology and this website is devoted to them and to their contribution to the finding of geological resources. It is through them that fresh water circulates underground and reaches the ground surface. Without their contribution to the water cycle, life on earth would not have developed as it did. These two types of water vessels have the following key features :

  • Water arteries are produced at the exurgence – or leakage points of geothermal reservoirs typically at a depth between 600 and 2,000 meters depending on the lithospheric context (see their forming mechanism called angiogeogenesis). These exurgences generally give rise to a cluster of water arteries (called connate from the Latin cum - natus: “born with”, i.e. rising from the same point). From the exurgence point of the geothermal reservoir water arteries typically rise to less than hundred meters from the surface where they flow into an aquifer. They produce there an overpressure that leads this aquifer “to leak” and to form a cluster of water veins which, themselves, will flow into another aquifer closer to surface or into the water table. The cases where these water arteries reach directly the surface are truly exceptional compared to the cases where they hit an aquifer or the water table. When they reach the surface directly, without passing through an aquifer, water arteries produce geothermal manifestations such as hot springs, geysers, mud pools, sulfur springs. Hot springs that are beneficial to the organism (not all are !) can be exploited as thermal springs. Geothermal reservoirs from which they come are then called hydrothermal reservoir.

  • Water veins have a significantly smaller flow rate and enthalpy and are much closer to the surface (their depth is typically a few tens of meters). They form a much denser network than water arteries. Ascending underground water flow typically goes through a few aquifers – which could be counted on the fingers of a hand – before ultimately either reaching the surface and forming a spring or feeding an unsaturated water table. Deep aquifers are permanently saturated (when unexploited by man). The water table is fed both by the infiltration of ground waters and by water veins..

Labeled mineral water is collected from "first order" aquifers preserved from any contamination ("first order aquifers" are aquifers fed directly by water arteries). Natural mineral water owes primarily its mineralization to the water arteries feeding the aquifer from which they are collected. Geological layers washed by the infiltration flow reaching these aquifers play an almost negligible role in the mineral content of those mineral waters (contrary to what the publicities over these waters often contends).

If the aquifers yielding mineral water have a natural incoming flow, they also have a natural outgoing flow (through their exurgence points). These exurgence points are their optimum collecting locations and can be determined by angiogeoscopy. It is not advisable to collect mineral water from elsewhere than from an exurgence point.

Main Properties of Water Vessels

  1. Water vessels are extremely stable:
  • in time: the deeper they are, the more flow goes through them and the closer they are to steady state. Water arteries which are our main focus for geothermal or hydrothermal surveys have all a steady flow rate. This steady state holds true for all properties of water vessels such as temperature or pressure or chemical content;
  • in space: their position and 3D structure remain unchanged over “geological” time scales. The network of water vessels from a whole water system which is identical today as it was tens of thousands of years ago.
  1. The flow of the geological fluid through the water vessels is always saturated. Water vessels should not be confused with the underground rivers which all have a free surface. Water infiltration from the ground surface does not form water vessels either.

  2. The axial pressure gradient of a water vessel varies barely between junctions. The pressure thus decreases quasi linearly in function of the distance from the origin (see pressure profiles) or from the latest junction.

  3. The temperature of the geological fluid varies mainly (i.e. drops) when the flow is transiting through aquifers (see temperature profiles).

  4. The level of mineralization is much more significant for water arteries than for water veins. As for the temperature, the mineralization level drops after a transition through an aquifer.

  5. Water vessels have a typical and rather regular elevation profile. Their slopes go down as they rise (their vertical shape forms a cycloid arch). The shape as viewed from above is more erratic and depends on the ground irregularities.

  6. Water capillaries are produced at regular intervals along the main path of a water vessel. These water capillaries form what is known as the “tail” of the water vessel.

  7. Water vessels tend to branch when transiting between geological layers (from a more compact one to a less compact one). When the geology is known this provides useful reference information over the actual depth of some points of their path. The understanding of their hydrodynamics enables a precise interpolation.

  8. The exurgence of water reservoirs generally form multiple "connate" water vessels (sometimes more than twenty) spreading more or less evenly in all directions.

  9. Seen from above, water vessels tend to flow outward from their origin. Their path viewed from above does not look like a Brownian motion around their origin.

Formation of Water Vessels (called "angiogeogenesis")

The formation of water vessels called angiogeogenesis is a direct consequence of the principle of minimization of the hydraulic energy dissipated during the evacuation of the geological fluid out of a water reservoir (or aquifer or water table). It happens when the pressure inside the water reservoir exceeds its hydrostatic confinement capacity.

Hydrodynamics of Water Vessels

Water vessels have reached an hydrodynamic equilibrium between the available pressure gradient and the pressure lost by intermolecular friction and by increase of the potential and kinetic energies (this last term being negligible). The equilibrium reached is stable at all points of their path.

The flow through water vessels goes steadily upwards. Their elevation profile tends to maximize the hydraulic energy evacuated from water reservoirs. This maximization principle enables to build hydrodynamic models used to interpret ground measurements through angiogeoscopy and, for example, infer the productivity potential of geothermal reservoirs.

Underground Water System

Water vessels form a treelike network getting denser as it comes closer to the surface. The upward increase in the number of water vessels is commensurate with the decrease of their flow rate so that the overall ascending flow rate stays constant (since it is stable over any relevant period considered). An underground water complex flows upwards through water vessels and downwards by infiltration from the ground surface. The proportion between those two feeding mechanisms varies in function of the depth.

A better understanding can be gathered from a view of the 3 D structure of a water system. This 3 D structure is detected by angiogeoscopy from the ground surface on. Its Projection on the ground surface is provided for a better understanding of what is being mapped during our surveys.

Technology

  • Direct Detection
  • Indirect Detection
  • Interpreting the Results
  • Benefits

Angiogeology

  • Scientific Background
  • Hydrodynamical models
  • Breakthrough
  • Paradigm shift

Services

  • Hydromineral Prospection
  • Hydrothermal Prospection
  • Geothermal Prospection
  • Water Supply Prospection

Benefits

  • Optimizing the Drilling Location
  • Reliability of the Specification
  • Results-based Fee only
  • Fast and Accurate