Thursday, December 13, 2007

ShalElog- an Electric Log for Wellbores

ShalElog- a Geochemical Log, made from cuttings retrieved from well drilling
Information is vital, when drilling a well for water, for hydrocarbons, or for steam. Not only should the one investing in an expensive borehole (twenty dollars or more per foot) have an estimate of the risks of failure or success, but he should have an accurate appraisal of the earth penetrated (in terms of encountered rock and fluids). He may find the fluid is obscure, even when it is present.
Water wells are usually drilled by individuals interested in finding water as shallow and as inexpensive as possible, on their properties. After all, water should be cheap, since it seems to be available wherever there is life. However, in the desert water is more elusive- for the quantity man needs, the amount found may prove to be skimpy.
The water table in desert areas (below which water saturates the rock) may be thousands of feet deep. People living near the Grand Canyon find that the gash in the earth has allowed water to percolate (drain down) into the canyon at 5000 feet depth or more. This fact makes domestic water in The Strip very dear. These expensive wells require as much information as possible from drilling, since the total cost is large, and the information found from drilling may incur only a small part of the total cost.
Landowners are reluctant to ask commercial well loggers to log shallow wells (measure rock properties continually from near the top to the bottom of the hole), since it may double the cost of the well to do so. However, they can get a log from the cuttings brought to the surface by the driller. This represents free information, providing it is analyzed or measured later.
Shale cuttings, made into a ShalElog
(patented shale Electric Log)

provide one method of analyzing the rock penetrated while drilling the hole. This may be valuable whenever the hole appears to be dry (there is no readily available fluid in it), and the owner has to decide on abandoning the hole.
The driller should wash and bag cuttings each 10 feet from the well, for use in evaluating the well whenever fluid is not found (this can be done if requested in advance, at no extra cost). These cuttings will keep indefinitely, and if they have been washed and dried they will not be contaminated when stored. The fine material, such as clay, silt, and fine sand stores both organic and inorganic chemicals and these may be measured later should the rock penetrated not be understood. Low Conductivity water (low salt content, with high Resistivity) can be found in zones with thick sands, suitable for drinking, using this log.
These chemicals may be flushed from the cuttings by means of making a mud or slurry from them. This is done by dis-aggregating the dried and heated (in a kitchen skillet) slivers of rock with a mortar and pestle (or stirring dish and mashing tool- not grinding), so that they appear to be clay-like. These then can be mixed with equal weights of distilled water to make a mud or slurry, which can be measured for several properties:

a. Electrical resistivity, R, or recipocally the conductivity of the mud, in ohm-meters or mho/centimeters (Mho is the inverse of Ohm- but not the WHO!);
b. The rate of fluid flow from the slurry, by means of a filter press, in minutes per cubic centimeter. This may vary from one to ten minutes per cubic centimeter, min/cc;
c. The color of the filtered fluid, called effluent, which can easily be graded into clear, slightly yellow, yellow, amber, and gold or brown visual colors;
d. Resistivity of the effluent or filtrate, ohm-meters;
e. Contents of the filtrate, Cion (ionic concentration) , such as Na+, K+, Ca++, or other dissolved chemicals, using an ion-sensitive membrane (measured in electrical millivolts); and
f. Trace elements, such as Boron or other constituent of interest. All of these operations may be made in ten minutes, to keep up with the driller collecting the drilled samples, and a record (Graph presentation) later can be made to present these data- which is called a Log.
Other parameters or calculated terms may be found from the above data, which can be used to evaluate the rock and fluids encountered. These include a factor F= Rmud/Rfluid, where R is resistivity, which is sensitive to the solids found in the cuttings (e.g. limey solids compared to silt). Some of these terms are shown in the following ShalElog, which was made in Turkey by me.

The Presentation of ShalElog is similar to Electric logs made for drilled wells
The left-hand curve, which presents the Na+ content (read left-ward), is a measure of the saltiness of the fluid. In oil wells, this saltiness increases with depth, and is particularly interesting around oil deposits, since the salt water and black oil seem to have an affinity for each other. It is somewhat similar to the SP log, which is conventionally made for oil wells, but the contents pertain to shales or fine sediments, and this is not necessarily the same as with sandstones which contain both salt water and oil (sometimes).
Potassium, K+, is an interesting ion, and it is not common in subsurface waters in large amounts. It is normally some one-twentieth to one-tenth of the concentration of Na+. I have found that it is present more so whenever an active fault or fracture allows fluid to rise vertically from a hotter zone in the earth. This occurs because of its small ionic size, its relatively small hydration with water (recall that physicians prescribe it in lieu of sodium for heart patients, who take on water with ordinary salt), and its increased solubility with higher temperatures. Generally, geologists do not agree that it indicates anything abnormal, so you may want to get other opinions. But I have mapped this ion on county-wide maps, and found that it occurs in linear map presentations in springs, in subsurface wells, and whenever there is abnormal temperature. It travels much more easily when the fluid is warmed, compared to Na+, and consequently may be mapped or measured in boreholes for anomalous geological circumstances. It is known to derive from weathered potash feldspars, shales with illite in them, and from granites. It may be more common whenever evaporites such as playa lakes occur, since it is more soluble than most other salts and occurs whenever the lakes completely dry (as in the desert).

Notice that K+ is highest on the Thrace log, near an amber filtrate, and that it generally increases with depth (temperature).

ShalElog in Geothermal Logs indicates abnormal K+ and anomalous Geology
Notice that K+ (following Photo) is plotted occasionally on the geothermal log shown below, and it indicates abnormal temperature or open fracturing or faulting. Again, it generally increases with depth in this hot hole in an area which produces steam and has fumaroles at the ground surface. In this case there is also an anomaly near the surface (60- 70 meters), and there is steam emission from the nearby area. Again, K+ is a small ion, which has small hydration, compared to Na+, consequently it moves easily through small fractures found at faulting or which are over-pressured.

Geothermal Well Logs shows wide Variations of Dissolved Ions
Sodium Ion variation in the Earth
Sodium ion is the most common ion in groundwater and in seawater, the reason being that it is a result of the dissolution of feldspars and hornblende- the most common soluble minerals in igneous rocks. It is also a result of HCl acid from volcanoes reacting with alkali rocks to produce a salt plus water:

HCl + Na Rocks > H20 + NaCl + anions or other minerals

For limestone areas, Ca++ and Mg++ will predominate in near-surface waters, but again the Na+ ion will increase in importance with depth and temperature, until it is dominant.
This is shown in the Thrace log, but not in the geothermal case, since K+ has supplanted Na+. Sodium and Potassium ions seem to compete, similarly as they do in the human body. Living cells generally contain K+ =10x the Na+ inside, compared with the free fluid outside having 1/10x the Na+. This is mentioned because shales act as membranes in the earth, which cause an ionic concentration contrast across their boundary- similarly to the cell wall. I conjecture that Life is involved with this chemical change, at least in taking advantage of it- notice that the highest K+ in the geothermal well occurs near the bubbling cuttings emissions.
A Model is shown below, which indicates depths where the various waters occur in Large Basins; this indicates that there are four types of Water- somewhat stratified in the Crust, according to temperature and compaction of the Rocks (Permeability or ease of water movement):
1. Meteoric Water, which is potable or drink-able;
2. Ionized Water, which may be too salty to drink;
3. Chemically-Reduced Water, containing stinking compounds; and,
4. Acid Water, which has a pH less than 7.0, depending upon abnormal temperature.

Model for a Large Basin, for vertical distribution of Water Types

Tuesday, December 11, 2007

Happy Holidays!

The “Rights” of the Holiday Season
Aside from the necessity of conforming to the institutions arranged throughout Time by charismatic (and Epiphanatic) Leaders, what does the Earth Scientist have to offer, to determine the Truth of Man’s relation to his world- at the termination of another Solar Year? Nowadays, science has determined that Man is just a part of the World- not the master of it. He does seem to have the ability to disrupt the orderly progression of the Earth’s Evolution, but does he have the Wisdom and Knowledge to allow the tremendous expansion of Population and the Use of the Earth’s Crust to “jive’? Man does have the numbers and the ability to reason and organize the population to exploit the Crust of the Earth for his selfish benefit, but does he have the foresight to exercise restraint in his Exploitation?
When as a graduate student at Texas A&M, I remember the professor asking the class to concentrate on how to conserve oil and gas resources. The accentuation was on ways to produce the resources without waste- not bypassing large amounts of oil in the haste to make use of it. This would involve ways to use secondary recovery to bring more oil to the surface economically, but more importantly not to “waste” it by leaving pockets of oil in the earth. At that tender age of 29, I inquired whether it was not more wasteful to burn the oil (as auto engine gasoline) - rather than to use it for petrochemicals. That it would be less wasteful to leave the energy and chemicals in the earth, than to burn them- where they are gone forever, leaving ash and waste products instead. In those days, Saudi Arabia was flaring off all of the gas produced with the oil, since it was too much trouble to fiddle with the less profitable gas cap. And there was actually too much production of oil possible- so that the Railroad Commission of Texas restricted production to 10 days or so monthly. Of course, the world population has doubled since the 50’s, and everyone is entitled to his own auto- if he can muster the wealth to invest in and maintain it.
Although there has been a sea change in the attitudes towards our interaction with the Earth and its Resources- what with the population becoming excessive- nevertheless, all still want their personal autos and the garaging and land space to accommodate all of this. People in the cities are arrayed against those in open spaces of the world, in idealizing a view of the earth (its cosmetic and natural appearance) rather than the economical use of it.
How then can people working in the various Earth Sciences accommodate their source of income via employers (which is to exploit the Earth and its resources), with the desire of the thinkers to allow the Earth to proceed on its natural course- where most processes occur with gradual and small changes, instead of at large rates as determined by the desire for immediate returns on investment? Haven’t there always been Jeremiahs who prophesy doom as the results of man’s material activities?
How about myself, who has spent most of his professional career in developing techniques which are faster, less expensive, and novel to find and develop natural resources such as fluids in the earth? Working almost alone, I found techniques which would locate subsurface water in the desert, and sense gas from chemical changes according to pressure and chemical change in cuttings measurements from wellbores. Wasn’t the end result of all this just to encourage more people to turn to the desert or to waste areas where there were not sufficient resources previously?

A Log may be made in a shallow well, from Surface Cuttings thrown out on the Ground
“Man is known by his Rubbish Pile” is one assessment fondly made by Archeologists, where middens yield knowledge of what Man did in the past. Is this to be the legacy of our generation- packrats leaving artifacts saved by virtue of coating their possessions with urine, for the delight of the archeologists? What we exhibited were analyze-able piles of trash, including that in the atmosphere and in our waters?
Evidently, Life has always adjusted its environment to accommodate its desired goals- to propagate itself and to decrease the Entropy of the Universe. The great engineer- the Beaver- has long ago upstaged Man in re-arranging his streams to make lakes which reduce erosion, save resources, and allow for his progeny and other life forms to take advantage of his activities.
Now we find hints that early Life has done the same- rearranged its environment, for the benefit of its successors. As deep as we drill, we find that there is Life, in the form of bacteria which eat on the crust. Since the Proterozoic, this has reduced the crust to that of a habitat, gradually changing the mainly basalts of the early days to that of granite (after re-melting) which is re-cycled again and again through subduction to increase in mass with time (Life takes out what it desires and leaves increasing silicates as the heavy minerals and ions are concentrated in fine sediments). It appears that the crust has become thicker with time since the 3 billion ybp eon.
Regardless of Man’s desire to increase his material possessions, there is a great need to understand the Earth - which is Man’s only domain so far. Man’s leaders can choose to accommodate both of these pursuits, by encouraging an interaction with the Earth just sufficiently to meet the material needs (minimizing his “wants”, while accentuating interest in earth processes). Evidently some primitive cultures did similarly, developing astronomy or other observations of natural events which stimulated the population to develop understanding- rather than just for the accumulation of excessive material wealth.

Christmas as a Time of Reflection

“It’s Unnatural”, the Observer stated- “this scurrying about to transfer the results of my Labor to Purchase material goods for Satisfaction of my Emotions”

All have felt it- the feeling of Charity and Communion, which is suddenly thrust upon the crowd during the end of the year season. People are racing to and fro to accumulate presents for their companions (not necessarily their “loved ones”). And it is not really an expression of trade of gifts for expectations of return. I believe that they genuinely have compassion and a desire to instill good will. The normally selfish person contributes “something for the Pot”. This charitable effort is laudable, but don’t expect it to continue post-Christmas, since selfishness and rationality will again prevail, once the period of goodwill has expired.

Capture the Time Now, while our Emotions allow
Us to embrace our better selves temporarily;
Yield to the Group, while rejecting the coop
Of our rational and advantaged side, summarily.

Question for the day- rationality to allay-
Is whether this decile is Characteristic?
Are we to believe, that there’s no reprieve
For the other nine-tenths- opportunistic?

Even the Muse’s Rhyme, for most of the Time
Cannot easily be brought to the Fore;
Hence we’re stuck with the Fact that the majority Act
Hinges on the dominant Desire at our Core.

Merchants are Adroit, and quick to Exploit
This Coming-out- of-ourselves almost annually.
So manage yourself, using some of your Stealth
For your Spirit to channel positives most Manually.

Harold L. Overton

Monday, December 10, 2007

Rock Canyon, AZ (Arizona Strip)

The Canyon Entrance is simpler at Rock Canyon- Flexure-Created Intersecting Fractures?

One Way of finding how the Hurricane fault Hf, originates is to look at canyons which cut it, so that it may be viewed in three dimensions.
We have found that the Laverkin Quarry introduces a double anomaly- there is the Hf in several splays (parallel presentations), simultaneously showing interference with Hf by grabens, slickensides, and beds dipping down in two different directions- to the west and to the north. This is an additional geological anomaly, since mostly the stratigraphy dips up to the west for local manifestations of Hf. This feature is near Pleistocene vulcanism, which might help explain the additional anomaly, but more likely both vulcanism and Hf are caused by the same phenomenon. The basalt ascends the near-vertical fractures opened by whatever pushes up the highlands to the east. It is instructive to look at canyons which represent the normal Hf- without the added complexity of the second anomaly (it is difficult to climb Hf for most of its scarp, but at Laverkin one may drive up the scarp face because of the gradually sloping multi-faulted terrain & switchbacks which allow road-building to the Colorado Plateau, CP above). We have several simple canyons cutting Hf nearby, and Rock Canyon is one just south of the AZ border. We will assume that it is more easily understood. This canyon may be approached most easily from Hurricane town, taking the airport road south, crossing the border of AZ, and proceeding south another two miles (avoiding roads to the right which connect with roads from St. George), and turning west then south again where the obvious arroyo crossing is reached. This same unmarked road eventually connects with Black Rock Canyon road- a deteriorating road towards Mount Trumbull along the Hurricane Cliffs.

Rock Canyon
(700 W from Hurricane, UT, south to AZ, just past border, four miles past the diagonal road in UT- west to connect with BLM 59), S1, 2, 11, and 12 T41N R10W, AZ:
Rock canyon
is a tributary of Fort Pierce Creek, and becomes Short Creek on the rim to the east above.
This canyon has Paleozoic Kaibab limestone, Pk, at the top and Toroweep, Pt, lower in elevation at the Hurricane cliffs. The dip of Pk is up to the west, at the present cliffs, but the red beds far to the west dip down to the west. Hike from the intersection of gravel road and arroyo, cross-country toward the canyon mouth- about one mile east.

The Kaibab and Toroweap Formations, occurring in the Grand Canyon, or upper Permian (Paleozoic) loom ahead of the canyon opening

The contact of Paleozoic vs. Mesozoic near Hf is covered with rubble over a 1/2 km zone E-W, so that the original fault plane cannot be seen. In this interval, some petrified wood can be spotted, so that one is certain that Mesozoic debris is at the ground surface, west of present cliffs.
Some small normal faults, falling down to the west, can be measured in the north wall of the canyon at the mouth in Pt or the underlying Queantoweap, Pq, with no more than 2 meters displacement.

Several small Normal Faults are easily measured at the Entrance of Rock Canyon

The fault planes are essentially vertical in all cases, parallel to N-S fracture surfaces in the creek bottom. Incidentally, N-S fractures in the creek bed cut older NW-SE oriented fractures and those at other angles, displaying horizontal displacement (shearing) of the older fractures. This demonstrates that the N-S shearing is younger, as would be expected for the N-S oriented Hurricane fault (and that some shear component is present, for the dominant normal faulting).
The conglomerates in the canyon walls appear to be young Pleistocene, Plc. The cementation is weak, and the boulders are mostly limestone. This Plc occurs in cross canyons west of the main cliffs, indicating very young N-S faults and associated washes.
Hike with Ben Everitt and Don Scholten, 12/5/07, eastward from the main gravel-Black Rock Canyon Road to the Rock Canyon Mouth:
Again, the fault trace is obscured by an outwash plain and alluvial fans, but splays on the east side of the main Hf can be measured as small displacement normal faults in the Pt or underlying Queantoweap, Pq (equivalent to Permian redbeds, or Supai).
Photo of Normal fault- buildup to Hf to the east

The North to South fractures and small faulting occur in a narrow band at the entrance to the canyon, but the main fault cannot be seen

Abrupt Terminations of westward-oriented outwash deposits may be seen in several outcrops to the north and south of the canyon, hinting that the youngest Hf is well west of the canyon mouth (but is obscured, except in one small outcrop of Pq at an abrupt outwash cutoff to the north). The 4 outwash terminations north and south of Rock Canyon do not align, and this can be expected if there is a discontinuity in the trend of Hf at the present scarp- canyon mouth. There seems to be a slight hinge across the Hf canyon, and this may have been the impetus for allowing Short Creek to exit at this weakness. An outstanding question concerning this feature is the presence of a few streams crossing Hf against the present topography (including this one- cutting through a hill), allowing creeks to exit across the Hf scarp when it dips up to the west. This present rise constitutes a barrier to stream flow, unless the water proceeded subsurface until it emerged as springs- which gradually increased in flow until a canyon was developed above them.
The hinge in the subsurface, allowing a flexure for fracture development, is rare near Ηf, and it has been investigated at the following locations: Laverkin quarry, Virgin River mouth, and Ash Creek. It is suspected that the exit of streams is dependent upon this geological anomaly- that hinges create subsurface fracture systems and this allows underground water to exit CP, when otherwise it would be blocked by a topographical barrier. With time, this subsurface flow creates channels (caves) and eventually creates canyons through the barrier. Laverkin quarry is the most prominent of these anomalies, while Rock Canyon is next- allowing the Short Creek to exit (but in a younger period of development).What needs to be confirmed is whether the NW-SE fracture systems were most necessary for this stream orientation (since the N-S fractures and their orthogonals do not show up in stream patterns (except for Rock Canyon). The Virgin River seems to follow NW-SE orientations and their orthogonals, allowing the river trace to zig-zag across the CP. Recall that I am testing the projection that the N-S fractures are younger than the NW-SE ones, and that they would have dominated drainage in the times since 2 mybp (Pleistocene).
The next projection is that these geological anomalies or weaknesses are accompanied by vulcanism- which allowed Mantle basalt to exit through the new fractures systems N-S and its orthogonal E-W weaknesses. This has happened near the Laverkin Quarry and the Ash Creek- Toquerville locations. This happens also at the Honeymoon Canyon, but it is not apparent at Rock Creek- which is a larger canyon carrying more water than Honeymoon. There is a vent SW 4 miles distant from the Rock Canyon mouth, but this seems too far for the magma to have been influenced by the suspected hinge. That Rock Canyon was created by a hinge is reinforced by the fact that Short Creek runs E-W, which would be on an orthogonal (perpendicular) to Hf fracturing.
We will proceed in this investigation, trying to determine whether:
1. Hf is initiated by a new stress system, which orients N-S, superseding the older NW-SE fracture system noticed over western outcrops from the CP into the B&R;
2. The new N-S system would be a normal faulting- dominated one, as contrasted with the older NW-SE shear stresses (from Pre-Pleistocene times);
3. Accompanying this new extensional system of normal faults would be vulcanism coming all the way from the Mantle. This would happen if the system is being initiated by equatorial bulge shrinkage, as the Earth slows (reducing the centrifugal force creating the initial bulge); and
4. A complication to all this conjecture about global shrinking is that of the type of stresses created by the reduction of centrifugal force as the Earth slows. The first result should be that of compression vertically, as the Crust shrinks vertically. Blocks of crust should move downward, as centrifugal force is replaced by gravitational attraction, and the relative movement would be determined by isostatic adjustment. Should blocks of crust be out of equilibrium with regional stresses (due to heating, subduction, erosion-rebound, or other slow stress-changing processes) this instability could be corrected simultaneously with the crustal shrinking. This would be similar to slinging a vial of mercury side-by-side with one of lower weight plastic hot rock altogether in a circular movement at the end of a string. As the circular swinging motion is reduced, the mercury would tend to drop back toward the center of swinging more than the lesser density rock. This would result in vertical shear between the two different materials, showing up as a normal fault. In a pure sense, there should be no lateral shear, but local density changes due to variations of stratigraphy could create shear. These effects should be minor and local- not regional.
This hike illustrates Hf for its simpler presentation, and no conclusions will be reached as to its incipience. Flexure of the crust, vulcanism correlation, updip-to-west stratigraphy, and broaching of Hf scarp by streams will be further cataloged.