Big Picture Geoscience

Kingfisher Oklahoma Geysers

2005-12-13T01:03:00.000-08:00

A geological mystery in Kingfisher Oklahoma. Geyers are appearing!

Leaky Wells Aren't Cheap to Fix

2005-12-08T21:51:00.000-08:00

Leaking gas wells in Colorado are causing headaches for the COGCC. Leaking wells are notoriously difficult to fix.

California Oil and Gas Seeps

2005-11-11T09:56:00.000-08:00

Here are two entertaining websites that feature California oil and gas seeps. Anytime you delve into natural oil and gas seepages you also learn about the history of oil and gas drilling in a region.

California Department of Conservation
USGS

Climate Confusion

2005-11-02T08:19:00.000-08:00

Climate change studies are a dime a dozen. Most of them involve computer models which makes it difficult to independently verify the output. A tweak of either the model's assumptions or an input parameter can drastically alter the results. Dramatic conclusions will tend to attract more attention and funding. Even the Drudge Report is paying attention to these studies. Today's New York Times article, New Study Warns of Total Loss of Arctic Tundra, is a good example of the kind of attention grabbing headline that climate scientists seem to love.

If you are truly interested in climate change, read through some of Michael Crichton's lectures.

Gory details are available from the Canadian Society of Petroleum Geologists

Texas Tea Time

2005-10-31T11:42:00.000-08:00

Although most of the time we need to look for oil, sometimes oil finds us!

Ig Nobel Prizes

2005-10-19T23:15:00.000-07:00

Science can be entertaining...

This lecture about the Ig Nobel prizes is fun. It includes a nice section on the origin of Murphy's Law.

Seeps Never Sleep

2005-10-19T22:34:00.000-07:00

Here's an interesting oil seep story...

Work continues on mitigating oil-seep problem
Town looking at interim measure, funding

Unconventional Gas

2005-09-30T10:38:00.000-07:00

Big Picture Geoscience is a Partner in the Unconventional Gas Technology Roadmap.

The PTAC Unconventional Gas Technology Roadmap (TRM) is being developed to outline the business and societal challenges to development, the state of current recovery technology and the best avenues for improved or new technology for coalbed methane, tight gas, shale gas and gas hydrates.

If you are interested in unconventional gas you can sign up HERE for one of the sessions.

Sandstone Hosted Uranium Deposits

2005-09-14T21:14:00.000-07:00

I don't know much about sandstone-hosted uranium deposits but Doug Underhill certainly does. It was my great fortune to be able to interact with him for a long day of learning and discussion.

I have never had my name on a press release before (at least one that I didn't write). I've highlighted my favorite part...

We are extremely pleased to collaborate with these highly qualified experts

Coalbed Methane Explained

2005-08-20T03:29:00.000-07:00

Coalbed Methane (or CBM) is becoming a significant exploration play in Western Canada. The B.C. Ministry of Energy and Mines has published a webpage devoted to CBM.

Gas Hydrates

2005-08-15T22:47:00.000-07:00

Kirk Osadetz of the Geological Survey of Canada has a webpage explaining the significance of natural gas hydrates:

Gas hydrates - Fuel of the future?

Coalbed methane and shale gas are currently the most active unconventional gas plays but there will be a time when gas hydrates are exploited on a commercial basis.

Shallow Gas in Calgary

2005-08-03T22:22:00.000-07:00

Alberta is blessed with a significant natural gas endowment. On occasion it shows up in undesireable locations. Natural gas (methane) was discovered by CP Rail this week in a Calgary residential area.

CP Rail has one of the best gas discovery records in Western Canada. They've been finding gas since 1883!!

Publications/Conference Presentations

2005-06-22T14:16:00.000-07:00

This is a list of papers and conference presentations that I have done to date. Most of these papers are connected to abnormally pressured resource plays.

Underpressuring Mechanism for Gas-Saturated Sands – Letourneau, AAPG Hedberg Research Conference “Understanding, Exploring and Developing Tight Gas Sands”, April 24-28, 2005, Vail, Colorado.

Carbon Isotope Geochemistry as an Exploration Tool: Examples from Central Alberta – Letourneau and Muehlenbachs, CSPG Hydrogeology Division Noon Talk, April 21, 2005.

Regional Underpressure and Gas-saturation in the Upper Cretaceous and Tertiary of Central Alberta - Letourneau, CSPG Technical Luncheon, March 24, 2005.

Identifying and Interpreting Basin-Centered Gas Accumulations in Western Canada - Letourneau, 2004 CSPG Convention May 31-June 4, 2004.

Regional Underpressure and Gas-saturation in the Upper Cretaceous and Tertiary of Central Alberta - Letourneau, CSPG Hydrogeology Division Noon Talk, May 11, 2004.

Unconventional Gas Systems in Western Canada, expert witness testimony for National Energy Board hearing, Calgary, Alberta, September 9, 2003.

Geochemical and Hydrogeological Correlation of Active Gas Macro-seeps in Alberta - Letourneau, Rostron and Muehlenbachs, AAPG Hedberg Research Conference “Near-Surface Hydrocarbon Migration: Mechanisms and Seepage Rates”, April 7-10, 2002, Vancouver, British Columbia.

Stable Isotope Geochemistry of Some Natural Gas Seeps in Alberta - Letourneau, Miller, Muehlenbachs, Rostron, CSPG Hydrogeology Division Noon Talk, October 18, 2000.

Widespread Gas-saturation and Underpressures in the Jean Marie Formation, northeastern British Columbia, Canada – Letourneau and Rostron, AAPG Hedberg Research Conference “Natural Gas Formation and Occurrence”, June 6-10, 2000, Durango, Colorado.

Applied Hydrogeology in Exploration – Letourneau, Rostron, Dahlberg, and Reid, conference conveners: AAPG Hedberg Research Conference “Applied Hydrogeology in Exploration”, July 27-30, 1997, Banff, Alberta.

The Willesden Green Second White Specks Pools, an Evaluation of Fluid Compartments and Seals - Letourneau and Jones, 1996 CSPG Convention, Calgary, Alberta.

The Effect of Multiple Fluid Phases on Hydrogeological Interpretations - Lies, Letourneau and Magee, CSPG Hydrogeology Division Noon Talk, 1996.

Numerical Modeling of the Hydrodynamically Trapped Milk River Gas Field, Western Canada - Lies and Letourneau, Journal of Canadian Petroleum Technology, 1995.

Petroleum Hydrogeology of Saskatchewan – Letourneau, 1995 CSPG Convention, Calgary, Alberta.

Petroleum Hydrogeology of the Jean Marie Member, Northeastern British Columbia – Letourneau, 1991 CSPG Convention, Calgary, Alberta.

Utilization of Computerized Pressure Data - Letourneau and Misner, 1990 Ontario Petroleum Institute Conference, London, Ontario.

Turner Valley Update

2005-06-17T00:36:00.000-07:00

It looks like the Government of Alberta is forking over some big bucks to help keep the Turner Valley gas plant from contaminating the Sheep River.

Retaining wall to be built around Turner Valley gas plant

Although the main concern appears to be contaminated soil washing into the Sheep River, it is likely that groundwater in the vicinity is contaminated as well. Every time it rains on the gas plant site, water will move down through the soil and pick up contaminants before migrating into shallow aquifers which discharge into the Sheep River.

A retaining wall may look nice but contaminated groundwater could move underneath a retaining wall the way Hogan's Heroes tunnelled under the perimeter of Stalag 13.

Sunny Saudi Aramco

2005-06-15T15:49:00.000-07:00

A Calgary radio station was advertising about interviews for Saudi Aramco. The allure of a big paycheck and international experience can be tempting. Obviously one question a prospective employee might ask is "what about security?". I am sure they have rehearsed this part of their sales pitch numerous times. For those who might be skeptical, here's some background...

Saudis search for clues after militant attack
22 people killed in Khobar; Britain warns more strikes likely

Saudi oil workers bemoan inadequate security

Saudi Petroleum Security: Challenges & Responses

As it currently stands it is probably easier for a terrorist to attack Saudi Aramco's human assets than it is to attack a refinery or tank farm.

River Deep Mountain High - Turner Valley Troubles

2005-06-10T21:46:00.000-07:00

If it rains for a solid week in semi-arid Southern Alberta eventually something will give. Rivers have flooded the last few days reminding everyone of the power of Mother Nature. Flood plains are great places to live, close to water, good soil, flat land. Unfortunately they are prone to flooding.

Alberta's booming oil industry got its start in Turner Valley. The Dingman #1 well was drilled beside a natural gas seep. Legend has it that the well's promoter cooked a frying pan of eggs to help raise drilling money. That seep is still active today.

Turner Valley Gas Seep

Gas Sample Collection

It was only logical that the gas plant be built beside the discovery well, the nice flat patch of ground on the inside bend of the Sheep River is now the Turner Valley Gas Plant Provincial and National Historic Site. The oil industry doesn't build gas plants in flood plains any more for all kinds of great environmental reasons. There have been efforts to remediate the contamination from the gas plant. Unfortunately, recent flooding has wrought havoc with remediation efforts and contaminated soil from the gas plant is now underneath the Sheep River.

The CBC reports that The Town of Turner Valley is concerned that not enough has been done to remediate the contaminated soil on the gas plant site:

Contaminated soil in Sheep River: town

If you look at the Jennifer Lee photo associated with the article, you will see an orange spot, slightly left of center. Natural gas leaks out of the riverbank and the area has been fenced off. A flare ignites the leaking gas to prevent any dangerous buildups from occurring.

Natural Gas Flare

It is interesting that this early geological cross-section between the Dingman #1 discovery well and the Dingman #2 well (shown below) doesn't show any evidence of gas seepage beside the #2 well. The area where the gas is flared is just a few meters down the river bank from the Dingman #2 well. This gas is likely migrating through a crack in the casing of the old well. Remediation of old leaky wells can be extremely difficult and expensive so the well's previous owners were probably happy to hand off the liability to the Government of Alberta.

Cross-section showing Dingman #1 and #2 Wells

One of the problems in remediating leaky gas wells is the fact that the gas might be not be coming from the original producing zone. There were numerous gas shows during the drilling of the Dingman #1 and #2 wells and any one of them could be leaking to surface. Dr. Muehlenbachs at the University of Alberta was instrumental in developing a method to fingerprint natural gases from different depths using carbon isotopes.

I collected gas samples from 4 locations (2 at surface and 2 from producing wells) and included the data in a paper called Stable isotope geochemistry of some natural gas macroseeps in Alberta. The best evidence for gas leakage from the Dingman #2 well comes from the old cross-section. It is highly unlikely that a gas seep the size of the one currently being flared would have been missed (for starters its a bit stinky due to the hydrogen sulphide content). My conclusions were as follows:

These 4 samples are all similar in isotopic composition and the natural gas plot (Chung et al., 1988) of the Turner Valley gases (Figure 1) indicate that they have a source with an isotopic composition of ~-23 ‰. The d¹³C C₁ values for the surface seep samples are both depleted in ¹³C relative to the production samples. Isotopically light methane from shallow Cretaceous gas accumulations may be making a small contribution to the surface seeps at Turner Valley.

A great website about Turner Valley's oil and gas history is Hell's Half Acre

Ghost of a Chance

2005-06-08T21:20:00.000-07:00

Has anyone heard of a Geological Ghostwriter? I could use one to wrap up some unpublished thesis research (just kidding).

I was at the dentist's office yesterday and couldn't put down the Canadian Business article about ghostwriting. While this form of ghostwriting is a time honored and noble profession I found out about the dark side...

MEDICAL GHOSTWRITING
Ghostwriting has reportedly become widespread in various areas of medicine, including cardiology and psychiatry, where pharmaceutical drugs play a significant role in treatment. Overworked doctors have become willing to serve as "authors" for papers written for them by ghostwriters paid by drug companies.

OUTSOURCED ENGINEERING
An overseas engineer – not licensed by APEGGA – does the work. An APEGGA member reviews and stamps it. Then the project goes ahead on Alberta soil. Are there problems in this increasingly popular system of completing engineering tasks? Are the reviews complete and thorough? Is the public adequately protected?

In the first situation, doctors find a way to increase their revenue. In the second, engineers scour the globe to find a way to lower their revenue.

Underpressure and Gas-saturation in the Upper Cretaceous and Tertiary of Central Alberta

2005-06-08T13:12:00.000-07:00

This talk was the result of some consulting work that I did for Rick Kunimoto (then at Stellarton Energy, which was bought by Tom Brown which in turn was bought by Encana) and my UofA research on gas seeps. This work predicted the "dry" nature of the Horseshoe Canyon coals.

Underpressuring in the Cretaceous of Western Canada is predominantly due to Darcy flow of natural gas to outcrop (it leaks to atmosphere). Decreasing pressures allow natural gas to desorb from coals and shales which helps to maintain gas saturations (see conclustion iv from Carsten Büker's modelling work).

The Upper Cretaceous and Tertiary sandstones of Central Alberta (Paskapoo, Scollard, Edmonton, Horseshoe Canyon and Bearpaw) form a major shallow, low-pressure gas resource. Potential sources of this gas are from associated coal seams and bacterial activity at the water/gas contact. These zones were initially bypassed due to formation damage and low gas prices.

A hydrostatic water gradient is up to 350% overbalanced in some of these formations. A detailed examination of over 800 pressure tests confirmed that the Scollard member and Edmonton Group are pervasively gas-saturated. Formation pressures decrease with proximity to formation outcrop along the Red Deer River. Conventional hydraulic head calculations using these data result in an east-west hydraulic gradient.

The extreme underpressures in these zones have been attributed to pore volume expansion associated with erosional unloading. This paper proposes an alternate hypothesis. Gas pressure gradients show a predominantly west to east gradient. The lowest measured formation pressures (<200 kPa) were usually found within 20 km of the formation outcrop. It appears that the bulk of the gas is migrating up dip in response to the regional gas pressure gradient. Post-Tertiary methane desorption has decreased coal gas content.

Lateral migration of gas towards outcrop along the Red Deer River Valley is proposed as a mechanism to create underpressures in the Upper Cretaceous and Tertiary sandstones in Central Alberta.

Petroleum Hydrogeology of the Jean Marie Member, northeastern British Columbia

2005-06-06T23:27:00.000-07:00

My first experience with a Basin Center Gas System came relatively early in my geological career. I was working at the Canadian Institute of Formation Evaluation (CIFE) and it was the first project I had to manage myself. I was completely bewildered as to how the observed conditions could be created. This is the abstract from a CSPG "Opportunities for the Nineties" Convention talk I gave in 1991.

The Jean Marie Member of the Redknife Formation in northeast British Columbia (NTS 94-I and 94-P) is a unique, gas-bearing silty limestone. A detailed evaluation of fluids and pressures from over 200 wells illustrates the presence of anomalously low fluid potentials. Pressure/depth ratios range from 8.0-4.4 kPa/m. A comparison with water gradients from adjacent aquifers illustrates that pressures are 30-3000 kPa below regional pore pressures and 2000 to 7000 kPa below normal pore pressures. Formation damage is common on drill-stem tests because of the large pressure differentials between formation pressure and hydrostatic drilling fluid pressure.

Very few wells have produced water during testing or production. Examination of chemical analyses of "water" samples indicates that most of the samples were of mud filtrate. It is gas, not water that forms the continuous reservoir phase of the Jean Marie Member.

Recent pressure tests are commonly several hundred kPa below regional pressure trends. These tests are from pools where there is gas production. The removal of gas can cause a lowering of formation pressures several kilometers from the producing well.

Numerous hypotheses exist to explain the subnormal fluid pressures. All require the existence of "seals" or low permeability strata. Regional trends in the Jean Marie Member are interpreted in terms of these hypotheses. The regional investigation of fluids and pressures has identified considerable potential for additional gas discoveries.

Today I'm convinced that gas migrates to outcrop in underpressured Basin Centered Gas Accumulations.

Early production by Czar Resources (Herb Vischer) and Polaris Petroleums (John Maher)helped pave the way for Encana's decision to exploit this play on a major scale.