3.1.2. Program Design and Overview of Major Projects
Early EGSP efforts were directed at determining the geologic character and magnitude of
the Devonian shale gas resource and toward increasing production of natural gas from the
resource base. Formation characterization required to update the resource knowledge
base and geological evaluations to ascertain basin limits and stratigraphic targets as
potential gas sources were the first tasks to be completed. With this understanding,
researchers identified large areas of the Devonian shale that exhibited certain
characteristics that required particular technological developments for extraction.
Figure 3.1.1: Extent of Eastern Gas Shales Distribution. (Click to enlarge)
Accordingly, EGSP activities were planned for each of a number of gas shale provinces
(Figure 3.1.1), namely:
1. Then-productive areas of Kentucky and West Virginia.
2. Ohio and related areas in New York, Western Pennsylvania, and Northern West
3. Appalachian Front in Pennsylvania, Maryland, West Virginia, and Virginia.
4. Deep Appalachian Basin in Pennsylvania and West Virginia.
5. Illinois and Michigan Basins.
6. Speculative areas in all Eastern states.
EGSP research identified the nature of producible gas containment to be the microfractures
and macro-factures of the shale formation.
Knowledge of these fractures, their
directionality, and density enabled the development and testing of effective techniques to
connect the gas-bearing natural fractures to the borehole.
Pilot tests of stimulation
techniques in light of the geologic environment in the respective gas provinces then
permitted the development of a rationale for stimulation strategy.
The EGSP was structured into the following functional categories or program activities:
- Resource and Site Characterization.
- Research, Instrumentation, and Modeling.
- Production Technology Development.
The first three activities provided for resource data acquisition and the development and
testing of techniques for locating probable areas of gas-bearing natural fracture systems
and for predicting the probable production from a particular stimulation method in a
certain geologic province.
The fourth activity was directed at the development and
testing of cost-effective methods for extracting gas from the various geologic provinces
in the shale.
Each of these program activities are briefly described below.
Evaluation -- The Evaluation activity was designed to integrate facts as they developed, to
assess recent technological developments and related industry activities, to ensure
compliance with environmental regulations and address site-specific environmental
problems, to develop a systems model for updating estimates of the potential resource,
and to develop and monitor program plans that reflected the integration of the technical,
geologic, economic, and other types of data.
Resource and Site Characterization -- This activity of the project was structured to
develop the necessary resource data base for characterizing the Devonian shale provinces
and to develop exploration rationales. Core information was used to assess the potential
of various resource areas, to guide modeling efforts, and to design stimulation tests.
Types of data collected included stratigraphic, structural, sedimentological, physical, and
chemical data for identification of gas-bearing fracture systems. Field work consisted of
coring and logging to provide data for lab work. Laboratory research included chemical,
physical, elemental, and mineralogical studies to determine the stratigraphic sources of
gas and the degree of fracturing in the reservoir. The data was developed through
contracts with universities and state geological surveys and the results were compiled and
synthesized by the USGS for the various geologic provinces. Shale characterization
studies were carried out through contracts with universities, research institutes, and
private industry to develop and improve methods of locating gas-bearing naturally
Research, Instrumentation, and Model Development -- This activity in the project was
directed at the development of new diagnostic tools, stimulation approaches, and
predictive capability to accurately forecast reservoir performance whenever extraction
methods are applied to particular geologic provinces in the Devonian shale. Meeting
these objectives required basic and applied R&D in the laboratory and the field and the
development of models. The models served to describe the current understanding of the
stimulation processes, gas flow from the reservoirs, and economic parameters related to
fracturing and production.
Production Technology Development -- This activity in the project was directed at the
development of effective stimulation methods for various geologic environments and the
testing of these designs in field applications. The designs tested were conceptual models
that evolved from sequential laboratory and simulation studies. Detailed documentation
of field tests under controlled conditions complemented with systematic well testing were
conducted through cost-sharing contracts with private industry.
Field tests (16) and
demonstration projects showed that advanced stimulation technology (foam, cryogenic,
MHF, and chemical explosive fracturing) could result in wells that produced considerably
more than those stimulated with conventional wellbore explosive fracturing, at least in
the gas province associated with historical shale production. Particular emphasis was
placed on the use of energy assisted fracturing fluid in low-pressure fractured shale
Directional deviated well technology was also investigated, as well as the
relationship of frac length and reservoir permeability to productivity. Location of regions
of increased fracture intensity was found to be required to assure the likelihood of a
commercial well, and the stress ratio concept (minimum horizontal-vertical) was
investigated as an estimator of fracture intensity.
The objectives of the EGSP that emphasized the definition and characterization of the
Eastern Gas Shales as a resource were completed as planned and provided an important
knowledge base and framework for exploration activity within three basins.
The objective of developing methods for extraction employed geologic and reservoirengineering
tests to understand/predict production performance in established areas of
potential. This was necessary to separate the effects of the stimulation method employed
from that of the reservoir itself.
While the milestones for comparing stimulation methods
in new areas of potential were completed as planned, the validation of a strategy for the
matching of a specific technology to a given geology was not. This required a shift in
project strategy from an R&D testing mode that produced gas to one that emphasized
Accordingly, a three well, highly instrumented field laboratory was
established to determine in situ gas storage, release mechanism and production rate, in
situ natural fracture system spacing and distribution, response to stimulation, and well
spacing required for development. This was successfully completed in one geologic
province having production potential.
The original EGSP plans to extrapolate this
knowledge to new areas of potential was subsequently terminated and thus it was left to
industry (motivated by tax credits) to assume this higher risk activity.
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