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Title: Innovative Methodology for Detection of Fracture-Controlled Sweet Spots in the Northern Appalachian Basin

Abstract

For two consecutive years, 2004 and 2005, the largest natural gas well (in terms of gas flow/day) drilled onshore USA targeted the Ordovician Trenton/Black River (T/BR) play in the Appalachian Basin of New York State (NYS). Yet, little data were available concerning the characteristics of the play, or how to recognize and track T/BR prospects across the region. Traditional exploration techniques for entry into a hot play were of limited use here, since existing deep well logs and public domain seismic were almost non-existent. To help mitigate this problem, this research project was conceived with two objectives: (1) to demonstrate that integrative traditional and innovative techniques could be used as a cost-effective reconnaissance exploration methodology in this, and other, areas where existing data in targeted fracture-play horizons are almost non-existent, and (2) determine critical characteristics of the T/BR fields. The research region between Seneca and Cayuga lakes (in the Finger Lakes of NYS) is on strike and east of the discovery fields, and the southern boundary of the field area is about 8 km north of more recently discovered T/BR fields. Phase I, completed in 2004, consisted of integrating detailed outcrop fracture analyses with detailed soil gas analyses, lineaments, stratigraphy,more » seismic reflection data, well log data, and aeromagnetics. In the Seneca Lake region, Landsat lineaments (EarthSat, 1997) were coincident with fracture intensification domains (FIDs) and minor faults observed in outcrop and inferred from stratigraphy. Soil gas anomalies corresponded to ENE-trending lineaments and FIDs. N- and ENE-trending lineaments were parallel to aeromagnetic anomalies, whereas E-trending lineaments crossed aeromagnetic trends. 2-D seismic reflection data confirmed that the E-trending lineaments and FIDs occur where shallow level Alleghanian salt-cored thrust-faulted anticlines occur. In contrast, the ENE-trending FIDs and lineaments occur where Iapetan rift faults have been episodically reactivated, and a few of these faults extend through the entire stratigraphic section. The ENE-trending faults and N-striking transfer zones controlled the development of the T/BR grabens. In both the Seneca Lake and Cayuga Lake regions, we found more FIDs than Landsat lineaments, both in terms of individual FIDs and trends of FIDs. Our fused Landsat/ASTER image provided more lineaments, but the structural framework inferred from these lineaments is incomplete even for the fused image. Individual lineaments may not predict surface FIDs (within 500m). However, an individual lineament that has been groundtruthed by outcrop FIDs can be used as a proxy for the trend of intense fracturing. Aeromagnetics and seismic reflection data across the discovery fields west of Keuka Lake demonstrate that the fields terminate on the east against northerly-striking faults that extend from Precambrian basement to, in some cases, the surface; the fields terminate in the west at N- and NW-striking faults. Seismic and well log data show that the fields must be compartmentalized, since different parts of the same field show different histories of development. T/BR fields south of the research area also terminate (on the east) against northerly-trending lineaments which we suggest mark faults. Phase II, completed in 2006, consisted of collection and analysis of an oriented, horizontal core retrieved from one of the T/BR fields in a graben south of the field area. The field is located along ENE-trending EarthSat (1997) lineaments, similar to that hypothesized for the study area. The horizontal core shows much evidence for reactivation along the ENE-trending faults, with multiple events of vein development and both horizontal and vertical stylolite growth. Horizontal veins that post- and pre-date other vein sets indicate that at least two orogenic phases (separated by unloading) affected vein development. Many of the veins and releasing bend features (rhombochasms) are consistent with strike-slip motion (oblique) along ENE-striking faults as a result of Taconic peripheral bulge and later collisional stresses. Later orogenic effects from possibly the Acadian, and certainly the Alleghanian, are also present. Although the core does not exhibit significant zones of high porosity, rubble zones and fault zones observed on an accompanying FMI log were apparently the sources of gas production that resulted in this well being a good producer in spite of the low matrix porosity.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
University Of New York
Sponsoring Org.:
USDOE
OSTI Identifier:
928208
DOE Contract Number:
AC26-00NT40698
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
03 NATURAL GAS; ANTICLINES; APPALACHIAN BASIN; BASEMENTS; DETECTION; EXPLORATION; FINGERS; FRACTURES; FRACTURING; GEOLOGIC STRUCTURES; NATURAL GAS WELLS; POROSITY; REFLECTION; RIVERS; SOILS; STRATIGRAPHY; STRESSES; UNLOADING

Citation Formats

Robert Jacobi, John Fountain, Stuart Loewenstein, Edward DeRidder, and Bruce Hart. Innovative Methodology for Detection of Fracture-Controlled Sweet Spots in the Northern Appalachian Basin. United States: N. p., 2007. Web. doi:10.2172/928208.
Robert Jacobi, John Fountain, Stuart Loewenstein, Edward DeRidder, & Bruce Hart. Innovative Methodology for Detection of Fracture-Controlled Sweet Spots in the Northern Appalachian Basin. United States. doi:10.2172/928208.
Robert Jacobi, John Fountain, Stuart Loewenstein, Edward DeRidder, and Bruce Hart. Sat . "Innovative Methodology for Detection of Fracture-Controlled Sweet Spots in the Northern Appalachian Basin". United States. doi:10.2172/928208. https://www.osti.gov/servlets/purl/928208.
@article{osti_928208,
title = {Innovative Methodology for Detection of Fracture-Controlled Sweet Spots in the Northern Appalachian Basin},
author = {Robert Jacobi and John Fountain and Stuart Loewenstein and Edward DeRidder and Bruce Hart},
abstractNote = {For two consecutive years, 2004 and 2005, the largest natural gas well (in terms of gas flow/day) drilled onshore USA targeted the Ordovician Trenton/Black River (T/BR) play in the Appalachian Basin of New York State (NYS). Yet, little data were available concerning the characteristics of the play, or how to recognize and track T/BR prospects across the region. Traditional exploration techniques for entry into a hot play were of limited use here, since existing deep well logs and public domain seismic were almost non-existent. To help mitigate this problem, this research project was conceived with two objectives: (1) to demonstrate that integrative traditional and innovative techniques could be used as a cost-effective reconnaissance exploration methodology in this, and other, areas where existing data in targeted fracture-play horizons are almost non-existent, and (2) determine critical characteristics of the T/BR fields. The research region between Seneca and Cayuga lakes (in the Finger Lakes of NYS) is on strike and east of the discovery fields, and the southern boundary of the field area is about 8 km north of more recently discovered T/BR fields. Phase I, completed in 2004, consisted of integrating detailed outcrop fracture analyses with detailed soil gas analyses, lineaments, stratigraphy, seismic reflection data, well log data, and aeromagnetics. In the Seneca Lake region, Landsat lineaments (EarthSat, 1997) were coincident with fracture intensification domains (FIDs) and minor faults observed in outcrop and inferred from stratigraphy. Soil gas anomalies corresponded to ENE-trending lineaments and FIDs. N- and ENE-trending lineaments were parallel to aeromagnetic anomalies, whereas E-trending lineaments crossed aeromagnetic trends. 2-D seismic reflection data confirmed that the E-trending lineaments and FIDs occur where shallow level Alleghanian salt-cored thrust-faulted anticlines occur. In contrast, the ENE-trending FIDs and lineaments occur where Iapetan rift faults have been episodically reactivated, and a few of these faults extend through the entire stratigraphic section. The ENE-trending faults and N-striking transfer zones controlled the development of the T/BR grabens. In both the Seneca Lake and Cayuga Lake regions, we found more FIDs than Landsat lineaments, both in terms of individual FIDs and trends of FIDs. Our fused Landsat/ASTER image provided more lineaments, but the structural framework inferred from these lineaments is incomplete even for the fused image. Individual lineaments may not predict surface FIDs (within 500m). However, an individual lineament that has been groundtruthed by outcrop FIDs can be used as a proxy for the trend of intense fracturing. Aeromagnetics and seismic reflection data across the discovery fields west of Keuka Lake demonstrate that the fields terminate on the east against northerly-striking faults that extend from Precambrian basement to, in some cases, the surface; the fields terminate in the west at N- and NW-striking faults. Seismic and well log data show that the fields must be compartmentalized, since different parts of the same field show different histories of development. T/BR fields south of the research area also terminate (on the east) against northerly-trending lineaments which we suggest mark faults. Phase II, completed in 2006, consisted of collection and analysis of an oriented, horizontal core retrieved from one of the T/BR fields in a graben south of the field area. The field is located along ENE-trending EarthSat (1997) lineaments, similar to that hypothesized for the study area. The horizontal core shows much evidence for reactivation along the ENE-trending faults, with multiple events of vein development and both horizontal and vertical stylolite growth. Horizontal veins that post- and pre-date other vein sets indicate that at least two orogenic phases (separated by unloading) affected vein development. Many of the veins and releasing bend features (rhombochasms) are consistent with strike-slip motion (oblique) along ENE-striking faults as a result of Taconic peripheral bulge and later collisional stresses. Later orogenic effects from possibly the Acadian, and certainly the Alleghanian, are also present. Although the core does not exhibit significant zones of high porosity, rubble zones and fault zones observed on an accompanying FMI log were apparently the sources of gas production that resulted in this well being a good producer in spite of the low matrix porosity.},
doi = {10.2172/928208},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Mar 31 00:00:00 EDT 2007},
month = {Sat Mar 31 00:00:00 EDT 2007}
}

Technical Report:

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  • In the structure task, we completed a N-S transect east of Seneca Lake that indicated a N-striking fault near the southeastern shore of Seneca Lake, and also indicated NE and ENE-trending FIDs and faults north of Valois. The orientation and existence of the NE-striking FIDs and faults are thought to be controlled by basement faults, rather than thrust ramps above the Salina salt controlled only by a far-field Alleghanian stress field. Structure contour maps based on well log analyses have been constructed but not interpreted. Soil gas data displayed a number of ethane-charged soil gas ''spikes'' on a N-S transectmore » from Ovid south to near Valois. The soil gas team found a larger number of spikes in the northern half of the survey, suggesting more open fractures (and faults) in the northern half of the survey. Seismic data has been purchased and reprocessed. Several grabens observed in the Trenton reflector are consistent with surface structure, soil gas, and aeromagnetic anomalies. The aeromagnetic survey is completed and the data is processed. Prominent magnetic anomalies suggest that faults in the Precambrian basement are located beneath regions where grabens in the Trenton are located.« less
  • In the structure task, we completed reducing the data we had collected from a N-S transect on the east of Seneca Lake. We have calculated the fracture frequency for all the fracture sets at each site, and constructed modified rose diagrams that summarize the fracture attributes at each site. These data indicate a N-striking fault near the southeastern shore of Seneca Lake, and also indicate NE and ENE-trending FIDs and faults north of Valois. The orientation and existence of the ENE-striking FIDs and faults are thought to be guided by faults in the Precambrian basement; these basement faults apparently weremore » sufficiently reactivated to cause faulting in the Paleozoic section. Other faults are thrust ramps above the Silurian salt section that were controlled by a far-field Alleghanian stress field. Structure contour maps and isopach maps have been revised based on additional well log analyses. Except for the Glodes Corners Field, the well spacing generally is insufficient to definitively identify faults. However, relatively sharp elevational changes east of Keuka Lake support the contention that faults occur along the east side of Keuka Lake. Outcrop stratigraphy along the east side of Seneca Lake indicates that faults and gentle folds can be inferred from the some exposures along Seneca Lake, but the lensing nature of the individual sandstones can preclude long-distance definitive correlations and structure identification. Soil gas data collected during the 2000 field season was reduced and displayed in the previous semiannual report. The seismic data that Quest licensed has been reprocessed. Several grabens observed in the Trenton reflector are consistent with surface structure, soil gas, and aeromagnetic anomalies. In this report we display an interpreted seismic line that crosses the Glodes Corners and Muck Farm fields. The final report from the subcontractor concerning the completed aeromagnetic survey is included. Prominent magnetic anomalies suggest that faults in the Precambrian basement are located beneath regions where grabens in the Trenton are located. The trend and location of these faults based on aeromagnetics agrees with the location based on FIDs. These data indicate that integration of aeromagnetic and topographic lineaments, surface structure, soil gas with seismic and well logs allows us to extrapolate Trenton-Black River trends away from confirmatory seismic lines.« less
  • In the structure task, the goals for this reporting period were to: (1) complete field work on the NNW-SSE transect along the west side of Cayuga Lake; (2) collect data at additional field sites in order to (a) trace structural trends between the two N-S transects and (b) fill in data gaps on the NS transect along the eastern shore of Seneca Lake; (3) enter the data gathered from the summer field work; (4) enter data from the previous field season that still had to be analyzed after a personnel change. We have completed data reduction for all the goalsmore » listed above, including the NNW-SSE transect on the west side of Cayuga Lake. In the soil gas task, the goals for this reporting period were to: (1) trace Trenton/Black River fault trends between the two N-S transects; and (2) enter the data gathered from the summer field work. We have completed data reduction for all the goals listed above, and have begun constructing maps that portray the data. These data continue to demonstrate that integration of aeromagnetic and Landsat lineaments, surface structure, soil gas and seismic allows us to extrapolate Trenton-Black River trends away from confirmatory seismic lines.« less
  • In the structure task, the goals for this reporting period were to: (1) complete analyses of field work on the NNW-SSE transect along the west side of Cayuga Lake. We have completed data input and analyses for this goal, and discuss the results. The additional data from the 2002 field season (and additional revised data from the previous season) demonstrate that zones of closely-spaced E-striking fractures bear a close spatial correlation with the E-striking Firtree Anticline. East-striking EarthSat (1997) Landsat lineaments also occur in the same general region as the Firtree Anticline. However, one E-striking lineament occurs where we havemore » no sites with a high E-striking fracture frequency. ENE-striking closely-spaced fractures occur where ENE-striking lineaments occur. From the Seneca lake transect, these fractures intensification domains and lineaments are thought to mark zones of reactivated Trenton/Black River faults. In the advanced seismic analyses task, the goals for this reporting period were to complete analyses of the seismic data. We have completed data the data analyses and find that high porosity zones can be recognized along some of the Trenton/Black River fault zones. These data continue to demonstrate that integration of aeromagnetic and Landsat lineaments, surface structure, soil gas and seismic allows us to extrapolate Trenton-Black River trends away from confirmatory seismic lines.« less
  • The primary goal was to enter Phase 2 by analyzing geophysical logs and sidewall cores from a verification well drilled into the Trenton/Black River section along lineaments. However, the well has not yet been drilled; Phase 2 has therefore not been accomplished. Secondary goals, not dependent upon well drilling, were completed. In the structure task, the objectives for this reporting period were to: (1) add additional sites along the west side of Cayuga Lake where we had critical gaps in our data set, and (2) complete analyses of structure data along the west side of Cayuga Lake. We have completedmore » data input and analyses for this goal, and discuss the results. The additional data from the 2003 field season (and additional revised data from the previous season) demonstrate that zones of closely-spaced NNW- and N-striking fractures (FIDs) occur west of Cayuga Lake. EarthSat (1997) did not recognize NNW- or N-striking Landsat lineaments in this area. Packets of E-and ENE-striking EarthSat (1997) lineaments coincide with FIDs observed in outcrop, but the bedrock FIDs are significantly more numerous than the lineaments. West of Cayuga Lake, NE-striking EarthSat (1997) were not confirmed by FIDs. It appears that Landsat lineaments (EarthSat, 1997) indicate parts of the structural fabric, but the ground-truthing reveals added significant complexity. The E-striking lineaments and FIDs are related to Alleghanian folds and faults (e.g., Firtree Anticline), and the ENE-striking lineaments and FIDs are probably related to reactivated Trenton/Black River faults. ASTER images, with an order of magnitude higher resolution than Landsat, are presently being analyzed for lineaments. The lineament patterns are more complex than the Landsat lineaments, and include a number of trends not observed in the Landsat data (EarthSat, 1997). These trends include NS, NNW and NNE. These data continue to demonstrate that integration of aeromagnetic and remote sensing lineaments, surface structure, soil gas and seismic allows us to extrapolate Trenton-Black River trends away from confirmatory seismic lines.« less