Advanced Analysis of Magnetic Resonance Finds Laminated ...
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CHALLENGE Discriminate intervals with the best produc- tion potential in what appears to be uniform matrix on standard log suites. SOLUTION Run the newly developed 50-burst mag- netic resonance acquisition application in combination with the Three-Detector Lithology Density (TLD) tool to discern both extremely low-porosity and medium- porosity laminations though statistical analysis. RESULTS Used the improved ability to locate oil- bearing laminated intervals to optimize placement of four additional laterals. Conventionally undifferentiated shales Standard log suites, which were developed for conventional reservoirs, characterize the Eagle Ford shale play as a uniform matrix. Analysis of logs with this conventional resolution cannot easily find where the best potential for oil production may occur. Fifty-burst magnetic resonance application and high-resolution density Magnetic resonance logging has long been applied to discern moveable from nonmoveable fluids regardless of the matrix, which is of great utility in clay-bearing formations. The new 50-burst application improves the statistics for the smallest pores by enabling the collection of more data by an advanced prepolarizing magnetic resonance tool. The result is a 6-in or greater resolution of the clay-bound micropore region of the rock. The TLD tool uses three detectors to obtain a high-resolution 8-in density output. The TLD detector with 2-in resolution is normally applied to correct for minor wellbore changes resulting from the hole condition and mudcake. In the Eagle Ford the matrix is primarily carbonate and the well- bores are typically smooth. This logging environment allows use of the 2-in detector as a stand- alone porosity device to improve the visibility and reliability of the TLD curves. Visible laminated pay The Eagle Ford is highly laminated with thin laminations. Run with a conventional logging suite, the 8-in-resolution density cannot differentiate laminations with substantial porosity. However, logging analysis combining the 50-burst magnetic resonance application and high-resolution TLD readily identifies laminated pay by differentiating very small pores, micropores, and poten- tially oil-bearing matrix. Standard-resolution analysis presents only an average of the matrix, which cannot discriminate laminations. CASE STUDY Wireline Advanced Analysis of Magnetic Resonance Finds Laminated Pay, Eagle Ford Shale Matrix nonuniformity detailed by combining 50-burst magnetic resonance application and high-resolution density logging
Transcript of Advanced Analysis of Magnetic Resonance Finds Laminated ...
CHALLENGEDiscriminate intervals with the best produc-tion potential in what appears to be uniform matrix on standard log suites.
SOLUTIONRun the newly developed 50-burst mag-netic resonance acquisition application in combination with the Three-Detector Lithology Density (TLD) tool to discern both extremely low-porosity and medium-porosity laminations though statistical analysis.
RESULTSUsed the improved ability to locate oil-bearing laminated intervals to optimize placement of four additional laterals.
Conventionally undifferentiated shales Standard log suites, which were developed for conventional reservoirs, characterize the Eagle Ford shale play as a uniform matrix. Analysis of logs with this conventional resolution cannot easily find where the best potential for oil production may occur.
Fifty-burst magnetic resonance application and high-resolution density Magnetic resonance logging has long been applied to discern moveable from nonmoveable fluids regardless of the matrix, which is of great utility in clay-bearing formations. The new 50-burst application improves the statistics for the smallest pores by enabling the collection of more data by an advanced prepolarizing magnetic resonance tool. The result is a 6-in or greater resolution of the clay-bound micropore region of the rock.
The TLD tool uses three detectors to obtain a high-resolution 8-in density output. The TLD detector with 2-in resolution is normally applied to correct for minor wellbore changes resulting from the hole condition and mudcake. In the Eagle Ford the matrix is primarily carbonate and the well-bores are typically smooth. This logging environment allows use of the 2-in detector as a stand-alone porosity device to improve the visibility and reliability of the TLD curves.
Visible laminated payThe Eagle Ford is highly laminated with thin laminations. Run with a conventional logging suite, the 8-in-resolution density cannot differentiate laminations with substantial porosity. However, logging analysis combining the 50-burst magnetic resonance application and high-resolution TLD readily identifies laminated pay by differentiating very small pores, micropores, and poten-tially oil-bearing matrix. Standard-resolution analysis presents only an average of the matrix, which cannot discriminate laminations.
CASE STUDY
Wireline
Advanced Analysis of Magnetic Resonance Finds Laminated Pay, Eagle Ford ShaleMatrix nonuniformity detailed by combining 50-burst magnetic resonance application and high-resolution density logging
CASE STUDY: Laminated pay identified by advanced magnetic resonance analysis, Eagle Ford Shale
Density
Pyrite
Salt 2-in Density-Porosity > 0.12 ft3/ft3
2-in Density Porosity
FMI* Formation MicroimagerOrientation North
0 120 240 360
Resistive Conductive
FMI* Formation MicroimagerOrientation North
0 120 240 360
Resistive ConductiveCoal
Siderite
Microporosity
T2 Distribution
Anhydrite and Gypsum
Pyrite
Carbonate
Quartz-Feldspar-Mica
Clay
DensityStandoff
g/cm3–0.9 0.1
SpectroLith* Lithology
lbm/lbm1 0
ft3/ft30.2 0
Standard-ResolutionDensity Porosity
ft3/ft30.2 0
8-in Density Porosity
ft3/ft30.2 0
ELANPlus* Mineralogy
Chlorite
Illite
Montmorillonite
Clay 1
Bound Water
Quartz
Calcite
Oil
Water
Moved Hydrocarbon
Moved Water
V/V1 0
0 29
Pyrite Volume
MeasuredDepth, ft
ft3/ft30 0.07
Kerogen
Pyrite
XX,470
XX,480 Track 3 overlays the standard-resolution density with the 8-in and 2-in curves. The resolution of the 2-in curve is consistent with the enhanced image curve in Track 4. The 2-in-resolution density shows higher porosity (circled) along certain layers that is as much as 5-pu higher than standard resolution. In the same inter-vals, the 50-burst application in Track 5 differentiates very small pores, micropores, and potentially oil-bearing matrix. Compared with the detail provided by the TLD and 50-burst logs, the standard-resolution analysis in Track 6 does not show any bedding but merely an average of the matrix.
1 2 3 4 5 6
Very high-resolution density and 50-burst magnetic resonance reveal laminated pay
Micropore region 3–33 ms
No visible difference seen in standard analysis
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Standard-resolution density porosity
8-in density porosity
2-in density porosity
