Scanning Electron Microscopy (FE-SEM and
routine SEM) of Shale Samples
我家是个动物园
Anadarko Petroleum
Adler 16-33 and Coland 5-16 wells Wattenberg Field, Weld Co., Colorado
Houston ATC Job File No.: 091209GD
qq关联怎么设置March 2011
Core Laboratories, Inc.
Houston Advanced Technology Center
6316 Windfern Road PETROLEUM SERVICES
March 30, 2011
Anadarko Petroleum 1099 18th Street Denver CO 80202
To: Ms. Rachel Mays
Re: Scanning Electron Microscopy (SEM) of lected core samples (e sample list) from the Adler 16-33 and Coland 5-15 wells, Wattenberg Field, Weld Co., Colorado.
Table 1 Sample List
Sample #
Plug Depth
(Ft)
孤陋Well Name
Formation
FE-SEM
松江泗泾SEM 1AC-2 7488.3 Adler 16-33 Greenhorn X 2AC-2 7518.05 Adler 16-33 Greenhorn X 3A-1 7532.90 Adler 16-33 Greenhorn X 4A-1 7538.70 Adler 16-33 Greenhorn X 5A-1 7599.8 Adler 16-33 Graneros
X 1C-1 7619.5 Coland 5-16 Greenhorn X 2C-2 7629.6 Coland 5-16 Greenhorn X 3C-1 7644.6 Coland 5-16 Greenhorn X 2CC-2 7658.7 Coland 5-16 Greenhorn X 4C-2 7670.95 Coland 5-16 Greenhorn X 5C-2 7685.1 Coland 5-16 Greenhorn X飞鸟集
Introduction Eleven samples were delivered to the Core Laboratories Rervoir Geology Group for scanning electron microscopy analysis. The samples reprent parts of two formations and are from two different wells. Standard SEM analysis was done on a freshly broken surface of two samples and FE-SEM (field emission scanning electron microscopy) was done on argon ion-milled surfaces of the remaining nine samples (e sample list for details). The objectives of the analysis include; 1) describe the texture and fabric of the samples, 2) identify and describe occurrences of organic matter, and 3) describe the occurrence and distribution of open pores. X-Ray diffraction data (XRD) data (reported earlier) is also attached .
Petroleum Services Division 6316 Windfern Road Houston, TX 77040 713-328-2576
Results
Greenhorn Formation
Ten of the eleven analyzed samples are from the Greenhorn Formation. SEM and XRD analysis indicates the samples are calcareous mudstone. The texture is generally heterogeneous (Plate 4, Photo A; Plate 6, Photo A) with medium to coar silt-size fossils (primarily cemented foraminifer tests) scattered throughout a finer-grained (clay to fine-silt size particles) matrix. The composition of the samples is predominantly calcite, quartz and clay minerals. Calcite occurs as fossil debris (broken foraminifer tests – Plate 6, Photo A; broken pieces of coccoliths – Plate 9, Photo D; rare shell fragments) and as cement (often filling foraminifer test chambers, Plate 4, Photo A). Small amounts of pyrite are identified in all of the samples. Pyrite that is disminated throughout the sample occurs as framboids (spherical aggregates of tiny crystals, Plate 3, Photo B) or larger individual crystals. Pyrite also occurs as cement, partially filling foraminifer test chambers. Clay minerals are predominantly mixed-layer illite/smectite (with 20-30% expandable layers) and 10-angstrom clay (illite and/or mica). Small amounts of kaolinite occur as authigenic clay, typically en filling foraminifer test chambers (Plate 11, Photo A).杜鲁门号航空母舰
The amounts of organic matter range from 6.2% to 7.8% (vol% kerogen). The organic matter occurs 1) as relatively large, discrete particles, and 2) as a pore-filling material that partially fills or coats interparticle pores or fills fractures (Plate 7, Photo B). Generally, the larger discrete particles have a smooth surface texture (Plate 6, Photo C), but some have a microporous surface texture. The occurrence and morphology of the organic matter that occurs in the interparticle and intraparticle pore space (Plate C, Photos C and D) suggest this is hydrocarbon residue (bitumen). Generally the bitumen contains open pores, some of which are relatively large (Plate 11, Photo C).
Graneros Formation
A standard SEM analysis of a broken surface was done on the one sample from the Graneros Formation. SEM and XRD analysis indicates this rock is an argillaceous mudstone. The sample has and indistinctly oriented fabric (Plate 5, Photos A and B). The composition is predominantly clay minerals (predominantly mixed-layer illite/smectite and 10-angstrom clays (illite and/or mica)). Pyrite is the most common authigenic mineral, and typically occurs as framboids that are disperd through the sample (Plate 5, Photo B). Organic matter accounts for 8.3% of the volume of the sample. The organic matter appears to be discrete particles that are disperd throughout the sample (Plate 5, Photo A).
Methodology: Scanning Electron Microscopy (SEM and FE-SEM)
The samples were cut to a small cube. The standard SEM samples were subquently broken to provide a fresh surface of analysis. The FE-SEM samples were subquently polished with an argon ion mill in order to create an extremely flat, artifact-free surface suitable for analysis with back scattered electrons. All of the samples are analyzed using relatively low beam energy (10K-15K volts), in a high pressure (~60 Pascal's) vacuum chamber environment. Back scattered electron images or back-scattered electron images with superimpod condary electron images are generated to document the nature of the sample. Using relatively low beam-energy and a 'low vacuum' (high pressure) mode also helps to avoid the evaporation of any volatiles that may be associated with organic matter. Charging effects associated with condary electron imaging of non-conductive material are minimized when using back scattered electron imaging. Another benefit of back scattered electron imaging is that the various 'grey-levels' of the image is a function of the density of the mineral. The higher density
minerals are white (e.g. pyrite) and the lowest density grains (e.g. organic matter) are black. Additionally, an energy dispersive spectrometer (EDS) system is ud to identify the elemental chemistry of the various minerals. The EDS system us x-rays generated by the electron beam in t
he SEM to identify the characteristic radiation of each element prent in the target area under the electron beam. The EDS system is provided with a light element detector which can measure x-rays from all elements heavier beryllium. The density contrast (gray-levels) of the grains coupled with the elemental data provided by the EDS system is ud to identify the mineralogy of the sample.
Thank you for this opportunity to be of rvice. If you have any questions, or if we can be of further assistance, plea feel free to give us a call. This report was delivered to Ms. Rachel Mays (Anadarko, Denver).
Sincerely,
Barry Wawak
Geologist
Senior
Core Laboratories汪中求
Houston Advanced Technology Center
Houston,
77040
Texas
713-328-2576
科学家的名言Barry.
