Sequence Stratigraphic Analysis and Facies Architecture of the Cretaceous Mancos Shale on and Near the Jicarilla Apache Indian Reservation, New Mexico-their relation to Sites of Oil Accumulation

Ridgley, Jennie L.

doi:10.2172/784573

Cited by 7 publications

(18 citation statements)

References 8 publications

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“…The cracks vary in length and are randomly oriented, although their abundance does increase towards the surface of the sample. These results are consistent with the findings of Ridgley (2000), who demonstrated that one the main factors that controls production from Mancos shale is fractures.…”

Section: Data Analysis and Discussionsupporting

confidence: 93%

Impact of Matrix Acidizing on Shale Formations

et al. 2013

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Matrix acidizing is typically used to remove drilling and completion damage to reservoir conductivity around the wellbore and dissolve calcite in natural fractures. Despite being a common procedure, few studies have investigated the effect of matrix acidizing on the physical properties and oil recovery factors in shales. This paper describes the effect of HCl treatment on porosity, spontaneous imbibition, and crack distribution in samples from the Eagle Ford, Mancos, Barnett and Marcellus shale formations. Samples measuring 2.54-3.81 cm in diameter and 2.54-5.08 cm in length were exposed to acid with concentrations between 0.8-3% active HCl (4 and 15% of 20% diluted HCl). Active acid concentrations of 0.8% were optimal for balancing enhanced oil recovery while maintaining samples structural stability and integrity. The Pre and post HCl treated samples were saturated with Soltrol 130 TM . Oil recovery was determined by measuring the quantities of oil displaced by uptake of saline water. Recovery factors for Mancos and Eagle Ford shale samples improved from 4 and 16% for non-treated samples to 36 and 71% for the treated samples. In contrast, no change in Barnett and Marcellus shale recovery factors were observed. Porosities were calculated using X-ray computed tomography (CT-scanning). Average porosities prior to acid treatment were 1.6 -3.7% versus 1.6-10.7% after acid treatment. The CT-scanning studies of treated samples also shows that in the Mancos shale randomly oriented cracks developed, while in the Barnett and Marcellus shales cracks developed along bedding planes; very little crack development was observed in Eagle Ford shales. These results are encouraging for the application of matrix acidizing in shale formations to improve microfractures conductivity at distances along strike from the wellbore. Pre HCl Post 3% Active HCl Post 3% Active HCl Pre HCl Post 3% Active HCl Pre HCl Post 3% Active HCl Pre HCl

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Section: Data Analysis and Discussionsupporting

confidence: 93%

Impact of Matrix Acidizing on Shale Formations

et al. 2013

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“…The cracks vary in length and are randomly oriented, although their abundance increases towards the surface of the sample. These results are also consistent with the findings of Ridgley [15], who demonstrated that one of the main factors that control production from Mancos shale is fractures.…”

Section: Cracks Distribution After Matrix Acidizingsupporting

confidence: 92%

“…The CT-scanning images of postacid treated samples of Barnett and Marcellus shales also show the presence of high density material, not observed in untreated samples (white-colored in Figures 2B and 3B). Based on the higher abundances of pyrite in the Marcellus and Chlorite clay minerals in the Barnett rocks [15,16], the white-colored material was interpreted to be iron oxide-hydroxide precipitation resulted from chlorite dissolution (in the case of Barnett) in acidic solutions and pyrite oxidation (in the case of Marcellus). The precipitation of iron negatively affected the calculated average porosity per slice in some areas in Barnett and Marcellus shale samples (next section).…”

Section: Cracks Distribution After Matrix Acidizingmentioning

confidence: 99%

Matrix Acidizing Characteristics in Shale Formations

Morsy¹

2014

J Pet Environ Biotechnol

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Matrix acidizing is typically used to remove drilling and completion damage to reservoir conductivity around the wellbore and dissolve calcite in natural fractures. Despite being a common procedure, few studies have investigated the effect of matrix acidizing on the physical properties and oil recovery factors in shales. This paper describes the effect of HCl acid on porosity, spontaneous imbibition, mechanical properties, and crack distribution in samples from the Eagle Ford, Mancos, Barnett and Marcellus shale formations. Some of the samples were completely immersed in different HCl solutions (1-3 wt%) at 93°C. We measured the porosity in both the acid-treated and non-treated samples. The treated and non-treated samples were then exposed to spontaneous water imbibition experiments to measure the improvement in oil recovery in both parallel and perpendicular to bedding planes. The mechanical properties of the acid-treated and non-treated samples were also measured in both parallel and perpendicular to bedding planes using the same acid concentrations. The samples were 2.54 and 3.81 cm in diameter and 2.54 to 5.08 cm in length. The measured porosities were 1-3% for the non-treated samples and 1.3-10.5% for the treated samples. We observed that the oil recovery factors of the spontaneous imbibition for the samples treated with acid were 47% from Eagle Ford, 53% from Mancos, 28% from Barnett, and 38% from Marcellus. The recovery factors from the non-treated samples were 12% from Eagle Ford, 4% from Mancos, 13% from Barnett, and 3% from Marcellus. Furthermore, we observed that spontaneous imbibition parallel to bedding planes is higher than imbibition in perpendicular to bedding planes direction, especially for Marcellus samples where the recovery factors varied from 4% for the samples drilled parallel to bedding planes to 38% for the samples drilled in perpendicular to bedding planes. Eagle Ford and Mancos samples showed a reduction in confining compressive strength ranging from 50-60% when exposed to 3 wt% HCl solutions with more reduction in the samples drilled parallel to bedding planes.

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“…The Juana Lopez Member of the Mancos Shale, considered to be nearly isochronous in the study area, was used as a datum. A discussion of the correlation of units with the Mancos Shale are reported elsewhere (Ridgley, 2000).…”

Section: Methods Of Studymentioning

confidence: 99%

Subsurface Analysis of the Mesaverde Group on and near the Jicarilla Apache Indian Reservation, New Mexico-its implication on Sites of Oil and Gas Accumulation

Ridgley¹

2001

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Sequence Stratigraphic Analysis and Facies Architecture of the Cretaceous Mancos Shale on and Near the Jicarilla Apache Indian Reservation, New Mexico-their relation to Sites of Oil Accumulation

Cited by 7 publications

References 8 publications

Impact of Matrix Acidizing on Shale Formations

Impact of Matrix Acidizing on Shale Formations

Matrix Acidizing Characteristics in Shale Formations

Subsurface Analysis of the Mesaverde Group on and near the Jicarilla Apache Indian Reservation, New Mexico-its implication on Sites of Oil and Gas Accumulation

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