Fracture Development and Mechanical Stratigraphy of Austin Chalk, Texas: DISCUSSION

AAPG Bulletin ◽  
1989 ◽  
Vol 73 ◽  
Author(s):  
Richard C. Nolen-Hoeksema (2)
Keyword(s):  
Mechanical Stratigraphy ◽  
Fracture Development ◽  
Austin Chalk

Mechanical stratigraphy in Mesozoic rocks of the San Juan Basin: Integration of stratigraphic and structural terms and concepts

2021 ◽  
Vol 58 (2) ◽  
pp. 159-204
Author(s):  
Bruce Hart ◽  
Scott Cooper
Keyword(s):  
Depositional Environments ◽  
Rock Properties ◽  
San Juan ◽  
Primary Control ◽  
Natural Fractures ◽  
Fracture Characterization ◽  
San Juan Basin ◽  
Mechanical Stratigraphy ◽  
Fracture Development ◽  
Shoreline Progradation

We characterize relationships between stratigraphy and natural fractures in outcrops of Mesozoic strata that rim the San Juan Basin in New Mexico and Colorado. These outcrops expose fluvial and shallow-marine siliciclastic deposits and calcareous mudstones deposited in a distal marine setting. We focus primarily on a regionally extensive fracture set formed during the Eocene to minimize localized tectonic effects on fracture development. Where possible, we supplement our observations with wireline log- or laboratory-derived measurements of rock properties. Our goals are twofold: 1) to illustrate how direct integration of data and concepts from stratigraphy and structural geology can lead to better fracture characterization, and 2) to develop thought processes that will stimulate new exploration and development strategies. Genetic beds form one scale of stratification in the outcrops we describe. For example, sandstone beds can be arranged into coarsening and thickening upward successions that are the depositional record of shoreline progradation. In fluvial settings, cm- to dm-scale sandstone beds can also be part of m-scale single-storey channel complexes that, themselves, can be arranged into amalgamated channel complexes 10s of m thick. In these and other settings, it is important to distinguish between beds and features that can be defined via wireline logs because it is the former (cm- to dm-scale) that are usually the primary control the distribution of natural fractures. The extension fractures we describe are typically bed-bound, with bedding being defined by lithology contrasts and the associated changes in elastic properties. Fracture spacing distributions are typically lognormal with average spacing being less than bed thickness. Although mechanical bedding and depositional bedding are commonly the same, diagenesis can cut across bed boundaries and complicate this relationship, especially where lithologic contrasts are small. Deposits from similar depositional environments which undergo different diagenetic histories can have substantially different mechanical properties and therefore deform differently in response to similar imposed stresses.

scholarly journals Modeling of the Dammam outcrop fractures: Case study for fracture development in salt-cored structures

GeoArabia ◽  
2014 ◽  
Vol 19 (1) ◽  
pp. 49-80
Author(s):  
Mohammed Al-Fahmi ◽  
L. Cooke Michele ◽  
John C. Cole
Keyword(s):  
Arabian Gulf ◽  
Data Interpretation ◽  
Karst Collapse ◽  
Gulf Region ◽  
Near Surface ◽  
Reflection Seismic ◽  
Mechanical Stratigraphy ◽  
Study Results ◽  
Fracture Development ◽  
Regional Stresses

ABSTRACT The exposed Cenozoic carbonates of the Dammam Dome are studied to: (1) characterize fractures and associated structures; (2) interpret the fracture mechanism; and (3) gain insights into fracture development within dome-like structures in the subsurface of the Arabian Gulf region. The fieldwork is integrated with structural analysis of the near-surface horizons mapped from interpretations of 3-D reflection seismic and borehole logs. Fractures are mapped from the outcrops of the middle limestone unit of the Eocene Rus Formation. The outcrops are concentrated in the central, northern and western areas of the Dammam Dome. The fractures are interpreted as opening-mode, bed-bounded joints that form orthogonal sets in most areas. The primary (older) joint set (J1) developed in long lineaments, some of which can be traced for over 300 m across entire exposures. The J1 set is found to be broadly consistent in its trend over the dome, indicating that formation of J1 fractures was systematic and not influenced by local structural anomalies (including karst collapse) formed during the Miocene to Recent. The trend of the J1 set does not correlate with the NE-SW compressional orientation of regional stresses associated with the Zagros Orogeny. Field data interpretation, allied with analysis of dome’s growth and curvature, suggest that the overall joint pattern reflects the growth of the strata as a dome. In addition, the joint density is controlled by structural position on the dome and mechanical stratigraphy. The study results provide a first-order conceptual fracture model for the subsurface reservoirs to guide future development.

scholarly journals Risk Factors for Failure in Conservatively Treated Osteoporotic Vertebral Fractures: A Systematic Review

2021 ◽  
pp. 219256822098227
Author(s):  
Max J. Scheyerer ◽  
Ulrich J. A. Spiegl ◽  
Sebastian Grueninger ◽  
Frank Hartmann ◽  
Sebastian Katscher ◽  
...  
Keyword(s):  
Risk Factors ◽  
Systematic Review ◽  
Treatment Failure ◽  
Patient Specific ◽  
Mineral Density ◽  
Radiographic Findings ◽  
Specific Risk ◽  
Fracture Development ◽  
Predict Treatment Failure

Study Design: Systematic review. Objectives: Osteoporosis is one of the most common diseases of the elderly, whereby vertebral body fractures are in many cases the first manifestation. Even today, the consequences for patients are underestimated. Therefore, early identification of therapy failures is essential. In this context, the aim of the present systematic review was to evaluate the current literature with respect to clinical and radiographic findings that might predict treatment failure. Methods: We conducted a comprehensive, systematic review of the literature according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) checklist and algorithm. Results: After the literature search, 724 potentially eligible investigations were identified. In total, 24 studies with 3044 participants and a mean follow-up of 11 months (range 6-27.5 months) were included. Patient-specific risk factors were age >73 years, bone mineral density with a t-score <−2.95, BMI >23 and a modified frailty index >2.5. The following radiological and fracture-specific risk factors could be identified: involvement of the posterior wall, initial height loss, midportion type fracture, development of an intravertebral cleft, fracture at the thoracolumbar junction, fracture involvement of both endplates, different morphological types of fractures, and specific MRI findings. Further, a correlation between sagittal spinal imbalance and treatment failure could be demonstrated. Conclusion: In conclusion, this systematic review identified various factors that predict treatment failure in conservatively treated osteoporotic fractures. In these cases, additional treatment options and surgical treatment strategies should be considered in addition to follow-up examinations.

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