Standalone Cased-Hole Formation Evaluation and Uncertainty Propagation to Increase Well Deliverability in Challenging Environments

2018 ◽  
Author(s):  
Fabio Vinci ◽  
Marco Pirrone ◽  
Giuseppe Galli ◽  
Daniela Macaluso ◽  
Francois Rocco ◽  
...  
Keyword(s):  
Uncertainty Propagation ◽  
Hole Formation ◽  
Formation Evaluation

Drilling, Completion, and Open-Hole Formation Evaluation of High-Angle HPHT Wells in High Density Cesium Formate Brine: The Kvitebjorn Experience, 2004-2006

2007 ◽  
Author(s):  
Per Cato Berg ◽  
Erik Sandtorv Pedersen ◽  
Aashild Lauritsen ◽  
Nader Behjat ◽  
Siri Hagerup-Jenssen ◽  
...  
Keyword(s):  
High Density ◽  
High Angle ◽  
Hole Formation ◽  
Formation Evaluation ◽  
Open Hole

LESSONS LEARNED FROM CASED-HOLE FORMATION EVALUATION ALONG UNCONVENTIONAL HORIZONTAL WELLS

2019 ◽  
Author(s):  
Michael Sullivan ◽  
Haijing Wang ◽  
Alexei Bolshakov ◽  
Lisa Song ◽  
Michael Lazorek ◽  
...  
Keyword(s):  
Horizontal Wells ◽  
Lessons Learned ◽  
Hole Formation ◽  
Formation Evaluation

scholarly journals Exploration of Hidden Hydrocarbons in Old Wells Magid Field - Sirte Basin, Libya

2021 ◽  
Vol 9 (9) ◽  
pp. 1189-1192
Author(s):  
Alfageh Z. A.
Keyword(s):  
Development Strategy ◽  
Cost Effective ◽  
Hole Formation ◽  
Formation Evaluation ◽  
The Development Strategy ◽  
Formation Resistivity ◽  
Sirte Basin ◽  
Resistivity Logging ◽  
Bypassed Oil ◽  
Petrophysical Evaluation

Abstract: It is increasingly important to improve field productivity in today's competitive market. One way to achieve this, is to add new wells which are expensive and time consuming. The other alternative is to identify bypassed hydrocarbons, track changes in saturations and detect movement of reservoir fluid contacts from existing well bores already in place. It is considerably more cost effective and often more environmentally friendly to explore for those hidden hydrocarbons in old wells rather than drill new wells. As the field matures, there is a need to reevaluate the formation in older reservoirs and to focus the development strategy and approach on bypassed oil pockets and depletion levels in producing intervals. The ability to acquire essential logging data behind casing adds a new dimension to cased hole formation evaluation for locating and evaluating potential hydrocarbon zones in a mature field as in Magid field. A basic petrophysical evaluation was performed incorporating the data recorded behind casing by applying {Cased Hole Formation Resistivity Logging (CHFRL)} in each of these wells. Based on the analysis of cased hole formation evaluation results. The un-depleted intervals were commercially exploited adding reserve to the asset. Keywards: Hydrocarbon zones, Majid Field, Sirte Basin, Libya, CHFRL

Quantitative log interpretation and uncertainty propagation of petrophysical properties and facies classification from rock-physics modeling and formation evaluation analysis

Geophysics ◽  
2012 ◽  
Vol 77 (3) ◽  
pp. WA45-WA63 ◽  
Author(s):  
Dario Grana ◽  
Marco Pirrone ◽  
Tapan Mukerji
Keyword(s):  
Reservoir Characterization ◽  
Uncertainty Propagation ◽  
Rock Physics ◽  
Integrated Approach ◽  
Physical Models ◽  
Well Log ◽  
Petrophysical Properties ◽  
Formation Evaluation ◽  
Facies Classification ◽  
Well Location

Formation evaluation analysis, rock-physics models, and log-facies classification are powerful tools to link the physical properties measured at wells with petrophysical, elastic, and seismic properties. However, this link can be affected by several sources of uncertainty. We proposed a complete statistical workflow for obtaining petrophysical properties at the well location and the corresponding log-facies classification. This methodology is based on traditional formation evaluation models and cluster analysis techniques, but it introduces a full Monte Carlo approach to account for uncertainty evaluation. The workflow includes rock-physics models in log-facies classification to preserve the link between petrophysical properties, elastic properties, and facies. The use of rock-physics model predictions guarantees obtaining a consistent set of well-log data that can be used both to calibrate the usual physical models used in seismic reservoir characterization and to condition reservoir models. The final output is the set of petrophysical curves with the associated uncertainty, the profile of the facies probabilities, and the entropy, or degree of confusion, related to the most probable facies profile. The full statistical approach allows us to propagate the uncertainty from data measured at the well location to the estimated petrophysical curves and facies profiles. We applied the proposed methodology to two different well-log studies to determine its applicability, the advantages of the new integrated approach, and the value of uncertainty analysis.

Open- and Cased- Hole Formation Evaluation Workflows Running Together for Reducing Uncertainties in Gas Reservoirs: An Acquisition Data and Evaluation Strategy in Dnieper-Donets Basin, Ukraine

2021 ◽  
Author(s):  
Rafael Zambrano ◽  
Michael Sadivnyk ◽  
Yevhen Makar ◽  
Chiara Cavalleri ◽  
David Rose
Keyword(s):  
Magnetic Resonance ◽  
Donets Basin ◽  
Neutron Spectroscopy ◽  
Petrophysical Properties ◽  
Hole Formation ◽  
Gas Reservoirs ◽  
Formation Evaluation ◽  
Open Hole ◽  
Pulsed Neutron ◽  
Evaluation Techniques

Abstract Formation evaluation using cased-hole logs is a primary option for re-evaluating old wells in brownfields or contingency logging in new wells. Its consistency with a robust open hole evaluation is vital for its future implementation in field development. This work describes detailed open- and cased- hole evaluation workflows integrating different advanced subsurface measurements and alternative interpretation techniques to reduce the uncertainties of deriving the main petrophysical properties across the conventional and tight gas reservoirs in the Dnieper-Donets basin. Since not all open-hole measurements can be recorded behind casing and some of the cased hole logs are not characterized for open hole conditions, it is not always possible to implement the same evaluation techniques for measurements done in open hole and cased hole. Nevertheless, different measurements provide different formation responses that supplement their gaps from one another. A wireline data acquisition strategy has been elaborated to carry out formation evaluation workflows using open- and cased-hole data independently but learning from each other. The methodology is based on novel and non-standard evaluation techniques that use measurements from advanced wireline technology such as nuclear magnetic resonance (NMR) and advanced pulsed neutron spectroscopy logs. The methodology was applied to log data recorded on the Visean and Serpukhovian (Lower Carboniferous) productive gas zones, characterized by porosity (5-15pu) and permeability (0.1-100mD). The principal challenge for the formation evaluation of these reservoirs is deriving an accurate estimation of porosity, which requires removing the gas and matrix effects on the log responses. An inaccurate porosity estimation will result in an inaccurate permeability and water saturation, and the problem worsens in low-porosity rocks. In the open hole, the porosity computation from the Density-Magnetic Resonance (DMR) technique has proven to be more accurate in comparison with common single porosity methods. The same problem is addressed in cased hole conditions with the advanced pulsed neutron spectroscopy logs and a novel technique that combines the thermal neutron elastic scattering and fast neutron cross sections to obtain a gas-free and matrix-corrected porosity, as well as a resistivity independent gas saturation. The consistency of petrophysical properties independently estimated from the two separate workflows add confidence to the approach, and this is reflected in the gas production obtained from the perforated intervals. This script describes in detail the open- and cased- hole formation evaluation workflows and the wireline technology and methodologies applied. Actual examples illustrate the effectiveness of these quantitative approaches in the Dnieper-Donets basin.

Migration to Cased Hole Petrophysics: Are We Ready?

2021 ◽  
Author(s):  
Ulises Bustos ◽  
Carlos Duran ◽  
Alexander Duarte ◽  
Alfonso Salguero ◽  
Yira Vasquez ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Neutron Cross Section ◽  
Northern Region ◽  
Wellbore Stability ◽  
Total Carbon ◽  
Hole Formation ◽  
Formation Evaluation ◽  
Simultaneous Inversion ◽  
Well Completion ◽  
Open Hole

Abstract In the present Oil & Gas business context, the uncertainties reduction for hydrocarbon production increase in an operational costs and risk reduction scheme, are among the main drivers in several operating companies in the northern region of South America (Colombia & Ecuador). Electrical logging and drilling tools stuck events due to differential pressures, fishing operations, high wellbore tortuosity, difficult geometries and unconsolidated formations affecting wellbore stability, are among the main problems increasing non-productive time and operating costs. Minimizing open hole operations with a full migration to cased hole data acquisition, providing inputs for petrophysical uncertainty reductions without jeopardizing well completion decisions or initial reservoir characterization, would constitute an attractive solution for operators. Following those initiatives, we start by achieving a complete open hole formation evaluation and then migrating to case hole data acquisition and petrophysical assessment while benchmarking against open hole results. Low and variable formation water salinity, complex mineralogy's affecting resistivity and radioactive minerals, are common petrophysical challenges in our reservoirs. We had to implement Archie and salinity-independent formation evaluation solutions with cased hole technologies and in absence of open hole logs. The open hole petrophysics consist on simultaneous assessment of matrix and fluids saturations, while evaluating the oil mobility and water cut with the incorporation of multi-depth of investigation sensors in single logging runs (spectroscopy, dielectric dispersion, and magnetic resonance). We then moved to cased hole formation evaluation, with spectroscopy & nuclear-based petrophysics in gas, light oil, and heavy oil-bearing reservoirs. By implementation of non-archie fluids volumetric computation (that relies on conversion of dry weight total carbon to oil saturation and fast neutron cross section to gas saturation- done through a simultaneous inversion by solving matrix-porosity-fluids volumes into an elemental analysis), we obtained a representative formation saturation range behind casing. We then discussed on the different scenarios were migrating to cased hole is sustainable and its potential limitations.

Hole Formation in Gold Films

1972 ◽  
Vol 30 ◽  
pp. 510-511
Author(s):  
R. W. Vook ◽  
R. Cook ◽  
R. Ziemer
Keyword(s):  
Deposition Rate ◽  
Quartz Crystal ◽  
Evaporation Rate ◽  
Gold Films ◽  
Hole Density ◽  
Hole Formation ◽  
Microscope Slide ◽  
Crystal Film ◽  
Glass Microscope Slide ◽  
Glass Microscope

During recent experiments on Au films, a qualitative correlation between hole formation and deposition rate was observed. These early studies were concerned with films 80 to 1000A thick deposited on glass at -185°C and annealed at 170°C. In the present studies this earlier work was made quantitative. Deposition rates varying between 5 and 700 A/min were used. The effects of deposition rate on hole density for two films 300 and 700A thick were investigated.Au was evaporated from an outgassed W filament located 10 cm from a glass microscope slide substrate and a quartz crystal film thickness monitor. A shutter separating the filament from the substrate and monitor made it possible to obtain a constant evaporation rate before initiating deposition. The pressure was reduced to less than 1 x 10-6 torr prior to cooling the substrate with liquid nitrogen. The substrate was cooled in 15 minutes during which the pressure continued to drop to the mid 10-7 torr range, where deposition was begun.

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