Methodology for Petrophysical and Geomechanical Analysis of Shale Plays. Case Study: La Luna and Capacho Formations, Maracaibo Basin.

2017 ◽  
Author(s):  
C. Lobo ◽  
A. Molina ◽  
A. Faraco ◽  
J. Mendez ◽  
J. Delgadillo ◽  
...  
Keyword(s):  
Maracaibo Basin ◽  
Geomechanical Analysis ◽  
La Luna

scholarly journals The Cogollo Group and the oceanic anoxic events 1a and 1b, Maracaibo basin, Venezuela

2015 ◽  
Vol 45 (suppl 1) ◽  
pp. 41-61 ◽  
Author(s):  
José Alejandro Méndez Dot ◽  
José Méndez Baamonde ◽  
Dayana Reyes ◽  
Rommel Whilchy
Keyword(s):  
Source Rock ◽  
Organic Geochemistry ◽  
Sedimentary Facies ◽  
Source Rocks ◽  
Maracaibo Basin ◽  
Pelagic Environment ◽  
Anoxic Events ◽  
Anoxic Environment ◽  
Platform System ◽  
La Luna

ABSTRACTCarbonates of Cogollo Group (Apón, Lisure and Maraca formations) constitute the broader calcareous platform system originated during Aptian and Albian of Cretaceous in north-western South America, Maracaibo Basin, Venezuela. On the shallow shelf, a variety of calcareous sedimentary facies were deposited during marine transgressive and regressive cycles. Some of them developed porosity and constitute important hydrocarbon reservoirs. Due to some major marine transgressions, from early Aptian, the anoxic environment and characteristic facies of a pelagic environment moved from the outer slope and basin to the shallow shelf, during specific time intervals, favouring the sedimentation of organic matter-rich facies, which correspond to the oceanic anoxic events (OAEs) 1a and 1b. The source rock of Machiques Member (Apón Formation) was deposited during early Aptian OAE 1a (~ 120 Ma). The source rock of Piché Member, located at the top of the Apón Formation, was deposited during late Aptian OAE 1b (~ 113 Ma). Finally, La Luna Formation, from Cenomanian, that covers the OAE 2 (~ 93 Ma), represents the most important source rock in the Maracaibo Basin. In this way and based on sedimentological and organic geochemistry results from the determinations performed on 247 samples belonging to six cores in the Maracaibo Basin, we propose these two organic-rich levels, deposited on the shallow shelf of the Cogollo Group, as "effective source rocks", additional to La Luna Formation, with oil migration in relatively small distances to the porosity facies.

Geomechanical analysis of horizontal wells in terms of stability for drilling — A case study from the Peri-Baltic Syneclise

2021 ◽  
Vol 40 (11) ◽  
pp. 805-814
Author(s):  
Michał Kępiński ◽  
Pramit Basu ◽  
David Wiprut ◽  
Marek Koprianiuk
Keyword(s):  
Horizontal Well ◽  
Oil And Gas ◽  
Horizontal Wells ◽  
Microseismic Monitoring ◽  
Earth Model ◽  
Gas Field ◽  
Horizontal Section ◽  
Stress Regime ◽  
Geomechanical Analysis

This paper presents a shale gas field geomechanics case study in the Peri-Baltic Syneclise (northern Poland). Polish Oil and Gas Company drilled a vertical well, W-1, and stimulated the Silurian target. Next, a horizontal well, W-2H, drilled the Ordovician target and partially collapsed. The remaining interval was stimulated, and microseismic monitoring was performed. A second horizontal well, W-3H, was drilled at the same azimuth as W-2H, but the well collapsed in the upper horizontal section (Silurian). A geomechanical earth model was constructed that matches the drilling experiences and well failure observations found in wells W-1, W-2H, and W-3H. The field was found to be in a strike-slip faulting stress regime, heavily fractured, with weak bedding contributing to the observed drilling problems. An analysis of safe mud weights, optimal casing setting depths, and optimal drilling directions was carried out for a planned well, W-4H. Specific recommendations are made to further enhance the model in any future studies. These recommendations include data acquisition and best practices for the planned well.

Permeability prediction in shaly formations: The fuzzy modeling approach

Geophysics ◽  
2002 ◽  
Vol 67 (3) ◽  
pp. 817-829 ◽  
Author(s):  
Jose Finol ◽  
Xu‐Dong D. Jing
Keyword(s):  
Clustering Algorithm ◽  
Fuzzy Inference ◽  
Fuzzy Rule ◽  
Learning Task ◽  
Well Log ◽  
Rule Based ◽  
Maracaibo Basin ◽  
Core Permeability ◽  
Rule Based Approach

This paper shows how fuzzy rule‐based systems help predict permeability in sedimentary rocks using well‐log responses. The fuzzy rule‐based approach represents a global nonlinear relationship between permeability and a set of input log responses as a smooth concatenation of a finite family of flexible local submodels. The fuzzy inference rules expressing the local input‐output relationships are obtained automatically from a set of observed measurements using a fuzzy clustering algorithm. This approach simplifies the process of constructing fuzzy systems without much computation effort. The benefits of the methodology are demonstrated with a case study in the Lake Maracaibo basin, Venezuela. Special core analyses from three early development wells provide the data for the learning task. Core permeability and well‐log data from a fourth well provide the basis for model validation. Numerical simulation results show that the fuzzy system is an improvement over conventional empirical methods in terms of predictive capability.

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