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A computed dip arrow plot on any single well, absent of other information, is nothing more than a "bunch of dips." Resolving structural geology from dip information requires other correlative borehole information. External information, including log data from other wells, does not change the dip information, but it may change the interpretation of the dip data. Prior to an analysis of dip patterns, it is important to review original log quality and computer processing methods in order to determine if an adequate arrow plot is presented for subsequent analysis. The majority of successful dip analysts have a strong aptitude for dealing with spatial relationships and mental imagery, Auxiliary plotting methods may aid those who have difficulty in visualizing in more than one dimension. An understanding of structural geology is prerequisite. Structural interpretations may be extremely complex in some geographical areas and relatively simple elsewhere. Successful evaluations of dip data often require two or more people from different disciplines. Integrating different specialties, as well as different sources of information, provide for more profound structural dip analysis.
- Oceania > Australia (1.00)
- North America > United States > Oklahoma (1.00)
- North America > United States > New Mexico (1.00)
- (18 more...)
- Geology > Sedimentary Geology > Depositional Environment (1.00)
- Geology > Geological Subdiscipline > Stratigraphy (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.67)
- Geology > Structural Geology > Fault > Dip-Slip Fault > Normal Fault (0.45)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying (0.92)
- Government > Regional Government > North America Government > United States Government (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- North America > Canada > Alberta > Kirby Field > Aecog (E) Kirby 6-21-73-3 Well (0.98)
- North America > Canada > Alberta > Graham Field > Ath Graham 4-25-79-5 Well (0.98)
- North America > Canada > Alberta > Colorado Field > Bonavista Colorado 6-32-90-4 Well (0.98)
- North America > Canada > Alberta > Border Field > Anglo Pacific Et Al Czar 11-33-41-5 Well (0.98)
At radio frequencies (i.e., tens of MHz) the responses of induction logging tools can be influenced by both the resistivities (Rt) and relative dielectric constants (Kt) of the geological formations surrounding the borehole. Moreover, laboratory experiments have shown that dielectric constants measured at radio frequencies on brine and oil saturated reservoir rocks are generally indicative of their water saturations. Thus, dielectric constant logging at radio frequencies offers a method for differentiating between a water bearing zone and a hydrocarbon bearing zone. This method, unlike conventional induction logging does not require a contrast in fluid resistivities in order to differentiate between water and hydrocarbons. In this study, the basic ideas and physical principles underlying High Frequency Induction Logging (HFIL) are discussed, and the results of computer simulation studies of a model HFIL device in some simple logging geometries are presented. It is shown that for invaded zone diameters exceeding several borehole diameters that the effects of the invaded zone on the tool responses can be the dominant influence. In these cases, at least five independent measurements of the tool response are required in order to solve even the simplest inverse logging problem. A four-receiver device provides the required measurements and therefore represents the most basic device needed to practice high frequency induction logging. Synthetic logs are computed to determine the response of a HFIL device as it approaches and traverses a plane interface separating a freshwater saturated zone from a hydrocarbon saturated zone. Synthetic logs are also computed for the response of an HFIL device as it approaches and traverses a thin hydrocarbon saturated zone sandwiched between two freshwater zones. These results indicate that the response of an HFIL device in a freshwater saturated zone is significantly different from its response in a hydrocarbon saturated zone even in the case where the two zones have identical resistivities. Moreover, the thin-bed computations illustrate that the HFIL response has excellent vertical resolution.
- South America (1.00)
- Oceania > Australia (1.00)
- North America > United States > Oklahoma (1.00)
- (17 more...)
- Instructional Material (0.92)
- Research Report > New Finding (0.47)
- Geology > Mineral (0.92)
- Geology > Geological Subdiscipline (0.92)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.45)
- Government > Regional Government > North America Government > United States Government (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- North America > United States > California > San Joaquin Basin > Lost Hills Field (0.99)
- Europe > Netherlands > Groningen > Southern North Sea - Anglo Dutch Basin > Groningen License > Groningen Field > Upper Rotliegend Formation (0.99)
- Europe > Netherlands > Groningen > Southern North Sea - Anglo Dutch Basin > Groningen License > Groningen Field > Limburg Formation (0.99)
- (7 more...)
Quantitative determination of fluid saturation in naturally fractured reservoirs has proven difficult. Conventional quantitative well log evaluation techniques cannot be applied successfully because of the complex nature of fractured formations. Well logs have, hence, been used almost exclusively for qualitative fracture detection. This paper presents a quantitative evaluation technique that makes use of the Pickett crossplot to identify oil-bearing formations. This method does not emphasize fracture detection; instead, it attempts to directly compute the "total oil saturation" in the zones of interest. The parameter "total saturation" is an oil saturation index combining the effect of both the intergranular pore system and fractures. Furthermore, this study introduces a new method used to correct the Neutron Log readings for borehole effects induced by fractures. The proposed quantitative interpretation method was successfully applied in several naturally fractured intervals of 23 wells drilled in the Chapayal basin of Guatemala. The evaluation of three typical wells is included.
- Oceania > Australia (1.00)
- North America > United States > Oklahoma (1.00)
- North America > United States > New Mexico (1.00)
- (17 more...)
- Geology > Rock Type > Sedimentary Rock (0.67)
- Geology > Mineral (0.67)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.92)
- Asia > China > Tianjin > Bohai Basin > Huanghua Basin > Dagang Field (0.99)
- North America > Canada > Alberta > Western Canada Sedimentary Basin > Alberta Basin > Calgary Field (0.98)
- North America > Canada > Alberta > Lane Field > Barr Lane 5-32-65-7 Well (0.98)
- Europe > United Kingdom > North Sea > Central North Sea > Kittiwake Area > Block 21/18 > Fulmar Formation > Eagle Well (0.98)
Over the years the resistivity of mud, formation water and mud filtrate have been corrected using Figure 1, which first appeared in the Schlumberger Chartbooks. This has been the reference and assumed to be the most correct conversion available. Arps is credited with developing the following approximation:
- South America > Brazil (1.00)
- Oceania > Australia (1.00)
- North America > United States > Oklahoma (1.00)
- (18 more...)
- Geology > Geological Subdiscipline (1.00)
- Geology > Mineral (0.67)
- Geology > Rock Type > Sedimentary Rock (0.67)
- Government > Regional Government > North America Government > United States Government (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- North America > United States > Alaska > North Slope Basin > Bear Tooth Area > Willow Field (0.99)
- Asia > China > Tianjin > Bohai Basin > Huanghua Basin > Dagang Field (0.99)
- North America > Canada > Alberta > Kirby Field > Aecog (E) Kirby 6-21-73-3 Well (0.98)
- (4 more...)
Note also that statistical inaccuracies may be greater. This effect is due to the reduced countrate. Wherever sizeable Downhole Sigma measurements have been with us for more washouts exist behind cemented pipe the gamma curve will be than a decade. Many opportunities for optimal usage are still greatly reduced as compared to an open hole gamma curve.
- South America > Brazil (1.00)
- Oceania > Australia (1.00)
- North America > United States > Texas > Harris County (1.00)
- (28 more...)
- Geology > Geological Subdiscipline (1.00)
- Geology > Mineral (0.92)
- Geology > Rock Type > Sedimentary Rock (0.46)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Seismic Processing (0.45)
- Materials (1.00)
- Government > Regional Government > North America Government > United States Government (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- (6 more...)
- Asia > China > Tianjin > Bohai Basin > Huanghua Basin > Dagang Field (0.99)
- North America > Canada > Alberta > Colorado Field > Bonavista Colorado 6-32-90-4 Well (0.98)
- North America > Canada > Alberta > Border Field > Anglo Pacific Et Al Czar 11-33-41-5 Well (0.98)