scholarly journals A Petrophysical Approach to Evaluation from Measured While Drilling Gamma Ray, Case Study in the Powder River and Delaware Basins

2021 ◽  
Vol 13 (07) ◽  
pp. 282-300
Author(s):  
Stephanie E. Perry
Keyword(s):  
2021 ◽  
Author(s):  
Stanley Oifoghe ◽  
Nora Alarcon ◽  
Lucrecia Grigoletto

Abstract Hydrocarbons are bypassed in known fields. This is due to reservoir heterogeneities, complex lithology, and limitations of existing technology. This paper seeks to identify the scenarios of bypassed hydrocarbons, and to highlight how advances in reservoir characterization techniques have improved assessment of bypassed hydrocarbons. The present case study is an evaluation well drilled on the continental shelf, off the West African Coastline. The targeted thin-bedded reservoir sands are of Cenomanian age. Some technologies for assessing bypassed hydrocarbon include Gamma Ray Spectralog and Thin Bed Analysis. NMR is important for accurate reservoir characterization of thinly bedded reservoirs. The measured NMR porosity was 15pu, which is 42% of the actual porosity. Using the measured values gave a permeability of 5.3mD as against the actual permeability of 234mD. The novel model presented in this paper increased the porosity by 58% and the permeability by 4315%.


2018 ◽  
Vol 176 (4) ◽  
pp. 1639-1647 ◽  
Author(s):  
Akram Aziz ◽  
Tamer Attia ◽  
Liam McNamara ◽  
Renee Friedman

2020 ◽  
pp. SP509-2019-148
Author(s):  
Andrew J. Barnett ◽  
Lucy Fu ◽  
Tolu Rapasi ◽  
Cinzia Scotellaro ◽  
Jaydip Guha ◽  
...  

AbstractThe lacustrine Itapema Formation in the Santos Basin locally comprises 102 m thick clinoforms identified seismically and corroborated by several well penetrations. Individual clinoforms, as proven by well penetrations, are composed of 102 m thick successions of basinward-dipping molluscan grainstones and rudstones. Manual dip picking of borehole images shows upward-increasing dips consistent with seismic geometries and a predominance of longshore sediment transport. Clinoforms are bound at their top and base by strata with significantly lower dips recognizable on both seismic and borehole images. Elevated gamma-ray log responses together with sidewall core samples indicate that these intervals correspond to more argillaceous facies which are interpreted as lake flooding events. While the existence of bona fide clinoforms is demonstrated by a range of subsurface data, their precise origin remains enigmatic. The majority of the bivalve genera that make up the grain-supported carbonates appear to be infaunal or semi-infaunal. As such the clinoforms represent large bars produced through the re-working of bivalves from lower-energy depositional environments by shore-parallel currents.


1990 ◽  
Vol 123 ◽  
pp. 463-468
Author(s):  
M. Matsuoka ◽  
N. Kawai ◽  
T. Imai ◽  
M. Yamauchi ◽  
A. Yoshida ◽  
...  

AbstractWe propose an X-ray all sky monitor for Japanese Experimental Module (JEM) on the space station. Considering practical circumstances, we show as a case study that the all sky monitor with slit hole cameras is most promising for monitoring the short-term and long-term X-ray transients. We call this all sky monitor as MAXI (Monitor of All-sky X-ray Image). Position determination of gamma-ray bursts could be achieved with accuracy less than one degree observing the X-ray component of the burst. Weak X-ray sources such as active galactic nuclei could be also monitored with time resolution less than one day. The X-ray all sky monitor will work to discover X-ray novae and transient phenomena and give us the alarm for further detailed observations. The obtained data will be also used for archival study.


Author(s):  
N. Dorrell

It has been known for many years that certain weather events (e.g., precipitation, low barometric pressure, etc.) can affect the results of outdoor gamma-ray surveys, particularly those where gamma spectroscopy is being used for the detection of uranium and its progeny. These effects are a result of a natural phenomenon that produces anomalous results that are contrary to the true concentrations present at the survey site. Gamma-ray survey results sometimes overestimate uranium concentrations during and immediately following rain or snowfall events. The effects that a precipitation event has upon a drive-over gamma-ray survey are discussed in this paper. Surveys were conducted using a sensitive array of sodium iodide (NaI) detectors mounted to an all-terrain vehicle in late fall/early winter where snow was encountered. Isotope-specific measurements taken before and during precipitation events are compared and visually presented in iso-contour maps.


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