Quality Assurance of the Evaluation of Hydrocarbon Saturation From Resistivity Logs

2006 ◽  
Author(s):  
Paul Francis Worthington
Keyword(s):  
Quality Assurance ◽  
Resistivity Logs ◽  
Hydrocarbon Saturation

Detecting Skrugard by CSEM — Prewell prediction and postwell evaluation

2014 ◽  
Vol 2 (3) ◽  
pp. SH67-SH77 ◽  
Author(s):  
Lars Ole Løseth ◽  
Torgeir Wiik ◽  
Per Atle Olsen ◽  
Jan Ove Hansen
Keyword(s):  
Data Acquisition ◽  
Barents Sea ◽  
Hydrocarbon Exploration ◽  
Seismic Structure ◽  
Well Location ◽  
Resistivity Logs ◽  
Resistivity Model ◽  
Joint Interpretation ◽  
Hydrocarbon Saturation ◽  
Scenario Testing

The discovery of Skrugard in 2011 was a significant milestone for hydrocarbon exploration in the Barents Sea. The result was a positive confirmation of the play model, prospect evaluation, and the seismic hydrocarbon indicators in the area. In addition, the well result was encouraging for the CSEM interpretation and analysis that had been performed. Prior to drilling the 7220/8-1 well, EM resistivity images of the subsurface across the prospect had been obtained along with estimates of hydrocarbon saturation at the well position. The resistivity distribution was derived from extensive analysis of the multiclient CSEM data from 2008. The analysis was based on joint interpretation of seismic structures and optimal resistivity models from the CSEM data. The seismic structure was furthermore used to constrain the resistivity anomaly to the Skrugard reservoir. Scenario testing was then done to assess potential alternative models that could explain the CSEM data in addition to extract the most likely reservoir resistivity. Estimates of hydrocarbon saturation followed from using petrophysical parameters from nearby wells and knowledge of the area, combined with the most likely resistivity model from CSEM. Our results from the prewell study were compared to the postwell resistivity logs, for horizontal and vertical resistivity. We found a very good match between the estimated CSEM resistivities at the well location and the corresponding well resistivities. Thus, our results confirmed the ability of CSEM to predict hydrocarbon saturation. In addition, the work demonstrated limitations in the CSEM data analysis tools as well as sensitivity to acquisition parameters and measurement accuracy. The work has led to more CSEM data acquisition in the area and continued effort in development of our tools for data acquisition and analysis.

Estimation of in situ hydrocarbon saturation of porous rocks from borehole measurements of spontaneous potential

Geophysics ◽  
2020 ◽  
Vol 85 (6) ◽  
pp. D199-D217
Author(s):  
Joshua Bautista-Anguiano ◽  
Carlos Torres-Verdín
Keyword(s):  
Drilling Mud ◽  
Porous Rocks ◽  
Spontaneous Potential ◽  
The Matrix ◽  
Resistivity Logs ◽  
Petrophysical Model ◽  
Hydrocarbon Saturation ◽  
The Difference ◽  
Mud Filtrate

It has been previously shown that Nernst’s equation is not reliable for the interpretation of spontaneous potential (SP) measurements acquired in hydrocarbon-bearing rocks. We have examined whether the difference between borehole SP measurements and Nernst-equation predictions could be used to estimate in situ hydrocarbon saturation of porous rocks. For this purpose, a new petrophysical model and a mechanistic finite-difference algorithm for simulating SP borehole measurements in the presence of mud-filtrate invasion are used to establish the limits of detectability of hydrocarbon saturation using only SP logs. We find that the optimal conditions for the detection of hydrocarbon saturation from SP borehole measurements are when (1) capillary forces dominate the process of mud-filtrate invasion, (2) the matrix-pore interface region, known as the electrical double layer, has a relevant impact in the diffusion of counterions, and (3) the electrolyte concentration of drilling mud is greater than that of formation water. We also determine why high values of the endpoint of the water relative permeability favor the detection of hydrocarbon-saturated rocks with the SP log. Using measurements acquired in three key wells within a mature and active hydrocarbon field, three blind tests find that our petrophysical model together with the mechanistic SP simulation algorithm enable the estimation of hydrocarbon saturation from SP borehole measurements without the need for resistivity logs or porosity calculations. The estimation is reliable when the volumetric concentration of shale is negligible, the pore network structure is constant throughout the reservoir, and radial invasion profiles are similar to those observed in the calibration key wells.

scholarly journals Evaluation of Petrophysical Parameters of Reservoir Sand Wells in Uzot-Field, Onshore Niger Delta Basin, Nigeria

2021 ◽  
Vol 25 (2) ◽  
pp. 157-171
Author(s):  
UC Omoja ◽  
T.N. Obiekezie
Keyword(s):  
Niger Delta ◽  
Gamma Ray ◽  
Depth Range ◽  
High Hydrocarbon ◽  
Hydrocarbon Production ◽  
Petrophysical Parameters ◽  
Resistivity Logs ◽  
Hydrocarbon Saturation ◽  
Niger Delta Basin ◽  
Sand Bodies

Evaluation of the petrophysical parameters in Uzot-field was carried out using Well log data. The target for this study was the D3100 reservoir sand of wells Uz 004, Uz 005, U008 and Uz 011 with depth range of 5540ft to 5800ft across the four wells. Resistivity logs were used to identify hydrocarbon or water-bearing zones and hence indicate permeable zones while the various sand bodies were then identified using the gamma ray logs. The results showed the delineated reservoir units having porosity ranging from 21.40% to 33.80% indicating a suitable reservoir quality; permeability values from 1314md to 18089md attributed to the well sorted nature of the sands and hydrocarbon saturation range from 12.00% to 85.79% implying high hydrocarbon production. These results suggest a reservoir system whose performance is considered satisfactory for hydrocarbon production. Keywords: Petrophysical parameters, porosity, permeability, hydrocarbon saturation, Niger Delta Basin

Detailed quantitative sequence stratigraphic interpretation for the characterization of Amangi field using seismic data and well logs

2021 ◽  
Vol 19 (3) ◽  
pp. 63-82
Author(s):  
S. Inichinbia ◽  
Halidu Hamza
Keyword(s):  
Seismic Data ◽  
Gamma Ray ◽  
Hydrocarbon Exploration ◽  
Well Logs ◽  
Rock Properties ◽  
Sequence Stratigraphic ◽  
Resistivity Logs ◽  
Hydrocarbon Saturation ◽  
Shaly Sand ◽  
Net To Gross

The sequence stratigraphy of Amangi field of the Niger Delta was studied using seismic data and well logs. The field is a structurally  complex one and presents serious challenges to hydrocarbon exploration and production. The main objective of these analyses is to  identify sand intervals using the available data. Well log data were used as additional tools to constrain the seismic correlations in order to solve the correlation problem. The well logs were evaluated for the field’s petrophysical properties by combining the gamma ray and resistivity logs to determine reservoir zones with considerable hydrocarbon saturation. Also, the relationship between some basic rock properties/attributes and litho-types were determined for the study area. Next, well-to-seismic ties were produced and two horizons were picked. Acoustic impedance inversion was also performed which revealed “hard sands” due to mixed lithologies (heterolithics). This made it difficult to discriminate the sands from shales in the P-impedance domain alone. So, progress was made to determine the net-to-gross of the field. The analysis revealed that these reservoirs have shaly sand with shale content of 10%, porosity averaging 21%, and hydrocarbon saturation of 90%. The result established a vertical stack of a series of reservoirs in an anticlinal structure of which the H1000 and H4000 stand out for their huge volumes of rich gas condensate accumulation. This discovery provoked the drive for the first phase of development of this field. Keywords: stratigraphy, facies, net-to-gross, horizon, lithology, well-to-seismic tie, impedance

Quality assurance: one school's response

1990 ◽  
Vol 54 (4) ◽  
pp. 228-229
Author(s):  
KJ Wittemann
Keyword(s):  
Quality Assurance

Outcomes/Quality Assurance

1999 ◽  
Vol 8 (1) ◽  
pp. 15-17
Author(s):  
Michael Groher ◽  
Caryn Easterling
Keyword(s):  
Quality Assurance

Percutaneous Tracheostomy: A Multidisciplinary Approach

2008 ◽  
Vol 18 (2) ◽  
pp. 87-98 ◽  
Author(s):  
Vinciya Pandian ◽  
Thai Tran Nguyen ◽  
Marek Mirski ◽  
Nasir Islam Bhatti
Keyword(s):  
Health Care ◽  
Quality Assurance ◽  
Data Collection ◽  
Health Care Professionals ◽  
Multidisciplinary Approach ◽  
Percutaneous Tracheostomy ◽  
Johns Hopkins Hospital ◽  
Prospective Data ◽  
Comprehensive Service ◽  
Over Time

Abstract The techniques of performing a tracheostomy has transformed over time. Percutaneous tracheostomy is gaining popularity over open tracheostomy given its advantages and as a result the number of bedside tracheostomies has increased necessitating the need for a Percutaneous Tracheostomy Program. The Percutaneous Tracheostomy Program at the Johns Hopkins Hospital is a comprehensive service that provides care to patients before, during, and after a tracheostomy with a multidisciplinary approach aimed at decreasing complications. Education is provided to patients, families, and health-care professionals who are involved in the management of a tracheostomy. Ongoing prospective data collection serves as a tool for Quality Assurance.

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