Well‐logging method

Geophysics ◽  
1980 ◽  
Vol 45 (11) ◽  
pp. 1667-1684 ◽  
Author(s):  
F. F. Segesman
Keyword(s):  
Gamma Ray ◽  
Neutron Density ◽  
Accurate Analysis ◽  
Resistivity Logs ◽  
Computer Input ◽  
The 1960S ◽  
Log Interpretation ◽  
Resistivity Log ◽  
Self Potential ◽  
Continuous Temperature

By 1930, the resistivity log was recorded commercially in several countries, and in 1931 the self‐potential (SP) measurement was added. An electromagnetic (EM) teleclinometer was introduced in 1932, a continuous temperature log in 1933, and an anisotropy dipmeter ca. 1935. The significance of the SP was an ongoing study until about 1962. The bases for the quantitative interpretation of resistivity for saturation were formulated by 1941. The years from about 1940 into the 1960s saw the development of other basic logs—dipmeter, gamma ray, neutron, induction, microresistivity, focused resistivity, density, and acoustic velocity—as well as other miscellaneous logs. Suites of resistivity logs were evolved to provide more accurate analysis. Much effort was expended on the interpretation of shaly sands. Neutron, density, and acoustic logs yielded information on porosity, lithology, gas saturation, and/or shaliness. Availability of porosity from these logs facilitated resistivity‐log interpretation. In the late 1950s, interest developed in the use of computers for log interpretation. By about 1961, dipmeter logs were being recorded on digital magnetic tape suitable for computer input, and other logs were available by about 1965. Digital recording has also facilitated transmission of logs via radio and telephone. Recently, digital systems for wellsite computations have been introduced.

scholarly journals Characterization of Mishrif Formation Reservoir in Amara Oil Field, Southeast Iraq, Using Geophysical Well-logging

2021 ◽  
pp. 4702-4711
Author(s):  
Asmaa Talal Fadel ◽  
Madhat E. Nasser
Keyword(s):  
Reservoir Characterization ◽  
Gamma Ray ◽  
Water Saturation ◽  
Total Porosity ◽  
Effective Porosity ◽  
Oil Field ◽  
Neutron Density ◽  
Reservoir Water ◽  
Resistivity Logs ◽  
Reliable Knowledge

     Reservoir characterization requires reliable knowledge of certain fundamental properties of the reservoir. These properties can be defined or at least inferred by log measurements, including porosity, resistivity, volume of shale, lithology, water saturation, and permeability of oil or gas. The current research is an estimate of the reservoir characteristics of Mishrif Formation in Amara Oil Field, particularly well AM-1, in south eastern Iraq. Mishrif Formation (Cenomanin-Early Touronin) is considered as the prime reservoir in Amara Oil Field. The Formation is divided into three reservoir units (MA, MB, MC). The unit MB is divided into two secondary units (MB1, MB2) while the unit MC is also divided into two secondary units (MC1, MC2). Using Geoframe software, the available well log images (sonic, density, neutron, gamma ray, spontaneous potential, and resistivity logs) were digitized and updated. Petrophysical properties, such as porosity, saturation of water, saturation of hydrocarbon, etc. were calculated and explained. The total porosity was measured using the density and neutron log, and then corrected to measure the effective porosity by the volume content of clay. Neutron -density cross-plot showed that Mishrif Formation lithology consists predominantly of limestone. The reservoir water resistivity (Rw) values of the Formation were calculated using Pickett-Plot method.   

scholarly journals Petro physical properties analysis of beani bazar gas field, Bangladesh using wireline log interpretation

2017 ◽  
Vol 5 (2) ◽  
pp. 95
Author(s):  
G. M. Ariful Islam ◽  
Farzana Yeasmin Nipa ◽  
Md. Shaheen Shah
Keyword(s):  
Physical Properties ◽  
Gamma Ray ◽  
Combination Method ◽  
High Resistivity ◽  
Neutron Density ◽  
Gas Field ◽  
High Gamma ◽  
Average Water ◽  
Log Interpretation ◽  
Gamma Ray Log

The study on analysis of petro physical properties which are done into two well such as BB-1 and BB-2 of Beani Bazar Gas Field using wire line log data. In BB-1, Upper Gas Sand (UGS), Lower Gas Sand (LGS), Sand-1 and Bellow Lower Gas Sand (BLGS) zones and in BB-2, UGS and LGS are identified through high gamma ray log, high resistivity, low neutron and low density log response. The thickness of UGS, LGS, Sand-1, BLGS of BB-1 and UGS, LGS of BB-2 are respectively 47.69m, 14.326m, 17.526m, 17.526m and 26.37m, 21.03m. The Shale volumes of UGS, LGS, Sand-1 and BLGS of BB-1 are respectively 14.87%, 21.58%, 11.69% and 21.28% and UGS and LGS of BB-2 are respectively 17.91% and 29.33%, which are measured through Schlumberger Clavier method. The average porosity of UGS, LGS, Sand-1 and BLGS of BB-1 are respectively 17.55%, 16.60%, 18.07% and 31.10% and UGS and LGS of BB-2 are respectively 13.19% and 11.29%, which are very effective for hydrocarbon prospect by using neutron-density combination method. The average water saturations of UGS, LGS, Sand-1 and BLGS of BB-1 are respectively 24.97%, 23.78%, 80.18% and 19.85% which revised to hydrocarbon saturations as respectively 75.03%, 76.22%, 19.82% and 80.15% and UGS and LGS of BB-2 are respectively 41.20% and 69.50% which revised to hydrocarbon saturations as respectively 58.80% and 30.50% that are followed by Simandoux method. By analysis of petro physical properties of those zones, the UGS and LGS are very effective hydrocarbon bearing zones where production is running at the present time, the Sand-1 zone is water bearing zone. This study impose high important on BLGS. This zone is satisfied all criteria for hydrocarbon prospect. This study recommends that more study is needed for BLGS, and it may be commercially economical viable in a future.

scholarly journals FORMATION EVALUATION FOR JERIBE FORMATION IN THE JARIA PIKA GAS FIELD

2020 ◽  
Vol 53 (2F) ◽  
pp. 83-93
Author(s):  
Salam Abdulrahman
Keyword(s):  
Gamma Ray ◽  
Total Porosity ◽  
Neutron Density ◽  
Secondary Porosity ◽  
Gas Field ◽  
Sonic Log ◽  
Porosity Effect ◽  
Log Interpretation ◽  
Sonic Logs ◽  
Gamma Ray Log

The Jaria Pika Gas field is a domal anticlinal structure in the northeast of Iraq NW trending, about 3.6 km long and 1.9 km wide. The 55 m thick gas bearing Jeribe Formation is the main reservoir. This study intends to well log interpretation to determine the petrophysical properties of the Jeribe Formation in the Jaria Pika Gas Field. Total porosity, effect porosity, and secondary porosity have been calculated from neutron, density, and sonic logs. Porosity is fair to good in the Jeribe formation. From RHOB-NPHI and N/M cross plot, the Jeribe Formation is composed mainly of dolomite, limestone with nodules of anhydrite. The Fatha Formation contains considerable amounts of anhydrite layers, so it's represented the cap rocks for the Jeribe Reservoir which is recognized based on the reading of Gamma-ray log, Density log, Neutron log, and Sonic log. The Jaria Pika is considered as gas field as the Jeribe reservoir rocks are gas saturated ones.

scholarly journals A review of basic well log interpretation techniques in highly deviated wells

2022 ◽  
Author(s):  
Sayantan Ghosh
Keyword(s):  
Cross Sections ◽  
Gamma Ray ◽  
Horizontal Wells ◽  
Well Logs ◽  
Well Log ◽  
High Porosity ◽  
Resistivity Logs ◽  
Log Interpretation ◽  
Well Log Interpretation ◽  
Deviated Wells

AbstractDrilling deviated wells has become customary in recent times. This work condenses various highly deviated and horizontal well log interpretation techniques supported by field examples. Compared to that in vertical wells, log interpretation in highly deviated wells is complex because the readings are affected not only by the host bed but also the adjacent beds and additional wellbore-related issues. However, understanding the potential pitfalls and combining information from multiple logs can address some of the challenges. For example, a non-azimuthally focused gamma ray logging while drilling (LWD) tool, used in combination with azimuthally focused density and neutron porosity tools, can accurately tell if an adjacent approaching bed is overlying or underlying. Moreover, resistivity logs in horizontal wells are effective in detecting the presence of adjacent beds. Although the horns associated with resistivity measurements in highly deviated wells are unwanted, their sizes can provide important clues about the angle of the borehole with respect to the intersecting beds. Inversion of horizontal/deviated well logs can also help determine true formation resistivities. Additionally, observed disagreement between resistivity readings with nuclear magnetic resonance (NMR) T2 hydrocarbon peaks can indicate the presence or absence of hydrocarbons. Furthermore, variations in pulsed neutron capture cross sections along horizontal wells, measured while injecting various fluids, can indicate high porosity/permeability unperforated productive zones. Finally, great advances have been made in the direction of the bed geometry determination and geologic modeling using the mentioned deviated well logs. More attention is required toward quantitative log interpretation in horizontal/high angle wells for determining the amount of hydrocarbons in place.

scholarly journals Facies Analysis and Depositoinal Environment of D-3 Reservoir Sands Vin Field, Eastern Niger Delta

2019 ◽  
pp. 1-19
Author(s):  
Onyewuchi, Chinedu Vin ◽  
Minapuye, I. Odigi
Keyword(s):  
Seismic Data ◽  
Niger Delta ◽  
Depositional Environment ◽  
Gamma Ray ◽  
Facies Analysis ◽  
Depositional Environments ◽  
Width Ratio ◽  
Neutron Density ◽  
Wireline Logs ◽  
Isopach Map

Facies analysis and depositional environment identification of the Vin field was evaluated through the integration and comparison of results from wireline logs, core analysis, seismic data, ditch cutting samples and petrophysical parameters. Well log suites from 22 wells comprising gamma ray, resistivity, neutron, density, seismic data, and ditch cutting samples were obtained and analyzed. Prediction of depositional environment was made through the usage of wireline log shapes of facies combined with result from cores and ditch cuttings sample description. The aims of this study were to identify the facies and depositional environments of the D-3 reservoir sand in the Vin field. Two sets of correlations were made on the E-W trend to validate the reservoir top and base while the isopach map was used to establish the reservoir continuity. Facies analysis was carried out to identify the various depositional environments. The result showed that the reservoir is an elongate , four way dip closed roll over anticline associated with an E-W trending growth fault and contains two structural high separated by a saddle. The offshore bar unit is an elongate sand body with length: width ratio of >3:1 and is aligned parallel to the coast-line. Analysis of the gamma ray logs indicated that four log facies were recognized in all the wells used for the study. These include: Funnel-shaped (coarsening upward sequences), bell-shaped or fining upward sequences, the bow shape and irregular shape. Based on these categories of facies, the depositional environments were interpreted as deltaic distributaries, regressive barrier bars, reworked offshore bars and shallow marine. Analysis of the wireline logs and their core/ditch cuttings description has led to the conclusion that the reservoir sandstones of the Agbada Formation in the Vin field of the eastern Niger Delta is predominantly marine deltaic sequence, strongly influenced by clastic output from the Niger Delta. Deposition occurred in a variety of littoral and neritic environment ranging from barrier sand complex to fully marine outer shelf mudstones.

scholarly journals Petrophysical Properties and Digenetic Evolution of Shuaiba Formation in Nasiriyah Oil Field, Southern Iraq

2021 ◽  
pp. 4810-4818
Author(s):  
Marwah H. Khudhair
Keyword(s):  
Gamma Ray ◽  
Water Saturation ◽  
Middle Part ◽  
Effective Porosity ◽  
Oil Field ◽  
Neutron Density ◽  
Petrophysical Properties ◽  
Secondary Porosity ◽  
Primary Porosity ◽  
Gamma Ray Log

     Shuaiba Formation is a carbonate succession deposited within Aptian Sequences. This research deals with the petrophysical and reservoir characterizations characteristics of the interval of interest in five wells of the Nasiriyah oil field. The petrophysical properties were determined by using different types of well logs, such as electric logs (LLS, LLD, MFSL), porosity logs (neutron, density, sonic), as well as gamma ray log. The studied sequence was mostly affected by dolomitization, which changed the lithology of the formation to dolostone and enhanced the secondary porosity that replaced the primary porosity. Depending on gamma ray log response and the shale volume, the formation is classified into three zones. These zones are A, B, and C, each can be split into three rock intervals in respect to the bulk porosity measurements. The resulted porosity intervals are: (I) High to medium effective porosity, (II) High to medium inactive porosity, and (III) Low or non-porosity intervals. In relevance to porosity, resistivity, and water saturation points of view, there are two main reservoir horizon intervals within Shuaiba Formation. Both horizons appear in the middle part of the formation, being located within the wells Ns-1, 2, and 3. These intervals are attributed to high to medium effective porosity, low shale content, and high values of the deep resistivity logs. The second horizon appears clearly in Ns-2 well only.

scholarly journals Petrophysical Properties of Nahr Umar Formation in Nasiriya Oil Field

2020 ◽  
Vol 21 (3) ◽  
pp. 9-18
Author(s):  
Ahmed Abdulwahhab Suhail ◽  
Mohammed H. Hafiz ◽  
Fadhil S. Kadhim
Keyword(s):  
Gamma Ray ◽  
Water Saturation ◽  
Oil Field ◽  
Well Logs ◽  
High Porosity ◽  
Reservoir Properties ◽  
Petrophysical Parameters ◽  
Resistivity Logs ◽  
Lithology Prediction ◽  
Porosity And Permeability

   Petrophysical characterization is the most important stage in reservoir management. The main purpose of this study is to evaluate reservoir properties and lithological identification of Nahr Umar Formation in Nasiriya oil field. The available well logs are (sonic, density, neutron, gamma-ray, SP, and resistivity logs). The petrophysical parameters such as the volume of clay, porosity, permeability, water saturation, were computed and interpreted using IP4.4 software. The lithology prediction of Nahr Umar formation was carried out by sonic -density cross plot technique. Nahr Umar Formation was divided into five units based on well logs interpretation and petrophysical Analysis: Nu-1 to Nu-5. The formation lithology is mainly composed of sandstone interlaminated with shale according to the interpretation of density, sonic, and gamma-ray logs. Interpretation of formation lithology and petrophysical parameters shows that Nu-1 is characterized by low shale content with high porosity and low water saturation whereas Nu-2 and Nu-4 consist mainly of high laminated shale with low porosity and permeability. Nu-3 is high porosity and water saturation and Nu-5 consists mainly of limestone layer that represents the water zone.

DENSITY LOGGING

Geophysics ◽  
1960 ◽  
Vol 25 (4) ◽  
pp. 891-904 ◽  
Author(s):  
J. J. Pickell ◽  
J. G. Heacock
Keyword(s):  
Bulk Density ◽  
Gamma Ray ◽  
Petroleum Industry ◽  
Core Data ◽  
Response Characteristics ◽  
Calibration Curves ◽  
Ray Density ◽  
Log Interpretation

This review of density logging is primarily a compilation of information presented in the petroleum industry literature. It includes a brief discussion of some of the theory involved in gamma‐ray density logging, various calibration curves, comparisons of density‐log and core data, and comments on density‐log interpretation. Conclusions are that the density log, under good borehole conditions, provides an accurate means for measuring bulk density of the formation adjacent to the borehole. If grain density is known, valid estimates of porosity can also be made. Because of the response characteristics of the system, accuracy in determining porosity is best when formation densities are low and porosities are high.

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