scholarly journals Lithological Study of Mishrif, Rumaila, Ahmadi and Mauddud Formations Using Vp/ Vs Ratio, Acoustic Impedance and Well Logging at Amara Oil Field, Southern Iraq

2021 ◽  
Vol 54 (2D) ◽  
pp. 39-58
Author(s):  
Hiba Tareq
Keyword(s):  
Acoustic Impedance ◽  
Gamma Ray ◽  
Water Saturation ◽  
Rock Physics ◽  
Shear Velocity ◽  
Oil Field ◽  
High Porosity ◽  
Shale Volume ◽  
Sonic Logs ◽  
Gamma Ray Log

The lithology of four formations from the Cretaceous period (Mishrif, Rumaila, Ahmadi, and Mauddud) was evaluated using the Acoustic Impedance and Vp/Vs ratio cross plot from Rock Physics Templates. Dipole sonic logs in Am-6-Am-10 well log were used to calculate compression velocity then the estimated shear velocity using Greenberg Castagna equations. RHOB and VP logs were used to calculate Acoustic Impedance. The ratio of Vp/Vs was measured then used with Acoustic Impedance colored by shale volume which is measured from gamma ray log, porosity and water saturation to estimate lithology type of the considered formations using cross plots and rock physics chart in the Techlog software. The lithology of the formations found to be of high porosity limestone alternating with hard limestone layers and the shale volume increases in the Ahmadi formation. The water bearing zone was found in all Formations, this zone is indicted by high Vp/ Vs ratio and low AI. The hydrocarbon bearing zones were indicated by low amount of both Acoustic Impedance and Vp/Vs ratio and this observation was shown in Mishrif and Mauddud formations.

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.

scholarly journals Shale volume and permeability of the Miocene unconsolidated turbidite sands of Bonga oil field, Niger delta, Nigeria

2017 ◽  
Vol 5 (1) ◽  
pp. 37 ◽  
Author(s):  
Inyang Namdie ◽  
Idara Akpabio ◽  
Agbasi Okechukwu .E.
Keyword(s):  
Niger Delta ◽  
Gamma Ray ◽  
Water Saturation ◽  
Strong Dependence ◽  
Water Injection ◽  
Oil Field ◽  
Reservoir Properties ◽  
Injection Wells ◽  
Log Data ◽  
Shale Volume

Bonga oil field is located 120km (75mi) southeast of the Niger Delta, Nigeria. It is a subsea type development located about 3500ft water depth and has produced over 330 mmstb of hydrocarbon till date with over 16 oil producing and water injection wells. The producing formation is the Middle to Late Miocene unconsolidated turbidite sandstones with lateral and vertical homogeneities in reservoir properties. This work, analysis the petrophysical properties of the reservoir units for the purpose of modeling the effect of shale content on permeability in the reservoir. Turbidite sandstones are identified by gamma-ray log signatures as intervals with 26-50 API, while sonic, neutron, resistivity, caliper and other log data are applied to estimate volume of shale ranging between 0.972 v/v for shale intervals and 0.0549 v/v for turbidite sands, water saturation of 0.34 v/v average in most sand intervals, porosity range from 0.010 for shale intervals to 0.49 v/v for clean sands and permeability values for the send interval 11.46 to2634mD, for intervals between 7100 to 9100 ft., Data were analyzed using the Interactive Petrophysical software that splits the whole curve into sand and shale zones and estimates among other petrophysical parameters the shale contents of the prospective zones. While Seismic data revealed reservoir thickness ranging from 25ft to over 140ft well log data within the five wells have identified sands of similar thickness and estimated average permeability of700mD. Within the sand units across the five wells, cross plots of estimated porosity, volume of shale and permeability values reveal strong dependence of permeability on shale volume and a general decrease in permeability in intervals with shale volume. It is concluded that sand units with high shale contents that are from0.500 to0.900v/v will not provide good quality reservoir in the field.

scholarly journals Prospect evaluation and hydrocarbon potential assessment: the Lower Eocene Facha non-clastic reservoirs, Hakim Oil Field (NC74A), Sirte basin, Libya—a case study

2019 ◽  
Vol 10 (2) ◽  
pp. 351-362 ◽  
Author(s):  
Mohamed A. Kassab ◽  
Ali El-Said Abbas ◽  
Mostafa A. Teama ◽  
Musa A. S. Khalifa
Keyword(s):  
Gamma Ray ◽  
Water Saturation ◽  
Oil Field ◽  
Thickness Variation ◽  
Oil Accumulation ◽  
Lower Eocene ◽  
Log Data ◽  
Shale Volume ◽  
Volume Porosity ◽  
Sirte Basin

Abstract Petrophysical assessment of Facha Formation based on log data of six wells A1, A3, A4, A5, A8 and A13 recorded over the entire reservoir interval was established. Hakim Oil Field produces from the Lower Eocene Facha reservoir, which is located at the western side of Sirte basin. Limestone, dolostone and dolomitic limestone are the main lithologies of the Facha reservoir. This lithology is defined by neutron porosity—density cross-plot. Noteworthily, limestone increases in the lowermost intervals of the reservoir. Structurally, the field is traversed by three northwest–southeast faults. The shale of the Upper Cretaceous Sirte Formation is thought to be the source rock of the Facha Formation, whereas the seals are the limestone and anhydrite of the Lower Eocene Gir Formation. In this study, the Facha reservoir’s cutoff values were obtained from the cross-plots of the calculated shale volume, porosity and water saturation values accompanied with gamma ray log data and were set as 20%, 10% and 70%, respectively. Isoparametric maps for the thickness variation of net pay, average porosity, shale volume and water saturation were prepared, and the authors found out that the Facha Formation has promising reservoir characteristics in the area of study; a prospective region for oil accumulation trends is in the north and south of the study area.

scholarly journals Depositional Environment and facies analysis of Useni- 1, Niger Delta Basin, using well logs, core data

2019 ◽  
Vol 7 (1) ◽  
pp. 58
Author(s):  
G. O. Aigbadon ◽  
E. O. Akpunonu ◽  
S. O. Agunloye ◽  
A. Ocheli ◽  
O. O .Akakaru
Keyword(s):  
Gamma Ray ◽  
Water Saturation ◽  
Oil Field ◽  
Well Logs ◽  
Depth Range ◽  
Depositional Facies ◽  
Core Data ◽  
Delta Plain ◽  
Niger Delta Basin ◽  
Gamma Ray Log

This study was carried out integrating well logs and core to build reservoir model for the Useni-1 oil field. Core data and well logs were used to evaluate the petrophysical characteristics of the reservoirs. The paleodepositional environment was deduce from the wells and cores data. The depositional facies model showed highly permeable channels where the wells where positioned. The environments identified that the fluvial channel facies with highly permeable zones constituted the reservoirs. Four reservoirs were mapped at depth range of 8000ft to 8400ft with thicknesses varying from 20ft to 400ft. Petrophysical results showed that porosity of the reservoirs varied from 12% to 28 %; permeability from 145.70 md to 454.70md; water saturation from 21.65% to 54.50% and hydrocarbon saturation from 45.50% to 78.50 %. Core data and the gamma ray log trends with right boxcar trend indicate fluvial point bar and tidal channel fills in the lower delta plain setting. By-passed hydrocarbons were identified in low resistivity pay sands D1, D2 at depth of 7800 – 78100ft in the field.  

scholarly journals The Use of Gamma Ray Log Data to Compute and Study the Deposition of Shale Volume of Mishrif Formation in Middle and Southern Parts of Iraq

2021 ◽  
pp. 3932-3941
Author(s):  
Hiba Tarq Jaleel ◽  
Ahmed S. Al-Banna ◽  
Ghazi H. Al-Sharaa
Keyword(s):  
Gamma Ray ◽  
Oil Field ◽  
Log Data ◽  
Shale Volume ◽  
Carbonate Formation ◽  
Regional Area ◽  
Isopach Map ◽  
Gamma Ray Log ◽  
Surfer Software

The shale volume is one of the most important properties that can be computed depending on gamma ray log. The shale volume of Mishrif Formation (carbonate formation from middle Cenomanian- early Turonian) was studied for the regional area of the middle and southern parts of Iraq. The gamma ray log data from seventeen  wells ( Kf-3,Kf-4, Ad-1,Ad -2,Dh-1, Bu-47, Ns-2, Ns-4, Am-1,Am-2,Hf-2,Hf-115,Mj-3,Mj-15, Su-7,Wq-15 and  Lu-7) distributed in the study area were used to compute the shale volume of Mishrif Formation. From the available data of the considered wells, a regional isopach map of Mishrif Formation was obtained. The isopach map indicates that the maximum thickness of Mishrif Formation is located at the eastern part of the study area. The results of the CPI and the shale volume map, which were computed using the Techlog and surfer software,  show that the maximum value of shale volume is located at the southern part of the study area (Su-7  well), while the minimum value is at the eastern  part (Hf-2well). According to the classification of Kamel and Mabrouk (2003), Mishrif Formation seems to be a Shaly Formation in the study area, except Halfaya oil field at the eastern part of the study area, which seems as a Clear Formation. The top map of the shale marker bed, which appears in most studied wells, shows a regional trend of the formation toward the northeast. According to the variation of the thickness of the shale marker bed, the study area is divided into four zones.

scholarly journals Evaluation of Petrophysical Properties Using Well Logs of Yamama Formation in Abu Amood Oil Field, Southern Iraq

2021 ◽  
Vol 54 (1E) ◽  
pp. 67-77
Author(s):  
Buraq Adnan Al-Baldawi
Keyword(s):  
Gamma Ray ◽  
Water Saturation ◽  
Bulk Water ◽  
Carbonate Reservoir ◽  
Oil Field ◽  
Well Logs ◽  
Water Volume ◽  
High Porosity ◽  
Petrophysical Properties ◽  
Reservoir Properties

The petrophysical analysis is very important to understand the factors controlling the reservoir quality and production wells. In the current study, the petrophysical evaluation was accomplished to hydrocarbon assessment based on well log data of four wells of Early Cretaceous carbonate reservoir Yamama Formation in Abu-Amood oil field in the southern part of Iraq. The available well logs such as sonic, density, neutron, gamma ray, SP, and resistivity logs for wells AAm-1, AAm-2, AAm-3, and AAm-5 were used to delineate the reservoir characteristics of the Yamama Formation. Lithologic and mineralogic studies were performed using porosity logs combination cross plots such as density vs. neutron cross plot and M-N mineralogy plot. These cross plots show that the Yamama Formation consists mainly of limestone and the essential mineral components are dominantly calcite with small amounts of dolomite. The petrophysical characteristics such as porosity, water and hydrocarbon saturation and bulk water volume were determined and interpreted using Techlog software to carried out and building the full computer processed interpretation for reservoir properties. Based on the petrophysical properties of studied wells, the Yamama Formation is divided into six units; (YB-1, YB-2, YB-3, YC-1, YC-2 and YC-3) separated by dense non porous units (Barrier beds). The units (YB-1, YB-2, YC-2 and YC-3) represent the most important reservoir units and oil-bearing zones because these reservoir units are characterized by good petrophysical properties due to high porosity and low to moderate water saturation. The other units are not reservoirs and not oil-bearing units due to low porosity and high-water saturation.

scholarly journals Re-evaluation of Petro physical Properties in Yammama Formation at Nasiriya Field

2019 ◽  
Vol 20 (3) ◽  
pp. 59-66
Author(s):  
Karrar Hayder Jassim ◽  
Jalal A. Al-Sudani
Keyword(s):  
Physical Properties ◽  
Gamma Ray ◽  
Water Saturation ◽  
Uranium Content ◽  
Geological Model ◽  
North West ◽  
Shale Volume ◽  
The North ◽  
Volume Porosity ◽  
Gamma Ray Log

Nasiriya field is located about 38 Km to the north – west of Nasiriya city. Yammama, a giant lower cretaceous reservoir in Nasiriya field which is lithologically formed from limestone. Yammama mainly was divided into three main reservoir units YA, YB1, YB2 and YB3 and it is separated by impermeable layers of variable thickness. An accurate petro physical evolution of the reservoir is of great importance perform an excellent geological model so that four petro physical properties which are shale volume, porosity, water saturation and permeability was re-evaluated. The volume of shale was calculated using the density and neutron logs (VSH-DN) rather than using gamma ray log because of presence a uranium content in the formation that makes overestimation of shale volume. Cross plots of Density Neutron logs are used to determine porosity by using IP software, which is correcting automatically Density Neutron logs for the effect of shale. Indonesian equation was used to estimate water saturation for five wells rather than Archie equation in order to consider shale volume. Fuzzy logic was adopted to predict permeability instead of regression analysis (cross plot) because of presence of errors in the results in this method. The results are shown that units YB2 and YB3 have best reservoir quality.

scholarly journals Cross plot Analysis of Rock Properties from Well Log Data for gas detection in Soku Field, Coastal Swamp Depobelt, Niger Delta Basin

2018 ◽  
Vol 3 (4) ◽  
pp. 180
Author(s):  
Okoli Emeka Austin ◽  
Okechukwu Ebuka Agbasi ◽  
Onyekuru Samuel ◽  
Sunday Edet Etuk
Keyword(s):  
Acoustic Impedance ◽  
Niger Delta ◽  
Gamma Ray ◽  
Rock Physics ◽  
Oil Field ◽  
Rock Properties ◽  
High Resistivity ◽  
S Wave ◽  
Lithology Identification ◽  
Well Data

The cross plotting of rock properties for fluid and lithology discrimination was carried out in a Niger Delta oil field using well data X-26 from a given oil field in the coastal swamp depobelt. The data used for the analysis consisted of suites of logs, including gamma ray, resistivity, sonic and density logs only. The reservoir of interest Horizon 1, was identified using the available suite of logs on the interval where we have low gamma ray, high resistivity and low acoustic impedance specifically at depths 10,424ft (3177.24m) to 10 724ft (3268m). We first obtained other rock attributes from the available logs before cross plotting. The inverse of the interval transit times of the sonic logs were used to generate the compressional velocities and the S-wave data was generated from Castagna´s relation. Employing rock physics algorithm on Hampson Russell software (HRS), rock attributes including Vp/Vs ratio, Lambda-Rho and Mu-Rho were also extracted from the well data. Cross plotting was carried out and Lambda Rho (λρ) versus MuRho (μρ) crossplots proved to be more robust for lithology identification than Vp versus Vs crossplots, while λρ Versus Poisson impedance was more robust than Vp/Vs versus Acoustic impedance for fluid discrimination, as well as identification of gas sands. The crossplots were consistent with Rock Physics Templates (RPTs). This implies the possibility of further using the technique on data points of inverted sections of various AVO attributes within the field in areas not penetrated by wells within the area covered by the seismic.

Application of instantaneous-frequency attribute and gamma-ray wireline logs in the delineation of lithology in Serbin field, Southeast Texas: A case study

2018 ◽  
Vol 6 (4) ◽  
pp. T1023-T1043 ◽  
Author(s):  
Osareni C. Ogiesoba ◽  
William A. Ambrose ◽  
Robert G. Loucks
Keyword(s):  
Instantaneous Frequency ◽  
Acoustic Impedance ◽  
High Frequency ◽  
Gamma Ray ◽  
Low Frequency ◽  
High Porosity ◽  
Southeastern Part ◽  
High Gamma ◽  
Southeast Texas ◽  
Frequency Map

Although Serbin field in Southeast Texas was discovered in 1987, lithologic and petrophysical properties in the southeastern part of the field have not been fully evaluated. We have generated instantaneous frequency from 3D seismic data and predicted gamma-ray response volume from seismic attributes. By extracting maps of the instantaneous frequency and gamma-ray response along interpreted horizons, and crossplotting the instantaneous frequency against gamma-ray logs and integrating core data, we generated lithology maps to identify shale-prone zones that stratigraphically trapped hydrocarbons in the southeastern part of the field. We determine that Serbin field is separated into two areas: (1) a high-frequency, high-gamma-ray, and high-acoustic-impedance area in the northwest and (2) a low-frequency, low-gamma-ray, and low-acoustic-impedance area located in the southeast. By developing a lithologic map and relating it to the corresponding instantaneous-frequency map and log data, we also find that the southeastern part of the field can be divided into three zones: (1) zone 1, composed of approximately 0.7–2.7 m (approximately 2–8 ft) thick sandstone-rich beds of moderate frequency (25–30 Hz); (2) zone 2, composed of high-frequency (33–60 Hz) shale-rich zones that serve as stratigraphic-trapping-mechanisms; and (3) zone 3, composed of approximately 1.7–4 m (approximately 5–13 ft) thick sandstone-rich beds of low frequency (0–18 Hz) and relatively high porosity. These methods can be applied in other areas of the field with limited well control.

Sign in / Sign up

Export Citation Format

Share Document