scholarly journals Integrated petrophysical study to validate water saturation from well logs in Bahariya Shaley Sand Reservoirs, case study from Abu Gharadig Basin, Egypt

2020 ◽  
Vol 10 (8) ◽  
pp. 3139-3155
Author(s):  
Mohamed El-Bagoury
Keyword(s):  
Clay Minerals ◽  
Oil And Gas ◽  
Water Saturation ◽  
Exchange Capacity ◽  
Fine Tuning ◽  
Well Logs ◽  
Gas Reservoirs ◽  
Reservoir Rocks ◽  
Resistivity Logs ◽  
Petroleum Fields

Abstract Water saturation is a key parameter in evaluating oil and gas reservoirs and calculating OIIP and GIIP for petroleum fields. The late Cretaceous Bahariya reservoir contains variable amounts of clay minerals. Bore hole logs are affected with those clay minerals particularly the density and resistivity logs. Several methods are acknowledged to determine the true water saturation from well logs in shaley sand reservoirs. Each method assumes a sort of corrections to amount of shale distributed in the reservoir. The scope of this petrophysical study is to integrate core analysis and bore hole logs to investigate the characteristics of water saturation in the Bahariya reservoirs. Comparison between most of the significant shaley sand methods is presented in this research. Reservoir lithology and mineralogy are explained by Elan-model while bore hole images are used for fine-tuning the electrofacies. Siltstone, shaley sand and clean sandstones are the main electrofacies that is characterizing the Bahariya reservoir rocks. For accurate saturation results, some core samples have been used for validating the log-derived water saturation. Dean stark and cation exchange capacity experiments are integrated with bore hole logs to calculate the error in water saturation for each method for best calibration. The successful integration between logs and core measurements led to convenient log evaluation and accurate understanding for the Bahariya reservoir in the prospective part of Abu Gharadig basin.

Experimental Study on the Saturation Model of Volcanic Rock Based on Fluid Distribution

2021 ◽  
Vol 62 (4) ◽  
pp. 422-433
Author(s):  
Baozhi Pan ◽  
◽  
Weiyi Zhou ◽  
Yuhang Guo ◽  
Zhaowei Si ◽  
...  
Keyword(s):  
Volcanic Rock ◽  
Oil And Gas ◽  
Water Saturation ◽  
Early Stage ◽  
Evaluation Model ◽  
Acoustic Velocity ◽  
Distribution Model ◽  
Fluid Distribution ◽  
Water Drainage ◽  
Gas Reservoirs

A saturation evaluation model suitable for Nanpu volcanic rock formation is established based on the experiment of acoustic velocity changing with saturation during the water drainage process of volcanic rock in the Nanpu area. The experimental data show that in the early stage of water drainage, the fluid distribution in the pores of rock samples satisfies the patchy formula. With the decrease of the sample saturation, the fluid distribution in the pores is more similar to the uniform fluid distribution model. In this paper, combined with the Gassmann-Brie and patchy formula, the calculation equation of Gassmann-Brie-Patchy (G-B-P) saturation is established, and the effect of contact softening is considered. The model can be used to calculate water saturation based on acoustic velocity, which provides a new idea for the quantitative evaluation of volcanic oil and gas reservoirs using seismic and acoustic logging data.

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 Petrophysical Analysis of Well Logs for Asmari Reservoir in Abu Ghirab Oil Field, South Eastern Iraq

2020 ◽  
pp. 2979-2990
Author(s):  
Buraq Adnan Al-Baldawi
Keyword(s):  
Gamma Ray ◽  
Water Saturation ◽  
Bulk Water ◽  
Computer Processing ◽  
Oil Field ◽  
Well Logs ◽  
Asmari Formation ◽  
Petrophysical Properties ◽  
Resistivity Logs ◽  
Environmental Corrections

The present study includes the evaluation of petrophysical properties and lithological examination in two wells of Asmari Formation in Abu Ghirab oil field (AG-32 and AG-36), Missan governorate, southeastern Iraq. The petrophysical assessment was performed utilizing well logs information to characterize Asmari Formation. The well logs available, such as sonic, density, neutron, gamma ray, SP, and resistivity logs, were converted into computerized data using Neuralog programming. Using Interactive petrophysics software, the environmental corrections and reservoir parameters such as porosity, water saturation, hydrocarbon saturation, volume of bulk water, etc. were analyzed and interpreted. Lithological, mineralogical, and matrix recognition studies were performed using porosity combination cross plots. Petrophysical characteristics were determined and plotted as computer processing interpretation (CPI) using Interactive Petrophysics program. Based on petrophysical properties, Asmari Reservoir in Abu Ghirab oil field is classified into three sub formations: Jeribe/ Euphrates and Kirkuk group which is divided into two zones: upper Kirkuk zone, and Middle-Lower Kirkuk zone. Interpretation of well logs of Asmari Formation indicated a commercial Asmari Formation production with medium oil evidence in some ranges of the formation, especially in the upper Kirkuk zone at well X-1. However, well X-2, especially in the lower part of Jeribe/ Euphrates and Middle-Lower Kirkuk zone indicated low to medium oil evidence. Lithology of Asmari Formation demonstrated a range from massive dolomite in Jeribe/ Euphrates zone to limestone in upper Kirkuk zone and limestone and sandstone in middle-lower Kirkuk zone, whereas mineralogy of the reservoir showed calcite and dolomite with few amounts of anhydrite.

scholarly journals Analysis of Petrophysical Studies of Deep Oil and Gas Reservoirs of Onshore and Offshore Fields in Azerbaijan

2020 ◽  
Vol 20 (3) ◽  
pp. 204-213
Author(s):  
Vagif Sh. Gurbanov ◽  
◽  
Latif A. Sultanov ◽  
Nurlana I. Gulueva ◽  
◽  
...  
Keyword(s):  
Oil And Gas ◽  
Sedimentary Basin ◽  
Oil Industry ◽  
Gas Reservoirs ◽  
Reservoir Rocks ◽  
Deep Wells ◽  
Long Time ◽  
Enhance Efficiency ◽  
The Cost ◽  
Natural Hydrocarbon

The paper presents results of generalized laboratory studies from an array of petrophysical parameters of reservoir rocks (potential hydrocarbon reservoirs). The study is targeted at well-known horizons of productive strata of the Meso- Cenozoic sedimentary basin. The area under study includes oil and gas onshore and deep offshore fields in Azerbaijan that have been under active continuous developments. The development of these natural hydrocarbon accumulations has over a century-long history, which has shown that the major oil and gas deposits are associated with the South Caspian and Kura depressions subjected to an intensive submersion over the Meso-Cenozoic period. Although many of the fields in these depressions have been exploited for a long time, the commercial potential is high enough, especially in deep-seated areas. Nonetheless, problems associated with extracting oil and gas therefrom are pending final resolutions. Subsoil developments in the region are currently performed at an intensive rate at depths above 4-4.5 km, since most oil and gas deposits have already been explored at shallow and moderate depths (even in hard-to-reach areas). As known in oil industry, the wells with a depth of over 4 km are referred to deep wells, while those with a depth of over 6 km are referred to ultra-deep wells. Moreover, drilling of such wells is associated with serious costrelated challenges. For example, the cost of developing deep and even ultra-deep wells is high enough, ranging from $ 2-3 to $ 9-12 million. This fact emphasizes the need to enhance efficiency of such operations, which requires a highscale geological reasoning of a field’s potential and choice of a good location.

scholarly journals Petrographical characteristics and post-depositional alteration affecting porosity and permeability of Oligocene sandstones, block 15-1/05, Cuu Long basin

2020 ◽  
Vol 4 (2) ◽  
pp. First
Author(s):  
Thanh Ngoc Do ◽  
Duyen Thi Pham ◽  
Phuong Kim Lieu
Keyword(s):  
Clay Minerals ◽  
Oil And Gas ◽  
Gas Storage ◽  
Early Diagenesis ◽  
Burial Depth ◽  
Reservoir Rocks ◽  
Potential Reservoir ◽  
Negative Effect ◽  
Porosity And Permeability ◽  
Grain Sorting

Petrographical characteristics and post-depositional alteration studies of sandstones are the two important factors to reservoir rocks, which affect oil and gas storage and permeability of reservoir rocks. This study revealed petrographical characteristics, post-depositional alteration, and their influence on the porosity and permeability of Oligocene sandstones, including C, D, and E and F sequences, block 15-1/05, Cuu Long Basin. The results show that most of the sandstones were arkose, lithic arkose, and sporadically interbedded by feldspathic greywacke. The post-depositional alteration was progressively increasing following the burial depth from early diagenesis of sequence C, to intermediate diagenesis of sequence D and advanced diagenesis of sequence E and F. The post-depositional alterations significantly influenced on the porosity of the Oligocene sandstone were the cementation and mechanical compaction. They reduced the porosity and permeability of the sandstone. Additionally, authigenic clay minerals have a negative effect on permeability in which sandstones were rich illite and illite-smectite clay minerals, and the permeability tended to decrease stronger than others. Our results showed that the potential reservoir rocks of Oligocene sandstones, block 15-1/05 were sequence E and F sandstones that are in well grain sorting, well grain roundness shape, and contained a small number of cement, particularly the absence of illite and illite-smectite.

scholarly journals The geochemical role of meteoric waters as a factor in the formation of the void space of oil and gas reservoirs

2020 ◽  
pp. 3-13
Author(s):  
O.P. Abramova ◽  
A.V. Goreva ◽  
R.R. Gumerova
Keyword(s):  
Oil And Gas ◽  
Water Saturation ◽  
Upper Permian ◽  
Genetic Profile ◽  
Void Space ◽  
Gas Reservoirs ◽  
Filtration Properties ◽  
The Relationship ◽  
Gas Bearing

The features of the chemical composition of formation waters of the Upper Permian, Lower and Middle Triassic aquifers within individual structures of the Malozemelsk-Kolguev monocline of the Timan-Pechora oil and gas bearing basin are examined. It is shown that the aquifers that, despite their remoteness from the recharge areas, had experienced repeated processes of dipping and uplifting of the territory, preserved the infiltration waters, but significantly transformed ones. To identify their genetic profile and determine the relationship with the processes of catagenetic changes, hydrochemical coefficients and indices of water saturation of calcium carbonate and calcium sulfate are calculated. It is established that the examined infiltration waters are characterized by high aggressiveness, dissolution ability, leaching and removal of main minerals. It is pointed out that the consequence of these processes is the formation of secondary void space and the creation of high capacitive and filtration properties of rocks. The universality of geochemical interaction between water and rocks in thermodynamically open geological systems is emphasized and it is confirmed by individual geological examples that the heterogeneity of the hydrochemical field can act as a cause of screening zones of oil and gas accumulation, as well as provide appropriate conditions for localization of hydrocarbon fluids.

Geological and Field Feasibility Study of Field Development Management Using Marker-Based Production Profiling Surveillance in Horizontal Wells: The Case Study of the Yuzhno-Vyintoiskoye Field

2021 ◽  
Author(s):  
Marat Rafailevich Dulkarnaev ◽  
Yuri Alexeyevich Kotenev ◽  
Shamil Khanifovich Sultanov ◽  
Alexander Viacheslavovich Chibisov ◽  
Daria Yurievna Chudinova ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Oil And Gas ◽  
Water Saturation ◽  
Clay Content ◽  
Horizontal Wells ◽  
Integrated Approach ◽  
Geological Structure ◽  
Gas Field ◽  
Field Development ◽  
Reservoir Rocks

In pursuit of efficient oil and gas field development, including hard-to-recover reserves, the key objective is to develop and provide the rationale for oil recovery improvement recommendations. This paper presents the results of the use of the workflow process for optimized field development at two field clusters of the Yuzhno-Vyintoiskoye field using geological and reservoir modelling and dynamic marker-based flow production surveillance in producing horizontal wells. The target reservoir of the Yuzhno-Vyntoiskoye deposit is represented by a series of wedge-shaped Neocomian sandstones. Sand bodies typically have a complex geological structure, lateral continuity and a complex distribution of reservoir rocks. Reservoir beds are characterised by low thickness and permeability. The pay zone of the section is a highly heterogeneous formation, which is manifested through vertical variability of the lithological type of reservoir rocks, lithological substitutions, and the high clay content of reservoirs. The target reservoir of the Yuzhno-Vyintoiskoye field is marked by an extensive water-oil zone with highly variable water saturation. According to paleogeographic data, the reservoir was formed in shallow marine settings. Sand deposits are represented by regressive cyclites that are typical for the progressing coastal shallow water (Dulkarnaev et al., 2020). Currently, the reservoir is in production increase cycle. That is why an integrated approach is used in this work to provide a further rationale and creation of the starting points of the reservoir pressure maintenance system impact at new drilling fields to improve oil recovery and secure sustainable oil production and the reserve development rate under high uncertainty.

scholarly journals APPARATUS AND METHODICAL COMPLEX FOR DETERMINATION OF OIL-GAS RESERVOIRS PARAMETERS WHILE DRILLING HORIZONTAL WELLS

2019 ◽  
pp. 20-25
Author(s):  
M. Bondarenko ◽  
V. Kulyk ◽  
Z. Yevstakhevych ◽  
S. Danyliv ◽  
V. Zinenko ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Water Saturation ◽  
Small Diameter ◽  
Horizontal Wells ◽  
Physical Models ◽  
Gas Reservoirs ◽  
Exploration And Production ◽  
Oil And Gas Companies ◽  
Oil Gas ◽  
Logging Tool

The paper is devoted to the basic principles of the trend of logging, namely logging while drilling (LWD), which is new for Ukraine. The LWD technology has a number of advantages over other logging types, in particular, in supplementary exploration and production of hydrocarbons in fields that are in longterm development. In this case, the drilling of horizontal wells, which by productivity is much higher than the vertical ones, is important. For the investigations of horizontal wells, we proposed a universal compact radioactive logging tool with small diameter, which is placed in entire drill collar just before drilling. The combined radioactive logging tool LWD-КПРК-48 (48 mm in diameter) contains dual-spacing modules of neutron logging, neutron-gamma logging, density logging, as well as separately placed gamma-logging unit. Calibration works with the developed combined tool were carried out on physical models of reservoirs in the presence of drill collars and corresponding calibration dependences on porosity and density were obtained. They, together with the developed methods and other data, allow us to determine an extended set of petrophysical parameters, namely, the porosity of water-, oil- and gas-saturated reservoirs, the identification parameters of fluid: water – oil and water – gas, oil-, gas- and water saturation, volume content of oil and gas, etc. Test of a logging tool LWD-КПРК-48 when drilling a horizontal well in an oil-bearing bed showed high informativity and efficiency of product. The created apparatus and methodical complex for the investigation of horizontal oil and gas wells while drilling has several advantages over known analogues, in particular, is universal, convenient, more available to mining and well logging oil and gas companies.

scholarly journals Microscopic Imbibition Characterization of Sandstone Reservoirs and Theoretical Model Optimization

2021 ◽  
Author(s):  
Xuan Xu ◽  
Yujing Wan ◽  
Xizhe Li ◽  
yong Hu ◽  
qingyan mei ◽  
...  
Keyword(s):  
Porous Media ◽  
Transition Zone ◽  
Oil And Gas ◽  
Large Deviation ◽  
Water Saturation ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Gas Reservoirs ◽  
Phase Saturation ◽  
Oil And Gas Reservoirs

Abstract Traditional porous media imbibition models deviate from the actual imbibition process in oil and gas reservoirs. Experimental studies on gas-water imbibition in reservoirs were carried out to describe the dynamic profile variation process of wet phase saturation in reservoirs and to further reveal the variation of the imbibition front and the imbibition amount. Optimization and correction methods were established, and experimental verifications were performed. Studies have shown the following: (1) Unlike homogeneous porous media, the water phase imbibition process in oil and gas reservoirs is more complicated, and it is impossible for the maximum saturation of imbibition to reach 100%. (2) Contrary to the theoretical hypothesis, the imbibition of water is not piston-like, and there is a clear transition zone at the imbibition front. This transition zone is the main cause of water saturation variations in the imbibition zone; with the expansion of the imbibition zone, the influence of the transition zone on water saturation weakens. (3) Traditional theoretical models predict a positive correlation between the imbibition amount and the measurements; however, there is a large deviation in the numerical values, which must be corrected. (4) The L-W model was optimized and the parameter group fluid factor and the reservoir factor were proposed to characterize the properties of the fluid and the reservoir, respectively. These two parameters have a clear physical significance and are easy to accurately test. After experimental correction, the parameters are favourably suitable for oil and gas reservoirs.

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