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.

Pore-scale fluid distributions determined by nuclear magnetic resonance spectra of partially saturated sandstones

Geophysics ◽  
2019 ◽  
Vol 84 (3) ◽  
pp. MR107-MR114 ◽  
Author(s):  
Chunhui Fang ◽  
Baozhi Pan ◽  
Yanghua Wang ◽  
Ying Rao ◽  
Yuhang Guo ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Water Saturation ◽  
Acoustic Property ◽  
P Wave ◽  
Distribution Model ◽  
Fluid Distribution ◽  
Pore Scale ◽  
Saturation Model ◽  
Partially Saturated ◽  
P Wave Velocity

The acoustic property and the P-wave velocity of partially saturated rocks depend not only on the water saturation but also on the pore-scale fluid distribution. Here, we analyzed the pore-scale fluid distribution using nuclear magnetic resonance (NMR) [Formula: see text] spectra, which present the variation of porosity components associated with NMR transverse relaxation time [Formula: see text]. Based on the [Formula: see text] spectra, we classified the pore-scale fluid distribution during water imbibition and drainage into three models: a low-saturation model, a patchy distribution model, and a uniform distribution model. We specifically assigned the low-saturation model to deal with the acoustic property of the rocks at the imbibition starting stage and the drainage final stage because cement softening has a nonnegligible effect. We studied the acoustic properties of sandstone rocks with various pore-scale fluid distributions, at the imbibition process and the drainage process. We confirmed that, once the variations in water saturation and pore-scale fluid distribution are taken into account, the P-wave velocity prediction matches well with the laboratory measurement of samples, representing nearly tight sandstone rocks that are partially saturated with distilled water.

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.

RESERVOIR SIMULATION OF THE GIPPSLAND BASIN

1984 ◽  
Vol 24 (1) ◽  
pp. 170
Author(s):  
S. T. Henzcll A. A Young A K. Khurana
Keyword(s):  
Reservoir Simulation ◽  
Single Phase ◽  
Oil And Gas ◽  
Initial Pressure ◽  
Fluid Distribution ◽  
External Boundary ◽  
Gas Reservoirs ◽  
Oil And Gas Reservoirs ◽  
Gippsland Basin ◽  
Exploration And Development

A three-dimensional, single-phase reservoir simulation model of the entire Gippsland Basin aquifer system, together with its oil and gas reservoirs, was first developed in 1973. It was replaced by an improved version in 1975. Now, after fifteen years of production, pressure predictions from the model still compare very well with data obtained from current exploration and development wells.The model, consisting of 4186 grid blocks, incorporates the geological description, and pressure and fluid distribution of the basin. The geological description includes porosity, net-to-gross ratio and permeability with fluid properties representing the aquifer. A well-established initial pressure/depth relationship for the Gippsland Basin is included in the model. Although it is a single-phase model, oil and gas reservoirs are represented by pseudo rock and fluid properties.The model is regularly updated with historical and forecast production rates in order to predict pressure behaviour and therefore aquifer strength in various areal and stratigraphic locations in the basin. Such information is essential for defining external boundary conditions in individual reservoir simulation models and assists in gas deliverability forecasts. In exploration wells, measured pressures are compared with model predictions to help understand the degree of pressure communication with the basin aquifer and hence the level of pressure support. Detailed predictions of the pressure gradients expected in both exploration and development wells are often of assistance in identifying fluid contacts, overpressure and reservoirs with limited communication with the aquifer.

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.

Optimisation of Well and Layer Selection for Re-fracturing

2021 ◽  
Author(s):  
Qi Zhu
Keyword(s):  
Oil And Gas ◽  
Evaluation Model ◽  
Machine Intelligence ◽  
Parameter Method ◽  
Gas Reservoirs ◽  
Fracture Conductivity ◽  
Oil Distribution ◽  
Well Pattern ◽  
Elasto Plasticity ◽  
Single Well

Abstract In initial fracturing of tight oil and gas reservoirs, due to the influence of geological and technological factors, the fracture conductivity has decreased, and the single-well productivity has been reduced. It is urgent to repeat transformation to restore or increase productivity. Well selection and layer selection is one of the key factors that affect the design of re-fracturing and the effect of stimulation. Based on a big database of well-sites, establishing machine intelligence theory determines the elasto-plasticity, permeability, porosity, completion parameters, production decline parameters and skin coefficient that affect the effect of re-fracturing stimulation by dimensionless parameter method of well and layer selection and its stimulation evaluation model. Combined with artificial neural network and BP algorithm, the index weights of strata with different reservoir physical properties are calculated to analyze the final evaluation value of fracturing effect. On the basis of remaining oil distribution research, scale extended fracture repeated fracturing is increased, injection-production well pattern is improved, scale repeated fracturing effect is increased, well pattern is improved, target layer is repeatedly fractured, and oil increase effect is obvious after fracturing.

De-Risking Fluid Compartmentalization of the Barik Reservoir in the Khazzan Field, Oman - An Integrated Approach

2021 ◽  
Author(s):  
Abdullah Al Anboori ◽  
Stephen Dee ◽  
Khalil Al Rashdi ◽  
Herbert Volk
Keyword(s):  
Oil And Gas ◽  
Water Pressure ◽  
Integrated Approach ◽  
Fluid Distribution ◽  
Geological Time ◽  
Gas Reservoirs ◽  
Gas Field ◽  
Development Costs ◽  
Potential Reservoir ◽  
Reservoir Compartmentalization

Abstract The degree of fluid compartmentalization has direct implications on the development costs of oil and gas reservoirs, since it may negatively impact gas water contacts (GWC) and fluid condensate gas ratios (CGR). In this case study on the Barik Formation in the giant Khazzan gas field in Block 61 in Oman we demonstrate how integrating independent approaches for assessing potential reservoir compartmentalization can be used to assess compartmentalization risk. The three disciplines that were integrated are structural geology (fault seal analysis, movement and stress stages of faults and fractures, traps geometry over geological time), petroleum systems (fluid chemistry and pressure, charge history) and sedimentology-stratigraphy including diagenesis (sedimentological and diagenetic controls on vertical and lateral facies and reservoir quality variation). Dynamic data from production tests were also analyzed and integrated with the observations above. Based on this work, Combined Common Risk Segment (CCRS) maps with a most likely and alternative scenarios for reservoir compartmentalization were constructed. While pressure data carry significant uncertainty due to the tight nature of the deeply buried rocks, it is clear pressures in gas-bearing sections fall onto a single pressure gradient across Block 61, while water pressures indicate variable GWCs. Overall, the GWCs appear to shallow across the field towards the NW, while water pressure appears to increase in that direction. The "apparent" gas communication with separate aquifers is difficult to explain conventionally. A range of scenarios for fluid distribution and reservoir connectivity are discussed. Fault seal compartmentalization and different trap spill points were found to be the most likely mechanism explaining fluid distribution and likely reservoir compartmentalization. Perched water may be another factor explaining variable GWCs. Hydrodynamic tilting due to the flow of formation water was deemed an unlikely scenario, and the risk of reservoir compartmentalization due to sedimentological and diagenetic flow barriers was deemed to be low.

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.

scholarly journals Seismic multi-attribute analysis for petrophysics reservoir prediction with probabilistic neural network in “FA” field

2020 ◽  
Vol 200 ◽  
pp. 06010
Author(s):  
Fadlan Ardinda ◽  
Agus Riyanto
Keyword(s):  
Neural Network ◽  
Oil And Gas ◽  
Reservoir Characterization ◽  
Water Saturation ◽  
Probabilistic Neural Network ◽  
Distribution Model ◽  
Reservoir Prediction ◽  
Attribute Analysis ◽  
Geological Conditions ◽  
Well Data

Oil and gas reserves are increasingly difficult to find due to more complex geological conditions. This complex condition causes difficulties in determining reservoir distribution. Therefore, a better method is needed to overcome these complex geological conditions. In this study, the petrophysics analysis by using the multi-attribute and the Probabilistic Neural Network (PNN) used to make reservoir distribution model on seismic horizontal slice. This multi-attribute method and Probabilistic Neural Network (PNN) that can search for correlation between seismic attributes and the data sought, for the prediction of property values from surrounding rocks. From this method, the distribution of porosity data with a correlation value of 0.52 was generated, water saturation with a correlation value of 0.73, and shale content with a correlation value of 0.58. Where the combination of porosity data, water saturation, shale content, and acoustic impedance (AI) data of inversion results can be a clue to identify reservoir distribution. From the porosity and saturation values, hydrocarbon dispersion can be made, wherein this study values were obtained between 0.01 0.03. This “FA” field has a reservoir between wells F-06, FA-05, FA-15, and FA-18 and spreads westward from wells FA-05, FA-15 & FA-18. The distribution of petrophysical parameters generated from the validation of well data using the multi-attribute method. This thing prove that Multi-attribute and neural network analysis can be used to determine predictions of porosity, water saturation, and shale content well and can be used for reservoir characterization.

scholarly journals Microscopic imbibition characterization of sandstone reservoirs and theoretical model optimization

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xuan Xu ◽  
Yujin Wan ◽  
Xizhe Li ◽  
Yong Hu ◽  
Shanshan Tian ◽  
...  
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

AbstractTraditional 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 F and the reservoir factor R 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 optimized model is favourably suitable for oil and gas reservoirs.

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