Sharif Digital Repository

With the production from the reservoirs, the amount of in-situ oil storage has decreased and there is a need to increase oil recovery (EOR) from the reservoir. Increased oil recovery (EOR) includes operations such as acidizing and hydraulic fracturing. Considering the economic and high operational costs and geomechanical complexities, as well as the technical progress of hydraulic fracturing and its future; It is necessary to manage hydraulic fracturing operations optimally. This research is about hydraulic fracturing and its main goal is to optimize the parameters of the fracture or the geometry of the fracture. The research study was carried out on the Bangistan Reservoir located in the... 

Today, with the reduction of world oil prices and the development of competing energy sources, fossil fuels such as nuclear energy, electricity, wind, etc., in order to increase the economic efficiency of oil sales, we must Reduce production costs to a minimum. If the components of oil extraction costs are examined, the cost of drilling production wells is one of the main economic components that affect the cost of producing oil. Therefore, according to the above explanations, the cost of drilling wells should be reduced.To reduce the cost of drilling a well to be drilled, it is better to predict the drilling parameters (for example ROP) before starting the drilling process. For this... 

The technique of geosteering has been widely adopted within the petroleum industry for proper wellbore positioning through involving predicting the geology ahead of the bit, furthermore, the advantages of this technique became more pronounced as drilling environments became more complex. the fundamental concept of geosteering is to put and maintain the well within the target zone(s), so as to promote safe and economical production of the well. Geosteering-related technologies, like downhole information-gathering tools and real time data transmission and data analysis applications, are continuously and significantly improved to support geosteering decisions.This study demonstrates how the use... 

Rapid gas kick detection is an essential tool in safe well control operation. Gas kick can be defined as the uncontrolled release of gas from the formation into the wellbore due to insufficient hydrostatic pressure of the drilling mud. Delay in gas kick detection makes it challenging to control the well properly and may lead to blowout when gas reaches the surface, causing irreparable damage to life, property, and the environment. The usual method of identifying this phenomenon is through surface parameters such as increasing the return flow rate of drilling mud at the surface or increasing pit gain. The use of oil-based mud makes it more challenging to detect. Because, unlike water-based... 

In the recent two decades Lattice Boltzmann method has been introduced as a class of computational fluid dynamic methods for fluid simulation. In this method instead of solving Navier-Stocks equation, Boltzmann equation is solved to simulate the flow of a fluid. This method originally was developed based on uniform grids which makes lattice Boltzmann a time consuming technique. This feature already exists in the case of simulation of fluid flow in porous media. To eliminate this limitation some research has been done on methods to formulate lattice Boltzmann on unstructured grids. On the basis of this research a method on non-uniform grids has been selected. Here using object oriented... 

The static and dynamic properties of a porous medium are highly dependent on its internal geometry. CT scan images are used to obtain porous media geometry. These images are not directly suitable for computational purpose. Because these images are not easy computable, the pore-throat network models are used to geometrical conversation. Extracting these models from CT scans is done using statistical-probabilistic methods based on image processing. In this study, new methods for extracting the 3D pore network model from 2D/3D CT scan images and pore connection detection are presented. In this method, the geometric static parameters of the rock, including the porosity, the porosity-based... 

Given that the mean of the cost of drilling operation related to the required martials and preparation of the drilling fluids, therefore, the design and construction drilling fluid which omit has to be a proper rheology is essential in drilling operations and oil industry. A desirable property of the drilling fluid is the minimum fluid loss volume which can be achieved by formation of a low permeability filter cake on the wellbore. Drilling fluid filtrating invasion into the formation can cause formation damage and reduction in the productivity of the well. In drilling fluids, a series of natural synthetic and polymers may be used as fluid (filtration) loss control additives. However, high... 

With the considerable increase in academic publications and ever-growing concern for academic writing, academic literacy, and plagiarism in recent years, investigating academic writers’ ‘authorial identity’ and ‘authorial voice’ has been of utmost importance in academic milieu. The main purposes of this study were achieved by going through five main phases including 1) hypothesizing a model of authorial identity, 2) developing and validating a questionnaire based on the model, 3) testing the model based on the questionnaire data, 4) searching for possible significant difference in authorial identity of academic writers from three different fields of English, Biology, and Engineering, and 5)... 

An important step in the early stages of an oilfield development is the accurate identification of the location of production and injection wells which has a significant impact on productivity and profitability of the reservoir. Recently, operation companies in petroleum industry focus on production optimization, recovery enhancement and cost reduction; as a result, application of non-conventional wells (NCW) or non-vertical wells have dramatically increased. Well placement optimization is a complicated task as it is a function of several contributing factors including reservoir heterogeneities and economic constraints. The complexity of this task increases when it is considered as a... 

Most of petroleum reservoirs of Iran are fractured reservoirs which has different properties, geometrical structure and drive mechanism in comparison with conventional reservoirs. The major difference is the existence of interaction between fractures and matrix respectively with a high and very low permeable (or imperable) medi. One simulation method for these fractures is discrete fracture network (DFN) modeling which is used in this study to investigate dynamic properties of these fractures. In this study, matrix is assumed as an impermeable media then dynamic properties like effective permeability of fracture network for different realization reservoirs are calculated and and evaluated by... 

Oil reservoirs, have integrated identity; that is they consist of different parameters such as wettablity, initial water saturation, capillary and gravity forces, etc. which are related to each other and affect ultimate recovery simultaneously. In fractured reservoirs, other parameters such as fractures and complex geological structures are also considered  among  important  parameters  which  affect  ultimate  recovery.  Due  to  large  amount  of reserves,  fractured  reservoirs  are  subject  to  different  studies  and  simulations.  In  this  research, different  parameters  which  affect  ultimate  recovery  in  fractured  reservoirs,  are  studied  and simulated. Different  studies ... 

Today, due to a massive increase in accuracy of reservoir characterization models, multiphase flow simulation on real permeability fields faces a serious challenge. Using multiscale methods in reservoir flow simulation of a heterogeneous environment has led to huge speed-up of the simulation. In multiscale methods, instead of replacing a heterogeneous medium by an equivalent homogeneous medium, used in upscaling, the problem is solved on the original resolution. In this thesis, multiscale finite volume method (MSFV) has been used to simulate flow and saturation behavior of a black oil model. Unlike the original multiscale finite volume methods that were unable to solve compressible fluid... 

The aim of this research is to model the separation and transport of multi-component gas mixture through a nanoporous membrane by using pore network models (PNM).
The first part of this project represents the membrane simulating by means of the PNM. A three-dimensional network is used to represent the membrane’s pore space and it consists of two parts; pore and throat. The pores are the main parts of the network and their diameter is characterized according to the pore size distribution of the membrane. Every throat connects two pores and the number of throats which is connected to each pore is named "coordination number". Using a variety size of pores and throats leads to production of... 

Clogging of the pores of the porous medium occurs in different processes such as geothermal injection pumps, hydrocarbon wells, and underground water extraction wells. We need a model that can simulate these blockages in order to predict how fundamental variables of the porous medium change under different flow regimes and different particle sizes in the fluid (for example, the relationship between porosity and permeability changes). The aim is to simulate clogging in a porous medium using a pore network model. Simulations should model pore clogging and show how the permeability of the sample changes due to pore clogging. In the pore network, there are often thousands (or millions) of pores... 

Injection of acid into the carbonate rock dissolves the rock, and the porous medium is constantly changing. As a result, the boundaries between the acid and the porous medium, which are in fact the interface between the solid phase and the liquid phase, are constantly changing. Therefore, on the issue of acid injection into carbonate rock, we are facing dynamic boundary conditions. Also, due to the simultaneous solution of transfer and reaction phenomena, modeling acid injection into carbonate rock faces many challenges.In such problems, the ALE method, which is a combination of the best features of the Lagrangian method and the Eulerian method, offers a very precise solution and is used as... 

Acidizing operation is performed in oil and gas reservoirs with the aim of overcoming formation damages, increasing permeability and reducing skin factor. In carbonate reservoir, the hydrochloric acid increases the permeability of the areas around the well to a more than its initial value by dissolving part of the formation minerals. Considering that most of Iran's oil and gas reservoirs are in the category of carbonate reservoirs, it is important to study the reaction kinetics of carbonate minerals and acids used in acidizing operation. The complex and multifactorial nature of the acidizing operation in the reservoirs has made it very difficult to design a successful and optimal operation.... 

In drilling operations, cost, time, and quality are the three factors to consider for evaluation. Drilling optimization means reducing project costs and completing them as quickly as possible while still meeting the standards. Due to the complexity and specificity of directional drilling and the increasing need for this type of drilling, optimizing the directional drilling operation is of great importance. Drilling rate of penetration and hydromechanical specific energy are considered as two main indicators of drilling performance in this thesis. In the first step, drilling rate of penetration is predicted using drilling data and machine learning algorithms and then single-objective and... 

The efficiency of acidizing operation is usually assessed through Build up or Drawdown test (calculation of skin). These methods are performed only after the acidizing operation, so it is impossible to evaluate the efficiency of acidizing during the real time operation. Analysis of the acidizing efficiency during the operation by using the acidizing operation data is a viable approach to this costly and challenging process. In this project, it has been tried to present a well testing method for calculating changes of skin value of a carbonate reservoirs during acidizing operation by using the real field data (surface pressure, injection rate and etc.).
The estimation of skin changes... 

In drilling the percolation structure reservoirs (such as offshore Channelized reservoirs), one of the most important factors in the effectiveness of wells is drilling permeable areas (Channels), while Channel constraints make it possible for two wells to collide. On the other hand, if the desired reservoir is an offshore reservoir, these restrictions have been increased because usually several wells are drilled near together from one platform. Therefore, proper well collision analysis method is also important in these situations. In this project, anti-collision analysis is performed using the MWD device error model between two or more wells in a static reservoir model with channel... 

Carbonate matrix acidizing using hydrochloric acid which causes CO2 generation is one of the most popular well stimulation techniques in recent decades. Lots of the wormhole propagation models developed for laboratory scale, assumes that the cores are fully saturated with aqueous solution and no CO2 gas is produced. Final purpose of this research is to develop a geochemical model describing equilibrium composition of a 3 phase system of acidic solution-gas-rock accurately in common pressure and temperature conditions of carbonate matrix acidizing to obtain main inputs of acid reactive flow in porous media from it. In this regard, concept of the “extent of the reaction” is defined and after...