Sharif Digital Repository

The acid fracturing process is a thermal, hydraulic, mechanical, geochemical and geomechanical coupled phenomena in which the behavior of these variables are interrelated. To model the flow behavior of an acid into a fracture, mass and momentum balance equations are used to draw 3D velocity and pressure profiles. Part of the fluid diffuses or leaks off into the fracture walls and dissolves part of the fracture face.An acid balance equation is used to draw the concentration profile of the acid and to account for the quantity of rock dissolved. An algorithm is developed for this process to generate the final conductivity distribution after fracture closure. The objective of modeling acid... 

Production of solid particles is a phenomenon that occurs in most oil and gas well. This phenomenon can cause many problems in every life stage of a well such as erosion of surface equipment, subsurface equipment and environmental problems associated with solid particles disposal. On the other hand, this phenomenon can increase the permeability of near wellbore areas, which is considered to be the advantages of solid particles production. In this study, nine sandstone samples were prepared and different pressure ratios have been used for evaluation production of sand in different situations. Also, in the next step, by numerical simulations, studies of stresses around a well and... 

One of the most common methods for determining elastic moduli of rocks and porosity is acoustic velocity log. The elastic moduli of reservoir rock are widely used in geomechanical modelling, borehole stability and hydraulic fracture design. Carbonate oil reservoirs are known for heterogeneity and anisotropic nature. Therefore correlation of acoustic velocity and rock properties are generally challenging. Rock’s shear modulus is very important during saturating of sample with pore fluid because assumed it is independent of pore fluid type. However due to the several fluid-solid interaction mechanisms such as velocity dispersion, surface energy reduction and viscous coupling, shear modulus... 

The wellbore instability is one of the challenging problems in the oil industry, which entails huge costs for the industry every year. This phenomenon not only causes numerous problems in drilling and completion of wells, but also reduces production and loss of wells. In recent years, this problem has become much more serious in the Kupal oilfield. As a result, a large number of wells drilled in the field shortly after completion face with the problem of instability, integrity and casing collapse. According to the studies, one of the main causes of such a problem is the Gachsaran high pressure formation. Despite the complexity and importance of this issue, there is not a comprehensive study... 

Increasing the permeability of hydrocarbon reservoirs by creating artificial cracks that are induced by injection of fluids under high pressures is called Hydraulic Fracturing operation. This method is widely used in petroleum reservoir engineering. For design of Hydraulic Fracture operations, a number of methods have been developed. KGD and PKN are the first and most used methods in this area and despite the development of advanced softwares in recent years, these methods are still popular and are used in a number of softwares. KGD is commonly used for induced fractures where the height of fracture is greater than its length, and PKN is normally used where the length of the fracture is... 

In the oil and gas industry, in different stages of exploration and production of oil from hydrocarbon reservoirs, there are several challenges, most of which are due to unbalanced physical-mechanical conditions of the formations. Today, geomechanics of reservoirs is recognized as a key to analyze and solve such problems.Activities such as drilling, perforation, fracturing, production and fluid injection into the reservoir can alter the reservoir stress field and can cause rock deformation. Excessive compaction of reservoir rock can cause surface or seabed subsidence and damage to surface facilities and subsurface tubular. In general, rock compaction can cause many problems if not predicted... 

Due to a rapid growth in the consumption of fossil fuels, the emission of greenhouse gases has multiplied in the atmosphere in the past few decades. This issue can directly affect on the rise of global temperature. Because of the intensification of the global warming, international organizations are looking for ways to reduce the greenhouse effect. One of these methods is injecting and trapping greenhouse gases, especially carbon dioxide, resulting from the operation of power plants and other large industries and preventing it from entering the atmosphere. The injection of carbon dioxide in underground salt water reservoirs can have various effects such as mechanical, hydraulic, thermal, and...