Improved/enhanced oil recovery (IOR/EOR) has the potential to unlock a significant amount of residual and trapped oil from existing and new hydrocarbon resources. This chapter addresses the various IOR/EOR strategies in carbonates and sandstone reservoirs, including chemical EOR, and hybrid EOR procedures. Each of these EOR approaches has its own set of challenges and preferences when it comes to the environment where it is used. Recent investigations have provided new insights into COBR systems, which have helped to improve the performance of these EOR methods. Detailed awareness of COBR systems can aid in better implement EOR methods in the field to maximize oil recovery (i.e., cost-effective) while also reducing environmental impact (i.e., CO2 footprint). Consequently, the primary goal of this chapter is to increase the reader's understanding of the extent of fluid-fluid and fluid-rock interactions to enable efficient IOR/EOR project designs that accurately reflect the requirements of candidate reservoirs for upstream oil and gas applications.
Sandstone formations are very complex in terms of mineralogy; it consists of a variety of minerals with different properties, minerals such as carbonate, clays, feldspars, iron oxides, and other minerals. This complex mineralogy will make it very difficult to have an ideal stimulation fluid; hence several stages and fluids are used. This chapter will cover the interactions of different fluids and additives with rock minerals utilizing experimental and simulation aspects. The basic chemistry of sandstone acidizing and the composition and additives of sandstone acidizing fluids are covered. This chapter will shed light on the compatibility between different fluid stages and the fluid in the same stage. Acidizing fluids such as HCl, HF, corrosion inhibitors, and clay stabilizers is discussed. Fluid/rock interactions that may cause fines migration, clay swelling, fluid retention, fluid adsorption, variations in porosity and permeability, and wettability alterations are analyzed.
Drilling fluids are designed to optimize the drilling performance and minimize the formation damage. Various compositions can be used to prepare the drilling fluids depending on the wellbore demands and environmental concerns. This chapter discusses the drilling fluid properties and their functions as well as the common additives used in the drilling operations. The recommended rheological range of different fluids is presented. In addition, the recent technologies for enhancing the drilling fluids' efficiency (such as using nanotechnology) are discussed. The impact of several additives on the compatibility of drilling and completion fluids is presented. Finally, the interactions of drilling and completion fluid solids with the formation rocks for conventional and unconventional reservoirs are presented. Enhancing the fluids' stability is a key factor in achieving successful drilling and completion operations. Using polymeric materials and nanoparticles as fluid additives can significantly improve the thermal stability, rheological, and filtration properties.
The environmental impacts of offshore oil and gas exploration, drilling, production, and operation are identified. The importance of controlling and managing emissions, discharges, and disposal to minimize impacts and consequences is emphasized. The impact of drilling and dredging activities on the marine environment is highlighted as one of the main threats to the marine ecosystem. The chapter emphasizes that risk management and business continuity are fundamental to avoid threatening project safety and investment development. The risk management approach as the roadmap to achieve regulatory compliance is emphasized. The key advantages of comprehensive HSE and risk management systems are summarized. The chapter explores the produced water and ballast water effluent quality and regulations requirements. The KPIs are presented with steps required to conduct further analysis in case of noncompliance. HSE aspects, impacts, mitigations, and compensation measures are presented, addressing concerns from exploration to production.
Tight and unconventional reservoirs such as shales are rich in clay minerals that give rise to several fluid–rock interactions. The effect of such fluid–rock interactions is manifested at multiscales. The fluid–rock interactions induce changes in various physical responses of the rock, which is termed as multiphysics. An underlying property that influences the multiphysics process is wettability which has remained a conundrum for shale researchers. This chapter provides a detailed perspective on shale wettability in the context of fluid–rock interactions. Pore structural alteration induced by fluid–rock interactions is also discussed specifically from the standpoint of recent advances using digital techniques. The chapter also presents recent developments in explaining the role of pore sizes in causing configurational diffusion of water and oil in shales. Lastly, multiphysics constitutive modeling to predict shale rock responses is discussed. Specifically, new developments regarding the incorporation of sorptive fluid–rock interaction in constitutive models are presented.
The use of nanoparticles (NPs) in the hydrocarbon industry has seen a remarkable interest lately due to their tremendous potential while the stability issues associated with NPs remain a key challenge in terms of the large-scale application. This chapter demonstrates the use of several NPs such as SiO2, TiO2, CuO, Al2O3, and ZnO, in oil field applications, and addresses their inherent stability as a governing factor. Moreover, this chapter illustrates the advantages, applicability, and technical qualifications of NPs to understand the pertinent governing principles from a physicochemical perspective. Several oil field practices such as drilling, cementing, fracturing fluid, stimulation, and enhanced oil recovery are demonstrated in this chapter via a critical analysis of the laboratory investigations and field trials. Thus, this chapter summarizes the NP applications for the upstream industry and may add value to understanding the real field challenges and provide insights into the outlook of the subject matter.
Rheology is an important characterizing technique as it affects all types of fluids. While oil and gas recovery is an operation that depends mainly on the interaction between different fluids, it is therefore important to understand and analyze the flow behavior of these fluids. This chapter presents the basic practices and applications of rheology in the different stages of petroleum operations. The chapter starts by introducing rheology fundamentals and presenting the most common rheological models in the upstream applications to lay the ground for the upcoming discussions. Following, fluid rheology in several applications has been discussed such as reservoir fluids, drilling fluids, emulsion, cement slurries, and polymeric gels. The discussions covered the importance of rheology in these applications and the most common practices in the oil and gas industry.
Hydrocarbon derived from tight shale and other low-permeable reservoirs is an important and rapidly expanding front in energy development. Untapped hydrocarbon reserves can be exploited by fracturing these rocks using pressure-fracturing fluid. Different forms of fracturing fluids have been created, employed, and tested in fields for their efficiency and applicability. Aqueous polymer-based fracturing fluids and acid fracturing fluids are the most prominent class of field-employed fracturing fluids. Hydraulic fracturing procedures leave chemically complex fluids in the shale formation for at least 2 weeks. This gives the hydraulic fracturing fluid (HFF) plenty of chances to react with the formation at reservoir temperature and pressure. The interaction of fracturing fluid with the reservoir rocks and formation fluids has been discussed in this chapter. Furthermore, reaction kinetics, formation damage, and classes and mechanics of fracturing techniques have been elaborated.
The chapter begins with the concept of permeability and introduces Darcy's Law. The formal analytical reasoning for Darcy's Law arising from Navier–Stokes equation is presented. The necessary boundary conditions for Darcy's Law to hold are analyzed. Different models of connected pore space are introduced sequentially, and the permeability of a porous medium from the perspective of each model is analyzed. Important pore space attributes are defined from the perspective of stream tube model, which is an extension of the conventional capillary bundle model, pores, and the pore throats model. The fractal models of pore spaces are analyzed in detail. The analysis has been carried out in such a manner that it stays relevant to log measurements being instrumental in deriving these pore space attributes. The focus of the analysis is principally connected pore space and primary porosity applicable to clastic rocks. Different models for permeability prediction that use petrophysical inversion of logs as the source of input data, as well as those that use NMR-derived data have been discussed. Both the pore space and the pore attributes have been related to the analyses.
The pore space of rocks is the theme of this chapter. Pore space here is also meant to include fractures, cleats, and cracks which may be found in rocks, besides the pore assemblages as normally understood. Pore space is built up of pores. The different attributes of pores, e.g., shape, size, orientation in space, degree of connection with the surrounding pore space, and the morphology and dimensions of the junction between two pores, define the pore space. In rocks, pores occur as assemblages of connected pores, forming pore networks, isolated pores, and unconnected pore assemblages. The morphology of the pore networks in a rock is as important as the set of attributes that characterize individual pores. This is because morphology plays an equal role to that played by pore attributes in determining the elastic properties, fluid transport properties, electric conductance, and the dielectric permittivity of rocks. Logs measure the abovementioned properties of rocks. Therefore, inversion of log data is useful in interpreting macroscopic and pore level attributes. In fact, one of the important methods through which the quantitative understanding of the pore networks within rocks is achieved is by inverting simultaneously multiple types of log measurements. The forward models required for inversion are largely guided by the lab investigations carried on representative samples from cores cut from the relevant rock strata. These investigations characterize the grains pores and the pore networks (that together comprise pore space). The objective of log data inversion could be single or a combination of the macroscopic attributes of the pore space. These data are crucial for the understanding of the reservoir dynamics in the context of production of oil and gas from rock strata. This chapter, however, is limited to introducing some of the laboratory study–based characterizations of pore space within different types of rocks, and introducing the context and relevance of these data to the log data inversion. How the log data help to understand the pore size heterogeneity and the degree of pore connectivity are also discussed.
The attributes of the pore space of a rock include the gross attributes viz., pore volume per unit rock volume, cumulated surface area of the pores and the ratio it bears with the total pore volume, the characteristic length scale of the pore space relevant to fluid transport through it, permeability to fluid flow, and the formation factor of the pore space. The attributes of the pore space also include the pore shape, representative pore size and representative pore throat size associated with the pore assemblage, and the distribution of the pore size and pore throat size within rocks/sediments. This chapter introduces the basic concepts in terms of which these attributes are defined. Forward models of the pore space are introduced conceptually. We also discuss how the model attributes of the pore space can be inverted from log measurements. The analysis has been illustrated in a way that aims not to lose the focus on its relevance to retrieving the pore space attributes from the different log measurements. The analysis presented in the current chapter is limited to conventional reservoir development.
