Chemical flooding processes for

Sodium Silicate in Chemical Flooding Processes for Recovery of Crude Oils... 

In chemical flooding processes for enhanced oil recovery, alkaline chemicals can be useful for hardness ion suppression or removal, reaction with acidic crude oils to generate surface-active species, reduction in surfactant adsorption on reservoir rock surfaces, changes in interfacial phase properties, mobility control and increased sweep efficiency, oil wettability reversal and increased emulsification. 

The proceedings cover six major areas of research related to chemical flooding processes for enhanced oil recovery, namely, 1) Fundamental aspects of the oil displacement process, 2) Microstructure of surfactant systems, 3) Emulsion rheology and oil displacement mechanisms, 4) Wettability and oil displacement mechanisms, 5) Adsorption, clays and chemical loss mechanisms, and 6) Polymer rheology and surfactant-polymer interactions. This book also includes two invited review papers, namely, "Research on Enhanced Oil Recovery Past, Present and Future," and "Formation and Properties of Micelles and Microemulsions" by Professor J. J. Taber and Professor H. F. Eicke respectively. 

Alkaline/surfactant/polymer compositional reservoir simulator, 3-dimensional compositional reservoir simulator, for high-pH chemical flooding processes [178]... 

In this section, several important aspects of microemulsions in relation to enhanced oil recovery will be discussed. It is well recognized that the success of the microemulsion flooding process for improving oil recovery depends on the proper selection of chemicals in formulating the surfactant slug. 

From the previous discussion, it may be seen that many uncertainties are associated with the use of sacrificial adsorbates. Although preflushes with sacrificial adsorbates may show some improvement in chemical flooding processes (149), it remains to be demonstrated that the additional costs related to sacrificial materials can be fully compensated for by lowering the requirements for the primary surfactant. 

Polymers are used for mobility control in chemical flooding processes such as micellar-polymer and caustic-polymer flooding and in polymer augmented waterflooding. Selection of a polymer for mobility control is a complex process because it is not possible to predict the behavior of a polymer in porous rock from rheological measurements such as viscosity/ shear rate curves. Polymers used for mobility control are non-Newtonian fluids. Flow characteristics are controlled by the shear field to which the polymer is subjected. Properties of polymers can be measured under steady shear in rheometers. However, in porous rock, it is difficult to define the shear environment a polymer experiences as it flows through tortuous pores. 

The correlation developed between the mobility of Flocon biopolymer and brine permeability following polymer contact in Berea cores has implications for mobility control in chemical flooding processes. Because the mobility of a polymer solution is not a linear function of the rock permeability, a polymer solution that provides mobility control in one rock may not maintain mobility control in another rock of the same type which has a significantly lower permeability. 

Example 5.17 illustrates the application of these concepts to choose the viscosities of the chemical slug and the mobility at the leading edge of the polymer buffer for a chemical flooding process. 

Micellar flooding is a promising tertiary oil-recovery method, perhaps the only method that has been shown to be successful in the field for depleted light oil reservoirs. As a tertiary recovery method, the micellar flooding process has desirable features of several chemical methods (e.g., miscible-type displacement) and is less susceptible to some of the drawbacks of chemical methods, such as adsorption. It has been shown that a suitable preflush can considerably curtail the surfactant loss to the rock matrix. In addition, the use of multiple micellar solutions, selected on the basis of phase behavior, can increase oil recovery with respect to the amount of surfactant, in comparison with a single solution. Laboratory tests showed that oil recovery-to-slug volume ratios as high as 15 can be achieved [439]. 

Polyaromatic hydrocarbons absorb strongly to humus and other soil components, rendering these contaminants difficult to remove by thermal, physical, or chemical means, and unavailable for biodegradation. To desorb polyaromatic hydrocarbons from soil, surfactant flooding processes and soil-washing processes or treatments to enhance the biodegradation of polyaromatic hydrocarbons have been considered. 

The physicochemical aspects of micro- and macroemulsions have been discussed in relation to enhanced oil recovery processes. The interfacial parameters (e.g. interfacial tension, interfacial viscosity, interfacial charge, contact angle, etc.) responsible for enhanced oil recovery by chemical flooding are described. In oil/brine/surfactant/alcohol systems, a middle phase microemulsion in equilibrium with excess oil and brine forms in a narrow salinity range. The salinity at which equal volumes of brine and oil are solubilized in the middel phase microemulsion is termed as the optimal salinity. The optimal salinity of the system can be shifted to a desired value hy varying the concentration and structure of alcohol. 

If the economic cutoff of 98% water cut is used for both waterflooding and chemical flooding, then the total injection pore volumes (PVs) from these two processes could be different. Generally, the total injection PV in waterflooding... 

A publication that specifically focuses on the screening criteria for chemical processes has not been seen in the literature. Screening criteria for broader EOR processes have been discussed by several researchers—for example, Taber et al. (1997a, 1997b), Al-Bahar et al. (2004), and Dickson et al. (2010). This section briefly summarizes several critical parameters regarding chemical EOR application conditions. Many parameters could affect chemical EOR processes however, the most critical parameters should be reservoir temperature, formation salinity and divalent contents, clay contents, and oil viscosity. Eor polymer flooding, permeability is another critical parameter. 

This book is written mainly for petroleum professionals. Because overwhelming parameters are needed to describe a chemical EOR process, it is not practical to measure every one of them therefore an effort has been made to collect, synthesize, and suimnarize available data, especially Chinese information that is inaccessible in Western literature. An effort has also been made to cover comprehensively the fundamental theories and practices related to alkaline (A), surfactant (S), and polymer (P) flooding processes, especially alkaline-surfactant-polymer (ASP) flooding that has barely been discussed in any enhanced oil recovery book in English. 

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