N G van Kampen 1981 Amsterdam: North-Holland xiv + 419 pp price Dfl 180 This is a book which, at a lower price, could be expected to become an essential part of the library of every physical scientist concerned with problems involving fluctuations and stochastic processes, as well as those who just enjoy a beautifully written book. It provides an extensive graduate-level introduction which is clear, cautious, interesting and readable.

https://iopscience.iop.org/article/10.1088/0031-9112/34/4/040/pdf

Stochastic Processes in Physics and Chemistry

to be done in this area. Face recognition is a problem that scarcely clamoured for attention before the computer age but, having surfaced, has involved a wide range of techniques and has attracted the attention of some fine minds (David Mumford was a Fields Medallist in 1974). This singular application of mathematical modelling to a messy applied problem of obvious utility and importance but with no unique solution is a pretty one to share with students: perhaps, returning to the source of our opening quotation, we may invert Duncan's earlier observation, 'There is an art to find the mind's construction in the face!'.

Linear and nonlinear waves, by G. B. Whitham. Pp.636. £50. 1999. ISBN 0 471 35942 4 (Wiley).

With the decline in oil discoveries during the last decades it is believed that EOR technologies will play a key role to meet the energy demand in years to come. This paper presents a comprehensive review of EOR status and opportunities to increase final recovery factors in reservoirs ranging from extra heavy oil to gas condensate. Specifically, the paper discusses EOR status and opportunities organized by reservoir lithology (sandstone and carbonates formations and turbiditic reservoirs to a lesser extent) and offshore and onshore fields. Risk and rewards of EOR methods including growing trends in recent years such as CO2 injection, high pressure air injection (HPAI) and chemical flooding are addressed including a brief overview of CO2-EOR project economics.

Enhanced Oil Recovery: An Update Review

http://abollegend.persiangig.com/Theory_of_Gas_Injection_Processes_-_Franklin.pdf

Theory of Gas Injection Processes

Particle detachment from the rock during suspension transport in porous media was widely observed in laboratory corefloods and for flows in natural reservoirs. A new mathematical model for detachment of particles is based on mechanical equilibrium of a particle positioned on the internal cake or matrix surface in the pore space. The torque balance of drag, electrostatic, lifting and gravity forces, acting on the particle from the matrix and the moving fluid, is considered. The torque balance determines maximum retention concentration during the particle capture. The particle torque equilibrium is determined by the dimensionless ratio between the drag and normal forces acting on the particle. The maximum retention function of the dimensionless ratio (dislodging number) closes system of governing equations for colloid transport with particle release. One-dimensional problem of coreflooding by suspension accounting for limited particle retention, controlled by the torque sum, allows for exact solution under the assumptions of constant filtration coefficient and porosity. The explicit formulae permit the calculation of the model parameters (maximum retention concentration, filtration and formation damage coefficients) from the history of the pressure drop across the core during suspension injection. The values for maximum retention concentration, as obtained from two coreflood tests, have been matched with those calculated by the torque balance on the micro scale.

Modified Particle Detachment Model for Colloidal Transport in Porous Media

Edge-Water Drive Recovery Enhancement by Induced Fines Migration


 One of the key parameters for subsurface CO2 storage in well injectivity. There are multiple factors that can affect injection rate including formation dry-out, fines migration, and salt precipitation that can increase or decrease the injectivity. In this study, we experimentally investigated the cumulative effect of rock drying-out and fines migration on well injectivity for a formation in the Cooper – Eromanga Basin, South Australia.
 Four core plugs with a range of clay content and permeability were chosen from the formation. Each core was fully saturated with artificially made formation water to measure initial permeability. The core samples were then subjected to a constant flow of gas (air or CO2) at reservoir pressure for up to 185,000 PVI. The effluent fluid was sampled continuously to measure the concentration of solid particles produced from the core during gas injection. The tests were followed by injection of formation water to eliminate the salt precipitation effect and then DI water to identify the maximum possible formation damage in each core sample.
 Overall injectivity increased significantly during continuous injection of CO2or air into fully saturated core samples despite permeability damage due to fines migration. Fines migration was observed during gas injection, resulting in a pressure drop increase across the cores and fine release at the core outlet. 30-60% reduction of core permeabilities were observed during connate water evaporation. The damaging effect of fines migration on injection rate was negligible compared to 4-30 times pressure drop decrease due to reduction in liquid saturation.

Near-Wellbore Damage Associated with Formation Dry-Out and Fines Migration During CO2 Injection


 Fines detachment is an important component of methane production from Coal Bed Methane reservoirs. Production of coal fines is widely observed during dewatering and simultaneous gas-water production. The theory for fines detachment by drag against electrostatic attraction, model of the transport of those detrital fines, and their validation by laboratory test is widely used for planning and design of Coal Seam Gas developments. However, clay particles that naturally grow on coal grains and asperous parts of coal surfaces (authigenic and potential coal fines) are detached by breakage. To the best of our knowledge, the analytical theory for detachment of authigenic and potential coal fines is not available. The present paper fills the gap. Based on Timoshenko's beam theory, we derive failure conditions for breakage of authigenic and potential coal fines of the rock surface. It allows defining maximum retention function for fines breakage. The maximum retention is incorporated into transport equation of mobilized fines, allowing developing analytical models for linear flow of core flooding and radial flow of well inflow performance. Matching of laboratory coreflood data from four laboratory studies show high agreement. The model coefficients obtained by treatment of laboratory data allow predicting skin growth in production wells under fines migration.

Fines Migration and Production in CSG Reservoirs: Laboratory & Modelling Study

The new method to assess permeability damage in geothermal reservoirs and predict well productivity decline is presented. The laboratory methodology developed aims to determine permeability decline from mobilisation, migration and straining of natural reservoir fines. Laboratory coreflood testing with constant and stepwise decreasing ionic strength has been performed with measurements of the pressure drop along the core and accumulated effluent particle concentration. Stabilisation of rock permeability occurs after injection of numerous pore volumes, suggesting slow drift of mobilised particles if compared with the carrier water velocity. Low ionic strength water increases electrostatic repulsion forces between clay particles and sand grain surfaces, further mobilising particles and resulting in formation damage. Kaolinite and illite/chlorite mixed layer clay minerals are identified by SEM-EDAX analysis and are the minerals primarily responsible for the permeability damage. The competitive effects of decreasing water viscosity and weakening electrostatic attraction on the attached particle concentration during temperature increase have been observed. The micro-modeling of the fine particle mechanical equilibrium shows that the water viscosity effect on the fine particle attachment dominates. It results in decreased fines detachment and permeability decline at high temperatures.

New laboratory method to assess formation damage in geothermal wells

Enhanced oil recovery (EOR) using CO2 injection is being investigated as a feasible technique for oil reservoirs. The ability of a reservoir to store CO2 for a long time presents an opportunity to create sustainable solutions to the problems posed by the continued use of fossil fuels and climate change, and to support the commitment to regional, national, and global agreements to reduce CO2 emissions. Injection strategies such as water-alternate-gas (WAG) or carbonised water injection (CWI) have been proposed to overcome the issue of low sweep efficiency of CO2 flood in the reservoir. An understanding of the relative permeability and capillary pressure behaviour is necessary to simulate these processes in porous media. The steady-state coreflood test is a widely accepted industrial method to determine relative permeability (Kr), but the capillary pressure (Pc) must be found from other sources (porous plate, mercury injection, and centrifuge tests). A significant difference between the capillary pressure determined from corefloods and by other methods is widely presented in the literature. This work presents a novel coreflood method for the simultaneous determination of relative permeability (Kr) and capillary pressure (Pc). The main idea is to use the stabilised data of the steady-state method along with the transient data of the pressure drop. Therefore, in the proposed steady-state-transient test (SSTT), the transient pressure drop data across the core, between the sequential steady-states, are used instead of the traditionally utilised Pc-curve.

Pavel Bedrikovetsky

Papers

Edge-Water Drive Recovery Enhancement by Induced Fines Migration

Near-Wellbore Damage Associated with Formation Dry-Out and Fines Migration During CO2 Injection

Fines Migration and Production in CSG Reservoirs: Laboratory & Modelling Study

New laboratory method to assess formation damage in geothermal wells

A novel method for simultaneous determination of relative permeability and capillary pressure from corefloods (gas/CO2–water systems)