This paper describes the study of a method for controlling the physical and chemical properties of an oil reservoir in order to increase its oil recovery by injecting a GBA-F acid composition into the reservoir. An experimental testbed is developed to physically simulate the effect of the acid composition on the oil reservoir. Experiments are carried out using the flat model with a single injection of the reagent into the central wellbore. Experimental results confirm the effectiveness of the acid composition.

Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation V. I. Pen'kovskiy, N. K. Korsakova; Application of embedded continua method for fluid flow simulation in a porous medium. AIP Conference Proceedings 16 February 2023; 2504 (1): 030096. https://doi.org/10.1063/5.0134931 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAIP Publishing PortfolioAIP Conference Proceedings Search Advanced Search |Citation Search

A case of two-dimensional motion of thermal waters under the action of two wells comprising a spaced dipole is investigated on the basis of a reservoir model in the form of a heterogeneous structure consisting of disjoint continua, one of which is embedded into the other. Calculations are performed for specific physical parameters of the reservoir and running wells.

In this paper, we use a hydrodynamic model of two wells with equal in quantity but different in sign production. The wells are located at a given distance from each other in an unbounded formation. The model is a spaced dipole in which the velocity of the potential fluid flow decreases inversely with the square of the distance from the center of the dipole. The model makes it possible to estimate the size of closed oil inclusions depending on the characteristics of the oil displacement regime in the rated reservoir area. On a flat physical model of the stratum that implements the spaced dipole scheme, experiments were conducted to increase oil recovery by the MFK-1 surfactant composition. It has been experimentally founded that the MFK-1 composition promotes coalescence of oil ganglia and their involvement in the general fluid flow. Thereby, the oil recovery coefficient increases. The injection of the MFC-1 composition into the pumping well significantly increases its intake capacity and, as a result, increases the efficiency of the oil displacement process.

In a previously published mathematical model of blood circulation in the cerebral cortex, it was assumed that the circulatory system of the brain consists of a distribution network of relatively large arteries and a collector network of veins similar in structure [1]. The connection between the networks is carried out through a network of numerous small capillaries, in which arterial blood as a result of metabolic processes with the cellular tissue of the brain turns into venous. A system of equations of viscous fluid motion in a heterogeneous medium consisting of three interpenetrating, but not intersecting, continuums is written out. Intersections are pathology for a healthy human organism. Multiple calculations show that pathologies localized even in small areas of the brain significantly affect the nature of the distribution of blood pressure in the arterial and venous channels. The finite element method is used in the calculations. The network of elements is refined in the subdomains of pathologies in the form of malformation or embolism with a decrease in the conductive properties of a heterogeneous environment. The numerical solution of the planar problem was carried out with parameters close to the real conditions of blood circulation in the human brain.

The size of the zone of wave action on the formation is determined when the sucker rod pump is operated with a rocker-type drive. An axisymmetric fluid flow to a well is considered against the depression permanently acting on a stratum of infinite length. Reversion of fluid flow influences on the change in nature of the rock wettability in vicinity of well. This change stimulates increasing its production rate. The results of experiments on a flat laboratory stratum model are presented.

A review of models of the blood circulation in the tissues of the human brain and lower extremities is presented. The models take into account the well-known laws of physiology and theoretical mechanics. Mathematical models are based on the representation of organ tissues as a heterogeneous continuous medium consisting of three interpenetrating continua: living cells, and circulating arterial and venous blood. The results of numerical calculations of boundary value problems of the pulse blood flow in the brain of a healthy person and cases of pathologies such as arteriovenous malformation and embolism are presented. The distribution of blood pressure in the lower extremities is studied under the action of gravity and other overloads.

Two schemes of closed circulation of thermal waters are considered. The first scheme is filtration in a single stratum. In the second scheme, the flow in a formation with a weakly permeable bottom is considered. The effective for designers formulas are obtained. The thermal formation model is used in the form of a heterogeneous structure consisting of two embedding continuums.

The paper uses a mathematical model of hydraulic fracturing, obtained by the methods of the elastic filtration theory of oil-displacing fluid injected into the formation, which is a heterogeneous, fractured-porous medium. The rock formation undergoes elastoplastic destruction with the generation of cracks when the pressure difference in the fluid reaches a critical value. An increase in the volume of the system of fractures in the cracking zone leads to a decrease in the porosity of the blocks in accordance with the pore volume strain compatibility condition. Engineering formulas are obtained for the radius of cracking and crack opening. The flow rate of a well with a hydraulic fracture decreases over time. This phenomenon, which is also characteristic of carbonate formations with natural jointing, is explained by the increasing effect of capillary locking of the formation water accumulating near the walls of the cracks. Laboratory studies on the flat micromodel of the reservoir showed the possibility of restoring the well production rate with a fracture by injection of an acidic oil-displacing composition based on surfactants, inorganic acid adduct and polyhydric alcohol. The results of successful field tests of the composition on the Permian-Carboniferous deposit of high-viscosity oil from the Usinsk oilfield with fractured-porous reservoir rock are presented.

The solution is presented for the problem on oil percolation in a reservoir at the present and time-varying pressure difference between the injection and production wells. The area of water blocking under capillary pressure in the well bottom zone is determined. The algorithm is proposed for calculating fluid pressure on the well bottom by readings of echo sounder installed at the well mouth. The penetration zone of pressure fluctuations in the reservoir is estimated, and their effect on enhanced well production is shown.

Blood circulation process in inferior limbs is considered in the terms of the previously proposed mathematical model of sanguimotion in living organism tissues. The model includes the equations of homogeneous fluid flower in heterogeneous medium that consists of two or more interpenetrating continua. The continua (distributing net of arteries and collecting net of veins) interact through ramified capillary net. A volume of blood flowering from arterial net to venous one is proportional to pressure (head) difference in the nets. Some analytical solutions and numerical results are given.

The problem on oil filtration in the reservoir model with the preset differential pressure harmonically varying in time on its faces is solved. Hysteresis effects of capillary pressure under change in the direction of fluid expulsion are considered. The influence exerted by liquid fluctuations on cleaning the near-well zone from possible capillary blocking of aqueous phase is estimated. The action of alternating pressure pulses on the oil-saturated reservoir model is investigated. It is shown that harmonic change in liquid pressure promotes removal of immobile capillary-blocked water from the near-well zone. The results of in-situ experiments on wave action on the wellbottom zone and oil production stimulation are presented.

Two aspects of the controlling the physicochemical properties of the formation with the purpose of enhancing oil recovery are considered: mechanical wave action and physicochemical treatment of the reservoir with a GBK oil displacing acidic composition. The problem of the wave action of the oil reservoir has been solved within the framework of the model of the axisymmetric distribution of pressure in the near-well zone. It is shown that the imposition of a wave field as harmonic fluctuations of the fluid pressure on a mean depression results in a periodic change in the direction of fluid flow in the near-well zone. Cyclic reciprocating flow is accompanied by a hysteresis of the rock wettability, a reduction in the negative effect of capillary locking of the water phase, and an increase in the production rate of the oil producing well. The results of experiments on the oil displacement by the GBK composition on a flat model of the formation and on a high-pressure filtration unit are presented. The injection of the oil-displacing GBK composition into the injection well increases its injectivity, promotes the coalescence of residual oil particles and the creation of a dynamic oil saturation bank. All these factors result in the increase in oil production.

Drilling filtrate invasion into the producing formation and native water accumulating of the near-well zone in well operation reduce the well productivity. As a result of that, depending on characteristic capillary pressure scale and differential pressure drawdown, oil production rate may become lower than expected one. In this paper, it is considered the hysteresis effects of capillary pressure after reversion of displacement. As applied to laboratory experiment conditions, the solution of problem of oil flow in formation model with a pressure drop on the model sides harmonically varied with time is presented. It was estimated a range of fluid vibration effective action on the near-well zone cleaning from capillary locking water. The plant simulating extraction of oil from formation using widely practised sucker-rod pump has been created. Formation model is presented as a slot filled with broken glass between two plates. In the process, natural oil and sodium chloride solution were used as working fluids. The experiments qualitatively confirm a positive effect of jack pumps on the near-well zone cleaning.

A mathematical model for hydraulic fracturing is proposed. The model is based on the presentation of the fractured portion of the stratum adjacent to the well as a heterogeneous fractured porous medium. Assumptions usually used in the theory of elastic flow are applied. Formulas for determining the size of the hydraulic fracturing zone and the degree of fracture opening under conditions of relative equilibrium are derived.

A mathematical model of the axisymmetric distribution of the phases in the zone of invasion of the water-based drilling mud into the productive stratum whose porous space can simultaneously contain three immiscible fluids (oil, gas, and natural water) is constructed; the model takes into account the high rate of heat transfer between the fluids and the rock matrix. It is shown that the resistivity of the invaded zone depends not only on saturation of the latter by the fluids and the concentration of salts in the water phase, but also on the drilling mud filtrate temperature. It is also shown that there is a jump in the function of stratum saturation by oil on the thermal front.

Various conditions of formation of motionless closed hydrocarbon inclusions are considered: viscous instability of fluid displacement and inhomogeneous rock structure. Conditions of dynamic equilibrium of the inclusion in a water flow are given for one-dimensional and two-dimensional motion. Distributions of the oil content in inclusions of different shapes are numerically calculated. It is found that the amount of unrecovered oil depends on the ratio of the pressure gradients in the filtration flow of water pumped into the reservoir and the characteristic capillary pressure on the boundary of immiscible phases. It is demonstrated that the use of chemical reagents can substantially reduce the effect of capillary forces and promotes oil entrainment by the overall flow.

Penetration of distilled water into a clay soil sample saturated by a sodium chloride solution is experimentally studied. Changes in filtration characteristics of soil due to penetration of fresh water and swelling of clay particles, as well as due to the action of an electrical field on the replacement process are quantified. It is demonstrated that electrokinetic processes play a key role at the final stage of replacement of the solution by fresh water. Reasons for the emergence of clay self-polarization potentials owing to violation of electrical equilibrium conditions are studied.