Rock Saturation Research Articles

Mineral Thermometry and Fluid Inclusion Studies of the Pea Ridge Iron Oxide-Apatite–Rare Earth Element Deposit, Mesoproterozoic St. Francois Mountains Terrane, Southeast Missouri, USA

Mineral thermometry and fluid inclusion studies were conducted on variably altered and mineralized samples from the Mesoproterozoic Pea Ridge iron oxide-apatite (IOA)-rare earth element (REE) deposit in order to constrain P-T conditions, fluid chemistry, and the source of salt and volatiles during early magnetite and later REE mineralization. Scanning electron microscopy (SEM)-cathodoluminescence and SEM-backscatter electron images show that quartz and rutile precipitated before, during, and after magnetite and REE mineral growth. Ti-in-quartz and Zr-in-rutile equilibration temperatures range from ≤350° to 750°C in the amphibole, magnetite, hematite, and silicified zones where T increased during magnetite and quartz growth and dropped precipitously after fracturing and brecciation. Late drusy quartz cements within a REE-rich breccia pipe record the lowest T (≤315°–400°C). Liquid-, vapor-rich, and hypersaline (±hematite, calcite) fluid inclusions are common and liquid CO 2 is present locally. Salinities define three populations: saline (10–27 wt % NaCl equiv), hypersaline (34–>60 wt % NaCl equiv), and dilute (0–10 wt % NaCl equiv ). The wide range of eutectic melting temperatures (−67° to −19°C) suggests that saline inclusions trapped variable proportions of a CaCl-MgCl-FeCl-bearing fluid end member and an NaCl-KCl fluid end member. Homogenization temperatures and pressures of these saline inclusions suggest they were trapped when fluids unmixed into brine and vapor at T The Na/Cl, Na/K, and Cl/Br ratios of fluid inclusion extracts provide evidence for mixtures of magmatic hydrothermal fluids and evaporated seawater. Extracts from magnetite, hematite, and pyrite plot in the magmatic-hydrothermal field, indicating that Fe was derived from a magmatic source. Their enrichments in Mg and Ca are consistent with a mafic magmatic source. The positive correlation between Na/Mg and Na/Ca ratios may be due to halite saturation or albitization of igneous rocks. Extracts from barite in the REE-rich breccia pipes are enriched in Na and Br and plot near the seawater evaporation trend. He is highly enriched relative to Ne and Ar in fluid inclusion extracts, which precludes air as a source of He. Although the He is mostly of crustal origin, pyrite with a 3 He/ 4 He (R/R A ) of 0.1 contains up to 12% mantle He. Many extracts have low 20 Ne/ 22 Ne ratios due to nucleogenic production of 22 Ne in high F/O minerals such as fluorapatite or F biotite. The arrays of data for 3 He/ 4 He (R/R A ) and 22 Ne/ 20 Ne suggest that volatiles were derived from two sources, a moderate F mafic magma containing mantle He and a high F silicic magma with crustal He. Together with other evidence cited in this report, these data (1) support a magmatic hydrothermal origin for the Mesoproterozoic magnetite-apatite deposit with ore fluids derived from a concealed mafic to intermediate-composition intrusion, (2) suggest that the REE minerals in breccia pipes were either derived from apatite or precipitated in response to decompression and cooling during breccia pipe formation, (3) provide evidence for the influx of basinal brine, magmatic fluids from granitic intrusions, and meteoric water after breccia pipe formation, and (4) show that Pea Ridge was relatively unaffected by the late Paleozoic Mississippi Valley-type (MVT) Pb-Zn system in overlying Cambrian sedimentary rocks.

A novel high-pressure vessel for simultaneous observations of seismic velocity and in situ CO2 distribution in a porous rock using a medical X-ray CT scanner

Understanding the relationship between seismic wave velocity or attenuation and CO2 saturation is essential for CO2 storage in deep saline formations. In the present study, we describe a novel upright high-pressure vessel that is designed to keep a rock sample under reservoir conditions and simultaneously image the entire sample using a medical X-ray CT scanner. The pressure vessel is composed of low X-ray absorption materials: a carbon-fibre-enhanced polyetheretherketone (PEEK) cylinder and PEEK vessel closures supported by carbon-fibre-reinforced plastic (CFRP) joists. The temperature was controlled by a carbon-coated film heater and an aramid fibre thermal insulator. The assembled sample cell allows us to obtain high-resolution images of rock samples during CO2 drainage and brine imbibition under reservoir conditions. The rock sample was oriented vertical to the rotation axis of the CT scanner, and seismic wave paths were aligned parallel to the rotation axis to avoid shadows from the acoustic transducers. The reconstructed CO2 distribution images allow us to calculate the CO2 saturation in the first Fresnel zone along the ray path between transducers. A robust relationship between the seismic wave velocity or attenuation and the CO2 saturation in porous rock was obtained from experiments using this pressure vessel.

Experimental Simulation of the Radionuclide Behaviour in the Process of Creating Additional Safety Barriers in Solid Radioactive Waste Repositories Containing Irradiated Graphite

Results of the experimental modeling of radionuclide behavior when creating additional safety barriers in solid radioactive waste repositories are presented. The experiments were run on the repository mockup containing solid radioactive waste fragments including irradiated graphite. The repository mockup layout is given; the processes with radionuclides that occur during the barrier creation with a clayey solution and during the following barrier operation are investigated. The results obtained confirm high anti-migration and anti-filtration properties of clay used for the barrier creation even under the long-term excessive water saturation of rocks confining the repository.

A Mechanism Causingb‐Value Anomalies Prior to a Mainshock

Observations show the appearance of abnormal b ‐values prior to a mainshock. The precursor time T of b ‐value anomalies prior to a forthcoming mainshock is related to the magnitude M of the event in an equation: log( T )= q + rM , in which q and r are two constants. In this study, implications of this equation will be explained. In addition, the mechanism causing b ‐value anomalies prior to a mainshock will be explored. From numerical simulations based on the 1D Knopoff–Burridge spring‐slider model, Wang (1995) found a power‐law correlation between b and s , in which the parameter s is the ratio of the spring constant ( K ) between two sliders to that ( L ) between a slider and the moving plate. The power‐law correlations are b ∼ s −2/3 for the cumulative frequency and b ∼ s −1/2 for the discrete frequency. Because L of a source area is almost constant for a long‐time period, b directly relates to K . Smaller (larger) K results in a higher (lower) b ‐value. Wang (2012) found ![Graphic][1] , in which ρ A and V P are the areal density and P ‐wave velocity of a fault zone, respectively. Experimental results show that V P is strongly influenced by the water saturation in rocks. The water saturation in the source area varies with time, thus leading to a temporal variation in V P as well as K . This results in the temporal variation in b ‐values. [1]: /embed/inline-graphic-1.gif

Mechanisms of imbibition during hydraulic fracturing in shale formations

Abstract Hydraulic fracturing technology has been proven to significantly increase production from shale gas and oil formations. However, during a hydraulic fracturing treatment a large percentage of the fracturing fluid usually remains unrecovered. Therefore, the reasons for this low fracturing fluid recovery have become the focus of many studies. Imbibition of fracturing fluid in the shale is believed to be one of the explanations for the low amount of the fracture fluid recovery. The fluid is imbibed by the shale matrix and trapped inside the rock. Capillarity has generally been the primary mechanism considered during imbibition in conventional formations, such as sandstone and carbonate formations. In shale formations osmosis diffusion also exists and cannot be ignored because the clay in the shale rock functions similarly to that of a membrane. It is believed that both capillarity and osmosis diffusion work together to result in imbibition during hydraulic fracturing in shale formations. This paper investigates the effects of both capillarity and osmosis diffusion as the key mechanisms in fluid imbibition through simultaneous imbibition experiments. The results of these tests illustrate that the imbibition process is dominated by both capillarity and osmosis diffusion. This domination is based on the change of water saturation in shale rocks. In addition, the capillary and osmotic pressures, which influence the imbibed rate, can be qualitatively determined by the contact angle and salinity, respectively. Higher capillary and osmotic pressures correlate to faster rates of imbibition. This study, which examines the mechanisms of imbibition and their influences, can improve the understanding of fluid behavior when imbibition occurs during hydraulic fracturing in shale formations. The understanding of this behavior is useful for further simulation research.

The changes in the electric conductivity of the lithosphere in the source region of the strongest Olyutora earthquake in the Koryak highlands

The results of the magnetotelluric (MT) soundings before and after an earthquake are analyzed. The interpretation is based on the longitudinal and transverse MT curves (along and across the strike of the main tectonic elements, respectively). The MT curves are distorted by the ρ- and coast effect. The distortions due to the coast effect are estimated by the testing three-dimensional (3D) model. It is established that the coast effect distortion at the periods up to 1000 s is small and can be disregarded. The divergence of the longitudinal and transverse MT curves, which points to the presence of the deep faults, is thoroughly studied. The inversion of the MTsounding curves is carried out by the REBOCC program of the numerical two-dimensional modeling. This program implements the procedures of elimination of the ρ-effect and the joint inversion of the longitudinal and transverse MT sounding curves. The obtained geoelectrical cross sections provide an insight into the structure of electrical conductivity of the lithosphere before and after the earthquake. The more intense variations in the electric conductivity are observed in the zone of the deep faults. These variations are related to the changes in the porosity and saturation of the rocks by the highly mineralized fluids.

Evaluating fractures in rocks from geothermal reservoirs using resistivity at different frequencies

One of the key issues to a successful EGS (Enhanced or engineered Geothermal System) is the creation of a great density of fractures. The detection and characterization of the created fractures is crucial in evaluating the geothermal energy resources in such EGS projects as well as in reservoirs for CO2 sequestration and storage. Methods to evaluate the fractures after stimulations are few, and limited in application. To this end, an approach to detecting and evaluating the fractures using resistivity data measured at different frequencies was developed in this study. The effects of fractures on resistivity measurements at different frequencies have been investigated as a function of water saturation in rocks with different porosity, permeability and lithology. Different rocks (Berea sandstone, and greywacke from The Geysers geothermal reservoir) were used in this study. The permeability of the samples ranged from 0.5 to over 1000 md for the matrix. The frequency ranged from 100 to 100,000 Hz. It was found that the effect of frequency on resistivity is different in rocks with and without fractures, especially in the range of low water saturation. The validity of the Archie equation depends on the existence of fractures, the frequency, and the range of water saturation. The relationship between resistivity and water saturation did not follow the Archie equation at low water saturation in some rocks with fractures. Models for characterizing different types of rocks with specific fracture patterns have been established using the resistivity data measured at different frequencies and different water saturations.

Low-field nuclear magnetic resonance for petroleum distillate characterization

Low field nuclear magnetic resonance (LF-NMR) has several applications in the oilfield industry such as in predicting the viscosity and evaluating porosity, permeability, fluid saturation of reservoir rocks, and the water content in fluids. However, the studies to determine the physical and chemical properties of petroleum distillates are uncommon. So, the aim of this study was to determine the physical and chemical properties of distillates using the transverse relaxation time (T2) in the range from 73.43 to 1810.74ms. LF-NMR was employed in this research, due to its rapid and non-destructive analytical method. From LF-NMR data, it was possible to estimate the molar mass, correlation index, characterization factor, API gravity, relative hydrogen index, and number of hydrogen in distillates obtained up to 350°C. T2 and the properties determined by standard methodologies (ASTM D-1218, D-445-06, D-664-06, D-2892, and D-4052) were strongly correlated. So, low field NMR constitutes an interesting alternative to ASTM methods. The results also show that changes in the chemical and physical properties depend on boiling point and molecular mobility. Besides, LF-NMR enabled the classification of the fractions into gasoline, kerosene, and light and heavy gas oil.

The geothermal potential of the underground of the Salento peninsula (southern Italy)

The low-enthalpy geothermal energy systems exploit the underground as a heat reservoir, by coupling it with highly efficient heat pumps: in winter, the energy stored in the subsoil can be transferred to the surface to heat buildings, whereas in summer the surplus heat in buildings can be transferred back to the ground providing a cooling action. Despite the high costs for installation, low-enthalpy geothermal systems have high energy efficiency and, therefore, contribute to energy saving, to the use of renewable energy sources, to environmental sustainability (the effects on the hydrogeological cycle are often negligible) and to the reduction in fuel consumption and in gas emissions. In this paper, a simple methodology is proposed to assess the geothermal potential of the underground of the Salento peninsula (southern Italy) at the regional scale, by calculating the equivalent thermal performance of the subsoil, which expresses the thermal power that is potentially extractable and useful to heat or cool a building. Since the possibility of exploiting the underground as a heat reservoir depends on the physical properties and water saturation of rocks, previous detailed studies on the hydrostratigraphic setup of the region are the basis for this analysis of geothermal potential. The equivalent thermal performance depends on the thermal efficiencies of different lithological units, whose ranges of values, for heating only, are provided in literature. For this case study, a stochastic approach has been applied: several combinations of thermal efficiencies were randomly selected from the intervals of reference values for every hydrostratigraphic formation and the corresponding minimum depths below the ground surface that must be reached to get the desired equivalent thermal performance are computed. The results show that the underground of the Salento peninsula has great potentialities for heating of buildings, except for some coastal areas because the saltwater intrusion phenomenon could cause problems for the realization of low-enthalpy geothermal energy systems.

Basics of Metals Theory of Extraction by Means of Chemical Water Solutions Filtration through Underground Ores

Abstract. Geo-technological extraction methods recently are widely used in the mining industry. Removing the metals from underground ore deposits is carried out by injecting chemicals (solvents, oxidants, reducing agents) into wells drilled in them, and the subsequent extraction of metals from saturated solutions. Particularly, this method utilized for the extraction of uranium from flooded sediments and copper from poor (substandard) ores, as well as some non-ferrous and rare metals from waste dumps and tailings of substandard ore mines and processing enterprises. The paper discusses methods developed for prediction of moisture content (water saturation) in rocks under filtration of liquid with incomplete saturation of pores while changing the concentration of the metal in the liquid phase (in an ore body), as well as problems of dissolution and desorption of metal salts on the surface cracks or pores on ore body based on molecular diffusion equation of metal salts. The present work conducted for developing the methods for calculating the liquid filtration through underground deposits of minerals and forecasting of dissolving and washing out metals. It is shown that the processes which take place with the use of chemical reagents are different comparing to the similar processes with water injection. These data allow to predict the changes in the concentration of salts and metals in the liquid and solid phases depending on time.

Three-Dimensional Compressional Attenuation Model (QP) for the Salton Trough, Southern California

Abstract I present a frequency‐independent 3D seismic attenuation model (indicated by ) for the crust of the Salton trough and the adjacent regions in southeastern southern California. The simul2000 tomographic algorithm was used to invert the frequency‐independent attenuation operator t * values measured from amplitude spectra of 23,378 P ‐wave arrivals of 1203 events through a recently developed 3D velocity model. The Q P model has a uniform horizontal grid spacing of 5 km, and the vertical‐node intervals range between 2 and 5 km down to 27 km depth. In general, the Q P values increase with depth and agree with the surface geology in the shallow depth layers. Low Q P values are observed in the Imperial Valley, California, which are consistent with the sedimentary deposits and may also reflect the presence of pore fluid in the active fault zones, whereas greatly elevated Q P values are shown in the surrounding crystalline ranges. The new Q P model provides an important complement to the existing velocity models for interpreting structural heterogeneity and fluid saturation of rocks in the study area. Online Material: Figures of checkerboard resolution tests, Q P versus V P , and Q P versus heat flow.

Modeling for geophysical monitoring of multiple phase saturation of rocks: Applications to CO2 sequestration

A numerical study of measured petrophysical properties was used to develop and demonstrate a workflow for monitoring [Formula: see text] sequestration in a subsurface reservoir. Amplitude versus offset (AVO) attributes can be sensitive discriminators for [Formula: see text] presence. The sensitivity of AVO attributes to [Formula: see text] saturation increased when an upscaling scheme that propagated the effects of small-scale heterogeneities was used. A global sensitivity analysis was then performed to study the importance of various rock properties that would be used as inputs in reservoir characterization. An extensive rock properties database for a carbonate reservoir containing natural variability was used. The various rock properties were ranked by their importance to the quality of the remote characterization. Defining and using the intrinsic correlations among petrophysical properties were essential to evaluating whether a particular reservoir was amenable (sensitive) to this AVO characterization method.

Three‐dimensional compressional wave attenuation tomography for the crust and uppermost mantle of Northern and central California

AbstractI present a frequency‐independent three‐dimensional (3‐D) compressional wave attenuation model (indicated by quality factor Qp) for the crust and uppermost mantle of Northern and central California. The tomographic inversion used t∗ values measured from amplitude spectra of 80,988 P wave arrivals of 3247 events recorded by 463 network stations through a 3‐D seismic velocity model. The model has a uniform horizontal grid spacing of 15 km, and the vertical node intervals range between 2 and 10 km down to 45 km depth. In general, the resulting Qp values increase with depth and agree with the surface geology at shallow depth layers. The most significant features observed in the Qp model are the high Qp values in the Sierra Nevada mountains and low Qp anomalies in the western fault zones. Low Qp values are also imaged in Owens Valley and Long Valley at shallow depths and the Cape Mendocino region in the lower crust (∼25 km depth). An overall contrast of Qp values across the fault is observed in the creeping, Parkfield and Cholame‐Carrizo sections of the San Andreas Fault. The new 3‐D Qp model provides an important complement to the existing regional‐scale velocity models for interpreting structural heterogeneity and fluid saturation of rocks in the study area.

Using of Pickett’s plot in determining the reservoir characteristics in Abu Roash Formation, El-Razzak Oil Field, North Western Desert, Egypt

The present work was devoted to evaluate the reservoir characteristics of the Abu Roash Formation in the vicinity of El-Razzak Oil Field, North Western Desert, Egypt. The area of study is bounded by latitudes 30° 25′ and 30° 55′ N and longitudes 27° 50′ and 28° 40′ E. Nine distributed wells were utilized for this study.A new technique has been applied through Pickett’s plot, to develop some of reservoir petrophysical parameters. These parameters include capillary pressure, pore throat aperture radii, height above the free water table and bulk volume of water. This technique depends on the use of log–log plots of effective porosity versus resistivity combined with empirical relationships for calculating the capillary pressure expressed as a function of permeability, porosity and water saturation. Also, this technique gave the values of petrophysical exponents (m, n and a) which were used to calculate the accurate value of water saturation in both clean and shaly rocks and then adjust estimation of hydrocarbon saturation. The integration of these petrophysical parameters on a log–log graph of porosity versus resistivity gives the importance for Pickett plot to be used in reservoir interpretation.

Contribution of multi-method geophysics to the understanding of a high-temperature geothermal province: The Bouillante area (Guadeloupe, Lesser Antilles)

The Bouillante high-temperature geothermal field (Guadeloupe, French Lesser Antilles) is located on the west coast of Basse-Terre Island, about 15km from the currently active Soufrière volcano. We have studied the shallow structure of the geothermal zone using a compilation of all available gravity, magnetic and resistivity data, both subaerial and marine, acquired during the last 30years. Geophysical models have been developed based on geological constraints and previous geophysical interpretations. The resistivity distribution from electromagnetic surveys is interpreted in terms of water saturation of rocks, hydrothermal alteration and presence of hydrated minerals. Gravity is used to distinguish and characterize the denser formations from the low density areas. Finally, we are able to differentiate structures which pre- and post-date various recent magnetic inversions using the polarity of the magnetic anomalies. By integrating these results the previous conceptual model for the geothermal province has been improved, with the layering of the geological formations as defined by geophysical parameters now being taken into account, in agreement with the classical scheme of geothermal reservoirs. The shallow resistive layer is explained in terms of recent massive formations. The conductive intermediate layer marks the low density, demagnetized clay cover of the altered geothermal system. The deep resistive layer is associated with dense formations increasing in age with depth, and corresponds to the deep geothermal reservoir. Based on our geophysical data, the geothermal activity could be more developed towards the east and north compared to the previously proposed area. A volcano-structural control seems to affect the internal structure of the province, and consequently the development of geothermal activity. This current work could be used as a basis for future surveys of the Bouillante province in order to improve constraints, and to increase our knowledge of the island's overall evolution.

Electrical conductivity of porous media with two-phase saturation

Relations are derived for calculating the electrical conductivity of porous media with two-phase saturation. The considered calculations are based on a capillary-lattice model of a porous medium, the model being composed of several unequally scaled three-dimensional cubic lattices of capillaries. Each lattice may be represented as a large number of analogous cubic cells with the same structure of pore space and a preset pore size distribution over the cells. The distribution of porosity over pore sizes serves as a starting datum for the calculation of all model parameters. The number and scale of lattices are determined by the peculiarities of this distribution. The possibilities of practical use of the considered model are shown by the example of experimental data on samples of porous rocks. The results obtained, in particular, suggest that the model is applicable to solving problems of applied geophysics relevant to determining the saturation of rocks with water and hydrocarbons.

Carbonate rock characterization and modeling: Capillary pressure and permeability in multimodal rocks—A look beyond sample specific heterogeneity

Carbonate rocks are known for their heterogeneity and petrophysical complexity. This commonly leads to large uncertainties in reservoir models that are intended to predict fluid storage and fluid flow. In this article, focus is given to the characterization of pore systems at core-plug scale to provide improved models for permeability and saturation prediction. These methods fall under a wider rock-typing workflow. We examine the use of mercury-air capillary pressure data for rock-type definition and for predicting saturation and permeability. We present new methods for modeling saturation in rocks with multimodal pore-throat size distributions. The methods bear similarity to those previously published but with some key differences, mainly by relating the capillary pressure data to the pore systems representative for a rock type. We also present a new method for relating permeability to pore-throat sizes that is more versatile, in that it can be employed for all types of pore-throat size distributions—unimodal or multimodal. We demonstrate that a normalized pore-throat radius parameter forms a straight line relationship with permeability over six orders of magnitude. It appears to be a fundamental property for all pore systems so far examined. The wider implication of the workflows presented is that they offer better integration between the methods used for saturation prediction and the methods used for permeability prediction, something that is desirable for all subsurface studies.

An Experimental Investigation of Optimum Capillary Number on Vertical Immiscible Gas Injection in Iranian Carbonate and Sandstone Rocks

The authors' purpose was twofold: (a) to study optimum capillary number for acquiring maximum oil recovery in vertical gas-oil displacement using carbonate and sandstone cores, and (b) to investigate the influence of capillary end effect on optimum capillary number extracted from experimental data. Two sets of forced gravity drainage experiments were performed on carbonate and sandstone cores. The first set of experiments comprised seven vertical nitrogen injection tests using carbonate core, which had been saturated by kerosene in ambient laboratory condition. The second set consisted of six vertical nitrogen injection tests using sandstone core that had been saturated by live oil under reservoir temperature and pressure conditions. In each set of experiments, in constant bond number, one optimum capillary number (optimum flow rate) was recorded in which the maximum oil recovery was achieved. When capillary end effect was negligible, optimum capillary number was compatible with critical capillary number, which was calculated in critical gravity drainage velocity while in considerable end effect, optimum capillary number was higher than the calculated critical capillary number. In addition, the residual oil saturation in carbonate rock showed a declining trend when capillary number increased, whereas the minimum of residual oil saturation in sandstone core has been observed in optimum capillary number.

Acoustic wave propagation in cracked porous rocks and application to interpreting acoustic log data in tight formations

Rocks in earth's crust usually contain both pores and cracks. Typical examples include tight sandstone and shale rocks that have low porosity but contain abundant microcracks. By extending the classic Biot's poroelastic wave theory to include the effects of cracks, we obtain a unified elastic wave theory for porous rocks containing cracks, adding crack density and aspect ratio as two important parameters to the original theory. The new theory is applied to interpret acoustic velocity log data from tight sand and shale gas formation, whereas the classic Biot theory has difficulty in explaining such data. Because the flat- or narrow-shaped cracks can easily deform under acoustic wave excitation, the acoustic property of a cracked porous rock is quite different for different saturation conditions. This allows the new theory to correctly predict the trend of velocity variation with gas saturation in low-porosity rocks, providing a useful interpretation tool for acoustic logging in tight formations.

Case Studies of Water Shut-Off Treatments in Oil and Gas Production Wells

In this study some of the experimental results of water shut-off treatments in oil and gas production wells were presented. The effect of water saturation of Miocene rocks of the Carpathian Foredeep on the relative permeability to gas was analyzed. Also, wide review of the worldwide publications from the point of view of the results obtained in water shut-off treatments in oil and gas formation was presented. Based on experimental results efficiency of relative permeability modification of sandstone from Szydlowiec to brine and nitrogen by four selected chemicals polymers and microgels was evaluated.Experimental results indicated that trend changes of permeability modification strongly depends on the fluid used in the RPM treatment. Moreover, efficiency of permeability modification to brine depends on flow rate of brine through the core - the lower brine flow rate the higher efficiency of the RPM treatment. RPM product number 1 caused significant loss of permeability to brine ca. 60% and slight permeability modification to gas ca. 18%. This permeability change to brine and gas was obtained by modification of formation wettability what affects well productivity. In the case of product number 2 which is based on microgels technology, also significant modification of selective permeability to brine was observed. Loss of permeability to brine was in the range of 65 to 90% while to gas ca. 50%.