Application of Renewable Natural Materials for Gas and Water Shutoff Processes in Oil Wells

Abstract

We propose a complex sealing compound for increasing the efficiency of shutoff operations based on natural materials processing for materials such as sand, peat, rice, and husks. We studied the influence of mechanical activation processes on the mechanical and rheological properties of the developed sealants. Through mechanochemical activation, sand dissolution in a low-concentrated alkali solution was possible, and gelling the resulting sodium silicate while reinforcing it with undissolved sand particles to obtain a sealant composition. We used this approach to produce a hybrid sealing compound based on activated rice husks with up to 20% biogenic silicon dioxide combined with mechanically activated peat: the maximum shear strain of the hybrid sealant was 27.7 ± 1.7 Pa. We produced hydrogels based on sodium silicate, polyacrylamide, and chromium acetate, reinforced with mechanically activated rice husks. We studied the sealants’ rheological and filtration properties and observed the respective viscoplastic and viscoelastic properties. An increase in the dispersion concentration from 0 to 0.5% increased the maximum strain value of undestroyed hydrogel’s structure in the range 50–91 Pa and the maximum shear strain from 104 to 128 Pa. The high residual resistance factor values of the ideal fracture model make the natural and plant-renewable raw materials very promising for repair and sealing work.

1. Introduction

Currently, the development of energy- and resource-efficient and environmentally friendly technologies for processing natural raw materials is becoming a promising direction in the development of chemical and technological engineering [1]. Gas and water shutoff in oil wells drilled in porous–fractured and fractured reservoirs is one of the most geotechnically complex and problematic types of repair and sealing operations, the success of which usually does not exceed 35–60% [2,3]. The cement slurries used for such operations are ineffective due to low filterability into fractured porous rocks [4,5]. Polyacrylamide (PAM)-based hydrogels are expensive, and their polymer proportion is, as a rule, 0.3–0.5% [6,7]. PAM-based compound application in horizontal wells is also problematic, since the injection of large volumes of these hydrogels is difficult due to the high viscosity and difficult-to-control gelation time, especially at high temperatures [8,9].

The use of affordable natural materials for water and gas shutoff is limited to water-swellable clays and wood flour [10,11], or a mixture of cellulose-containing microfiber powder products and finely dispersed hydromica stabilized by a polymer additive [12]. It should be noted that similar publications are few, and most importantly that the water and gas shutoff technologies in oil production wells using natural materials are not widely used in industry.

This work aims to develop a method for processing natural materials into sealing compositions for oil well treatment. We suggest using hydrogels based on affordable inexpensive natural materials, such as river sand, peat, rice husk, and sawdust flour, as gas and water shutoff screens. We applied mechanochemical activation methods for converting these solid materials into a soluble gel-forming state. In this technology we developed, mechanical activation was carried out using vibratory and centrifugal mills with a capacity from 20 to 200 kg per hour. Such mills are essentially flow-type mechanochemical reactors. Intense mechanical action on the processed materials provides particle size reduction, an increase in the specific surface area, and the destruction of the crystal lattice and partial amorphization of the materials. For example, the mechanical treatment of river sand increases the specific surface area of the sand, the formation of structural defects inside the sand particles, and an amorphous layer on its surface. As a result, partial dissolution of sand is observed when interacting with alkali, with the formation of the corresponding silicate. The undissolved sand remains suspended, forming a suspension of sand particles and an aqueous-alkaline solution of sodium silicate. Different particle sizes (up to tens of μm) can be selected depending on mechanical activation and dissolution conditions. When neutralizing such a suspension, reinforced gels with high values of ultimate shear strain are obtained, indicating the formation of a solid three-dimensional structure and the possibility of using this material as a sealing screen. In this case, it is possible to obtain a synergistic water- and gas-sealing effect similar to the widely used polymer-dispersed systems based on PAM [13,14,15]. The combination of mechanically activated river sand and peat also produces hybrid barrier materials due to dissolving the materials in hot, dilute alkaline solutions with subsequent neutralization.

Solid-phase mechanical activation of natural silica-containing raw materials (for example, rice husks) provides a high degree of silicon oxide extraction; it increases the reactivity of river sand in the reaction with an aqueous alkali solution. Solid-phase mechanical activation also homogenizes solid mixtures to form reactive composites with increased solubility. Thus, mechanical activation is a new and environmentally safe technology that makes it possible to obtain reagents for water and gas shutoff materials not directly derived from sodium silicate, as is the case with many patented technologies [16,17,18,19]. In this case, it is possible to obtain reagents for water and gas shutoff materials by producing a composite solution of sodium silicate, using readily available, inexpensive waste materials such as river sand, spent catalysts (zeolites), broken glass, and rice husks.

Adding mechanically activated rice husk to a hydrogel based on sodium silicate and PAM increases the stability of the sealing material during filtration in cracks, which has been proven by rheological and filtration experiments in fractures of variable openness.

2. Materials and Methods

We used top-layer peat samples from the Orlovskoye deposit in the Tomsk region for this work. Peat grinding was executed for three minutes using a Nossen 8255 disintegrator (VEB Maschinen- und Anlagenbau, Nossen, Germany) with a rotor diameter of 300 mm. The effective rotating speed relative to the grinding particles was equal to 3000 rpm due to their colliding action against prongs attached to the rotating disk.

The mechanical treatment of rice husk, river sand, and a mixture of river sand and peat was carried out on a flow reactor CM-7 with a capacity of 20–25 kg/h. The obtained rice husks particles had the following size: 90% of particles were less than 59 μm, and 50% of particles were less than 17.2 μm.

As a result of the sand’s mechanical treatment, its specific surface area increased from a few square centimeters to 4.2 m²/g. The solubility of such activated sand in hot alkali reached 5–6%wt within a few hours.

The hydrogel composites were prepared based on sodium silicate (4.5%), partially hydrolyzed A345 grade PAM (0.05%), crosslinked with chromium acetate (1.9%) with a filler of crushed rice husk at concentrations of 0, 0.1, and 0.5%, respectively.

2.1. Methodology of Rheological Experiments

The rheological characteristics were recorded using a Haake Viscotester iQ rotary viscometer (Thermo Fisher Scientific, Waltham, MA, USA). Measurements were made using the geometry of a coaxial cylinder of CC25 DIN/Ti type. The viscosity detection limit for this cylinder was 0.002332–174932 Pa·s; the shearing rate was 0.01294–1941.0 s⁻¹. The relationship of the shear strain to shearing rate was determined using the tested samples and according to which the effective viscosity was calculated; the shearing rate ranged from 0.1 to 300 s⁻¹.

The oscillation experiments were carried out using a HAAKE MARS III rheometer (Thermo Fisher Scientific, Waltham, MA, USA) with a test sample placed between disks having a diameter of 60 mm and a 1 mm gap between them. The elastic modulus G′ and the loss modulus G″ were determined by the tangential shearing strain τ at a frequency of 1 Hz with scanning (sweep). The creep and recovery tests based on Maxwell, Kelvin–Voigt models, and Burgers analog models are the best illustrative and quantitative representation of the viscoelastic properties of the samples. Burgers analog models are widely used to illustrate the behavior of the polymer materials [20]. The Burgers model’s strain value γ in the case of a series connection of an elastic Maxwell body (γ_el), a viscous Maxwell body (γ_vs) with a Kelvin–Voigt body (γ_KV) (elastic and viscous bodies connected in parallel) was calculated as a sum of the listed variables:

$${\mathsf{\gamma }=\mathsf{\gamma }}_{\mathrm{el}}{ + \mathsf{\gamma }}_{\mathrm{vs}}{ + \mathsf{\gamma }}_{\mathrm{KV}}$$

(1)

The impact of stress produces a general strain, which develops over time, as shown in the equation below:

$${\mathsf{\gamma }\left(\mathrm{t}\right)}_{ }={\frac{\mathsf{\tau }}{\mathrm{G}}}_{\mathrm{el}}+\frac{\mathsf{\tau }}{{\mathsf{\mu }}_{\mathrm{vs}}}\mathrm{t}+\frac{\mathsf{\tau }}{{\mathrm{G}}_{\mathrm{KV}}}(1 -{ \mathrm{e}}^{-\frac{\mathsf{\tau }}{\mathsf{\theta }}}),$$

(2)

where τ is the effective stress, G_el is the elasticity modulus, μ_vs is the viscosity, θ = μ_KV/G_KV, μ_KV, and G_KV are the viscosity and elasticity of the elements of the Kelvin–Voigt body, and θ is its relaxation time.

During dynamic oscillation measurements, the disk performs rotational oscillations with angular frequency ω, produced by changing the force moment of the disk’s shaft, and sinusoidally varying shear strain arises under its impact. The concepts of the complex module G* are introduced into rheology for the description of oscillatory processes as described below:

$${\mathrm{G}}^{\ast }=\mathrm{G}\prime +\mathrm{iG}″=\frac{\mathsf{\tau }\left(\mathrm{t}\right)}{\mathsf{\gamma }\left(\mathrm{t}\right)},$$

(3)

where G′ = |G*|cos(δ) is the modulus of elasticity, G″ = |G*|sin(δ) is the loss modulus, and δ is the phase difference between the acting stress and the resulting shear, $\mathrm{i}=\sqrt{-1}$, $\left|{\mathrm{G}}^{\ast }\right|=\sqrt{{\mathrm{G}}^{\prime }{}^2{+\mathrm{G}}^{″}{}^2}$. If the substance is purely elastic, the phase shift angle is δ = 0; If the substance is viscous, then δ = 90°. The complex viscosity (µ*= G*/ω) is determined from the complex module.

Dynamic measurements were performed using the HAAKE MARS III rheometer, and the elastic modulus G′ and the loss modulus G″ were correlated. The data obtained made it possible to identify a linear measurement range (LMR) corresponding to the stress interval from zero to τ, up to which point the elastic modulus G′(τ) showed no significant decrease (this value of τ is output in the rheometer interface).

2.2. Filtration Testing Methods

We used natural low-permeability core samples to create an ideal fracture model (slot model—Figure 1). Core samples were pre-treated with an alcohol–benzene mixture and washed with bidistilled water to remove any salts in the Soxhlet extraction apparatus. The samples were dried in a drying cabinet at 105 °C.

Later, cylindrical core samples were sawn lengthwise into two equal parts, then glued together to make a composite model with a length of at least 12.8 cm. After polishing the contact surfaces, strips of copper foil of the appropriate thickness were glued to one of the halves (to form a given crack opening). The parameters of the created ideal fracture model were as follows (cm): length 12.8; width 3.0; nominal gap (slot opening) 0.01, 0.05, and 0.1. The orientation was horizontal.

The surface of the slot model was carefully treated before the experiment: first cleaning off the dirt and then washing it with water and an alcohol solution. The following testing procedure was used. The ideal fracture model was placed in the core holder of the core filtration analysis unit SMP FES-2R (Kortekh, Mytishchi, Russia), and the required volume of hydrogel was filtered to study rheological properties. The technical characteristics of the SMP FES-2R unit were as follows:

• Linear length of the core model: from 100 to 300 mm;
• Core temperature control range: from +25 to +150 °C;
• Maximum rock pressure: 70 MPa;
• Maximum reservoir pressure: 55 MPa.

3. Results and Discussion

3.1. Development of a Mechanochemical Activation Method for Processing Natural Materials to Obtain Water-Sealing Compositions

A 5% NaOH solution was used to dissolve the mechanically activated sand at the fastest rate (at 90 °C for 6 h), and the solids-to-liquids phase ratio (s:l ratio) should be in the range from 1:1 to 1:2 for a greater yield of sodium silicate. According to the results of gravimetric analysis, the solubility of sand in the experiments averaged from 5 to 6% by weight.

The gel formed from peat swelling in the alkali could be used as a medium for dissolving activated sand. In this case, it was impossible to achieve a solids-to-liquids ratio of sand close to 1:1–1:2 due to the formation of a very viscous gel that prevents mixing. Therefore, the sand should be dissolved at lower solids-to-liquids phase ratios.

Dissolution experimentations were carried out using a mixture of peat and sand with the mass fraction of 1:1 and a solids-to-liquids ratio of 1:3; the cumulative mass of the sand and peat was counted as the solids phase. The dissolution temperature was 90 °C, the dissolution time was about 6 h, and the concentration of the NaOH was 5%. A comparative analysis of the gels’ rheological characteristics produced by hydrochloric acid neutralization of alkali suspensions with equal amounts of peat and sand showed that the addition of peat increased the yield strength from 5.8 to 14.2 Pa. Furthermore, the resulting gel was stable up to 90 °C.

The following experiments were conducted to determine the optimal mechanical activation method for the components for gel-dispersed compositions. In the first case, mechanical activation of a mixture of sand and peat with 1:1 mass fraction was carried out using a ball mill. In the second case, sand and peat were activated separately in the ball mill with the same pulverizing intensity and then mixed at a mass fraction of 1:1. The dissolution for the first and second cases occurred simultaneously; sand dissolved in the presence of peat. After dissolution, the resulting composite gel was a low-viscosity suspension of black color with properties similar to an inorganic gel from sand: gelation occurred from the acidification of the neutral medium (using concentrated hydrochloric acid). The yield stress of the gel produced by the activation of the sand and peat mixture was 8.4 ± 0.3 Pa (i.e., case 1), and 27.7 ± 1.2 Pa when sand and peat were separately activated (i.e., case 2).

It was necessary to analyze the structural changes occurring during the mechanical activation of peat and sand separately and of a mixture of peat and sand. Peat contains natural organic polymers and macromolecules such as hemicellulose, cellulose, lignin, humic acids, protein-like substances, and mineral components. Relative proportions for each of these components vary greatly depending on the origin and the age of peat. For example, the amount of protein-like substances could vary from 4 to 23%, and lignins could vary from 25 to 52% [21]. The particle size of peat ranges from 1–10 mm to 1–10 microns; this is determined by the degree of decomposition of peat-forming plants present in the peat and the composition of any accompanying soils. The mechanical treatment of peat in the Nossen 8255 disintegrator destroys plant tissues and reduces the peat’s particle sizes. Under such mechanical treatment conditions, any changes in the molecular weight of natural polymers and macromolecules contained in peat could be neglected. When peat and sand are processed separately, pulverization occurs in both cases. However, the skeletal bonds in peat are broken down, and the molecular weight of the polymers decreases [22], whereas, with sand, a reactive amorphous phase occurs during friction and shearing [23].

During combined grinding of peat and sand in the CM-7 flow reactor (Institute of Solid State Chemistry and Mechanochemistry of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia), the plasticity of peat reduces the coefficient of friction between the sand particles and thus reduces the amount of reactive amorphous phase of the sand. On the other hand, sand is an abrasive, which increases the effect of mechanical activation of the peat during the mechanical activation of the sand and peat mixture. Therefore, after mechanical activation of the sand and peat mixture, the solubility of sand is lower since the relative proportion of the amorphous phase decreases, and the dissolution of the peat components is higher due to better dissolution of low molecular weight polymers. However, the viscosity of such polymer solutions would also be lower according to the well-known Staudinger equation:

[η] = K · M^α,

(4)

where [η] is the characteristic viscosity of the solution, M is the molecular weight of the dissolved polymer, and K and α are empirical constants depending on the chemical nature of the solvent and polymer.

In the case of separate mechanical activation of peat and sand, the concentration of polymers and sodium silicate in the alkaline solution would be higher. Therefore, the viscosity of hybrid organo-inorganic gels produced by neutralizing mixed alkaline solutions would also be higher, as observed in the above-described experiments. It should be noted that understanding the mechanisms of gelation processes of compositions based on mechanically activated peat and sand provides ample opportunities for adjusting the rheological properties of hybrid organic-inorganic gels and producing sealant compositions with predetermined properties.

The bonds in the hybrid materials produced are different due to the complex composition of peat. Topological polymers in polymers–cellulose inorganic silicate systems could be formed between inorganic and organic polymers in addition to hydrogen bonds. The immobilization of humic acids on the surface of quartz sand particles is possible if we consider the presence of amino acids in peat [24]. However, it is necessary to conduct additional spectral studies and observe the very early stages of gelation in such systems to understand better the structure of the material obtained and the nature of the bond between their components [25].

Mechanical activation technologies have made it possible to use rice husk as a source of organic and inorganic components for gel/dispersed particle compositions. Thus, samples were dissolved in 5% NaOH solution at 90 °C for 6 h (solids-to-liquids ratio = 1:3). Later, concentrated HCl solution was added to the resulting suspension and titrated to neutral pH. As a result, yield strength increased from 1.8 ± 0.4 Pa for gelant to 16.2 ± 0.6 Pa for gel (almost by order of ten). Thus, the rice husks-based gel-dispersed compositions exhibited rheological properties comparable to mechanically activated sand and peat compositions.

All the resulting gel-forming compounds were mechanically stable: they restored their rheological properties after some time following mechanical impact.

Figure 2 shows the results of a comparative study of a gel based on liquid glass and gels based on mechanically activated sand and peat, and rice husks with similar concentrations of sodium silicate per volume under study (about 4%). The viscosity properties of the hybrid gels based on the sand and peat mixtures and the rice husks significantly exceed the viscosity properties of the gel obtained from pure sodium silicate.

3.2. Study of the Stability of Sodium Silicate-Based Hydrogels with Additives from Mechanically Activated Rice Husk during Fracture Filtration

The addition of mechanically activated rice husk to a hydrogel based on sodium silicate, chromium acetate, and PAM (with the latter concentration being only 0.05%) increased the isolating material’s stability. Rheological properties were measured using sodium silicate composition, PAM, and chromium acetate before and after filtration through the ideal fracture model with an opening of 0.01 and 0.1 cm (Figure 3).

As can be seen from Figure 3A, the rheological properties of hydrogel during filtration through a crack with a 0.01 cm gap decreased drastically (by two orders of magnitude). In the case of a 10-fold gap increase (up to 0.1 cm), the rheological parameters of hydrogel practically did not change before and after filtration (Figure 3B). Based on these results, we could conclude that the sealing material intensively degraded in small cracks.

The addition of rice husk dispersion resulted in a significant increase in the hydrogel resistance to mechanochemical destruction. Thus, from Figure 4, adding 0.1% rice husk enabled a substantial reduction (by order of ten) in the difference in effective viscosity before and after filtration through a 0.01 cm gap.

In the case of filtration through a slit of 0.1 cm (Figure 4B), there is no significant difference in the hydrogel’s rheology hydrogel with or without adding rice husks. On the contrary, a slight gel strengthening after filtration was observed at low shearing rates.

Such behavior of hydrogels was probably due to the fracture’s geometric dimensions reformatting the sealing material’s structure during filtration. The supramolecular formations, which provided the necessary complex of hydrogel properties, are deformed and destroyed in small cracks but preserved in large ones. The dispersed particles strengthen the composite, enabling the hydrogel to preserve its structural and mechanical properties. Indeed, the structure of the composite hydrogel was strengthened during filtration through a 0.1 cm opening (Figure 4B). Firstly, this was an indication of the interaction between the dispersed particles and the polymer macromolecules due to flocculation action. Secondly, the composite’s hydrogel structure was not destroyed but, on the contrary, was somewhat strengthened by shear loads during filtration.

A further increase in the rice husk content to 0.5% (Figure 5A) did not lead to any significant changes in rheological properties compared with the addition of 0.1% dispersed material. There is a noticeable increase in the effective viscosity of the hydrogel at low shear rates after filtration through a gap with an opening of 0.1 cm.

These results agree with the data provided by [26], which show the effect of silica dispersion on the PAM solution’s stability and rheological behavior. The results indicate that large cracks with the highest water inflow would also be most reliably sealed with dispersed particle composite hydrogel. Apparently, adding rice husks strengthens the hydrogel structure due to the dispersed particles’ flocculation by polymer macromolecules.

Previous results obtained from the hydrogel filtration study using our ideal fracture model showed high residual resistance factor values over a wide range of filtration rates; It is possible to recommend this material for remedial cementing operations in wells [27].

The approach we have put forward of adding dispersed mechanoactivated materials into hydrogels for water shutoff purposes suggests that future benefits could be gained by further developing mechanoenzymatic technologies for processing dispersed compositions. In particular, we have shown the fundamental possibility of obtaining new materials for water shutoffs using nature-like technologies.

Submicron and nanoscale fibers and particles are already known agents used to harden many polymers and polymer compositions [28,29]. We proposed using the same approach to strengthen gels (not solids), known in modern materials terminology as “soft matter”, materials which, due to various physical properties, occupy an intermediate position between solids and liquids. The effect of strengthening hybrid sealing materials with rice husk particles, similar in composition to the combined composition of mixtures based on sand and peat, was demonstrated above. Smaller particle sizes have a more noticeable strengthening effect. Small particles could be obtained either by crystallization from solutions, condensation from the gas phase, or by large destroying large particles. Obviously, the second method is only suitable for natural materials. However, economics has to be taken into account here: the smaller the particle size obtained as a result of grinding, the more energy is needed to obtain it, and energy costs should be correlated with the market value of the material. We proposed the mechanoenzymatic method for obtaining small wood and plant dispersions resulting in noticeable energy savings when grinding plant raw materials [30].

The above method combines the use of enzymes and mechanical processing. This technology could be considered as a nature-based technology (an example of such an action is the effective conversion of grain components into a digestible form in the stomach of a chicken using both mechanical and chemical devices—so-called gastroliths (small stones in the stomach) and enzymes) [31].

Table 1. Comparison of the results of grinding of raw materials using mechanochemical and mechanoenzymatic methods.

Raw Materials	Grinding Technology
	Mechanochemical	Mechanoenzymatic
	Fractions, Proportion Less than 50 μm, wt. %
Sawdust	11	48
Rice husk	15	87

shows the results of grinding coniferous sawdust and rice husk using mechanochemical and mechanoenzymatic technologies.

The costs of mechanical energy in both cases are the same. The amount of fine fraction obtained by mechanoenzymatic grinding increased several times compared with mechanical grinding with no extra energy costs; this grinding technology could be considered energy-saving and environmentally safe.

3.3. Oscillatory Rheometry of Hybrid Hydrogels

Having obtained encouraging results in terms of the impact of the dispersed fraction on the resistance of the hydrogel to mechanical impact, we studied its rheological properties using dynamic nondestructive measurements made by applying an oscillatory rheometry method. A hydrogel consisting of sodium silicate (4.5%), PAM grade A345 (0.05%), chromium acetate (1.9%), and rice husk (0; 0.15; 0.25; 0.5%) was chosen as the test object.

The two relaxation times (Figure 6; θ₁ and θ₂) of the viscoelastic medium are due to two types of crosslinking: firstly, ionic crosslinking due to the bonding of the chromium ion with the polymer, and secondly, flocculation due to the flocculation of dispersed particles by PAM macromolecules. Ionic crosslinking corresponds to a shorter relaxation time and flocculation to a longer relaxation time: a combination of these relaxation times leads to the necessary technical result, i.e., waterproofing.

The measurement results showed minor changes in G′ and G″, a significant increase in linear measurement range (τ_L), and a shift in the intersection point (crossover point τ_cr) of G′ and G″ curves toward higher shear strain values (Figure 7). It should be noted that the crossover point τ_Cr in oscillatory measurements is the maximum shear strain. In this figure, the shear strain values corresponding to the boundary of the linear range τ_L are indicated by a vertical segment crossing the line G′.

The crossover point (τ_Cr) corresponds to the vertical segment at the intersection of the line G′ and G″. For hydrogel samples with or without rice husk, the elastic behavior prevails over the viscous behavior until the crossover point τ_Cr. The gel begins to break down with a further increase in strain τ, thereby turning the gel into a highly viscous liquid medium. Comparison of the τ_Cr values for samples with or without rice husks showed that an increase in rice husk concentration from 0 to 0.5% resulted in more stable hydrogels and an increase in strain by 20% (τ_Cr increased from 104 to 128 Pa).

The same trend was manifested for the linear measurement range values; an increase in rice husk concentration unequivocally leads to an increase in τ_L. In the linear range of hydrogels, the elastic properties G′ ˃ G″ dominates by an order of magnitude. A graphical representation of τ_L versus rice husk concentration revealed a linear relationship (Figure 8). Increasing the rice husk concentration to 0.5% leads to an 82% increase in τ_L compared to the hydrogel without rice husk.

The circumstance observed above indicates that the shear deformation resistance of the water shutoff system increases with an increase in the rice husk quantity. Thus, the oscillation tests showed an increased hydrogel’s linear measurement range and ultimate shear strain when the rice husk dispersion content increased. The oscillation measurements enable us to define complex viscosity parameter values, essential for hydrodynamic modeling of water shutoff technological operations [32].

4. Conclusions

The use of mechanical activation methods of natural materials such as sand, peat, and rice husk makes it possible to develop a method for producing reinforced hydrogels for effecting water and gas shutoffs in oil wells.

The addition of mechanically activated rice husk to a sodium silicate-based hydrogel significantly increased its rheological properties and stability during filtration in cracks. A linear correlation between the hydrogel’s linear measurement range with rice husk concentration was established: a change in concentration from 0 to 0.5% leads to an increase in hydrogel’s linear measurement range from 50 to 91 Pa; and the maximum shear strain from 104 to 128 Pa.