In this paper, we consider a method of increasing biological resistance and biological durability of buildings and constructions that are subject to destruction from the impact of microorganisms activity. This article presents the results of studies of innovative materials in the field of bioresistant building materials. Powders of milled quartz sand and limestone were the fillers for the composites. Limestone used for the experiments is from the Chechnya depostits. We have implemented optimization for the cement composites compositions using the methods of mathematical experiment design. We derived the dependences describing how the bioresistance coefficient, the elastic modulus and the water demand depend on the granulometric composition after 3 and 9 months of aging in the environment of filamentous fungi. We have found that the multifractional compositions have a higher bioresistance coefficient. We determined the fungal resist compositions.

In this article, we consider a method of producing biostable innovative materials in order to improve the biological resistance and durability of buildings and structures based on them. We present the results of the research work focused on the study of the cement composites bioresistance. Powders of milled quartz sand and dolomite were the fillers for the composites. Mathematical methods of experiments design allowed us to derive the dependences describing how the bioresistance coefficient, the elastic modulus and the water demand depend on the granulometric composition after 3 and 9 months of aging in the environment of filamentous fungi. We have found that the multifractional compositions have a higher bioresistance coefficient. We determined that dolomite significantly enhances bioresistance of the samples and Portland cement composites, filled with quartz sand and dolomite, are fungal resist.

Important factors affecting acid fracturing efficiency include etched fracture geometry, cleanup, and optimum differential etching to retain open channels after fracture closure. A recently applied integrated approach combined improvements in all three factors: new fracture simulation techniques enabled fracture geometry optimization, single-phase retarded acid provided significant increase in half-length, and high retained permeability viscous fluids supported better fracture cleanup. The approach was successfully implemented in several carbonate oil fields and resulted in a substantial productivity index increase. The approach enables acid fracture optimization in three steps. First, the high retained permeability, low-pH pad fluids and polymer-free leakoff control acids are used in combination to enhance formation cleanup after a treatment and to reduce the concentration of polymers in fissures network of naturally fractured carbonate reservoirs. Second, a new single-phase retarded acid is used to achieve longer half-length due to retarded reaction with formation rock and favorable viscous fingering effects. Third, a new acid fracturing simulation model is used to optimize fracture geometry. The simulation technique employs an innovative transport model that includes the viscous fingering effect, advanced leakoff simulation, changing acid rheology upon spending, and a novel calculation approach to mixed fluids' rheology. This combined concept was applied during acid fracturing treatments in moderate permeability wells of carbonate reservoirs with target intervals up to 4,600 m TVD and temperatures up to 125°C. The treatments consisted of guar-free low-pH pad fluid, polymer-free leakoff control acid, and single-phase retarded acid. Treatment optimization was performed using an advanced acid fracturing simulator to properly address the transport processes within the fracture in a low-stress-contrast environment. After the treatments, the pressure transient analysis indicated a strong linear regime for more than 15 hours, indicating effective fracture half-length at least 25% higher than average half-length after acid fracturing in offset wells where the conventional approach had been applied. Post-treatment half-length calculations showed a good match with advanced simulator results and proved the importance of accounting for viscous fingering effects during acid fracture half-length calculations. Calculation of the productivity index from the production data showed at least 15% increase compared to conventional acid fracturing treatments. The post-fracturing production decline rate was at least 20% slower than that of the conventional treatment in offset wells, which can be explained by the longer conductive fracture.

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The paper presents the results of studies of the physical and mechanical properties of foam concrete on activated mixing water. Corrosion resistance of reinforcing steel in foam concrete with the use of activated water in the presence of mineral additives was studied. The use of activated with the electromagnetic field and electric current water of mixing enhances strength characteristics and reduce shrinkage deformation of composites. The increase of water resistance of foam concretes prepared on activated water of mixing compared with control compositions it was established. The comparative characteristic of foam concrete on the two types of foaming agent is given. The results of the anodic behavior of steel in activated water, characterizing the degree of aggressive influence on the steel depending on the activation mode and the chemical composition of mineral additives. This paper is a revised version of the paper (study) published earlier in the proceedings of the Creative Construction Conference 2018 (Karpenko et al., 2018).