A New Laboratory Technique to Enhance Proppant Consolidation During Propped Hydraulic Fracturing Treatment

The objectives of this investigation were to perform a rock mechanical study to evaluate long term stability of Resin-Coated Proppant (RCP), combined with various additives currently being used in screenless propped hydraulic fracturing completions in the sandstone formations. Thereby providing a tool for the industry to know exactly the duration of the shut-in time before putting a well back onto production. A new experimental method was developed to monitor the curing process of RCP as temperature increases. The velocity of both shear and compressional waves were being monitored as a function of temperature, while the tested RCP sample was being housed in a pressurized vessel. The pressurized vessel was subjected to a variable temperature profile to mimic the recovery of the reservoir temperature following a propped hydraulic fracturing treatment. The placed proppant should attain an optimum consolidation to minimize the potential for proppant flow back. The study has been performed on various types of RCP samples under a range of reservoir conditions. The role of closure stress, temperature, curing time and carrier fluids in attaining a maximum strength of RCP following a propped hydraulic fracturing treatment have been investigated. Also, the Unconfined Compressive Strength (UCS) of various types of RCP have been measured. The testing methods currently practiced in the industry to qualify proppant for field applications are based on physical characterization of several parameters such as the specific gravity of proppant, absolute volume, solubility, roundness, sphericity and bulk density. The sieve analysis, compressive strength, and API crush testing are also measured and reported. The API Recommended Practices; API RP56, API RP58 and API RP60 are the main procedures used to test the suitability of proppants for hydraulic fracturing treatment. However, there is no published API testing method for RCP; therefore this study introduces a new testing procedure, using acoustic velocity as a function of temperature and compressive strength as a function of time; to qualify a given RCP for a particular reservoir of known stress and temperature. The final outcome of this study is to establish a functional procedure for such measurements, in order to maximize the success of a propped hydraulic fracturing treatment and minimize the occurrence of flow back incidents.

Pengaruh Limbah Beton sebagai Pengganti Agregat Kasar terhadap Kuat Tekan Beton

Concrete is the main material factor in a construction project field that is often used, because concrete has a high compressive strength value so it is very useful for structural buildings to withstand axial forces or compressive forces on the building itself where the structure can be used. for the long term. However, along with the increase in construction development in Indonesia, it has a negative impact on the environment around the construction site because with the rampant construction of this building it will trigger environmental pollution due to the remaining concrete waste from the construction project. On this basis, it encourages the author to conduct research by utilizing waste concrete as a substitute for coarse aggregate for the compressive strength of concrete, by reusing the concrete waste will increase the life of the material from the waste itself. In this study, the materials used were tested first, such as; cement density, silt content, water content, specific gravity absorption, wear testing and sieve analysis on aggregates. Then for the concrete mixture using concrete waste with variations of 0%, 25%, 50%, 75% and 100% of the total weight of coarse aggregate. In this study, the compressive strength at the age of 21 days with a mixture of 0%, 25%, 50%, 75%, and 100% concrete had a compressive strength of 200.92 kg/cm2, 188.83 kg/cm2, 206, respectively. 96 kg/cm2, 177.50 kg/cm2, and 179.01 kg/cm2. Then experienced an average shrinkage of 9.53 kg/cm2 at the age of 28 days. The optimum compressive strength is at 50% mixed variation, with a value of 206.96 kg/cm2 because it has an increase of 3% higher than normal concrete compressive strength with a mixing ratio of 1:2.5:3.5 and a slump value of ±13.25 cm and the dry weight of the concrete is 7.69 kg.

Evaluation of soil replacement and cement grout injection in soil settlement

This paper discusses the process of original soil stabilization in Trans Sumatra Bakauheni-Terbanggi Besar Toll Road Project Package 2 Sidomulyo-Kotabaru. The soil replacement process was conducted at approximately 24 kilometres along the toll’s main road. The original soil bearing capacity analysis stage was by performing a Dynamic Cone Penetrometer (DCP) and Sondir test to analyze the deep of hard soil. A soil replacement was carried out to replace the original soil with soil that has appropriate specification. the piling up process was conducted in stages, which has Sandstone in such of the layer. The research done about the landfill sample was retaken and collected at 68 points. The stockpile soil samples collection was then followed by the analysis which was conducted in the laboratory to find the soil bearing capacity. There are 4 types of bearing capacity parameters analyzed, namely specific gravity, water content, aggregate analysis (Sieve Analysis), and consistency limit (Atterberg Limit). Referring to it, then there was the classification of soil types according to AASHTO M145 & Casagrande Soil Classification System. A point that has settlement after soil replacement is STA 52+000. So, there need to add soil stabilization, that is cement grout injection. Researchers analyzed the soil settlement by interpretation method. Results showed that soil replacement and cement grout injection could decrease a soil settlement by about 15.07 cm to become 0.93 cm.

Feasibility of recycling concrete construction waste in environmental and economic sides

n light of the conditions experienced by Syria and due to the destruction and demolition of its buildings built up rubble and occupied a large area of its territory. Therefore, it was necessary to develop an appropriate strategy to study these debris and provide the ideal solutions to be able to benefit from them as much as possible and thus mitigate the harmful impact on the environment and the surrounding environment. The work is divided into two parts: First: The study focuses on one of the mechanisms of benefiting from the recycled aggregate by using them in producing concrete, after studying their characteristics(Sieve Analysis-density- Absorption) and then mixing them with natural aggregate as replacement of natural coarse aggregate at different rates(15-30-45-75-100)%. Six concrete cubes were made for each mixture and 3 cubes were broken after 7 days and the other after 28 days . it was concluded The relationship between the percentage of recycled aggregates and compressive strength, as well as the relationship between the percentage of stones and the rate of Absorption The results showed that the acceptable percentage of replacement of natural aggregates with recycled aggregates may reach 100% with the recording of values of resistance of up to 21.9Mpa . Second :The environmental and economic feasibility of using recycled aggregates has been studied the results showed that use 75% of the recycled aggregates in structural concrete works will reduce energy consumption and carbon dioxide emissions by 28% and 33%, respectively, and the economic saving rate is 63.71%. . Through this study two objectives can be achieved: First: removing large quantities of environmental pollution sources resulting from these wastes and thus achieving an environmental goal. Second: Provide other sources of concrete aggregates and thus protect the natural quarries and achieve an economic goal.

Quality Assessment of Commercially Produced Sandcrete Blocks in Okitipupa Local Government Area, Ondo State, Nigeria

The frequent collapse of buildings in Nigeria has necessitated carrying out a quality check not only on the structural design of these buildings but also on the materials used in their construction. Sandcrete blocks are used as a walling unit mostly because they are cheap and fast to produce. They can also be use as either load-bearing or non-load bearing purpose. Hence, this paper gives an in-depth quality assessment of sandcrete blocks commercially produced in Okitipupa Local Government Area of Ondo State, Nigeria. Six sandcrete block producing locations were visited within the local government and both six inches (6″) blocks (450×150×225 mm) and nine inches (9″) blocks (450×225×225 mm) from each location were randomly collected, together with their soil samples. Twenty-four control samples of 6″ and 9″ sandcrete blocks were also produced in accordance with the Nigerian Industrial Standard (NIS 87: 2007). Specific gravity test, silt/clay content and sieve analysis test were performed on each soil samples from different locations to check their suitability for block production, in addition, bulk density, compressive strength and water absorption were performed on the collected sandcrete blocks. In general, the compressive strength of the block samples was between 1.09 N/mm2 to 1.19 N/mm2 for six inches and 1.37 N/mm2 to 1.64 N/mm2 for nine inches which falls below the 2.5 N/mm2 and 3.45 N/mm2 minimum recommendation given by the NIS.

Granulometric composition research of mine rocks as a material for backfilling the mined-out area in coal mines

Purpose. Determination of the granulometric characteristics and loosening coefficient of mine rocks formed during stope operations from undercutting the bottom rocks as a potential backfill material based on a set of mine and laboratory research. Methods. To do research, a complex methodology is used, which includes a photographic surveying the mass of destroyed rocks from undercutting the bottom rocks in mine conditions, digital processing and determining the granulometric composition in the software package, sampling the mine rocks at the surface complex, and reconstructing the granulometric composition, similar to the full-scale mine conditions in the laboratory. Sieve analysis, laboratory balance and laboratory container are used to determine the granulometric composition and loosening coefficient. Findings. The dependence between the granulometric composition and loosening coefficient of rocks, which increases by 33% within fractions of 0-50 mm and by 8% within fractions of 50-140 mm, has been revealed. It has been determined that the destroyed rocks in the face within fractions of 0-140 mm have a bulk density of 1.28 g/cm3, loosening coefficient of 1.7, the voidness of and the maximum reserve for the backfill mass compaction with mine rocks is 41.9%. An analytical assessment of the volumes of the formed cavities of the mined-out area in the longwall face and gobed mine workings, as well as the prospects and completeness of their filling with mine rocks have been performed. Originality. It has been determined that the loosening coefficient of mine rocks destroyed in the stope face by KA-200 shearer changes according to the logarithmic dependence on their granulometric composition. This makes it possible to control the granulometric characteristics of the backfill material to achieve the maximum density of the backfill mass. Practical implications. Further research can serve as a basis for determining the rational parameters for the formation and placement of backfill masses during complex-mechanized selective mining of coal seams using various methods of backfilling operations.

Determination of Types and Characteristics of Laterite Soil as Basic Land for Building Construction

Laterite soil is red soil because it contains iron and aluminum. It is an old type of soil, so it is suitable for all plants. Laterite soils are located in the reservoir area of the Wonogiri Dam - Central Java. The nature of laterite soil that quickly absorbs water and the soil texture is strong and dense indicates the type of soil used for a mixture to make roads. This study aims to identify and characterize the lateritic soils to support the construction of roads that will be used. It is needed to test the soil’s property index, including moisture content test, density test, Atterberg limit, and grain sieve analysis. At the same time, it tested the classification of laterite soil characteristics using standards of USCS and AASHTO. To test the shear strength of the laterite soil is using Direct Shear. Based on the analysis, the laterite soil from sedimentation in Wonogiri dam is classified as poor and does not meet the requirements to be used as a subgrade in building construction. It can be considered include need to improve to carried out first.

Analysis of blasted rocks fragmentation using digital image processing (Case study: Limestone quarry of Obajana Cement Company)

Purpose. Blasting is an important aspect of mining activities in which fragmentation is the key component that determines its efficiency. Fragmentation is the first result of blasting, and is directly related to the costs of mining. Methods. There are two basic methods for determining the degree of rock fragmentation, the direct and indirect methods. The direct method includes sieve analysis while the indirect method involves observational, empirical and digital image processing methods. The digital image processing method with the aid of Split Desktop software was used in this study, to analyze the size of fragmentation in Obajana limestone quarry. Two pits of similar line of operation were considered. Findings. In each of the pits considered, five muckpiles of blasted rocks after blasting with different blasting patterns were analyzed to study the fragmentation phenomenon. The F80 and F90 values from the Split Desktop image analysis for the 5×3 m and 4×3 m in Pit 1 and Pit 2 were approximately 87.96 and 96.20 cm; and 91.34 and 98.66 cm respectively. Also, the F80 and F90 values obtained from the Kuz-Ram model for the 5×3 m and 4×3 m of Pit 1and Pit 2 were 99.9967 and 99.9994 cm; and 99.9957 and 99.9993 cm respectively. The results of the Split Desktop were compared to the results of the Kuz-Ram experiential model. The values of F80 and F90 of the blasted rocks are very close to the crusher gape value of 1 m, which reduces the production costs, and that is an outcome practically realized for the two pits of Obajana quarry. Originality. The findings showed that the output obtained from the Split Desktop software which is a digital image processing method were in conformity with the Kuz-Ram experiential model which is based on empirical relationship. Practical implications. In conclusion, the results of the investigation have significant implications for the practical application. It gives more options to explore for rock blast fragmentation efficiency of the desired area.

Effect of Adding Surfactants to a Solution of Fertilizer on the Granulation Process

Granulated chelates are innovative fertilizers that are highly effective and versatile, and they ensure the best start-up effect for plants. The final properties of granules are influenced by the method of their preparation and the used substances. The diameters of the obtained granules, their size range, and the final costs of the produced fertilizer are of great importance. The paper describes granules that were produced using an agglomeration of ZnIDHA in a fluidized bed with the aid of an aqueous solution of this substance with a high dry matter content. The aim of the study was to evaluate the effect of surfactant addition to the solution on the evolution of granule size distribution during the process carried out in a batch mode and to access the possibility of describing the process dynamics using population balance approach. A sieve analysis was performed in order to determine the size of the granulate, and numerical calculations were performed to determine the value of the constant aggregation rate. Based on experimental studies, it can be seen that the increase in the diameters of granules is mainly caused by the agglomeration process, and to a lesser extent by the coating process. The addition of surfactant increased the median size of the granules in the initial granulation stage, and also lowered the surface tension. This in turn enables a lower spraying pressure to be used. A comparison of different aggregation kernels constituting an integral part of the population balance model proved that the physically motivated equipartition kinetic energy kernel performs best in this case. Moreover, the computational results show an increase in the aggregation rate when the surfactant additive is used and confirm that population balance allows the extraction of physical information about the granulation.