Podzemni radovi

Different approach to surfactant screening methods for ASP flooding

2024-01-30T09:23:41+00:00

Selection of adequate surfactant is one of the most important steps in preparation for ASP EOR. There are many parameters to be taken in considerations in this process but different authors are prioritizing different parameters. Shown here is comparative analysis of two surfactants chosen according difference set of priorities, in one low IFT and stability and type of created microemulsion was priority (Surfactant A) and in another mobility of created microemulsion (Surfactant B). Bottle test was done with both surfactants to assess the stability of microemulsion at formation temperature, and coreflood test to assess ability of surfactant to mobilize trapped oil. During first round of tests Surfactant A gave better results, very low IFT and stabile Windsor type III microemulsion while Surfactant B gave higher IFT and Windsor type I microemulsion. During coreflood test Surfactant B performed better in terms of oil recovery factor (ORF) and injection pressures. Apparently, stabile Windsor type III microemulsion that is considered desirable in ASP injection and widely prioritized in surfactant selection process can cause decrease in permeability and injectivity issues. Good results can be obtained with IFT in “moderately” low range and stability of microemulsion is not critical in terms of oil recovery factor.

Geological characteristics of the limestone deposit "Dobrilovići" - Loznica and its preparation for use in agriculture

2024-01-30T09:23:13+00:00

The paper presents the geological characteristics of the limestone of the "Dobrilovići" deposit and the characterization of the trench sample. The technological scheme of limestone preparation, which is used to obtain suitable sizes for use in agriculture, is presented in the paper. Chemical analysis showed the presence of CaCO3 above 80% and CaO above 44.80%. The content of trace metals is low: Cr 21 mg/kg, Pb 3 mg/kg, and Ni 7 mg/kg. The mean value of the loss of ignition is 39.40%, and the pH is 8.47. Based on the obtained results, it was concluded that the chemical and mineral composition of limestone meets the requirements necessary for the calcification of acidic soils. The results of the determination of the granulometric composition showed the dominant presence of large classes above 50 mm (68%). To obtain a class of 100% -2 mm that meets the requirements for application in the calcification of acidic soils, a technological scheme for the preparation of trench limestone is given, which includes crushing, grinding, and grading.

Criteria for evaluation the seismic effect of blasting

2024-01-30T09:24:46+00:00

The explosion that caused by blasting is accompanied by the release of a large amount of energy. That energy can be used for rock mass destruction. At the same time, one part of that energy is utilized for rock destruction while the second one gets lost in the rock mass in the form of seismic wave. Regarding that, blasting effects can be divided into two categories such as: useful work and useless work. Useful work is manifested in form of crushing and milling of the rock material in the limited zone around explosive matter and is defined as brisant effect of explosion. Useless work is a phenomenon known as seismic effect of explosion. Useless work is associated with the elastic displacement i.e., the oscillation of the rock mass particles in a very large space around the place of explosion and is felt as a shock. Oscillation velocity of the induced rock mass is most often taken as the parameter for the evaluation the seismic effect of blasting. It is considering that the oscillation velocity best relates and describes the danger of shocks and damages which can be caused, so the appropriate standards for the shock protection are based on the data related to the oscillation velocity. In many countries, regulations that control the shock level caused by blasting activities have been adopted. For our country, these regulations have not yet been adopted, so we used the regulations of other countries to solve these problems. In this paper, criterion of the Institute of Physics of the Earth, Russian Academy of Sciences, criterion according to the Russian standards for mining objects, criterion according to the German standards DIN and criterion according to the USA standards are presented.

Mitigating hydrate formation in onshore gas wells: A case study on optimization techniques and prevention

2024-01-30T09:25:14+00:00

Gas wells, particularly those situated onshore, play a vital role in the global energy sector by supplying a significant portion of natural gas. However, operational challenges, notably gas hydrate formation, pose substantial issues, leading to complications such as flowline blockages and unexpected well shutdowns. Gas hydrates, crystalline structures resembling ice, form under specific conditions of low temperature and high pressure. This paper explores the complex process of hydrate formation in gas wells, emphasizing the challenges it presents and the need for specialized strategies to address these issues.

The primary focus is a case study of an onshore gas well experiencing recurrent hydrate-related problems. Leveraging PipeSim software, a well model is developed, followed by a sensitivity analysis under various operational scenarios. The study investigates mitigation strategies, including choke position adjustments and methanol introduction, crucial for the safe production of oil and gas fields.

The significance of this study lies in its aim to optimize well performance and mitigate risks associated with hydrate formation. Findings contribute to existing knowledge and offer practical solutions for industry practitioners and researchers dealing with onshore gas wells. The paper's structure includes a review of related work, details on the experimental setup and results, and concluding remarks.

The perennial challenge of hydrate formation in gas wells necessitates a case-specific assessment and individualized approaches. Nodal analysis and well modeling software have become indispensable tools for engineers in developing preventative measures. This paper presents a methodological approach using a specific well as an example, evaluating the effectiveness of three methodologies: downhole choke installation, methanol dosing, and well transfer to a high-pressure separator.

Influence of natural minerals on contaminated solutions pH values

2024-01-30T09:25:42+00:00

The protection and arrangement of agricultural areas in order to obtain health-safe food is extremely important to know the mobility of heavy metals lead, cadmium, zinc and uranium as radionuclides. This research investigated the influence of mineral raw materials (apatite and zeolite) on the mobility of heavy metals and radionuclides in a column system with constant pressure at different pH values (5.0 and 7.0). The tested solutions were contaminated with metals (lead, cadmium, zinc and uranium), in a concentration of 300 mg/l in time intervals of 30, 60, 90, 120 and 180 minutes. It was experimentally determined that there were significant changes in the pH value of the filtrate. The results showed that both apatite and zeolite successfully immobilized lead at both pH values. Uranium immobilization was better performed in columns with apatite, zeolite showed better properties in cadmium immobilization, and tests on a solution contaminated with zinc showed that both apatite and zeolite show similar affinity. The obtained results were statistically processed using the method of two-factor analysis of variance with repeated measurements. Further research will be based on monitoring the morphophysiological properties of underground and aboveground parts of plants on contaminated soil samples when apatite and zeolite are applied.