The determination of prospective reservoirs in the slope environment of the Tarakan Basin (Indonesia) by using sequence stratigraphy, rock physics and AI inversion

Prospective reservoirs in the Tarakan Basin are mostly deposited in the Middle Miocene to Pliocene and related to the change of depositional environment from transgressive to regressive sedimentary environment. Log sequence stratigraphic analysis in well AST 1 shows that transgressive and lowstand system tracts were deposited during the study area. Hashin-Shtrikman method is used in the rock physics analysis to identify the relative rock hardness and integrated with gamma ray log, NPHI, and resistivity data analysis. The result show that potential reservoir exist at the depth range of 7650-7725 feets and associates with low velocity, low gamma ray, low NPHI, high resistivity values. The potential reservoir interval was deposited under low stand system tract of slope depositional environment. The acoustic impedance (AI) map shows that the low AI’s are mostly located in the northwestern part of the study area.

Research into influence of drilling-and-blasting operations on the stability of the Kusmuryn open-pit sides in the Republic of Kazakhstan

Purpose. Research into influence of drilling-and-blasting operations on the nature of deformation in near-side masses of the design open-pit contours and assessing the seismic impact of blasting operations, which are the basis for development of recommendations on the rational parameters of drilling-and-blasting operations. Methods. The influence of drilling-and-blasting operations at the limiting contour of the Kusmuryn field is studied using the analysis of the mining-and-geological conditions and tectonics of the rocks constituing the field, in-situ surveying the state of the open-pit sides, analysis of the physical and mechanical properties of the host rocks, analytical studies and instrumental measurements of the blasting effect. Findings. Based on the analytical methods, the calculation and analysis of the seismic stability of the rocks at the field have been performed. By means of instrumental measurement of the blasting effect in open pit, data have been obtained on the seismic impact of blasting operations on the near-side masses. According to the results of these works, rational parameters of drilling-and-blasting operations at the limiting contour of the open pit have been determined. In addition, the main provisions for the organization of drilling-and-blasting operations at the limiting contour of the open pit have been developed. Originality. In this work, for the first time, a joint research method is applied, which includes an analytical calculation of the shock wave seismic impact on a rock mass, based on the results of which the dependency graphs have been obtained of the seismicity coefficient on the rock hardness coefficient at the Kusmuryn field according to the Protodyakonov scale for various explosives, as well as using the method of instrumental measurements, which serves to determine the seismic impact of an explosion on a rock mass. This makes it possible to substantiate the technology of conducting the drilling-and-blasting operations at the contour, providing a long-term stable position of the permanent side of the open pit. Practical implications. The results of the work will be used to calculate the safe parameters of conducting the blasting operations when placing the side in the final position at the Kusmuryn field. This research method can be applied at any mining enterprise conducting open-cut mining of minerals.

Coal and Rock Hardness Identification Based on EEMD and Multi-Scale Permutation Entropy

This study offers an efficient hardness identification approach to address the problem of poor real-time performance and accuracy in coal and rock hardness detection. To begin, Ensemble Empirical Mode Decomposition (EEMD) was performed on the current signal of the cutting motor to obtain a number of Intrinsic Mode Functions (IMFs). Further, the target signal was selected among the IMFs to reconstruct the current signal according to the energy density and correlation coefficient criteria. After that, the Multi-scale Permutation Entropy (MPE) of the reconstructed signal was trained by the Adaboost improved Back Propagation (BP) neural network, in order to establish the hardness recognition model. Finally, the cutting arm’s swing speed and the cutting head’s rotation speed were adjusted based on the coal and rock hardness. The simulation results indicated that using the energy density and correlation criterion to reconstruct the signal can successfully filter out noise interference. Compared to the BP model, the relative root-mean-square error of the Adaboost-BP model decreased by 0.0633, and the prediction results were more accurate. Additionally, the speed control strategy based on coal and rock hardness can ensure the efficient cutting of the roadheader.

Rock hardness identification based on optimized PNN and multi-source data fusion

To solve the problem that it is difficult to identify the cutting rock wall hardness of the roadheader in coal mine, a recognition method of cutting rock wall hardness is proposed based on multi-source data fusion and optimized probabilistic neural network. In this method, all kinds of cutting signals (the vibration signal of cutting arm, the pressure signal of hydraulic cylinders and current signal of cutting motor) are analyzed by wavelet packet to extract the feature vector, and the multi feature signal sample database of rock cutting with different hardness is established. To solve the problems of uncertain spread and complex network structure of probabilistic neural network (PNN), a PNN optimization method based on differential evolution algorithm (DE) and QR decomposition was proposed, and the rock hardness was identified based on multi-source data fusion by optimizing PNN. Then, based on the ground test monitoring data of a heavy longitudinal roadheader, the method is applied to recognize the cutting rock hardness, and compared with other common pattern recognition methods. The experimental results show that the cutting rock hardness recognition based on multi-source data fusion and optimized PNN has higher recognition accuracy, and the overall recognition error is reduced to 6.8%. The recognition of random cutting rock hardness is highly close to the actual. The method provides theoretical basis and technical premise for realizing automatic and intelligent cutting of heading face.

Seismic Driven Geomechanical Modeling of Uplifted and Subsided Wells in Mumbai Offshore and Its Engineering Implications

Seismic data provide evidence about hydrocarbon deposition, geological and geophysical subsurface information, including geomechanical aspects. Deriving and understanding geomechanical properties is crucial for reservoir management as it can avoid drilling and production-related problems that cause environmental impacts associated with land subsidence and uplift. The Poison's ratio (PR), Young Modulus (YM), and elastic moduli for a reservoir block were estimated using 3D seismic pre-stack data and well data. 3D Mechanical Earth Models (MEM) were also developed using the well logs, seismic horizons, and drilling data. Seismic data-derived geomechanical properties were compared with the mechanical earth models for the first time for this field. Well-tie analysis was used for inversion of 3D seismic data to extract detailed waveform and amplitude information. The brittleness index of the subsurface layers was estimated, which is a critical rock property that provides information about rock hardness and fragility phenomenon. The brittleness index has a diverse range from 5-35%, with significant contrast at shallow zones. PR and YM models generated from 3D MEM and seismic data have average values of 0.2 -0.6 and 5 - 28 GPa with significant contrast from shales and carbonates. The study recommends that the drilling through these problematic zones should be avoided to avoid wellbore problems that cause challenges in maintaining wellbore integrity and reservoir management in the North-Heera field, Mumbai Offshore Basin.

Study on the wear mechanisms and rock destruction of core surface set bit in drilling for solid mineral exploration

In this paper, the authors present some research results of wearing process and rock destruction by diamond grit of core bit depending on drilling regime, rock hardness, diamond grit strength, etc. through the simulation of the interaction effect between diamond grit attached to the core bit and the rock. The relationship of the wear rate and rate of penetration of diamond core bit to the rotation per minute has been tested. On the basis of the research results, the authors have proposed solutions to select the appropriate technology for diamond drilling to improve the efficiency of solid mineral exploration in Vietnam.

Interpretasi Tingkat Kekerasan Batuan Bawah Permukaan di Daerah Rawan Gempa Bumi Kota Bengkulu

<p class="AbstractText">Bengkulu City is located in the subduction zone of the Indo-Australian and Eurasian plates, so it is prone to earthquake. To anticipate the impact of earthquake, disaster mitigation can be carried out, one of which is a study of the level of rock hardness in the area. This study aims to determine the level of rock hardness based on seismic wave velocity in several rock formations and to determine which rock formations have the potential to cause vulnerability to earthquakes. Field data acquisition uses the seismic refraction method with time-term inversion technique. The data obtained in the field are processed to obtain a 2-D cross-section of the subsurface seismic wave velocity values. The study results show that the level of rock hardness depends on the type of rock formation. The Andesite Rock Formation Unit (Tpan) has the highest level of hardness, while the transitional area between the Alluvium Rock Formation Unit (Qa) and the Swamp Sedimentary Rock Formation Unit (Qs) has the lowest level of hardness.</p>

Recognition of cutting rock hardness by hydraulic cylinder pressure

The online identification of rock hardness is the basis to adjust the rotation velocity and swing velocity of cutting head in real time. To effectively identify the hardness of rock around roadway under different cutting conditions, a novel method based on the hydraulic cylinder pressure signal is proposed. Here, we analyze the changing rule of cutting head load under different rock hardness through dynamic simulation, and the transfer characteristics between cutting dynamic load and the hydraulic cylinder pressure. On this basis, a function model between the hydraulic cylinder pressure and the protodyakonov scale of rock hardness is constructed to identify the rock hardness. The average recognition accuracy of the heavy-duty roadheader in the test is 92.01%. The experimental results indicate that the model can effectively identify the rock hardness under different cutting conditions. This study can be used for online identification of rock hardness and provide reliable basis for the automatic control of roadheader.

Holocene dust accumulation in the southern Levant: the role of local sources and fixation processes

&lt;p&gt;Initial soils covering archaeological ruins in the southern Levant include fine grain size fractions that may stem from aeolian sediments. Thus, ruins could act as effective dust traps which preserved rare Holocene aeolian records. We assessed physical parameters and chemical composition of initial soils covering archaeological ruins in the Negev and southern Jordan, including clay mineralogy and Sr- and Nd-isotopes, which we compared with modern dust from collectors installed close to the sites. A significant contribution from local weathered rocks could be observed in southern Jordan. In the Negev, the contribution of rocks was negligible, probably due to greater rock hardness and abundant biological crusts sealing surfaces. However, loessial paleosols surrounding the sampled archaeological ruins were &quot;recycled&quot; in the Negev. Compared to modern settled dust, archaeological soils in southern Jordan are enriched with various major and trace elements associated with clays and oxide coatings of fine silt particles. This was not due to in-situ weathering, which was found to be minimal. However, site-specific fixation processes may explain variations of dust records at the studied sites. In addition, modern dust samples associated with precipitation, in particular snow, were found associated with higher amounts of major and trace elements. Initial soils covering ruins in the southern Levant therefore suggest that the formation of soils in desert fringes may less be a function of dust supply, but more of dust deposition and fixation processes. There are multiple, local and regional dust sources and dust-generating processes active in drylands, but deep loessial soils form only when dust fixation is effective.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

Improvement of drilling cutter design

The article describes the design of drilling cutters most commonly used in coal mines in Russia. The area of their application is given versus the type of a drilling machine and hardness of rocks. The implemented research aimed at finding the causes of failure of drilling cutters shows the types of breakdowns of drilling cutters and their causes. A review of the recommendations and modern engineering solutions on increase in the life of rotary drilling tools is given. Percentages of the cutter failure causes over the period from 2010 to 2014 are presented. The main failure cause of cutters is found to be the blunting of the blades of tungsten-cobalt cutting plates. The studies conducted earlier by the authors of the article indicate the possibility of extending the life of a drilling tool by reinforcing its cutting plates with superhard composite materials. In this connection, the use of composites based on cubic boron nitride has been proposed for creating cutting inserts for drilling cutters. The article also describes the study of rock drilling rates with various cutters mounted on hydraulic and pneumatic drilling machines. The obtained information can be used when planning drilling in coal mines. It is shown that the highest drilling rate can be achieved with hydraulic drilling machines equipped with triple cutters. It is found that with the growth of rock hardness on the scale of Professor M. M. Protodyakonov, reduction in the drilling rate of a hydraulic drilling rig with a three-blade cutter occurs more intensively than with a pneumatic drilling rig with a two-blade cutter. It is revealed that at the rock hardness of 10 on the Protodyakonov scale, drilling rates of different design cutters differ slightly. The study was supported by the President of the Russian Federation, Grant for Young Candidates of Sciences—MK-6689.2018.8.