Exploitation Schemes Research Articles

Review on the Study of Microscopic Pore Structure and Seepage Characteristics

Pore structure, as the focus of researchers, is also one of the main contents of reservoir geological research, and the characteristics of percolation depend on the micro-pore structure of the reservoir. The study of the characteristics of fluid percolation in the reservoir plays an important role in formulating a reasonable oil and gas exploitation scheme. Understanding the micro pore structure of the reservoir, analyzing the pore throat structure inside the oil and gas reservoir, and systematically studying the micro seepage characteristics of the reservoir have far-reaching influence and great significance for the exploration and development of oil and gas fields.

Analysis of Inter-Layer Interference in Multi-Layer Reservoir Commingled Production Wells

During the operation of commingled production wells, inter-layer interference is a key factor affecting the recovery rate and flooding extraction efficiency. This study proposes a well deliverability equation that is characterized by a multi-parameter coupled inter-layer interference coefficient, which is applied to quantify the commingled production wells in a multi-layer reservoir. This study used principal component analysis (PCA) to study the combined effects of correlation parameters for inter-layer interference. The results show that the starting pressure gradient and the crude oil viscosity contrast have the most significant impact on inter-layer interference. Changes in these two parameters directly enhance the heterogeneity between different oil layers, thereby intensifying inter-layer interference. Additionally, the positive correlation between permeability and permeability contrast also highlights the contribution of physical property differences in the oil layers to the interference. The sensitivity analysis shows the main influencing factors of inter-layer interference in commingled production wells. providing references for subsequent improvements and optimization of the exploitation schemes and adjustments in reservoir management measures. The results not only enhance the understanding of the mechanisms of inter-layer interference in the exploitation of multi-layer oil reservoirs but also provide scientific evidence and technical support for oilfield development.

The Production Analysis and Exploitation Scheme Design of a Special Offshore Heavy Oil Reservoir—First Offshore Artificial Island with Thermal Recovery

More and more offshore heavy oil resources are discovered and exploited as the focus of the oil and gas industry shifts from land to sea. However, unlike onshore heavy oil reservoirs, offshore heavy oil reservoirs not only have active edge and bottom water but also have different exploitation methods. In this paper, a typical special heavy oil reservoir in China was analyzed in detail, based on geology–reservoir–engineering integration technology. Firstly, it is identified as a self-sealing bottom water heavy oil reservoir by analyzing its geological characteristics and hydrocarbon accumulation mechanism. Secondly, the water cut is initially controlled by oil viscosity, but subsequently, by reservoir thickness through the analysis of oil and water production data. Thirdly, the bottom oil–water contact of the reservoir was re-corrected to build an accurate 3D geological model, based on the production history matching of a single well and the whole reservoir. Lastly, a scheme of thermal production coupled with cold production was proposed to exploit this special reservoir, and the parameters of steam, N2, and CO2 injection and production were optimized to predict oil production. This work can provide a valuable development model for the efficient exploitation of similar offshore special heavy oil reservoirs.

Photovoltaic Capacity Management for Investment Effectiveness

The production of photovoltaic utility varies within the day/night cycle. At night, photovoltaic cells do not produce anything. However, their day-light production, unconsumed on a current basis and exported to the grid, is compensated for with supply from the grid at night. This scheme of exploitation is called net-metering and is considered herein. Solar energy produced by a prosumer and fed into the grid has to be equal to the electricity supplied from the grid at night; otherwise, a shortage or waste of photovoltaic production occurs. The above finding leads us to the proposition for the optimal solution of photovoltaic capacity. We derived a closed-form capacity solution to the maximized non-linear profit function. It solves harmonic and 2-point production functions that vary symmetrically around the mean production. To verify the solution methodology, harmonic and 2-point models from empirical production data are estimated. Then, the solution is presented together with its return rate and internal return rate. The main finding is that the unit cost of the grid electricity, photovoltaic capacity unit cost and exploitation time all affect the total profit and return rate values while not impacting the optimal capacity of the photovoltaics. The optimal capacity depends on the prosumer’s energy consumption volume and on the natural conditions of production captured here by the technology efficiency coefficient estimated from the production time series.

Groundwater potential assessment in parts of Nnewi Industrial Zone: Implications for sustainable development and conservation

Integrated field geological and geophysical (Vertical Electrical Sounding VES and 2D Electrical Resistivity Tomography ERT) investigations were carried out in the Nnewi Industrial Zone, SE Nigeria to identify and characterize productive aquifer, aquifer hydraulic properties, and aquifer vulnerability. Data acquired from 17 VES points and across a profile line of about 800 m for the 2D ERT were processed, interpreted, and modeled. Results from the geologic mapping showed that the outcropping units are mainly the sandstone, shaly-sandstone, and less commonly shale of the Nanka and Ogwashi-Asaba Formations which are relatively permeable and offer poor protective cover to the underlying aquifer. Models from the resistivity data showed that the depth-to and thickness of the aquifer vary from 38.60 to 98.80 m and 30.10–177 m, respectively. Aquifer properties estimated from the geophysical data gave values ranging from 0.611127 m2/day to 246.6576 m2/day and 0.1609 m/day to 5.6325 m/day for transmissivity and hydraulic conductivity, respectively, and suggestive of low – moderate aquifer potential. Aquifer Protective Capacity APC distribution modeled from the longitudinal conductivity values, and the aquifer vulnerability modeled using the DRASTIC method indicate that the study area is characterized by poor – moderate APC and low – moderate – high aquifer vulnerability, respectively. Analysis shows that the modeled aquifer parameters, APC, and aquifer vulnerability have similar trend which tends to improve towards the southern and more specifically southeastern parts of the study area, suggesting that even though aquifer units were identified all through the study area, the southeastern parts are best suited for the development of groundwater exploitation schemes. Also, aquifer vulnerability model results recommend that proper and efficient waste disposal schemes are put in place to conserve groundwater quality from pollution from industrial waste since the aquifer in the area is relatively vulnerable.

Numerical simulation of multi-field coupling in geothermal reservoir heat extraction of enhanced geothermal systems

The coupled analysis of multi-field heat and mass transfer in geothermal reservoirs is a pivotal concern within the realm of geothermal rock exploitation. It holds significant implications for the assessment of thermal energy capacity and the formulation of reservoir optimization strategies in the context of geothermal rock resources. Parameters governing production, along with fracture network characteristics (such as injection well temperature, injection well pressure, fracture width, and fracture network density), exert an influence on enhanced geothermal systems (EGS) heat production. In this study, aiming to comprehend the dynamic heat generation of EGS during prolonged exploitation, a coupling of various fields including permeation within the rock formations of geothermal reservoirs and the deformation of these rocks was achieved. In this study, we formulated the governing equations for the temperature field, stress field, and permeability field within the geothermal reservoir rock. Subsequently, we conducted numerical simulations to investigate the heat transfer process in an enhanced geothermal system. We analyzed the effects of injection well temperature, injection well pressure, primary fracture width, and secondary fracture density on the temperature distribution within the reservoir and the thermal power output of the production well. The research findings underscore that ill-conceived exploitation schemes markedly accelerate the thermal breakthrough rate of production wells, resulting in a diminished rate of geothermal resource extraction from the geothermal reservoir rock. Variations in influent well temperature and secondary fracture density exhibit an approximately linear impact on the output from production wells. Crucially, injection well pressure and primary fracture width emerge as pivotal factors influencing reservoir output response, with excessive widening of primary fractures leading to premature thermal breakthrough in production wells.

Numerical investigation of electricity generation potential by water circulating through three horizontal wells at Fengshun geothermal field in China

Fengshun geothermal field is the first medium and low temperature geothermal area in China, which is used for electricity generation. At present only vertical wells are employed to extract heat energy. After about 40 years of exploitation, the production temperature and rate are all declined. In this work, based on the hydrogeological data of the study area, the deep reservoir temperature and corresponding circulation depth of underground hot water are predicted with a silica thermometer. To fully develop the deep heat reservoir, we proposed a new heat exploitation scheme through three horizontal wells, computed the electricity generation potential and efficiency, and analyzed the main factors affecting heat production. The results indicate that under the reference conditions, the three horizontal well system attaches an electric power of 2.70–1.5 MW, a reservoir impedance of 0.13–0.27 MPa/(kg/s), a pump power of 0.29–1.16 MW, and energy efficiency of 7.34–1.30 during the reservoir lifetime of 43.6 years. Thus, this three-horizontal-well system has significant development potential in Fengshun deep geothermal reservoir. Sensitivity analysis indicates that water production rate, injection temperature and initial reservoir temperature have a significant impact on heat production performance. Reducing the water production rate and injection temperature within a certain range can improve energy efficiency. For the precise design of power generation systems and the accurate evaluation of production performance, field logging data is necessary.

Prospects for fisheries use of lake Sobache (Pionerskoe) in the Republic of Khakassia

We assess Sobache (Pionerskoe) lake located in The Republic of Khakassia for aquaculture using. The lake is drainless, the water-surface area is about 1.5 km2. The prevailing depths range from 2 to 4 m. We provide data on the hydrological regime of the lake (temperature, dissolved oxygen level, chemical water composition). 3 species of rotifers, 10 species of cladoceran and 3 species of copepods were found in the zooplankton. The dominant complex consists of the rotifer Asplanhna priodonta, Bosmina longirostris and Ceriodaphnia quadrangula. The zoobenthos community includes 13 groups of organisms, where chironomids predominate in abundance, and gastropods and bivalves predominate in biomass. The ichthyofauna of the lake consists of perch and pike, perch predominates in abundance. Four species of parasites were found, including trematodes and myxporidia. The infection of fish with trematode metacercariae indicates the presence of intermediate hosts in the zoobenthos community of the lake. The detected species of parasites do not pose a danger to human health. The natural fish productivity is estimated at 48.2 kg/ha. We recommended to use the lake for commercial cultivation of fish in polyculture way. We proposed two schemes of fishery exploitation of the lake on the principle of pasturable fish culture: annual cultivation of fish in polyculture (carp, trout, herbivorous fish species) and joint cultivation of fish in polyculture (carp and white amur) by continuous intensive technology (three-year turnover) with carp feeding. The expected yield of fish products varies from 460.0 to 400.0 kg/ha, depending on the chosen technology. These recommendations can contribute to the effective use of the fisheries potential of Sobache (Pionerskoe) lake to provide the region with fresh fish products and create jobs for the local population.

Comprehensive heat extraction performance and fractured reservoir cooling effect analysis of a novel mine enhanced geothermal system

Mining deep metal mines poses significant challenges due to the high-temperature conditions in such environments. However, the vast untapped geothermal energy within these mines holds great prospects for development and application. Herein, we proposed a novel technology for the deep mine cooling and enhanced geothermal system (DMC-EGS), which transforms the relationship between deep mining and geothermal resources from a source of heat harm to heat benefit, while also providing conditions for underground mining environment cooling. Understanding the fluid flow and heat transfer processes in the deep mine thermal reservoir is crucial for developing DMC-EGS. Based on the local thermal equilibrium theory, a three-dimensional thermal–hydraulic coupled model of the thermal reservoir in the Sanshan Island Mine containing multiple fractures was established. The impact of natural fractures and fracture number on the thermal recovery performance and cooling effect of the system was considered, and the optimization scheme of heat recovery wellbore was proposed for the deep thermal reservoir of Sanshan Island Mine. It can be found that fractures play a crucial role in fluid-rock heat exchange. Compared with scenarios without fractures, hydraulic fractures could significantly improve the heat transfer capacity and rock cooling effect, resulting in a 45.7% increase in the amplitude of rock matrix temperature decrease and more than a 1.76-fold increase in overall heat recovery efficiency. In addition, the number of fractures significantly impacted the temperature distribution within the rock formation, and an increased number of fractures was associated with more efficient heat recovery performance. When the number of fractures was 7, the cumulative thermal production could reach 6.767 × 109 J. Among the three thermal exploitation schemes compared, the DMC-EGS under the triple-well mode yielded the best heat recovery performance during the 40-year extraction period, superior to the conventional dual-well mode, while the one injection and two production mode demonstrated better heat recovery capacity and cooling effect.

Investigation of the emergency water supply schemes for youkou groundwater source field in Nanchang using a simulation–optimization model

To enhance the resilience of Nanchang’s water supply system and ensure a dependable emergency water supply. Taking youkou emergency groundwater source field as an example, a flow simulation model was developed through an analysis of the hydrogeological conditions in the study area. Additionally, an optimization model based on the genetic algorithm (GA) technique was constructed and integrated into the flow simulation model. Subsequently, various water supply schemes were simulated with the minimum cost of groundwater extraction as the objective function. The results show that the values of the objective function were reduced by 4.92%, 15.67%, and 42.35% for the three different optimization schemes, namely pumping rates, joint pumping rates and the number of wells, and joint pumping rates, number of wells and well location. Ultimately, the optimal emergency water supply scheme was determined by considering a comprehensive range of factors. These factors encompassed considerations such as the area of the water level depression funnel, the dewatering thickness of the aquifer and the recovery of the groundwater level. The practice shows that the simulation–optimization model could effectively simulate complex groundwater flow systems, meeting the objective function and constraints toachieve the optimal exploitation scheme.

Numerical simulation of electricity generation potential through five vertical wells at Fengshun geothermal field in China

Fengshun geothermal field is the first medium low temperature geothermal field to exploit geothermal energy for electricity generation in China. Due to poor economy and low efficiency, the geothermal power plant was forced to shut down in 2016. In this work, based on the geological data of the well ZK11, we proposed a new heat exploitation scheme with five vertical wells and a binary system, computed the power generation potential and efficiency, and analyzed the main factors influencing heat production. The results indicate that through the five vertical wells, the system attains an electrical power of 1.49–1.05 MW, a reservoir impedance of 0.23–0.29 MPa/(kg/s), a pump power of 0.30–0.49 MW, and an electrical energy efficiency of 4.55–2.12. The electric power of unit flow rate is 22.4–31.7 times that of the existing power plant. Thus, this five-vertical-well system has significant development potential for medium low temperature hydrothermal field. The sensitivity analysis indicates that overburden and underburden permeability, water production rate and injection temperature have a significant impact on heat production performance. Increasing the overburden or underburden permeability will significantly reduce reservoir impedance and increase energy efficiency. Reducing the water production rate and injection temperature within a certain range can improve energy efficiency. This work also provides a guideline for the exploitation and power generation of future medium low temperature hydrothermal field in Fengshun and other sites under similar conditions.

Modeling of PID controlled 3DOF robotic manipulator using Lyapunov function for enhancing trajectory tracking and robustness exploiting Golden Jackal algorithm

In this study, a three degrees of freedom (3 DOF) rigid-link robotic manipulator (RLM) has been simulated by using the Simscape model and the mathematical model derived by Lagrange method. The robot arm has been regulated by an Optimized PID Controller to achieve better tracking performance and reasonable robustness against disturbances and payload uncertainty. To optimize the controller, a novel nature-inspired Golden Jackal Optimization (GJO) algorithm has been used due to its efficient exploration that increases the diversity of the released solutions and its exploitation schemes which enhance the best-explored solutions. The tuning process has utilized a Lyapunov stability function as the objective function (OF) and the efficacy of the proposed algorithm is evaluated through a comprehensive comparison with various state-of-the-art metaheuristic techniques such as Particle Swarm Optimization (PSO), Artificial Bee Colony (ABC), Jellyfish Search Optimizer (JSO), Whale Optimization Algorithm (WOA), Arithmetic Optimization Algorithm (AOA) and Sine Cosine Algorithm (SCA). The assessment has been conducted on benchmark error-based functions, providing rigorous testing and validation of the algorithm's performance. Furthermore, the performance evaluation has focused on the system's robustness against disturbances, noise, and variations in the payload mass, particularly in the context of Pick and Place (PNP) industrial tasks. The results of simulation have demonstrated that the optimized system, employing the Lyapunov function, demonstrated superior performance in minimizing the objective function value compared to other benchmark functions.

Prediction of Dynamic Temperature and Thermal Front in a Multi-Aquifer Thermal Energy Storage System with Reinjection

The accurate temperature and thermal front prediction in aquifer thermal energy storage systems during reinjection are crucial for optimal management and sustainable utilization. In this paper, a novel two-way fully coupled thermo–hydro model was developed to investigate the dynamic thermal performance and fronts for multiple aquifer thermal energy storage systems. The model was validated using a typical model, and the evolution characteristics of wellbore temperature before and after the breakthrough of the hydraulic front and thermal front were deeply studied. Sensitivity analysis was conducted to delineate the influence of various reservoir and reinjection factors on the thermal extraction temperature (TET). The results revealed that thermal conductivity significantly impacts the thermal extraction rate among the various reservoir factors. In contrast, volumetric heat capacity has the weakest influence and negatively correlates with the TET. Concerning the reinjection factors, the effect of the reinjection volume rate on the TET was significantly more significant than the reinjection temperature. Furthermore, the correlation between the TET and different properties was observed to be seriously affected by the exploitation period. The coupled model presented in this study offers insight into designing the exploitation scheme in deep reservoirs and geothermal resources.

Numerical Investigation of the Depressurization Exploitation Scheme of Offshore Natural Gas Hydrate: Enlightenments for the Depressurization Amplitude and Horizontal Well Location

Numerical Investigation of the Depressurization Exploitation Scheme of Offshore Natural Gas Hydrate: Enlightenments for the Depressurization Amplitude and Horizontal Well Location

Dual-gas co-production behavior for hydrate-bearing coarse sediment with underlying gas via depressurization under constrained conditions

Hydrate reservoirs with underlying gas show significant potential for commercial exploitation. An experimental apparatus capable of applying confining pressure and axial pressure was built to simulate the accumulation and dissociation of naturally occurring marine hydrate and a novel method for synthesizing hydrate reservoirs with underlying gas was proposed. With the formed methane hydrate-bearing coarse sediment (HBCS) with underlying gas, hydrate dissociation experiments via depressurization under constrained conditions were carried out at different HBCS proportions. The characteristics of heat transfer and dual-gas co-production during the exploitation of hydrate reservoir at various HBCS proportions were presented. Due to the influence of hydrate decomposition, the diverging temperature variations of the underlying layer and upper HBCS layer were observed at HBCS proportions of 0.21, 0.48, and 0.77. The negative effect of the outside pressure on gas production was not observed in our experimental conditions owing to the adopted coarse quartz sand deposits. The final produced gas volume increases with the HBCS proportion increasing. The produced gas percentage is negative or positive related to the HBCS proportions respectively with the extended production time. In addition, the different production behavior of the underlying gas and hydrate decomposed gas may induce the unexpected exploitation accidents such as blowouts resulting from unstable gas production rate. These findings guide the design of exploitation scheme for reservoirs with different HBCS distribution. And an exploitation method by setting the production well in the underlying gas layer/underlying sediment layer with free gas is then proposed, which can inhibit hydrate reformation and ice generation and improve the production well stability during the hydrate exploitation process.

Lower limits of petrophysical parameters for effective reservoirs in ultradeep carbonate gas reservoirs: A case study from the Deng IV Member, Gaoshiti-Moxi Area, Sichuan Basin, SW China

Lower limits of petrophysical parameters (LLPP) of effective reservoirs are significant parameters for reserve evaluation and exploitation scheme formulation of hydrocarbon reservoirs. However, the existing LLPP determination method is not applicable to ultradeep carbonate reservoirs with diverse reservoir space and strong heterogeneity. Therefore, a systematic method for determining the LLPP of ultradeep carbonate gas reservoirs was developed in this study. First, the geological setting and reservoir characteristics were briefly introduced, and numerous cores were classified according to whether cavities and fractures were developed. Subsequently, the test data of petrophysical property, NMR, high-pressure mercury intrusion (HPMI), and fluid physical property were collected, and a series of LLPP values were obtained through static methods of cumulative frequency statistics, porosity–permeability relationship, irreducible water saturation, and minimum flowable pore throat radius (Rmin). The LLPP determined by static methods were then verified by dynamic methods of gas well testing, productivity model prediction, and productivity simulation experiment, and the LLPP of reservoirs that can form industrial gas flow were determined. Finally, the effect of reservoir heterogeneity on LLPP was revealed, the applicability of various LLPP determination methods were summarized, and the accuracy of the obtained LLPP was confirmed by well testing interpretations. The research results show that the reasonable classification of reservoir types is the prerequisite to accurately determine the LLPP of carbonate reservoirs. The lower limit of porosity is little affected by cavities, while the lower limit of permeability is greatly affected by fractures. Rmin of ultradeep carbonate reservoirs obtained by HPMI test and water film thickness calculation is approximately 60 nm. The significant heterogeneity of carbonate reservoirs requires that effective reservoirs should reach the lower limit of porosity and permeability simultaneously. LLPP determined through static methods and dynamic methods can be applied to evaluate geological and dynamic reserves, respectively. The LLPP of effective reservoirs that allow gas to accumulate, migrate, and form industrial gas production are 2.68% and 0.042 mD.

Multi-Lateral Well Productivity Evaluation Based on Three-Dimensional Heterogeneous Model in Nankai Trough, Japan

Widely employed in hydrate exploitation, the single well method is utilized to broaden the scope of hydrate decomposition. Optimizing the well structure and production strategy is necessary to enhance gas recovery efficiency. Complex wells represented by the multilateral wells have great application potential in hydrate mining. This study focused on the impact of multilateral well production methods on productivity, taking the Nankai Trough in Japan as the study area. The spatial distribution of physical parameters such as porosity, permeability, and hydrate saturation in the Nankai Trough has significant heterogeneity. For model accuracy, the Sklearn machine learning and Kriging interpolation methods were used to construct a three-dimensional heterogeneous geological model to describe the structure and physical property parameters in the study area of the hydrate reservoir. The numerical simulation model was solved using the TOUGH + Hydrate program and fitted with the measured data of the trial production project to verify its reliability. Finally, we set the multilateral wells for hydrate high saturation area to predict the gas and water production of hydrate reservoir with different exploitation schemes. The main conclusions are as follows: ① The Sklearn machine learning and Kriging interpolation methods can be used to construct a three-dimensional heterogeneous geological model for limited site data, and the fitting effect of the heterogeneous numerical simulation model is better than that of the homogeneous numerical simulation model. ② The multilateral well method can effectively increase the gas production rate from the hydrate reservoir compared with the traditional single well method by approximately 8000 m3/day on average (approximately 51.8%). ③ In the high saturation area, the number of branches of the multilateral well were set to 2, 3, and 4, and the gas production rate was increased by approximately 51.8%, 52.5%, and 53.5%. Considering economic consumption, the number of branching wells should be set at 2–3 in the same layer.

Deep reinforcement learning based controller for ship navigation

A majority of marine accidents that occur can be attributed to errors in human decisions. Through automation, the occurrence of such incidents can be minimized. Therefore, automation in the marine industry has been receiving increased attention in the recent years. This paper investigates the automation of the path following action of a ship. A deep Q-learning approach is proposed to solve the path-following problem of a ship. This method comes under the broader area of deep reinforcement learning (DRL) and is well suited for such tasks, as it can learn to take optimal decisions through sufficient experience. This algorithm also balances the exploration and the exploitation schemes of an agent operating in an environment. A three-degree-of-freedom (3-DOF) dynamic model is adopted to describe the ship’s motion. The Krisco container ship (KCS) is chosen for this study as it is a benchmark hull that is used in several studies and its hydrodynamic coefficients are readily available for numerical modeling. Numerical simulations for the turning circle and zig-zag maneuver tests are performed to verify the accuracy of the proposed dynamic model. A reinforcement learning (RL) agent is trained to interact with this numerical model to achieve waypoint tracking. Finally, the proposed approach is investigated not only by numerical simulations but also by model experiments using 1:75.5 scaled model.

Optimized geothermal energy extraction from hot dry rocks using a horizontal well with different exploitation schemes

In the foreseeable future, the geothermal exploitation from hot dry rocks (HDR) using a horizontal well will bear potential. Thus, in-depth studies should be conducted on the selection of injection-production scheme (IPS) and working fluid, design of reinjection parameters, optimization of wellbore structure and materials, and analysis of geological settings. This paper proposed a fully coupled model to study the above scientific questions. For Model A, the working fluid was injected into the annulus and then flowed out of the thermal insulation pipe (TIP). Its temperature passes through two stages of temperature rise and two stages of temperature decline. But for model B, the working fluid was injected into the TIP and then flowed out of the annulus. Its temperature undergoes five stages, four stages of temperature rise and one stage of temperature decline. The results show that the Model A is the best IPS owing to its high outlet temperature, stable thermal recovery, and low fluid injection volume. In Model A, when the working fluid was supercritical carbon dioxide and the liquid injection volume was 135.73 m3/d, the heat recovery ratio (HRR) was as high as 85.40%, which was 17.85% higher than that of the Model B whose working medium was water, and its liquid injection volume was only 25% of that. Meanwhile, over ten years of continuous production, the outlet temperature decreased by 7.5 °C and 18.38 °C in the latter. The optimal working fluid has a low volume heat capacity and thermal conductivity for any IPS. Sensitivity studies showed that for the area that met the HDR standard, the effect of reinjection temperature on the outlet temperature can be ignored. As for Model A, HRR drops sharply by 6.74–9.32% when TIP goes from completely adiabatic to nonzero thermal conductivity. Meanwhile, the horizontal segment length of the TIP is shorter when Model A obtains the optimal outlet temperature compared with Model B. In addition, the correlation between the outlet temperature and different formations of thermophysical properties was seriously affected by the IPS and exploitation period, which was summarized in detail.

Production Strategy Optimization of Integrated Exploitation for Multiple Deposits Considering Carbon Quota

Nowadays, the mining industry actively advocates and practices the concept of green and integrated exploitation to realize the sustainable development of resources with low-carbon emissions. The certain carbon quota for mining companies limits the production capacity and resource utilization efficiency. The integrated exploitation of multiple deposits could coordinate resource allocation and operation facilities, which would reduce capital expenditure and operating costs for the mining company from a systematic perspective. In this condition, some deposits located nearby could be treated as one entity to make plans and optimize. An optimization framework is proposed based on the analysis of the characteristics and advantages of integrated exploitation. A new mathematical programming model is presented to optimize production capacity and extracted ore grade for each deposit considering constraints of maximum and minimum mining capacity, extracted ore grade and concentrated ore grade requirement, and metal output target, which has a significant influence on the economic benefit and resource utilization rate for a mining company. The model is verified using the data collected from three deposits of a gold mining company in China to demonstrate its ability to optimize the allocation of production capacity and improve the technical and economic effect of mining under the limitation of carbon quota. The sensitivity analysis of some key parameters is carried out to generate a series of integrated exploitation schemes under different production and operation conditions, which is useful for the mining company to make decisions in different situations.