Drain Spacing Research Articles

Effects of Drainage System Design on Nutrient Leaching and Crop Yield

Highlights Tested drainage system designs had no clear effect on the total amount of drainage discharge. Tested drainage system designs had a clear effect on nutrient loads in drainage discharge. Corrugated plastic pipe drainage systems had higher N loads and lower P loads than tile drainage systems. Corrugated plastic pipe drainage systems gave higher yields than tile drainage systems and can be a profitable on-farm investment. Abstract. A clear strategy for adapting agricultural drainage to future climate change is important for environmental and economic reasons. In a study aimed at developing recommendations for the subsurface drainage design in clay soils, we evaluated the impact of replacing an old drainage system (1920) with new systems (2018) on nutrient leaching and crop yield. Our field experiment included 12 individually drained plots divided into four treatments: (A) old system with clay tiles at 10 m spacing, without an envelope; (B) new system with plastic pipes at 10 m spacing, gravel envelope; (C) new system with plastic pipes at 5 m spacing, gravel envelope; and (D) new system with plastic pipes at 10 m spacing, gravel envelope and lime incorporated in trench backfill. We conducted flow measurement and flow-proportional, logger-controlled water sampling of the drainage discharge from each plot at a measuring station. Preliminary results (first two years) show a clear effect of the new drainage systems on phosphorus and nitrogen loads in drainage discharge. The lowest total load of phosphorus and highest total load of nitrogen in all treatments were observed in treatment D (with 10 m drain spacing and lime incorporated in trench backfill). The highest total phosphorus load and lowest total nitrogen load in all treatments were observed for the old tile drainage system with 10 m drain spacing (treatment A). The environmental impact of new drainage systems on clay soils may thus be a trade-off between decreased phosphorus loads and increased nitrogen loads with more intensive drainage. Crop data from two experimental years indicated that investing in new drainage systems can be profitable for farmers, as crop yield was 3%-20% higher with new drainage systems compared with old tile drainage. More experimental years are needed to determine the long-term effects of the different drainage system designs. Keywords: Drain envelope, Drain spacing, Nitrogen load, Phosphorus load, Subsurface drainage.

Flood Risk Reduction Strategy With Vertical Drainage In Medan City, Indonesia

As the population of a city increases, there will be excessive exploitation of nature, uncontrolled land use change, and a decrease in the environment’s carrying capacity. These impacts cause flood disasters to increase in quantity and quality. Floods are still difficult to predict and avoid. Medan City is still haunted by the same problem as other cities in Indonesia, namely flooding. The government has focused on flood management by building a horizontal drainage network system, normalizing rivers, building embankments, but flooding still occurs frequently. Therefore, vertical drainage is needed for flood management. Vertical drainage drains surface water directly into the soil layer that horizontal drainage cannot accommodate. This research aims to study the ability of vertical drainage in Medan City to reduce flood risk. Based on the test results, vertical drainage has a discharge of 0.812 liters/second. Based on technical calculations, vertical drainage can distribute potential rainwater collected on the surface and with the addition of possible water from other sources at the research site within 9 minutes 1 second until it runs out as much as 440 liters. As a result, one vertical drainage system can effectively accommodate an area of 25 m2.

Hydraulic Characterization of Permeable Materials Used for Filling Mole Drain Channels in Structurally Unstable Soils

Highlights Permeable materials can be used to fill mole drains and provide support to the cavity walls in structurally unstable soils. Permeable materials extend the lifespan and improve the hydraulic performance of mole drainage systems. Darcy’s law for nonlinear porous flow explained the hydraulic performance of the permeable materials used in this study. A numerical method was established to assess the suitability of permeable materials of unknown hydraulic performance. Design guidelines were developed to assist in the planning of filled mole drainage systems installed in structurally unstable soils. Abstract. Mole drainage in soils with low permeability is a cost-effective technique for managing soil drainage. Following installation, the satisfactory performance of the system will depend on having sufficient soil fissure development extending from the soil surface to the roof of the mole channel and mole channel stability to avoid its collapse. Permeable materials such as river-run gravel and crushed stone can be used to fill mole channels to prevent channel collapse in halomorphic and high-silt content (e.g., 50%–70%) soils and extend the lifespan of the system. The objectives of this work were to: (i) characterize a range of permeable materials that can be used to fill mole drains and provide support to the cavity walls in structurally unstable soils; (ii) verify the applicability of Darcy’s law to explain the hydraulic performance of such materials, and (iii) develop a set of design and planning guidelines aimed at improving the performance of mole drainage systems that are filled with permeable materials. Five permeable materials were characterized, namely: three types of river-run gravels, crushed baked mud bricks, and crushed stone. The materials were characterized for their mechanical and hydraulic properties, and the applicability of Darcy’s law was experimentally determined. Small- and medium-sized gravels are easy to handle and apply during field installation due to their shape and flowability properties and the reduced risk of clogging when placed in the mole channel. However, the hydraulic performance of these materials would not allow for system designs longer than about 100 m, which therefore would limit their utilization in practice. Large-sized gravel offered an intermediate solution with overall satisfactory hydraulic performance. Crushed brick and crushed stone offered good alternatives to gravel, allowing for longer (e.g., >120 m) system designs for all combinations of drain spacing and drain gradient. However, their angularity, poor uniformity, and size range distribution can compromise the efficiency of handling and delivery in current mole plough systems. For all materials, the hydraulic conductivity (Kh) decreased with an increase in the hydraulic gradient. For a given hydraulic gradient, Kh was dependent on aggregate size, such that a larger D50 value led to increased Kh. The nonlinear performance of Darcy’s law was verified for all materials, and potential equations were fitted to represent such relationships, all showing acceptable fits to the nonlinear models (P<0.001). A linear relationship (P<0.05) between the parameter m of the potential model and total porosity was established. The set of equations developed by this study will enable estimating Kh based on the aggregate size distribution or as a function of the total porosity of the material. Crushed brick and crushed stone could provide a cost-effective solution for the installation of filled mole drain systems in structurally unstable soils. Keywords: Darcy’s law, Extreme rainfall, Halomorphic soils, Hydraulic conductivity, Reynolds number, Silty soils.

PRINCIPLES OF CALCULATIONS AND ARRANGEMENT OF LOCAL DRAINAGE SYSTEMS IN PRIVATE BUILDING TERRITORIES

Abnormally heavy rains in the first two spring months of 2023 revealed the unpreparedness and lack of protection of many settlements in the Kyiv region from excessive moisture and inundation. Among them, is Novi Petrivtsi village, where the natural conditions for surface runoff and precipitation infiltration (lack of visible surface slopes and poorly permeable cover sediments) are unfavourable and significantly complicated by buildings, and a network of highways. The long-term retention of water on the surface, the rise of groundwater levels, and the layered structure of the upper part of the geological section provide grounds for the use of combined local drainage systems with compliance with drainage standards of at least 3,0 m. Since the high density of buildings often does not allow for contour drainage around residential buildings, it is necessary to lay single-line horizontal drainage to a greater depth than for a conventional contour drainage of 3,5 meters or more. However, the lack of roadside ditches and other water intakes and means of orderly drainage do not allow homestead drainage systems to work as efficiently as possible. This requires the creation of an orderly system of water intakes (trenches and closed collectors) on the scale of the village. Foreign experience convinces that the rational planning of such systems is possible under the conditions of establishing the character of rainfall distribution with a resolution of 1–5 minutes in time and a step of 500 m across the area. Meteorological radar is used to record radar images of rain and study its intensity. An effective solution to the water drainage problem is impossible without detailed engineering and geological investigations. Due to them, litho-facies inhomogeneities in the aeration zone and water-saturated stratum, which lead to the retention and support of groundwater, were discovered in the local area. Taking into account the spatial boundaries of these engineering and geological elements allow drainage more efficiently. Drainage capacity is substantiated by forecasts of changes in the maximum amount of precipitation per day and two days in a row. Due calculating the drainage capacity, it should be taken into account that the maximum amount of precipitation in the future period will have a guarantee of 0,5-2,0% less than the actual maximum values. In the calculation part, the main attention is paid to the selection of equations for determining the width of influence of a single horizontal drain. Five formulas have been selected that can be used to solve similar problems. The time of onset of the established mode of operation of a single drain was calculated. Future research should focus on the collection of high-resolution rainfall and local urban runoff data, as well as the implementation of urban drainage models.

Calculation of horizontal collective drainage pipelines of reclamation systems in the presence of a ground water level slope

The purpose of this work is to develop a methodology for calculating the parameters of pressure horizontal collective drainage pipelines of reclamation systems that operate in the presence of a ground water level slope.
 The presented materials are based on the results of personal analytical studies of the main mathematical dependencies, which describe the pressure liquid flow in horizontal collective perforated pipelines, which operate in the presence of the ground water level slope.
 System of two differential equations, which describe the liquid motion in a drainage pipeline with variable flow rate and the conditions of liquid entry from the surrounding soil through the walls of the pipe in filtration mode, is considered. The explored pipeline is laid in the presence of the ground water level slope. By introducing new variables, the original system and its solution is presented in a dimensionless form.
 In this case the solution of the system depends on the value of three main factors: the resistance factor of the collecting drainage pipeline "ζl"; the generalized parameter "A", which comprehensively takes into account the structural and filtering characteristics of the stream; the ground water level slope «І». The analysis used the concept of an infinitely long drainage pipeline, which operates in the presence of the ground water level slope, or, what is the same, an inclined pipeline with an infinite filtering capacity of the side surface walls. Relatively simple and easy-to-use analytical dependencies were obtained on the basis of the conducted analysis. They allow to calculate the nature of the flow rate variations and pressure drop along the length.
 Corresponding graphic dependencies were constructed to simplify the calculations. It is shown that the value of the geometric slope of the ground water level, along with the resistance factor and the generalized parameter, significantly affects the calculated parameters of such pipelines.

Influence of layered degradable straw drainage system on eco-treatment of dredged sludge under vacuum preloading

In response to the long-term non-degradation and environmental pollution caused by the use of horizontal plastic drainage boards, a new approach is proposed in this study, which involves employing horizontal straw drainage system under vacuum preloading treatment for dredging sludge. Through laboratory model tests, the results show that horizontal straw drainage system exhibited excellent performance in treating dredged sludge, with an optimal spacing design of 40–60 cm. During the vacuum preloading test, the straw drainage system continuously degraded, and the degradation by-products of straw, in turn, enriched elements like nitrogen, phosphorus, potassium, etc., in the soil. The two processes of the degradation of straw drainage system and the eco-reinforcement of dredged sludge interacted actively with each other. Finally, a new reinforcement method for on-site dredging sludge was proposed by installing layered straw drainage boards. Therefore, straw drainage system was highly recommended for field application, due to their cost-effective and environmentally friendly characteristics.

The nonlinear wave dynamics of fractional foam drainage and Boussinesq equations with Atangana’s beta derivative through analytical solutions

The space–time fractional foam drainage and the Boussinesq equations are valuable mathematical models to describe different complex physical phenomena, including the drainage of soap films in bubbles and foams, the behavior of surface water waves in oceans and rivers, the propagation of long waves, etc. In this research, we explore several unrivaled and some existing analytical soliton solutions to the above-stated equations using an effective expansion scheme, known as the G′/(G′+G+A)-expansion scheme within the framework of Atangana’s beta derivative. A fractional composite transformation is used to interpret the considered equations into nonlinear equations of a single independent variable. The wave dynamics of the outcomes are illustrated through three- and two-dimensional graphical representations and contour plots. The solutions include kink, flat kink-shaped, the parabolic-shaped, the bell-shaped, and the compacton solitons. The study reveals that the fractional-order derivative in the projected equations influences the wave behavior, providing deeper insights into wave composition when the fractional derivative approaches larger. The comparison table demonstrates the effectiveness of the method across various fractional orders, with results approaching accuracy as the fractional-order approaches integer values. This study emphasizes the computational robustness and adaptability of the proposed method for investigating various phenomena across a wide range of physical science and engineering disciplines.

Earth-fill Dam Seepage Safety Risk Assessment: Randugunting Dam, Blora

Earth-fill dam, the most common dam, is constructed primarily using compacted earth materials from surrounding areas. Despite its simplicity, these dams have higher chances of failures caused by seepage or sliding. Randugunting Dam is an earth-fill dam located in the northern part of Blora, Central Java. This dam was built to accommodate irrigation and domestic needs in Blora, Pati, and Rembang Regencies. This study is conducted to monitor and assess the present Randugunting Dam’s seepage condition using Finite Element Analysis (FEA) and calculate the seepage safety factor. Geological and engineering geological mapping are combined by coring data to understand the rock and soil characteristics of the main dam location. The seepage rate analysis is conducted using Finite Element Analysis on GeoStudio 2021 SEEP/W. The results showed that Randugunting’s main dam and reservoir area primarily comprises calcareous siltstone, carbonaceous sandstone, claystone, and limestone. Weathering rates in this area range from slightly weathered to highly weathered. The seepage rate from FEA ranges from 4.39 - 5.31 litre/s and calculation of safety factor along the Randugunting Main Dam is 4.49. Those values are considered to be safe. Installing blanket type of horizontal drain and seepage berm can act as prevention step in the future.

Laboratory study on the spacing effect of vertical drains on the consolidation characteristics of clay

Sand drains are extensively utilized to fasten the consolidation rate, especially in soft clay deposits. However, due to the scarcity of sand, it should be substituted with some cost-effective material. In view of this, in the current investigation, along with sand, waste materials like rice husk ash, coir pith, fly ash, and quarry dust were used as drain materials. The consolidation test was performed using Kuttanad clay, filled in a mould of 15 cm diameter and 10 cm height, allowing single drainage. A triangular pattern of three drain system was used in the study. A parametric study on the effect of the spacing of the drain on consolidation characteristics was investigated by varying the spacing/diameter ratio (s/d ratio). It was observed that the consolidation rate is more for coir pith and quarry dust drains compared to rice husk ash and fly ash drain used in the study. The consolidation rate reduces with the increase in the spacing of the drain. For achieving a particular consolidation rate, the required drain spacing has to be known. Correlations were developed to predict the spacing between the drains for attaining a particular coefficient of consolidation.

Numerical Simulation of Seepage Surface and Analysis of Phreatic Line Control from a Fine-Grained Tailings High Stacked Dam under Complicated Geography Conditions

Background: It is adverse for the safety of a tailings dam to use fine-grained tailings as the materials for a high tailings dam because of the low penetration coefficient, the slow consolidating velocity, and the bad physical mechanical property. Furthermore, with the influence of complicated geography conditions, the phreatic line will be increased enormously when encountering special conditions, which directly affect the safe operation of the tailings dam. Methods: In this study, based on the engineering, geological, and hydrogeological conditions and survey results of a tailings dam, a 210 m fine-grained tailings dam located in three gullies was selected and used to simulate the three-dimensional seepage field of a tailings dam under a steady saturated state by using the finite element software MIDAS GTS. The permeability coefficient was inverted, the seepage field of the project under different working conditions was simulated, and the position of the phreatic line was obtained. The controlled position of phreatic lines was determined by combining the seepage field with the stability requirements. Results: Back analysis could accurately reflect the actual permeability coefficient of each partition of tailings dams. Due to the multiple areas of seepage accumulation, large valley corners, and narrowing of the dam axis, the phreatic line of the shoulder region was elevated by 2~3 m compared to the surrounding area and was thereby the most critical region of the tailings dam seepage control. The stability requirements and minimum controlled position of the phreatic line requirements could be met when the controlled position of the phreatic line was 23 m. Conclusion: This study revealed the key areas and reasons why the tailings dam’s phreatic line is prone to be uplifted under complicated geography conditions. It was very critical to control the local phreatic line by adopting local horizontal seepage drainage measures or radiation wells in the key areas of the tailings dam to ensure the safety of the tailings dam. In addition to strengthening the daily monitoring of the key areas and the exfiltration facilities of the tailings dam, it is recommended to carry out determination tests of the permeability coefficient and particle size at regular intervals. The findings could provide countermeasures for seepage control.

Protection of groundwater from the negative impact of a toxic waste polygon

The problem of protecting underground fresh water from the effects of solid household and liquid industrial waste containing toxic and highly toxic substances of the first and second hazard class is considered on the example of the Ufa municipal landfill of solid household waste and liquid industrial effluents. Based on the mathematical calculations, the filtration model of the polygon has been developed. The possibility of protecting the Southern water intake of Ufa city from pollution by creating horizontal and vertical drainage of wastewater interception, as well as the construction of a reservoir for collecting wastewater and disposing of it at sewage treatment plants in emergency cases is shown.

Effect of air-boost modes on clogging behavior for vacuum consolidation with prefabricated horizontal drain

The air-booster vacuum preloading method is considered a reasonable choice for alleviating clogging problems. However, research on the air-boost mode during the early consolidation stage is still lacking. In this study, a series of comparative experiments were designed to investigate the effects of applying different pressures and durations on the consolidation characteristics of dredged soil and clogging at two consolidation stages using indoor model tests and microscopic tests. The experimental results showed that the air-boost modes of low pressure and short duration should be adopted during the early consolidation stage, and as the continuous consolidation, the pressure and duration should be increased. Moreover, early gas injection had a more significant effect on alleviating clogging of the prefabricated horizontal drain (PHD), and the pore diameter of dredged soil was also smaller. The research results are an important guide for air-booster vacuum preloading to dewater high-moisture dredged soil.

Foam drainage equation in fractal dimensions: breaking and instabilities

Foam drainage equation in fractal dimensions: breaking and instabilities

Penerapan Soil Preloading, PVD, dan PHD untuk Analisis Penurunan Konsolidasi Tanah

Soft clay has a low bearing capacity, high compressibility and low permeability. This condition causes soft clay soil to have a long settlement time. To overcome this soft soil condition, soil improvement methods are needed. One of the efforts is to use a combination of soil preloading methods, Prefabricated Vertical Drain (PVD), and Prefabricated Horizontal Drain (PHD) methods. Calculating soil settlement with soil improvement is carried out using the Asaoka method, which is a field observation method, and the theoretical method using the Terzaghi method. Based on the calculation results of field observations using the Asaoka method, the average degree of soil settlement is 93.5%. The calculation results of the Asaoka method are recalculated using a back calculation to produce a new parameter value, namely the horizontal consolidation (Ch) value, which is then compared with the Ch value in the previous plan. In the Terzaghi method, the average soil settlement value is 1.205 meters. The results of soil settlement value are used to analyze the height of the embankment based on the load ratio requirement in SNI 8460: 2017, where the load ratio on the ground is ≥ 1.3 times the planned load under service conditions. Based on the monitoring results, a load ratio value of 0.875 was obtained so that the SNI requirements carried out a re-planning of the landfill. Then, proceed with the design of PVD and PHD. The results obtained in planning use triangular PVD patterns with a distance between PVDs of 1 meter.

Study Of Various Types Of Pvd And Ph.D. Joints On Vertical Drainage Performance

An important factor for increasing the effectiveness of the PVD (Prefabricated Vertical Drains) is the value of sufficient discharge capacity so that the PVD can work optimally. The use of PVD is usually accompanied by the use of PHD (Prefabricated Horizontal Drains) as horizontal drainage and combined with preloading. In the field, the connection is made by winding the PVD to the PHD and then tying it with cable ties. The connection system can cause deformation at the top of the PVD thereby reducing the effectiveness of the PVD discharge capacity. This study aims to find the optimal PVD-PHD connection system for the discharge capacity which is affected by confinement pressure, overburden pressure, and hydraulic gradient with a PVD-PHD connection system discharge capacity tester. The test specimens used were PVD (5mm thick; 100mm wide) and Ph.D. (20 mm thick; wide: 100 mm, 200mm, and 300mm). 4 types of connection systems have been tried, namely connections A1 and A2 where the PHD is connected in a horizontal position, and connections B1 and B2 where the PHD is connected in a vertical position. Of the four connection systems B1, the connection system has the largest discharge capacity value and a significant increase in PHD width from 100 mm to 300 mm with an increase of 7.694% at 50 kPa overburden pressure and 1.0 hydraulic gradient the highest compared to other connection types

Analytical Methods for Fractional Differential Equations: Time-Fractional Foam Drainage and Fisher’s Equations

In this research, we employ a dual-approach that combines the Laplace residual power series method and the novel iteration method in conjunction with the Caputo operator. Our primary objective is to address the solution of two distinct, yet intricate partial differential equations: the Foam Drainage Equation and the nonlinear time-fractional Fisher’s equation. These equations, essential for modeling intricate processes, present analytical challenges due to their fractional derivatives and nonlinear characteristics. By amalgamating these distinctive methodologies, we derive precise and efficient solutions substantiated by comprehensive figures and tables showcasing the accuracy and reliability of our approach. Our study not only elucidates solutions to these equations, but also underscores the effectiveness of the Laplace Residual Power Series Method and the New Iteration Method as potent tools for grappling with intricate mathematical and physical models, thereby making significant contributions to advancements in diverse scientific domains.

Pengetahuan Lokal Petani dalam Budidaya Tanaman Sayur di Desa Beruk, Kecamatan Jatiyoso, Kabupaten Karanganyar

<em>Population growth triggers the need for national food to increase, including the need for vegetable crops as a complement to human nutrition. Efforts made by farmers to meet the population’s needs for vegetable crops and a source of income, often have not paid attention to environmental conditions. Beruk Village is one of the villages where the people cultivate vegetables crops on the slopes of the mountains which should be used as a conservation area. This condition certainly requires farmers to always learn and apply appropriate local techniques so as not to harm the surrounding environment. This research aimed to explore the learning process of farmers in obtaining and examining local knowledge in vegetable cultivation.</em> <em>This study used a qualitative approach method with the interactive model analysis techniques of Miles and Huberman. The results showed that local knowledge of local farmers comes from parents/hereditary, local village farmers, and farmers outside the village through oral, experience, trial and error, and observation. The local knowledge includes seeding (garlic, onion, carrot), land processing stages and its frequency, ‘kalenan’ (horizontal drains), ‘kali gondhang’ (vertical drains), ‘plipit’ (the arrangement stones on the edge of ‘larikan’), benefits of spacing, planting time and season, intercropping, benefits of grass in agricultural land, fertilization methods, weeding, thinning, manual irrigation, utilization of agricultural and livestock waste, as well as method, age, and yield of harvest. The local agricultural tools used are hoe, crowbar, ‘ganco’, garden fork, trowel, sickle, bucket, sack, ‘lanjaran’, and its binder from natural material.</em>

Fractional-order modeling: Analysis of foam drainage and Fisher's equations

Abstract In this study, we use a dual technique that combines the Laplace residual power series method (LRPSM) and the new iteration method, both of which are combined with the Caputo operator. Our primary goal is to solve two unique but difficult partial differential equations: the foam drainage equation and the nonlinear time-fractional Fisher’s equation. These equations, which are crucial in modeling complex processes, confront analytical complications, owing to their fractional derivatives and nonlinear behavior. We develop exact and efficient solutions by merging these unique methodologies, which are supported by thorough figures and tables that demonstrate the precision and trustworthiness of our methodology. We not only shed light on the solutions to these equations, but also demonstrate the prowess of the LRPSM and the new iteration method as powerful tools for grappling with complex mathematical and physical models, significantly contributing to advancements in various scientific domains.

Machine-Learning Algorithms Optimize Drilling-Center Locations Offshore

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 211772, “Optimizing Future Drilling-Center Locations Using Advanced Analytics and Machine-Learning Algorithms Offshore Abu Dhabi,” by Rail Salimov, Benoit Jaffres, and Jamal Alblooshi, ADNOC, et al. The paper has not been peer reviewed. _ Long-term development planning requires infill drilling. Because of the limited number of slots in the offshore environment, new drilling centers (wellhead towers) are required. Optimized location of drilling centers can play a major role in reducing drilling expenses. Two main challenges related to wellhead-tower placement are discussed in the complete paper: first, where to place future drilling centers based on subsurface coordinates and drilling constraints; and second, how to allocate dozens of subsurface targets to multiple drilling centers. The drilling-center placement optimization algorithm developed by the authors is based on multiple optimization parameters related to well cost. Introduction To finalize well trajectories, and thus best manage well costs, before the drilling phase, the following detailed analyses are required: - Evaluation of horizontal trajectory in terms of landing point and total depth - Optimization of horizontal drain length - Optimization of the horizontal drain length in the best oil-bearing zone - Torque-and-drag evaluation - Anticollision assessment - Selection of optimal completion accessories However, for most giant offshore fields with complex plans, hundreds or even thousands of infill developments are required. Definition of optimal locations and allocations of wells to drilling centers will require multiple iterations of already tedious work. An alternative methodology is described in the complete paper that allows finalization of future facility placement with the use of open-source machine-programming tools and applied mathematics. The presented methodology was deployed successfully on two major offshore fields where current production is connected through wellhead towers. Evolution of the development plan and the ramp-up of production means that additional drilling is planned during the next 10 years. Approximately 100–150 development wells are planned to be drilled from yet-to-be-constructed wellhead towers. One of the main challenges in achieving cost efficiency is effective placement of the new towers to minimize the total drain length of all development wells. The methodology covers the two most important aspects of facility construction that play vital roles in optimization of capital investment in facility expansions of offshore oil and gas fields. These aspects are optimized allocation of future wells to drilling centers and placement of those drilling centers.

Dynamics Analysis of Droplets Collision with the Wall Driven by Buoyancy

Dynamics analysis of the oil droplet in water impacting on a rigid wall in the range of Re=9.3 ∼ 231.39, We=0.003 ∼ 0.637 was carried out by combining microscopic experiment with theoretical study. In the oil droplet’s force equation, we consider the added mass force and the water film induced force, in addition to the conventional forces, i.e. buoyancy and resistance to flow. Stokes-Reynolds drainage equation (i.e. SR model) and Young-Laplace equation (i.e. YL model) are combined with the force equation to numerically solve the motion law of oil droplets near the wall for different control parameters. The study indicates that coupled model would expect oil droplet velocities, motion trajectories and capture the kinetic behaviors of the water-film drainage evolution. The interfacial deformation of oil droplets causes changes in the pressure and the pressure distribution pattern has an important relationship with the shape of the oil droplet interface. These two forces play a dominant role in droplet motion during the collision and the maximum value of these two forces increases with increasing droplet size and Re number. Future research should shift towards complex oil-water systems and consider the effects of chemicals on oil droplets so that the application of the model will be more generalisable. At the same time, computer technology should be used to transfer the two-dimensional view to a three-dimensional view to analyse the deformation of the oil-water interface and to better understand the drainage process of the water film.