Slotted Pipe Research Articles

Optimization design of hydrocyclone with overflow slit structure based on experimental investigation and numerical simulation analysis

This study aims to address the issue of high energy consumption in the hydrocyclone separation process. By introducing a novel slotted overflow pipe structure and utilizing experimental and response surface optimization methods, the optimal parameters were determined. The research results indicate that the number of slots, slot angles, and positioning dimensions significantly influence the performance of the hydrocyclone separator. The optimal combination was found to be three layers of slots, a positioning dimension of 5.3 mm, and a slot angle of 58°. In a Φ100mm hydrocyclone separator, validated through multiple experiments, the separation efficiency increased by 0.26% and the pressure drop reduced by 24.88% under a flow rate of 900 ml/s. CFD simulation verified the reduction in internal flow field velocity and pressure drop due to the slotted structure. Therefore, this study provides an effective reference for designing efficient and low-energy hydrocyclone separators.

Research on directional rock blasting based on different slotted pipe materials of the combined charge structure

For shaped charge blasting projects in mining, civil engineering, and similar fields, it is proposed to modify the charge structure by combining slotted tubes and shaped charge liners to obtain a new type of charge structure. This aims to achieve directional rock breaking through the focused action of the shaped charge. The influence of different slotted pipe materials on the directional rock-breaking effect of concentrated energy using a new charge structure is explored through theoretical analysis combined with model test study, high-speed camera, stress–strain gauge, and other equipment. A comparison is made between slotted pipes made of aluminum, kraft paper, and PVC, with the cutting width of 2 mm. Based on the characteristics of the cracks formed after blasting, the new charge structure made of aluminum slotted pipe produces a penetrating crack that is almost consistent with the pre-cracking direction. Based on the corresponding characteristics of successively released blasting energy, the guiding and convergence effect of the new charge structure made of aluminum slotted pipe on the explosion energy is greater than that of the new charge structure made of the other two types of slotted pipe material. According to the strain data measured after blasting, the peak arrival time of the strain peak in the direction of the slotted pipe on one side of the shaped hood is shorter than that in the other two directions, and the peak strain is greater than that in the other two directions while having a better energy gathering effect. Based on the findings, the new charge structure with directional energy concentration has a damage reduction effect. Furthermore, the material of aluminum slotted pipe is found to be better than PVC slotted pipe, whereas the material of PVC slotted pipe is better than kraft paper slotted pipe in achieving directional rock breaking.

Failure mechanism and strengthening countermeasures of end-anchored cable free section under combined tension and shear

As an effective and economical reinforcement method, end anchorage cables are widely used for roadway support in coal mines. The failure of the free section of the end-anchored cable (FSEC) under the combined action of tension and shear is a key factor inducing roof collapse accidents in coal mine roadways. Based on cable bolt tensile and shear test results, this paper aims to reveal the failure mechanism of the FSEC under tension and shear by establishing a mechanical model of the interaction between the cable bolt and jointed rock mass. The results show that the axial and shear force coupling in the FSEC increases because of the joint plane shear action. The FSEC is subject to tensile–shear failure when the axial and shear forces meet the tensile–shear composite yield condition at the inflection point of the sheared cable bolt. The steel strands of the cable bolt experience and transmit shear force through the contact point, resulting in an uneven distribution of shear stress in the cable bolt cross-section, directly causing the FSEC’s local failure. Strengthening countermeasures are proposed using a high-strength slotted steel pipe to protect the cable bolt under shear, and a strengthening device has also been designed. Experimental results obtained in the laboratory have revealed that the strengthening device does not only effectively enhance the cable bolt’s shear capacity by increasing its shear strength and changing the shear transfer mode, but also significantly improves the cable bolt’s comprehensive performance. This study elucidated the failure mechanism of the FSEC and provides a practical and convenient method for increasing the shear strength of an end-anchorage cable system and enhancing roadway stability.

Strengthening Device for Improving Shear Performance of Anchor Cable in Rock Support.

Many designs of anchor cables are currently in use for rock support in civil and mining operations. Because of the exposed surface and weak shear performance of the cable bolt's free section (CBFS) in end-anchored structures, breaking failure frequently occurs. Numerical simulations and laboratory experiments were performed in this study to develop measures to improve CBFS resistance to shear failure. Analysis of shear characteristics of the CBFS showed that higher axial tension weakens the cable bolt's shear resistance, and that shear damage on the cable surface and uneven distribution of shear stress aggravate CBFS tensile-shear failure. A high-strength steel pipe is proposed to protect the shear cable bolt, and the preliminary design of a CBFS-strengthening device (CFSD) is presented. Numerical simulation revealed that the CFSD effectively improved CBFS shear resistance and provided protection from harmful shear damage. The optimal performance of a Q-type (slotted steel pipe) CFSD was confirmed. The mechanism of improvement of the cable's shear resistance to surrounding rock by employing the CFSD was analyzed. Double-shear tests were carried out on a bare cable bolt and a cable bolt with a Q-CFSD. The results revealed that the CFSD increased the peak shear force on the joint plane, cable peak axial force, and ultimate shear displacement by 31%, 18%, and 11%, respectively. The proposed device is effective in improving the shear performance of end-anchored cable bolts and enhancing surrounding rock stability.

Stress Detection of Precast Pipe Piles Based on the Low-Loss Slotting Method

Tilting of buildings due to uneven settlement, construction quality issues or other problems is one of the critical accidents threatening the safety of buildings. In order to determine a reasonable solution with respect to the rectification of the tilting building, detection of the stresses of the substructure is necessary. In this study, a stress release method to test the stress of prefabricated pipe pile under loading is studied by combining experimental research and finite element numerical simulation. Based on various measurements, such as traditional strain gauges, vibrating wire strain gauges, and three-dimensional digital image correlation (DIC) tests, the relationship between local residual stress and actual stress of the slotted area at different load levels is determined. Meanwhile, the stress release process in slotted precast pipe pile was numerically simulated with ABAQUS to investigate the influence of the slotting dimension parameters on the stress release rate at different load levels. Based on 1042 sets of finite element modeling results of multi-parameter combination, the quantitative relationship between slot width, depth, spacing, prestress level and stress release rate is studied. An explicit prediction model of the stress release rate is given by regression analysis of combined test results and simulation data. With the prediction model, the stress condition of a loaded precast pipe pile can be accurately predicted based on low-loss slotting. Compared to the traditional stress release method, the proposed method has better controllability and applicability, less damage to the structure, and stronger anti-disturbance ability.

Experimental study of pressure flushing of non-cohesive sediment through slotted pipe bottom outlet

ABSTRACT Among several techniques for prevention and mitigation of reservoir sedimentation, bottom outlets arise as a means of removing sediment deposited close to the dam. Given the reduced sediment removal provided by traditional bottom outlets under pressure flushing conditions, this article proposes a new type of structure that aims to increase sediment removal in the direction parallel to the dam axis. An experimental installation was employed to evaluate its operation as a function of the variation of its diameter and flow and sediment characteristics. Through analysis of the bathymetry generated by the structure, a dimensionless relation for predicting the scour pit length was obtained, presenting good fitness to the experimental data.

Application of selective water plugging technology for slotted pipe horizontal well

Chemical selectivity plugging technology is targeted to the slotted pipe horizontal wells which 70% domestic, 90% foreign horizontal wells using. However, according the practices in the field, there is low water shutoff effective because of chemistry plugging agents’ poor ability of water selectivity and plugging plans’ unreasonable. By analyzing the dynamics and PNN test data, there is a dot or segment water production section which producing water from the edge and bottom water in horizontal section. Basing on this, targeted plugging plan for well H2 is designed selecting high selective gel. Plugging construction results show that the pipe pressure climbing gently, displaying that gel DM103 can enter the reservoir deep. After reopen well H2, liquid production rate was maintained at 27 t/d, as well as oil production rate increased from 4 t/d to 20 t/d, while water cut was decreased from 75% to 25%. The success of water plugging proves the judgment of water production section and the limitation of PNN testing. In addition, a water shutoff successful demonstration is established for specific slotted pipe horizontal wells which are early in water channeling, far from the edge and bottom water in heavy oil reservoirs.

The Seepage and Stability Performance Assessment of a New Drainage System to Increase the Height of a Tailings Dam

Effective methods for extending the storage capacity of tailings for a mining company include expanding and increasing the height of the tailings dam. However, this change could lead to an uplift in the phreatic line and a decrease in the slope stability. In this paper, a new drainage system combining a horizontal drainage pipe with an upward bending slotted pipe was proposed and applied to the design of a seepage-proof system for the Xigou tailings dam with an increased height. To accurately simulate the performance of the seepage control system, a three-dimensional finite element model was established on the basis of a geological investigation of the site conditions. In this work, a substructure technique was used to model the drainage pipe with a small radius and dense spacing to reduce the difficulty in mesh generation, and a back-analysis method called MPSO-BP (modified particle swarm optimization algorithm and a back propagation neural network) was used to correct the measured permeability coefficients. The results show that the new drainage system can effectively dissipate the seepage pressure, decrease the phreatic surface, and improve the safety factors of the slope stability. The proposed drainage system can also meet the seepage stability requirements of the higher tailings dam. Additionally, this system can be widely deployed in similar projects.

Repellency-induced runoff from New Zealand hill country under pasture: A plot study

Soil water repellency is a common phenomenon which develops when surface soils become dry in summer and autumn. It is claimed that repellency is likely to result in a lower infiltration rate and a concomitant increase in surface runoff, particularly on slopes. This study quantifies the effect of water repellency on runoff from a series of small plots on a range of slopes (20° and 30°) and aspects (N, S and E) in a hilly landscape in the south-east of the North Island of New Zealand. The plots (1 m wide and 2 m long) were set up to capture runoff via a slotted PVC pipe and measure it using tipping bucket apparatus: at each of the slope/aspect locations there were duplicate plots. A meteorological station was also established at the site along with TDR probes to measure soil moisture down to 300 mm depth. When moist, the soil at the site had a very high infiltrability (>1.5 mm/min). On nine occasions, runoff was measured (ranging from 1 to 59% of rainfall) when the soil surface was dry and rainfall was intense (greater than 0.1 mm/min). However, during the two-year study period, this repellency-induced runoff equated to only 5% of the total rainfall. Furthermore, the infiltration rate of initially dry, repellent soil (ranging from 0.2 to 0.6 mm/min) partly recovered over a ten-minute period (0.6–1.0 mm/min) and, with sufficient rainfall, repellency completely disappeared within two days. The transitory nature of water repellency was confirmed in an experiment on large soil slabs conducted in the laboratory where repellency-induced runoff was observed to largely disappear over a period of 30 min. Overall, it is concluded that soil water repellency does not play a major role in the soil water balance of the hill country at the study site.

Теоретические исследования по обоснованию неравномерности распределения расхода воды по высоте загрузки фильтра с центральной перфорированной трубой

Теоретические исследования по обоснованию неравномерности распределения расхода воды по высоте загрузки фильтра с центральной перфорированной трубой

Исследования распределения расхода жидкости по высоте загрузки в фильтре для очистки воды с центральной перфорированной трубой

Исследования распределения расхода жидкости по высоте загрузки в фильтре для очистки воды с центральной перфорированной трубой

Floating faeces: Effects on solid removal and particle size distribution in RAS

The removal of solid wastes originating from faecal matter is one of the decisive challenges for future fish farming, in particular given the current emphasis on water reuse in aquaculture. This study compared solid waste removal performance in replicate recirculating systems in which the only difference was the removal concept being deployed. Rainbow trout (Oncorhynchus mykiss) of the test group were fed an innovative diet supplemented with 2.5% cork granules (0.5–1mm) resulting in buoyant faecal casts (density values below 1.00gcm−3). These were removed directly from the tank by a low cost slotted pipe at the water surface. The control group was fed a conventional diet, identical to the experimental feed except that it lacked the cork additive. The resulting solids in both systems were removed by sedimentation in a classic manure pit, which was drained to the drum filter twice a day. Wastewater from both treatments was mechanically cleaned by a drum filter and biologically treated by a moving bed bioreactor before being returned to the tanks.The cork treatment led to a substantially higher solid load being delivered to the drum filter via the wastewater outflow than in the control system. The average removal efficiency of cork-treated wastes was more than twice that achieved in the control system (59% vs. 25%). Total suspended solid (TSS) in the backwash stream of the drum filter was about five times greater in the cork diet treatment. There was no significant difference in the particle size distribution or TSS load of water passing the 100μm gauze of the drum filter in the two systems. Cork supplementation did not affect growth or mortality of rainbow trout. The present study shows that the application of floating faeces is an exciting prospect in recirculating aquaculture systems, offering significant improvements in solid removal efficiency.

Development of a sparging chamber for field radon analysis

Radon-222 has become a widely used tracer of submarine groundwater discharge. However, remote field studies are often limited by the need to pump water to a spray chamber which degasses dissolved radon for subsequent analysis in the gaseous phase. We develop here a new method of degassing dissolved 222Rn, utilizing a stream of bubbles driven by the internal air pump of a commercial radon analyzer to achieve air:water partitioning equilibrium, eliminating the need to pump water. This system utilizes a sparging chamber, comprised of a slotted vertically-oriented pipe with bubbles produced in the bottom. A non-slotted section of the pipe at the top of the chamber forms a sealed headspace, allowing air to be circulated in a closed loop between the sparging chamber and a radon-in-air monitor. We found that such a sparging chamber needs to allow bubbles to rise through at least 45 cm of water column to function at equal efficiency as the standard protocol of the spray chamber. Under our optimized configuration, the sparging chamber operates as efficiently as the standard protocol at measuring dissolved 222Rn activities when encountering increasing 222Rn activities, and offers even greater gas exchange efficiency when dissolved 222Rn activities decrease. The sparging chamber offers a more field-friendly alternative to measuring 222Rn activities, as it eliminates the need to maintain a submersible pump throughout the measurement and it offers increased temporal resolution when variable 222Rn activities are expected.

Evaluating two infiltration gallery designs for managed aquifer recharge using secondary treated wastewater

As managed aquifer recharge (MAR) becomes increasingly considered for augmenting water-sensitive urban areas, fundamental knowledge of the achievable scale, longevity and maintenance requirements of different options will become paramount. This paper reports on a 39 month pilot scale MAR scheme that infiltrated secondary treated wastewater through unsaturated sand into a limestone and sand aquifer. Two types of infiltration gallery were constructed to compare their hydraulic performance, one using crushed, graded gravel, the other using an engineered leach drain system (Atlantis Leach System®). Both galleries received 25 kL of nutrient-rich, secondary treated wastewater per day. The Atlantis gallery successfully infiltrated 17 ML of treated wastewater over three years. The slotted distribution pipe in the gravel gallery became clogged with plant roots after operating for one year. The infiltration capacity of the gravel gallery could not be restored despite high pressure cleaning, thus it was replaced with an Atlantis system. Reduction in the infiltration capacity of the Atlantis system was only observed when inflow was increased by about 3 fold for two months. The performance of the Atlantis system suggests it is superior to the gravel gallery, requiring less maintenance within at least the time frame of this study. The results from a bromide tracer test revealed a minimum transport time of 3.7 days for the recharged water to reach the water table below 9 m of sand and limestone. This set a limit on the time available for attenuation by natural treatment within the unsaturated zone before it recharged groundwater.

Study on Smooth Blasting of Tunnel in Fault Formation

From the characteristics of rock damage, the mechanism of rock blasting into seam was discussed. Based on the joint mechanism of stress waves and explosive gases, the blasting method adopting slotted pipe charge structure in fault formation was studied, and the test results were used in Guanjiao tunnel of Qinghai-Tibet railway. The field tests show that the perimeter hole adopting slotted pipe charge structure improves the phenomenon of over-excavation in fault formation obviously.

Study on Smooth Blasting of Tunnel in Fault Formation

From the characteristics of rock damage, the mechanism of rock blasting into seam was discussed. Based on the joint mechanism of stress waves and explosive gases, the blasting method adopting slotted pipe charge structure in fault formation was studied, and the test results were used in Guanjiao tunnel of Qinghai-Tibet railway. The field tests show that the perimeter hole adopting slotted pipe charge structure improves the phenomenon of over-excavation in fault formation obviously.

Finite Element Simulation of Deformation Process of 316L Expandable Slotted Base Pipe at Room Temperature

Expandable screen called slotted base pipe functions as skeleton structure in expandable screen. The expansion process is very complicated due to the existence of slots on slotted base pipe and contact friction between expansion tools and tubular. In this work, based on elastic-plastic mechanical analysis of the expandable slotted tube in expansion process, the 3D nonlinear finite element analysis model of contact process was built. Aiming at two specifications of 4-1/2 and 6-5/8 inches 316L stainless steel slotted tubular, expansion deformation process at room temperature with expansion ratios of 25-35% range was simulated. With those works, it hopes to provide a useful foundation for the formulation of expansion technology of expandable screen.

Design and Application of a Direct‐Push Vadose Zone Gravel Permeameter

A borehole permeameter is well suited for testing saturated hydraulic conductivity (K(sat)) at specific depths in the vadose zone. Most applications of the method involve fine-grained soils that allow hand auguring of test holes and require a small water reservoir to maintain a constant head. In non-cohesive gravels, hand-dug test holes are difficult to excavate, holes are prone to collapse, and large volumes of water are necessary to maintain a constant head for the duration of the test. For coarse alluvial gravels, a direct-push steel permeameter was designed to place a slotted pipe at a specific sampling depth. Measurements can be made at successive depths at the same location. A 3790 L (1000 gallons) trailer-mounted water tank maintained a constant head in the permeameter. Head in the portable tank was measured with a pressure transducer and flow was calculated based on a volumetric rating curve. A U.S. Bureau of Reclamation analytical method was utilized to calculate K(sat). Measurements with the permeameter at a field site were similar to those reported from falling-head tests.

Cost-Effective Solutions for Corrosion-Resistant Expandable Screen Base Pipe in Sour/Brine Service

Abstract In today's competitive environment in the oilfield industry, the end-user must choose the very lowest-cost material that will meet the technical needs of the application. This requirement is passed on to the manufacturer, who must use materials that are appropriate yet still meet economic criteria. Another factor has been the expansion of field development into deeper, more corrosive environments, increasing the demand for corrosion-resistant alloys (CRAs) at a time when the demand and cost for stainless materials has increased. In expandable sand control systems, an added burden to the manufacturer is that this new technology must compete with existing non-expandable screens that are low-cost to manufacture with commodity type raw materials. One such example is 13Cr, being the first choice in a CRA for the base pipe in conventional sand screens. Although 13Cr is one of the least costly of the CRAs, it does provide the necessary corrosion resistance in mild H2S environments under a variety of chloride/temperature conditions. However, it lacks the ductility needed for 20 to 25% expansion as a solid expandable. 316L or UNS S31603 is a commodity CRA material with sufficient ductility and strength for use as an expandable screen base pipe, but its corrosion resistance is often questioned; particularly its resistance to chloride stress-corrosion cracking (SCC). This paper provides the data necessary to establish a performance envelope for S31603 and discusses the potential application of the material in several projects. Thus, S31603 is shown to provide a cost-effective CRA material for base pipes in sandcontrol screens. Introduction In expandable screen systems, the capability exists for the screen to be expanded against the borehole ID, virtually eliminating the annulus around the screen and the need for gravel packing. Also, this increases the sand screen surface area, thus reducing pressure drop across the filter and increasing production rates. Because of its high strength, the expanded screen can provide superior support to stabilize the borehole, which then minimizes the potential for sand production(1). Finally, expandable screens can provide a larger production ID than is normally possible with traditional screens. The challenge with the expandable concept has been to provide not only materials that can maintain integrity in the more corrosive environments now being developed but also materials that provide the economic feasibility to allow them to be competitive in today's marketplace. The base pipe of a conventional, non-expanding sand screen is simply a pipe that has been perforated to allow fluid to flow in from the surrounding wellbore. The basic concept behind "solid expansion" of a screen system is simply to expand this perforated pipe downhole and thereby only slightly reduce the collapse strength as a result of having increased the diameter and reduced the wall. In contrast, a slotted pipe that has long thin slots cut lengthwise in the pipe has very little collapse strength after expansion. Therefore, while slotted pipe is easy to expand, it is also easy to collapse, and thus, is unable to prevent the wellbore from caving in.

Techbits: Multilateral-Well Strategies: Examining Benefits and Constraints

To address multilateral-well strategy for new field-development and -redevelopment opportunities, an SPE Applied Technology Work-shop (ATW) on “Multilateral Wells” was held in Bangkok, Thailand, in July. Attended by 60 participants representing 30 different organizations from 15 countries, the session presented an opportunity to explore the specifics of multilateral requirements and applications with emphasis on geological and geophysical identification of multilateral applications, junction selection, multilateral-well drilling/window systems, multilateral-well completions, field case histories, multilateral well performance, and intelligent completions. Tara Tiradnakorn, President of Unocal Thailand, set the stage for the technical agenda and discussion with the keynote address “Energy Demand Growth and Its Impact on Future Technological Development,” in which he reviewed the recent history and status of the energy industry in Thailand, technologies that have most effectively assisted area industry, and future development. Opening remarks also were offered by ATW Chairperson Ding Zhu, Assistant Professor, Harold Vance Dept. of Petroleum Engineering at Texas A&M U. The Program Committee included Bernt Aadnoy, Professor of Petroleum Engineering at the U. of Stavanger; Azlee Abu Bakar, Head of Well Engineering–Drilling for Petroliam Nasional (Petronas) Carigali Sdn. Bhd.; Ali Al-Saleh, Senior Drilling Engineer of Kuwait Oil Co.; Julie Bonner, Senior Drilling Engineer–Completion Engineering, Horizontals, and Multilaterals for Chevron Corp.; Neale Carter, Region Manager of Easywell Solutions; Henrik Dock, Drilling and Measurement Sales Manager of Schlumberger WTA (M) Sdn. Bhd.; Dave Knox, Completion Fluids Technical Manager of M-I Swaco; Drew Hembling, Completion Engineering Specialist of Saudi Aramco; Dan Hill, Professor, Harold Vance Dept. of Petroleum Engineering at Texas A&M U.; and Eric Upchurch, Consulting Drilling Engineer for Unocal Thailand. Facts From Five Fields Field-application experiences with the multilateral advanced-well concept spanned the use of reformable-metal technology in the North Sea, a maximum-reservoir-contact concept used in Saudi Arabia’s Shaybah field; fishbone wells in a heavy-oil field in Venezuela; window milling on a deep gas well in Saudi Arabia; and a trilateral intelligent completion in the Saudi Aramco Ghawar field. In the North Sea, workshop participants learned how reformable-metal technology was used to achieve two 5-in.-internal-diameter wellbores at junction to accomplish a Technical Advancement of Multilaterals (TAML) Level 6 junction with 7-in. casing above the junction. With drilling and completion on two wells deemed successful, two additional wells are planned. In the Shaybah field, lessons learned with the maximum-reservoir-contact concept included a best practice of a fork-type sidetrack, with flow controls installed in the main bore and long lateral length, regardless of lateral type (forked, fishbone, or both), resulting in the most benefit. The Zuata field has 7-in. fishbone wells with slotted pipe down the main wellbore, and the fishbone wells are openhole completions. If a lateral collapses, there is no option for repair. The fishbone multilateral configuration delivered doubled production on average without doubling cost. When compared to the use of the fishbone configuration in other fields, this configuration performs best in a low-permeability, heavy-oil environment.