Deepsea mining has been proposed since the 1960s to alleviate the lack of resources on land.Vertical hydraulic transport of collected ores from the seabed to the sea surface is considered the most promising method for...Deepsea mining has been proposed since the 1960s to alleviate the lack of resources on land.Vertical hydraulic transport of collected ores from the seabed to the sea surface is considered the most promising method for industrial applications.In the present study,an indoor model test of the vertical hydraulic transport of particles was conducted.A noncontact optical method has been proposed to measure the local characteristics of the particles inside a vertical pipe,including the local concentration and particle velocity.The hydraulic gradient of ore transport was evaluated with various particle size distributions,particle densities,feeding concentrations and mixture flow velocities.During transport,the local concentration is larger than the feeding concentration,whereas the particle velocity is less than the mixture velocity.The qualitative effects of the local concentration and local fluid velocity on the particle velocity and slip velocity were investigated.The local fluid velocity contributes significantly to particle velocity and slip velocity,whereas the effect of the local concentration is marginal.A higher feeding concentration and mixture flow velocity result in an increased hydraulic gradient.The effect of the particle size gradation is slight,whereas the particle density plays a crucial role in the transport.展开更多
Hydraulic transport in pipelines is the most promising conveying method for large ore particles in deepsea mining.The dynamic performances of particles during transportation in vertical,inclined and horizontal pipelin...Hydraulic transport in pipelines is the most promising conveying method for large ore particles in deepsea mining.The dynamic performances of particles during transportation in vertical,inclined and horizontal pipelines are significant for the design of hydraulic transport systems.In the present study,we focus on the statistical characteristics and flow regimes of the mixture composed of ore particles and seawater in the pipelines.Numerical simulations are conducted by using Computational Fluid Dynamics(CFD)and Discrete Element Method(DEM).The influences of inclination angle and particle diameter are evaluated through two sets of numerical tests.The regulation of the inclined transport is totally different from that of the vertical transport,whereas the dynamics of the mixtures in inclined and horizontal pipes are similar.A number of particles accumulate on the pipe wall even with a small inclination angle.Large hydraulic gradient and local concentration would occur when the inclination angle of the pipe is in the range of30°-60°.With the decrease of particle diameter,the particle flow becomes uniform,reflected by the almost uniform particle distribution in the vertical pipe and the clear interface between the suspended load and the bed-load in the inclined pipe.However,small particles will introduce larger local concentrations and hydraulic gradients in the inclined pipe,which is not conducive to particle transport.展开更多
In order to validate the simulation model and develop heave compensation control strategy,heave compensation model tests were performed.The model test installation includes themining ship motion simulator,the heave co...In order to validate the simulation model and develop heave compensation control strategy,heave compensation model tests were performed.The model test installation includes themining ship motion simulator,the heave compensation system,the lifting pipe simulator,the buffer simulator and the water pool.The tests ofmining ship motion simulator show that it is able to perform under the predetermined attitude path smoothly and can meet the requirements of themining ship motions.The heave compensation effect is more than 60% under random wave and the goal is set to be 50%.The model test results indicate that this heave compensation system is effective and feasible.展开更多
A new sampling method of deepsea microplankton with function of in-situ concentrated sampling and gastight sampling was proposed. In-situ concentrated sampling technique was realized as follows: a microplankton membra...A new sampling method of deepsea microplankton with function of in-situ concentrated sampling and gastight sampling was proposed. In-situ concentrated sampling technique was realized as follows: a microplankton membrane was used as filtration membrane, and a deepsea pump was used to pump seawater; the microplankton was captured and the density of microplankton was increased when seawater flow through the filtration membrane. Gastight sampling technique was realized as follows: a precharged accumulator was used as pressure compensator. During the process of lifting the sampler, the accumulator compensated the pressure drop continuously. The laboratory experimental results show that with in-situ concentrated sampling technique, in-situ concentrated sampling can be realized and the maximum concentration ratio reaches up to 500. With pressure compensation technique based on accumulator, gastight sampling can be realized. When sampling at 6 km and the precharge pressure of accumulator is 18 MPa, pressure drop of the sample is less than 2% compared with its original pressure. Deepsea experiment (at 1.9 km) results show that the sampler can realize in-situ concentrated sampling and gastight sampling.展开更多
In order to find an economic and effective water control method for horizontal wells in deep sea bottom-water gas reservoirs,we prepared modified coated gravel.Based on this,wear resistance,temperature resistance and ...In order to find an economic and effective water control method for horizontal wells in deep sea bottom-water gas reservoirs,we prepared modified coated gravel.Based on this,wear resistance,temperature resistance and water plugging capacity(WPC)tests were carried out on the coated gravel.Then,experiments were carried out using the 3D simulation device for the development of large-scale bottom-water gas reservoirs to compare the development effects of horizontal wells packed with conventional gravel and coated gravel in deepsea bottom-water gas reservoirs.And the following research results were obtained.First,the upper limit of temperature resistance of the gravel coating is 240℃ and the gravel packing speed can reach 4.48 m/s,which is 8 times the average flow velocity of gravel packing in actual open hole sections.Second,as the permeability of the coated gravel packing layer increases,its WPC gets weak.When the permeability is lower than 1500 mD and the displacement pressure difference is lower than 0.6 MPa,the WPC of the coated gravel packing layer is between 0.17 and 0.68.Third,the coated gravel layer functions as gas permeability and water plugging,so the horizontal well technology with coated gravel packing can reduce the flow capacity of water phase breaking into the dominant flow passage,so as to delay the rise of water production of gas well and prolong the gas production time.In this way,the gas recovery factor of bottom-water gas reservoir can be increased effectively.In conclusion,this technology has the function of spontaneous selective water plugging,i.e.,“water plugging in case of water and gas permeability in case of gas”,and its technical and economic advantages are remarkable,which can provide a new idea for the water-control development of deepsea bottom-water gas reservoirs.展开更多
基金financially supported by the Hainan Provincial Joint Project of Sanya Yazhou Bay Science and Technology City(Grant No.520LH052)the National Natural Science Foundation of China(Grant No.51909164).
文摘Deepsea mining has been proposed since the 1960s to alleviate the lack of resources on land.Vertical hydraulic transport of collected ores from the seabed to the sea surface is considered the most promising method for industrial applications.In the present study,an indoor model test of the vertical hydraulic transport of particles was conducted.A noncontact optical method has been proposed to measure the local characteristics of the particles inside a vertical pipe,including the local concentration and particle velocity.The hydraulic gradient of ore transport was evaluated with various particle size distributions,particle densities,feeding concentrations and mixture flow velocities.During transport,the local concentration is larger than the feeding concentration,whereas the particle velocity is less than the mixture velocity.The qualitative effects of the local concentration and local fluid velocity on the particle velocity and slip velocity were investigated.The local fluid velocity contributes significantly to particle velocity and slip velocity,whereas the effect of the local concentration is marginal.A higher feeding concentration and mixture flow velocity result in an increased hydraulic gradient.The effect of the particle size gradation is slight,whereas the particle density plays a crucial role in the transport.
基金financially supported by the National Natural Science Foundation of China (Grant No.51909164)the Hainan Provincial Joint Project of Sanya Yazhou Bay Science and Technology City (Grant No.520LH052)。
文摘Hydraulic transport in pipelines is the most promising conveying method for large ore particles in deepsea mining.The dynamic performances of particles during transportation in vertical,inclined and horizontal pipelines are significant for the design of hydraulic transport systems.In the present study,we focus on the statistical characteristics and flow regimes of the mixture composed of ore particles and seawater in the pipelines.Numerical simulations are conducted by using Computational Fluid Dynamics(CFD)and Discrete Element Method(DEM).The influences of inclination angle and particle diameter are evaluated through two sets of numerical tests.The regulation of the inclined transport is totally different from that of the vertical transport,whereas the dynamics of the mixtures in inclined and horizontal pipes are similar.A number of particles accumulate on the pipe wall even with a small inclination angle.Large hydraulic gradient and local concentration would occur when the inclination angle of the pipe is in the range of30°-60°.With the decrease of particle diameter,the particle flow becomes uniform,reflected by the almost uniform particle distribution in the vertical pipe and the clear interface between the suspended load and the bed-load in the inclined pipe.However,small particles will introduce larger local concentrations and hydraulic gradients in the inclined pipe,which is not conducive to particle transport.
基金Project(50675226) supported by the National Natural Science Foundation of China Project(DYXM-115-04-02-01) supported by the Eleventh Five-Year Plan of China
文摘In order to validate the simulation model and develop heave compensation control strategy,heave compensation model tests were performed.The model test installation includes themining ship motion simulator,the heave compensation system,the lifting pipe simulator,the buffer simulator and the water pool.The tests ofmining ship motion simulator show that it is able to perform under the predetermined attitude path smoothly and can meet the requirements of themining ship motions.The heave compensation effect is more than 60% under random wave and the goal is set to be 50%.The model test results indicate that this heave compensation system is effective and feasible.
基金Project(DY105-03-01-10) supported by China Ocean Mineral Resources Research and Development Association Project (1343-75221) supported by Central South University
文摘A new sampling method of deepsea microplankton with function of in-situ concentrated sampling and gastight sampling was proposed. In-situ concentrated sampling technique was realized as follows: a microplankton membrane was used as filtration membrane, and a deepsea pump was used to pump seawater; the microplankton was captured and the density of microplankton was increased when seawater flow through the filtration membrane. Gastight sampling technique was realized as follows: a precharged accumulator was used as pressure compensator. During the process of lifting the sampler, the accumulator compensated the pressure drop continuously. The laboratory experimental results show that with in-situ concentrated sampling technique, in-situ concentrated sampling can be realized and the maximum concentration ratio reaches up to 500. With pressure compensation technique based on accumulator, gastight sampling can be realized. When sampling at 6 km and the precharge pressure of accumulator is 18 MPa, pressure drop of the sample is less than 2% compared with its original pressure. Deepsea experiment (at 1.9 km) results show that the sampler can realize in-situ concentrated sampling and gastight sampling.
基金Project supported by Scientific and Technological Project of CNOOC(China)Limited“Study on Key Drilling and Completion Technologies for Deepwater Development Well”(No.:CNOOC-KJ 135 ZDXM 05 LTD 01 SHENHAI 2016).
文摘In order to find an economic and effective water control method for horizontal wells in deep sea bottom-water gas reservoirs,we prepared modified coated gravel.Based on this,wear resistance,temperature resistance and water plugging capacity(WPC)tests were carried out on the coated gravel.Then,experiments were carried out using the 3D simulation device for the development of large-scale bottom-water gas reservoirs to compare the development effects of horizontal wells packed with conventional gravel and coated gravel in deepsea bottom-water gas reservoirs.And the following research results were obtained.First,the upper limit of temperature resistance of the gravel coating is 240℃ and the gravel packing speed can reach 4.48 m/s,which is 8 times the average flow velocity of gravel packing in actual open hole sections.Second,as the permeability of the coated gravel packing layer increases,its WPC gets weak.When the permeability is lower than 1500 mD and the displacement pressure difference is lower than 0.6 MPa,the WPC of the coated gravel packing layer is between 0.17 and 0.68.Third,the coated gravel layer functions as gas permeability and water plugging,so the horizontal well technology with coated gravel packing can reduce the flow capacity of water phase breaking into the dominant flow passage,so as to delay the rise of water production of gas well and prolong the gas production time.In this way,the gas recovery factor of bottom-water gas reservoir can be increased effectively.In conclusion,this technology has the function of spontaneous selective water plugging,i.e.,“water plugging in case of water and gas permeability in case of gas”,and its technical and economic advantages are remarkable,which can provide a new idea for the water-control development of deepsea bottom-water gas reservoirs.
