The well head system that is used for geothermal tertiary system sandstone recharge
Technical field
Geothermal energy resources of the present invention are develop and useedd engineering, are specifically related to the recharging technique of geothermal well.
Background technology
At present, exploitation and utilization of geotherm resources has formed a comparatively ripe industry, particularly geothermal heating and the utilization of water resource, has greatly spurred the development of related industry.The exploitation target zone of geothermal energy resources mainly concentrates on mist fan mountain group and the hot reservoir of the 3rd sandstone that is.But because the characteristic of the hot reservoir of sandstone rock stratum, recharge in the process because the mass transfer between forming to the dissolving of unsaturated mineral under the fixed temperature and secondary mineral, and the dissolution precipitation of temperature rising mineral, make and in the hot reservoir of sandstone recharges, run into very big difficulty, the subject matter that is occurred has: 1. floating thing stops up: the suspension content of water is too high can to stop up the hole of porous media owing to inject, thereby the water recharge capacity of well is constantly reduced up to recharging; 2. microorganism is stopped up: injecting microorganism water or local may form biomembrane in breeding rapidly around water injection well under the suitable condition, and the blocking medium hole reduces the water transmitting ability in water-bearing layer; 3. chemistry stops up: change when injecting coolant-temperature gage, can produce separating out of chemical substance, form chemistry and stop up water in underpass; 4. bubble blocks: when well is gone in water filling, under certain mobility status, may carry a large amount of bubbles secretly in the water, simultaneously the dissolved gas in the water may Yin Wendu, the variation of pressure and discharging.In addition, also may generate gaseous matter because of biochemical reaction.
Summary of the invention
In order to solve the blockage problem of physics, chemistry, gas, the objective of the invention is to adopt the method for sediment outflow, filtration, degasification to propose that a kind of to be used for the 3rd be sandstone inverted well port system.
Below in conjunction with accompanying drawing technology contents of the present invention is narrated.The well head system that is used for geothermal tertiary system sandstone recharge mainly has desander 1, filter 2, recharges pump 3, exhaust tank 4, valve 5.Filter 2 comprises coarse filter and smart coarse filter.Desander 1 is installed in the production wellhead place, and desander mainly leaches fine sand in the hot reservoir of sandstone.Constitute thick filter for molten group by several coarse filters 2-1 with parallel way, also constitute thick filter for molten group with parallel way by several fine filters 2-2.Coarse filter (group) 2-1 and fine filter (group) 2-2 serial connection, desander 1 is connected in series with the coarse filter group.The underground heat current are tangentially imported by desander 1 cylindrical shell side, and on the counter steer, the cylindrical shell central authorities that flow through entered filter 2 through drainpipe after high speed rotated into cone end in the desander cylindrical shell.This process can effectively prevent from the sand grains in the sandstone formation brought into recharges filtration system, thereby alleviates the work load of filter 2.Because the amount of recharging is with adopting quantitative changeization, for the ease of installing, unpicking and washing and change filtrate, screen material is wanted heatproof and withstand voltage.Filter 2 is worked with a plurality of split parallel waies, in the import and export of coarse filter 2-1, fine filter 2-2 the maintenance valve is housed all.In case equipment breaks down or when changing filtrate, can not influence and recharge.For reused filtrate, in backwash process, the clean water of must use having filtered.When fluid was flowed through filter 2, flow velocity reduced, and pressure also changes to some extent, and former unsaturated portion gas may discharge, and therefore also automatic exhaust valve will be set on all filter 2 tops.Coarse filter group 2-1 and fine filter group 2-2 that the present invention adopts two-stage to constitute with parallel way, again with recharge pump 3, exhaust tank 4 composes in series recharge system.After injection water after filtering entered exhaust filling 4, because caliber changes, flow velocity reduced, and can further discharge by forced into solution gas, and the automatic exhaust valve on exhaust tank 4 is emitted.The back of exhaust tank 4 is provided with different branches and recharges pipeline, is made up of valve 5-2, valve 5-3 and recharges major trunk roads.Valve 5-4 and the two ends that are parallel to valve 5-2, valve 5-3 after valve 5-5 is connected in series; Valve 5-1 and the two ends that are parallel to valve 5-2, valve 5-3 after valve 5-6 is connected in series.Floss hole is located between valve 5-1 and the valve 5-6.Wherein the branch road of being made up of valve 5-4 and valve 5-5 is mainly used in the installation automatic monitoring system, so that pressure, the amount of recharging, temperature and inverted well water level are recharged in monitoring automatically, understands the dynamic change of the process of recharging at any time.Valve 5-1 is mainly used in relict sediment or anvil cinder in the flushing pipe to the floss hole branch road.Among the present invention, desander 1 adopts the spiral-flow type desander; The filter core of coarse filter 2-1, fine filter 2-2 adopts the polyethylene sintering processing to make; Recharge pump 3 and recharge pump for pressurization; Exhaust tank 4 is the forced action type exhaust tank.
Description of drawings
Accompanying drawing is a plant system drawing of the present invention.
Wherein: desander-1; Coarse filter 2-1; Fine filter 2-2; Recharge pump-3; Exhaust tank-4; Valve-5.
The specific embodiment
Below the present invention is described further by drawings and Examples.
It is that sandstone recharges that China just begins to pay close attention to the 3rd at early eighties, and tests at geothermal wells such as Tanggu, huge ports, but because unresolved blockage problem, recharge rate in time can be more and more lower, and recharge rate only reaches about 20-30%, have in addition can't recharge again.By the enforcement of the present invention in the Tianjin Dongli District China hot demonstration project in safe agriculture field, the amount of adopting is 60t/h, and the amount of recharging is 50t/h, and recharge rate can reach more than 80%.Owing to may have particle diameter bigger metal slag particle or sediment in the recovery well pipeline, filter process adopts the filter core of same precision can add the big filter load, increases operating cost.Therefore for present embodiment, geothermal fluid at first enters the coarse filter group 2-1 that the first order is composed in parallel by three filters, and filtration yield is 15-20t/h; The coarse filtration precision is 50-80 μ m, and material for core is third generation polyethylene sintered filter core or filter bag.After one-level was filtered, the particle of greater particle size was filtered, and has guaranteed water quality substantially.Then geothermal fluid enters the fine filter group 2-2 that the second level is composed in parallel by three filters through pipeline, and filtering accuracy is 3-5 μ m, and material for core is a third generation polyethylene sintered filter core.Because the filtering accuracy height, the suspension in the water, bacterium, chemistry are separated out the molecule of crystallization etc. and can be filtered.In design, the filtrate in the filter can adopt disposable and the two kinds of filtrates that repeatedly recoil, and the filtrate in the filter 2 has adopted disposable recoil filtrate in the present embodiment.Of the present invention recharging is divided into dual mode substantially, and one for recharging naturally, and the 2nd, pressurization is recharged.Naturally recharge is that pressure and gravity by system self recharges.The shunt valve of recharge water this moment in recharging pump 3 carries out nature and recharges.Can adopt pressurization to recharge pump 3 in the time of can not normally implementing when recharging naturally.For gas contained in the GEOTHERMAL WATER is fully discharged, to prevent in the process of recharging, forming bubble, cause gas stifled, therefore work as GEOTHERMAL WATER and enter before the inverted well, be introduced into exhaust tank 4.Between valve 5-2 and 5-3, water meter is housed, between valve 5-4 and 5-5, electromagnetic flowmeter is housed, automatically the monitoring amount of recharging.Initial stage, for relict sediment or anvil cinder in the abundant flushing pipe, it was underground to prevent that residue from pouring into, and stops up the subsurface flow passage when recharging.Open valve 5-1 branch road is closed other valve simultaneously, and the water that will have residue discharges by lateral, is fully rinsed well until pipeline.When recharge rate descended, inverted well need carry out Hui Yang, and at this moment Open valve 5-6 closes other valve simultaneously, and the waste water of Hui Yang is prolonged discharge of pipes.The pressure of paying close attention to simultaneously between the two-stage filter changes, because change to judge whether filtrate needs to clean and change in the filter by pressure.
The characteristics that the present invention has and beneficial effect: can prevent the gas that produced by reasons such as physics, microorganism, chemistry Resistance, it is about more than 30% to improve recharge rate, can realize that to the 3rd be the target of geothermal energy resources reasonable development and protection. System Installation and debugging are convenient, safeguard that simply monitoring means is complete. Although this is practical for sandstone formation, but still is applicable to The rock behavio(u)r on other stratum is such as basement rock etc.