CN101701516A

CN101701516A - Staggered automatic-seam-washing sand-controlled sieve tube

Info

Publication number: CN101701516A
Application number: CN200910059836A
Authority: CN
Inventors: 卢渊; 伊向艺; 张哨楠
Original assignee: Chengdu Univeristy of Technology
Current assignee: Chengdu Univeristy of Technology
Priority date: 2009-06-30
Filing date: 2009-06-30
Publication date: 2010-05-05
Anticipated expiration: 2029-06-30
Also published as: CN101701516B

Abstract

The invention belongs to a staggered automatic-seam-washing sand-controlled sieve tube belonging to the field of petroleum engineering, in particular to an underground sand-sieving tool for preventing stratum sand from entering a production passage in the production process of an oil-gas well. The invention relates to a precise fine-seam automatic-washing sand-controlled sieve tube which comprises a basal tube and a strip filter component embedded on the wall of the basal tube and is structurally characterized in that a shallower strip groove is arranged on the outer wall of the basal tube along the axis direction; the filter component is embedded in the strip groove and comprises one or more strip steel sheets which are arranged in parallel and have different rigidities (different cross sections or materials); and strip grooves can be distributed on the basal tube according to a certain rule; and the basal tube after assembling the embedded filter component forms a sand-controlled tube column. A fine seam between adjacent steel sheets of the strip filter component is utilized to filter stratum sand, and when pressure in a well changes, adjacent fine seam wall surfaces are staggered to finish automatic washing.

Description

Staggered automatic-seam-washing sand-controlled sieve tube

Technical field

The invention belongs to the petroleum works field, be used for oil gas well manufacturing process and prevent that reservoir sand from entering the down-hole filter sand instrument of producing passage.

Technical background

The down-hole sand preventing tool that wire-wrapped screen, laser slotted pipe, circumferential weld screen casing etc. utilize the slit to filter is used very general.This class sand screen advantage is a lot, can not prevent to filter the shortcoming that sews the sand plug plug but exist.The way of Xie Jueing was that outer narrow inner width type (as ladder type or Compound Cavity build) is made in the filtration slit in the past, to reach self-cleaning purpose.This self-cleaning essence is self-cleaning in the seam, prevents that promptly the reservoir sand of irregular form is blocked in the seam.But can't self-cleaningly be blocked in the diameter and the close formation particle of filtration gap width of sealing.This is that slit class sand-screen is used the not long main cause of period of validity.The present invention can also make two walls that constitute the filtration slit produce the relative changing of the relative positions with the borehole pressure fluctuation except that keeping above-mentioned self-cleaning function, and the formation particle that is stuck in sealing is come off, and reaches from washing purpose.

Summary of the invention

The present invention is that a kind of accurate slit is from washing sand control screen.It is made up of parent tube (available oil pipe or sleeve pipe are made parent tube) and the bar shaped filter assemblies that is embedded on the parent tube wall.Its architectural feature is: axis direction is offered more shallow strip groove in parent tube outer wall upper edge, and profile such as keyway, bottom land have the duct of leading in the pipe; Embed filter assemblies in the strip groove.Filter assemblies is arranged in parallel by many and the strip steel disc of different stiffness (varying cross-section or unlike material) is formed.The long strip type groove can be distributed on the parent tube according to certain rules, just constitutes sand control pipe through the parent tube that embeds after the filter assemblies assembling is finished.The strip filter assemblies utilizes the micro chink between the adjacent steel disc that reservoir sand is filtered.Utilizing the borehole pressure variation to make filter slotted wall face that the relative changing of the relative positions take place finishes from washing.

Operating principle of the present invention is as follows:

When identical, the amount of deflection of generation is different to the long strip type elastic steel sheet of different stiffness stressed.Promptly when being subjected to identical external force, the relative changing of the relative positions can take place in the bar shaped steel disc of two originally concordant different stiffness.

In the oil-gas mining process, borehole pressure can fluctuate with production technology and working system variation.It is that oil production method causes that this pressure changes majority, causes the borehole pressure fluctuation as electric submersible pump, screw pump when the frequency conversion, or oil pumper pumps borehole pressure is periodically fluctuateed etc.In addition, the pressure that also has borehole pressure fluctuation that the open and close well operations causes etc. all will cause acting on the filter sand tubing string fluctuates.Because filter element is made of the long strip type elastic steel sheet of different stiffness, the pressure oscillation meeting in the well makes the wall that constitutes the filtration slit produce the relative changing of the relative positions with pressure oscillation.Utilize the relative changing of the relative positions of filter slotted wall face, the reservoir sand that is stuck in sealing is come off, thereby finish washing certainly on the essential meaning, promptly the filter sand unit has from washing function.

Description of drawings

Fig. 1 is a monolithic type filter assemblies sand screen structure chart, and four figure are respectively sectional drawing, A-A sectional view, B position partial enlarged drawing and the C position partial enlarged drawing that constitutes the filter sand tubing string.

Fig. 2 is a multi-disc type filter assemblies sand screen structure chart, and four figure are respectively sectional drawing, A-A sectional view, B position partial enlarged drawing and the C position partial enlarged drawing that constitutes the filter sand tubing string.

The specific embodiment

Below by two specific embodiments the present invention is described in detail:

(1) monolithic type filter assemblies, promptly each filter sand unit has only an elastic steel sheet, utilizes the trough wall surface on steel disc and the tube wall to form two filtration slits, and basic structure is seen Fig. 1.Leave the straight wall groove that parallels to the axis on parent tube, the length of groove generally can be at 50～200mm, and width is at 2～5mm.The degree of depth of groove is generally about 4mm.The depth ratio middle part, two ends of groove is shallow, make that upper surface, steel disc embedding back is concordant substantially with the parent tube external surface, and there is certain space the lower surface apart from groove bottom.Intercommunicating pore in trench bottom is drilled with and manages.The length of steel disc is corresponding with the length and width of groove with width, requires decision with the gap of parent tube groove by sand block.Minimum clearance can reach in the 0.05mm.The stress deformation characteristic of steel disc is by the rerum natura and the reservoir properties decision of crude oil extraction.General viscosity of crude is high more, requires rigidity big more.The steel disc two ends are welded on the parent tube at groove two ends.

When gas stream enters sand screen by pit shaft by the slit, need pressure differential.This pressure differential also acts on parent tube and the steel disc simultaneously.Because parent tube intensity height does not deform substantially.And steel disc will bend in pipe under this pressure effect, forms the relative changing of the relative positions of steel disc with respect to the parent tube cell wall thus.Steel disc finally is subjected to the restriction of groove bottom to internal strain.Because destructive distortion can not take place in the supporting role of groove bottom, steel disc under the external pressure effect.Thisly produce result that sag changes with pressure oscillation and just produced and wash effect certainly.

(2) multi-disc type filter assemblies, promptly each filter sand unit is made up of many elastic steel sheets, utilizes the slit between the steel disc to form the filter seam, and basic structure is seen Fig. 2.Leave the straight wall groove that parallels to the axis on parent tube, the length of groove generally can be at 50～100mm, and width is at 8～15mm.The degree of depth of groove is generally 5mm.Intercommunicating pore in trench bottom is drilled with and manages.Filter element length behind the composition is corresponding with the length and width of groove with overall width.Minimum clearance in the filter element between steel disc can reach in the 0.05mm.The steel disc of different stiffness is spaced.The steel disc number should be odd number (being advisable for 3 or 5), and amount of deflection difference when guaranteeing that adjacent steel disc deforms under external force is to finish from washing.The steel disc two ends are fixed with pedestal earlier, so that guarantee the gap between the steel disc.Pedestal is welded on the parent tube at groove two ends during assembling.

Claims

1. an accurate slit that is applied to the petroleum works field is from washing sand control screen.Tubing string is made up of parent tube (available oil pipe or sleeve pipe are made parent tube) and the bar shaped filter assemblies that is embedded on the parent tube wall.Its architectural feature is: axis direction is offered more shallow strip groove in parent tube outer wall upper edge, and profile such as keyway embed filter assemblies in the strip groove.Filter assemblies is made up of the strip steel disc of many different stiffness that are arranged in parallel (varying cross-section or unlike material).The long strip type hole slot can be distributed on the parent tube according to certain rules, just constitutes sand control pipe through the parent tube that embeds after the filter assemblies assembling is finished.The strip filter assemblies utilizes the micro chink between the adjacent bar steel disc that reservoir sand is filtered.Utilize borehole pressure to change and make filter slotted wall face the relative changing of the relative positions take place and realize that oneself washes.

2. utilization according to claim 1 constitutes the relative changing of the relative positions of wall of micro chink and finishes from washing and self-cleaning filter sand modular construction;

3. according to claim 1ly utilize borehole pressure to change the elastomeric element deflection is changed and cause the relative changing of the relative positions of adjacent filter slotted wall face to be finished from the filter sand structure of washing;

4. the filter sand assembly of many micro chink structures that filter assemblies according to claim 1 is made up of the strip steel disc of the different stiffness that are arranged in parallel (varying cross-section or unlike material).