CN101144389A - Gridding type layer-through drilling pore group permeability-increasing gas pumping method - Google Patents

Abstract

The invention relates to a grid type across-seam drilling hole multi-hole anti reflection gas extraction method. Grid type across-seam drilling hole positions are set in the coal seal area where the gas extraction is performed; the grid type across-seam drilling hole positions set are drilled with holes one by one, forming a hole group; when the hole drilling construction enters the coal seam, hole punching is performed by using high pressure water with 5 to10MPa water pressure and 10 m<SUP>3</SUP>/h flow quantity to cause the drilling hole to spray holes, to form a crack between the coal seam hole and the hole, and to increase the coal seam permeability; after the drilling hole is penetrated through the coal seam of 0.5 m, the drilling hole is escaped from a drilling rod, and is inserted into a sealing tube for hole sealing. The drilling hole is connected with an extraction tube mesh through a sealing tube, a collecting tube, a gas collection tank and a branch tube, to perform gas extraction for the coal seam. The method leads the coal seam pre-drainage efficiency to be improved to over 40 percent from the original 20 percent, realizes safe, efficient and even extraction for the sole low permeability outburst coal seam, a high gas outburst dangerous coal seam is changed to be a low gas non-outburst dangerous coal seam, and the invention has a wide practicability.

Description

The gridding type layer-through drilling pore group permeability-increasing gas pumping method

Technical field

The present invention relates to the gridding type layer-through drilling pore group permeability-increasing gas pumping method, be particularly useful for the single low ventilative projecting coal bed zonal gas pumping in colliery.

Background technology

Along with the increase of mining depth, coal-bed gas pressure and content increase, and ature of coal is soft, and gas permeability of coal seam is low, and coal-bed gas is difficult for adopting preceding extraction, and coal and gas outburst risk are on the rise, and China has become the most serious outstanding in the world producing coal country.In order before adopting, to eliminate the outburst hazard in coal seam, make high gas layer be converted into the present low gas coal seam, need to adopt regional gas pumping method.Eighties of last century the seventies, China has once tested the base plate tunnel layer-through drilling successfully in colliery, the self-sufficient and strategically located region and Zhongliangshan Coal Mine and has taken out coal-bed gas in advance and prevent coal and the outstanding regional gas pumping method of gas, and obtained application in the outstanding serious mining area of part, obtained effect.But because gas permeability of coal seam is low, cause this method extraction time long, the gas pumping rate is low, can not satisfy the needs that the Modern coal mines high-efficiency intensifying is produced.

The projecting coal bed anti-reflection measure of adopting of single low-permeable at present mainly contains deep hole presplit blasting, hydraulic slotted liner technique etc., these methods are local anti-reflection measure, directly in projecting coal bed, implement, lack enough safety curtains, there is certain potential safety hazard, and antireflective effect is limited, can not satisfy the needs that large tracts of land gas is taken out in advance.

Summary of the invention

The objective of the invention is at the problem of depositing in the prior art, a kind of gridding type layer-through drilling pore group permeability-increasing gas pumping method of safe, efficient, even extraction coal-bed gas is provided.

Gridding type layer-through drilling pore group permeability-increasing gas pumping method of the present invention:

A. set the gridding type layer-through drilling position in needs carry out the zone, coal seam of gas pumping, bore diameter is 90mm, is as the criterion with thick face in the coal seam, and the spacing of wells is 5～8m;

B. implement boring one by one to setting the gridding type layer-through drilling position, form Kong Qun;

C. after drilling construction enters the coal seam, be that 5～10MPa, flow are 10m with hydraulic pressure ³The boring spray orifice is induced in the water under high pressure punching of/h, makes between hole, coal seam and the hole and forms the crack, to increase gas permeability of coal seam;

D. after boring penetrates coal seam 0.5m, withdraw from drilling rod, insert hole sealing tube and implement sealing of hole, sealed borehole length is not less than 10m, and hole sealing tube length is not less than 12m, diameter 40mm;

E. by hole sealing tube, collecting pipe, plenum chamber and arm boring is connected into the extraction pipe network, gas pumping is carried out in the coal seam, the drilling orifice negative pressure is not less than 25KPa, and the hole pumping and mining time was not less than 5 months.

Pore group permeability-increasing gas pumping method of the present invention, fully the projecting coal bed blowing characteristic of utilization is utilized high-pressure hydraulic to induce and is improved the spray orifice effect, forms the bigger loosening nip that unloads around boring, and between Kong Qun, form the conducting crack, realize zonal antireflective effect.The method is carried out operation under certain thickness security protection rock pillar shielding, can significantly improve gas permeability of coal seam, on average improves about 100 times.To be difficult to the extraction coal seam and change easy extraction coal seam into, single hole gas pumping amount on average can reach 0.0389m ³/ min, gas pumping concentration can reach 40～60%; Can also significantly improve the pre-pumping rate of coal-bed gas in the group's scope of hole, the pre-pumping rate in coal seam is brought up to more than 40% by original 20%, can not have projecting coal bed by the single low projecting coal bed present low gas that changes into of high gas of breathing freely; The driving mode of heading changes comprehensive mechanized driving into by original big gun pick, and the monthly average driving speed can be brought up to more than the 150m by 50 original～60m.Realize safe, efficient, the even extraction of the projecting coal bed gas of single low-permeable, uprising gas outburst danger coal seam is that present low gas does not have the outburst danger coal seam, has practicality widely

The specific embodiment

Gridding type layer-through drilling pore group permeability-increasing gas pumping method of the present invention: according to coal seam and gas bearing situation, utilization field trial and theoretical analysis method, optimize and determine the hole swarm parameter, in carrying out the zone, coal seam of gas pumping, needs set the gridding type layer-through drilling position, bore diameter is 90mm, be as the criterion with thick face in the coal seam, the spacing of wells is 5～8m; Safety is installed leads construction drill behind the spray drilling apparatus, treat to enable when boring penetrates coal seam 0.5m safety and lead the spray drilling apparatus; Under the effect of high-pressure hydraulic, induce the coal seam spray orifice, form crack between the hole, increase gas permeability of coal seam; Water under high pressure hydraulic pressure is that 5～10MPa, flow are 10m ³/ h, spray orifice coal amount 1～5t; Sealing of hole immediately after drilling construction finishes, sealed borehole length is not less than 10m, hole sealing tube length 12m, diameter 40mm.Incorporate the extraction pipe network into by collecting pipe, plenum chamber and arm behind the sealing of hole and in time carry out gas pumping, the drilling orifice negative pressure is not less than 25KPa, and on average finding time in advance is not less than 5 months.All the other borings are constructed according to above-mentioned steps in the Kong Qun; After boring group construction is finished, link up, the gas permeability of coal body in the group's scope of hole is improved by crack between the hole; Kong Qun is not less than 5 months extraction, can makes the regional outburst danger of eliminating in coal seam in the group's scope of hole, effectively reduce coal seam gas-bearing capacity, pre-pumping rate can reach more than 40%.

Claims (1)

1. gridding type layer-through drilling pore group permeability-increasing gas pumping method is characterized in that:

A. set the gridding type layer-through drilling position in needs carry out the zone, coal seam of gas pumping, bore diameter is 90mm, is as the criterion with thick face in the coal seam, and the spacing of wells is 5～8m;

B. implement boring one by one to setting the gridding type layer-through drilling position, form Kong Qun;

C. after drilling construction enters the coal seam, be that 5～10MPa, flow are 10m with hydraulic pressure ³The boring spray orifice is induced in the water under high pressure punching of/h, makes between hole, coal seam and the hole and forms the crack, to increase gas permeability of coal seam;

D. after boring penetrates coal seam 0.5m, withdraw from drilling rod, insert hole sealing tube and implement sealing of hole, sealed borehole length is not less than 10m, and hole sealing tube length is not less than 12m, diameter 40mm;

E. by hole sealing tube, collecting pipe, plenum chamber and arm boring is connected into the extraction pipe network, gas pumping is carried out in the coal seam, the drilling orifice negative pressure is not less than 25KPa, and the hole pumping and mining time was not less than 5 months.