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Method for cutting slot-like key seats in producing formation of producing or pumping wellsMethod for cutting slot-like key seats in producing formation of producing or pumping wells description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070187100, Method for cutting slot-like key seats in producing formation of producing or pumping wells. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0001]This invention relates to the fields of mining, specifically oil, gas and hydro-geological industries and is intended for relief of tangential stress which originates in well side areas of producing formation from underground pressure by means of cutting vertical slot-shaped seats in well side zones of producing formation. BACKGROUND OF THE INVENTION [0002]Cutting of slot-shaped seats which starts from the outer well wall and is directed deep down the rock is known as one of the most effective methods of enhancement of efficiency (productivity) of producing or pumping well by means of stress relief in the well side area of producing formation. The seat size depends on the characteristics of producing formation in the well side area, normally the seat width (slot opening) is 0,5-1 of well diameter, the depth (distance from the well edge deep into the rock) is 3-4 of well diameter. [0003]Practical cutting of slot-like seats is a quite difficult process. It is performed after construction and long-term exploitation of the well when its capacity considerably goes down. Productivity slowdown is the result of the abutment zone which is formed around the well in the course of exploitation. It essentially reduces rock permeability in the area. To increase well capacity one can decide on pressure relief in the well side area. [0004]By known input data (e.g. according to experimentally measured characteristics of the well and rock samples of the processed producing formation) required minimum dimensions of key seats are determined by the following formula: t = 2 ( P 2 - P 1 ) a ( 1 - .mu. 2 ) E [0005]where [0006]t--width of slot opening, a--depth (distance from the well edge deep into producing formation, P.sub.2--geostatic pressure, P.sub.1--bottom-hole pressure, .mu..sup.2--Poisson's ratio of producing formation, E--deformation module of producing formation (e.g. see Instructions on slot unloading of well side zone, VNIMI, Minugleprom, L, 1987). [0007]Construction of seats is carried out at significant depth in the producing formation area, i.e. distantly through a precut casing pipe and a cement sheath. There is no other path to producing formation which is subject to unloading. [0008]The casing pipe is lowered from the surface to the well bottom in order to preserve the well and to protect it from caving; the cement sheath around the casing pipe ensures isolation of layers, which were uncovered during well boring and prevents from cross-flows and communication between producing formations. [0009]The equipment for construction of a slot-like seat towards the producing formation, that is deep into the well, can be delivered only through the said casing pipe. There is no other way of equipment delivery to the place of seat construction. [0010]Cutting of casing pipe, cement sheath and well side area by hydro-abrasive jet of high pressure is the most commonly used method of slot-like seat construction in the mentioned heavy conditions with remote control. For that, the perforator which is operated from the hydro-abrasive pressure source (e.g. pump-and-compressor equipment with addition of abrasive) is placed on the lower end of the tubing string which is lowered into the casing pipe up to the place of seat construction. The perforator nozzles are directed from within the casing pipe towards the rock. From the well surface where the source of hydro abrasive pressure is mounted up to the place where the cutting nozzle of the perforator is mounted, hydro-abrasive liquid is pumped and piped along the tubing string which passes through the casing pipe. [0011]The depth of seat opening mainly depends on cutting period and characteristics of the casing pipe and the cement sheath (which have to be preliminary cut), as well as on rock characteristics. Naturally, the most important factors which determine cutting depth are parameters of the jetting device (jet pressure and abrasive material). [0012]Thus it becomes clear that when parameters of hydro-abrasive jetting device, rock characteristics as well as those of the casing pipe and cement sheath are known, the rated depth of the slot-like seat is provided with the duration of perforation. [0013]Examples of methods and devices for slot unloading of well side area of producing formation by hydro-sandblasting method are particularly stated in: Reference book on oil production, M, "Nedra". 1974 International Application PCT/RU93/00101 (WO94/05898 of Mar. 3, 1994). [0014]U.S. application Ser. No. 10/957,871 of Apr. 10, 2004. Author's certificates USSR #14645551, published on Aug. 11, 1988; #1167925 of 1983, published on Mar. 15, 1988. Russian Federation patent #2074957; published on Oct. 3, 1997. [0015]In these examples the slot-like key seat is formed by smooth and continuous movement of permanently operating hydro-abrasive perforator (nozzle) inside the casing pipe and along its wall opposite the unloaded producing formation. [0016]Devices which ensure such smooth and continuous movement are put into action by the abrasive jet pressure in the tubing string. The pressure is often put by means of tubing weight, which affects the hydro brake. The hydro brake can be performed, for example, on the cross-flow of viscous fluid between the hydro brake chambers which is controlled by the canal section and flowing fluid viscosity. [0017]Similar structures one can find in the above-mentioned reference bibliography. Continue reading about Method for cutting slot-like key seats in producing formation of producing or pumping wells... Full patent description for Method for cutting slot-like key seats in producing formation of producing or pumping wells Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Method for cutting slot-like key seats in producing formation of producing or pumping wells patent application. Patent Applications in related categories: 20090294127 - Optimized machining process for cutting tubulars downhole - The tubular cutting tool for severing downhole tubulars, the tool having a drive system, a pivoting system, a cutting head, a cutting member, and a lubricant delivery system. Cutting may be accomplished by rotatingly actuating the cutting head with an associated motor and extending the cutting member away from the ... ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Method for cutting slot-like key seats in producing formation of producing or pumping wells or other areas of interest. ### Previous Patent Application: Permeable zone and leak plugging using cross-linking composition comprising delay agent Next Patent Application: Hydraulic fracturing methods using cross-linking composition comprising delay agent Industry Class: Wells ### FreshPatents.com Support Thank you for viewing the Method for cutting slot-like key seats in producing formation of producing or pumping wells patent info. IP-related news and info Results in 0.7855 seconds Other interesting Feshpatents.com categories: Computers: Graphics , I/O , Processors , Dyn. Storage , Static Storage , Printers 174 |
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