CN101818620B - Mining method for maximum reservoir contact well - Google Patents

Abstract

The invention provides a mining method for the maximum reservoir contact (MRC) well, wherein the well structure comprises straight wells, horizontal wells, high-inclination horizontal wells and herringbone wells; the straight wells are communicated with the high-inclination horizontal wells and the herringbone wells; the high-inclination horizontal wells run through cracks indifferent layers; a plurality of high-inclination horizontal wells and horizontal wells, which are in layered arrangement, are both arranged in massive or thick layer-typed reservoirs, and multiple rows of horizontal wells or high-inclination horizontal wells are arranged in each layer, well planes of the horizontal wells or high-inclination horizontal wells in adjacent rows are in parallel and staggered arrangement, and the horizontal wells or high-inclination horizontal wells in adjacent layers are in vertical and staggered arrangement; a plurality of herringbone wells are arranged in the bottom layer of reservoirs, and also arranged in rows on the plane, and planes of the wells in adjacent rows are in parallel and staggered arrangement and are all on the same plane; and a plurality of high-inclination horizontal wells and herringbone wells form a vertical well network structure of planar crossing and vertical lamination and crossing. The technical scheme solves the problems of common low well yield, quick decrease and undesirable exploitation effect existing in the prior art due to the fact that most reservoirs are exploited by straight wells.

Description

A kind of maximum oil reservoir contact well type exploitation method

Technical field

The invention belongs to the oil reservoir development field, relate to the exploitation of bulk or thick-layer shape oil reservoir, especially a kind of maximum oil reservoir contact (MRC (Maximum Reservoir Contact)) well type United Technologies that are applicable to the massive oil pool exploitation are specially a kind of maximum oil reservoir contact (MRC) well type exploitation method.

Background technology

Straight well is widely used in all kinds of oil reservoirs as the main well type of oil reservoir development, and it has understanding and control reservoir, reduce to dispose risk, and drilling period is short, the advantage of easy operating and adjustment.Can be used for simultaneously the water filling early test and return oil recovery on the later stage.Early stage exploration phase of oil reservoir and reservoir evaluation stage are all adopted the straight well exploitation.Well spacing is mainly considered plane well pattern design, such as square or triangular pattern.These present straight well areal well patterns are more suitable for the thin layer oil reservoir, belong to two-dimentional well pattern structure design.When yet this well pattern designed for the massive oil pool multiple-zone production, have following defective: compare with horizontal well patterns, the oil reservoir longitudinal difference caused producing degree of reservoir low, and required well number is many; Initial potential of oil-well is low and production decline is fast; It is slow that oil reservoir is built product speed; Low and the flood effectiveness of rate of oil production is poor etc.Also exist the crack to bore that encountering rate is low, hard problem is selected in the well site for fractured reservoir.The Niuxintuo buried hill oil pool of Liaohe Oil Field adopts the straight well exploitation, the development scheme of straight well bottom water injection.Choose degree of depth layer position water filling under Production Wells well section, because the straight well finishing drilling degree of depth is different, the reservoir development degree is uneven simultaneously, can't form unified oil-water interfaces, causes that nearly well water floods, well water filling far away is ineffective.

Horizontal well technology has become one of main focus of World Oil Industry development, has been applied at present water fault block oil reservoir at the bottom of the limit, fractured reservoirs, self-contained high water-cut reservoir, thin interbed oil reservoir, glutenite oil reservoir, low-permeability oil deposit etc.Be widely used in that old filed is taped the latent power, the newly developed area Productivity Construction.In moisture second and third time of old filed oil recovery stage of height, excavate potentiality of remaining oil, and economical and effective develops thin poor reservoir, improve the recovery ratio aspect and play a part very important.Utilize the horizontal wells oil sheet, can improve reserves producing status, percolation ability and development effectiveness than straight well.Along with the development of drilling technology especially geosteering, horizontal well design is shifted to oil sheet, thin interbed by thick-layer.In the situation less and less of thick oil pay horizontal well screening position, a slice frontier has been opened in the success of oil sheet horizontal well.The breakthrough of super horizontal well drilling technique in thin reservoir becomes a reality the exploitation of thin sand oil reservoir.

Fish-bone well drilling technology grows up on the horizontal well drilling technology basis, refers to the left and right sides or one-sided a kind of drilling well new technology of creeping into again two or more branch well holes at the horizontal well horizontal segment.The Multilateral Wells technique functions comes from the 1950's, and first Multilateral Wells starts from Russia and the Ukraine area of the former Soviet Union, and the second batch Multilateral Wells was spudded in the Siberia of the former Soviet Union in nineteen sixty-eight.Until after nineteen ninety-five, along with the development of horizontal well completion technology and popularizing of 3-D seismics technology, fish-bone well technology has just obtained rapidly development.This technology is compared with the conventional levels well, and the fish-bone well helps to formulate rational development plan, with lower cost effective exploitation multilayered reservoir oil reservoir, and out-of-shape oil reservoir, hypotonic, viscous crude, thin layer, exhausted oil reservoir and Fractured Reservoir etc.

But, because well type optimal design only is confined to the single type research in planar space in same oil reservoir at present, the space optimization of many wells type and arrangement mode there is no precedent and can seek, straight well, single horizontal well or fish-bone well have been difficult to solve the practical problem of massive oil pool exploitation, how to use the spatial of many wells type coupling and three-dimensional well pattern structure, rationally effectively the exploitation oil reservoir needs to be resolved hurrily.

Summary of the invention

For overcoming above shortcoming, solve the practical problem that the exploitation of thick-layer or massive oil pool exists, in existing literature research only is the well pattern form of straight well and horizontal well combination, and lack on the Research foundation of being disposed by the MRC well development, this patent has proposed the technology of a kind of bulk or the design of thick-layer shape oil reservoir well structure, this technology contacts the theory of (MRC (Maximum Reservoir Contact)) based on maximum oil reservoir, the design that maximum oil reservoir contact (MRC) well type of proposition in same oil reservoir developed jointly, and to comprising the relative position of MRC well type, horizontal section length, fish-bone divides number, the fish-bone branch length, the parameters such as fish-bone branched angulation are further studied.

According to technical scheme of the present invention, a kind of maximum oil reservoir contact (MRC) well type exploitation method is provided, it uses maximum oil reservoir contact (MRC) well structure, this maximum oil reservoir contact (MRC) well structure is except straight well, comprise horizontal well, high-inclination horizontal well and fish-bone well, straight well is communicated with high-inclination horizontal well and fish-bone well, high-inclination horizontal well drills different intervals crack, the high-inclination horizontal well of many mouthfuls of layered arrangement, horizontal well all is arranged on the inside of bulk or thick-layer shape oil reservoir, and comprise many drainings horizontal well or high-inclination horizontal well in every layer of well, horizontal well among the adjacent row or high-inclination horizontal well well plane parallel interlaced arrangement, the horizontal well in the adjacent layer or the vertical interlaced arrangement of high-inclination horizontal well well; Many mouthfuls of fish-bone wells are distributed in the bottom oil reservoir and planar become to arrange shapes more and distribute, each the well plane parallel interlaced arrangement among the adjacent row, and be in the same level; Many mouthfuls of high-inclination horizontal wells and fish-bone well consist of that heave in the plane, vertical stacked staggered three-dimensional well pattern structure; Wherein, adopt less than the injector producer distance of water injection of horizontal well and be the fish-bone well of planar water filling, described fish-bone well is distributed in the oil reservoir bottom, and is in the same level, every mouthful of fish-bone well to divide a number be 2～5; Each branch length of fish-bone well is identical or different, and each branch length is 150 meters～400 meters; Angle between the fish-bone branch of fish-bone well and the fish-bone well main pipe is for being 10 °～50 °;

Described maximum oil reservoir contact (MRC) well type exploitation method may further comprise the steps:

(1) early stage at oil reservoir development, for reducing development risk, oil reservoir adopts the straight well exploitation to be used for understanding and control oil reservoir; Well spacing mainly considers to belong to the plane well pattern design of two-dimentional well pattern structure design; Straight well is used for simultaneously the water filling early test and returns oil recovery on the later stage;

(2) oil reservoir enters the natural energy development phase, adopts horizontal well, high-inclination horizontal well to develop in the oil reservoir main body section, is used for improving crack brill encountering rate and oil reservoir and bores chance thickness, increases producing degree of reservoir and oil well output; Weakened planes contradiction, overcome interlayer contradiction, improve rate of oil production and recovery ratio;

(3) in the energy supplement stage, oil reservoir adopts the fish-bone well in the oil reservoir bottom, does the exploitation of water injection well type; The fish-bone well can further improve on the one hand the crack and bore encountering rate, and oil well output further improves; Second aspect is increased to the wire water filling of horizontal well from the spot flooding of straight well, further expand the pattern water flooding of fish-bone well to, increases the water drive swept volume, improves waterflood injection rate and water injection intensity; The third aspect, because water injection intensity strengthens, reservoir thermal crack(ing effect strengthens, thereby improves flood effectiveness.

Preferably, many mouthfuls of fish-bone wells are arranged in the oil reservoir bottom, minute number of every mouthful of fish-bone well is 3; Each branch length is 168 meters or 210 meters or 280 meters or 400 meters; Branch's angle can be 15 ° or 25 ° or 35 ° or 45 °.

Use technical solutions according to the invention, solved straight well areal well pattern exploitation in the prior art, longitudinal difference causes producing degree of reservoir low, and required well number is many; Individual layer horizontal wells oil reservoir, the oil and gas reserves development degree is low; Straight well or the water filling of individual layer horizontal well patterns, the problem that the water drive sweep efficiency is low.

Description of drawings

Fig. 1 is varying level segment length's day produce oil and moisture content correlation curve schematic diagram;

Fig. 2 is the Fishbone well type structure schematic diagram;

Fig. 3 is the oil reservoir ultimate recovery correlation curve of the different branch's angles of fish-bone well and horizontal well;

Fig. 4 is the oil reservoir ultimate recovery correlation curve of the different minute numbers of fish-bone well and horizontal well;

Fig. 5 is the oil reservoir ultimate recovery correlation curve of the different branch length of fish-bone well and horizontal well.

The specific embodiment

Below in conjunction with accompanying drawing, to being elaborated according to maximum oil reservoir contact (MRC) well type exploitation method of the present invention and well structure.

1, maximum oil reservoir contact (MRC) well type exploitation method

Realize by the following technical solutions, it is optimized based on the combination of multiple well type and the well type of different development phases, mainly may further comprise the steps:

(1) early stage at oil reservoir development, for reducing development risk, oil reservoir adopts the straight well exploitation to be used for understanding and control oil reservoir; Well spacing mainly considers to belong to the plane well pattern design of two-dimentional well pattern structure design; Straight well is used for simultaneously the water filling early test and returns oil recovery on the later stage;

(2) oil reservoir enters the natural energy development phase, adopts horizontal well, high-inclination horizontal well to develop in the oil reservoir main body section, is used for improving crack brill encountering rate and oil reservoir and bores chance thickness, increases producing degree of reservoir and oil well output; Weakened planes contradiction, overcome interlayer contradiction, improve rate of oil production and recovery ratio;

(3) in the energy supplement stage, oil reservoir adopts the fish-bone well in the oil reservoir bottom, does the exploitation of water injection well type; The fish-bone well can further improve on the one hand the crack and bore encountering rate, and oil well output further improves; Second aspect is increased to the wire water filling of horizontal well from the spot flooding of straight well, further expand the pattern water flooding of fish-bone well to, increases the water drive swept volume, improves waterflood injection rate and water injection intensity; The third aspect, because water injection intensity strengthens, reservoir thermal crack(ing effect strengthens, thereby improves flood effectiveness

Wherein, in the whole well pattern of implementing maximum oil reservoir contact (MRC) well type exploitation method, straight well is communicated with high-inclination horizontal well and fish-bone well, high-inclination horizontal well drills different intervals crack, the high-inclination horizontal well of many mouthfuls of layered arrangement, horizontal well all are arranged on the inside of bulk or thick-layer shape oil reservoir, and comprise many drainings horizontal well or high-inclination horizontal well in every layer of well, horizontal well among the adjacent row or high-inclination horizontal well well plane parallel interlaced arrangement, the horizontal well in the adjacent layer or the vertical interlaced arrangement of high-inclination horizontal well well; Many mouthfuls of fish-bone wells are distributed in the bottom oil reservoir and planar become to arrange shapes more and distribute, each the well plane parallel interlaced arrangement among the adjacent row, and be in the same level; Many mouthfuls of high-inclination horizontal wells and fish-bone well consist of that heave in the plane, vertical stacked staggered three-dimensional well pattern structure.

2. horizontal well and fish-bone well construction parameter optimization

(1) horizontal well horizontal segment reasonable length research

The horizontal segment length of horizontal well chooses respectively 600 meters, 800 meters and 1000 meters, and simulation mining is 30 years during given injectionproduction pressure difference 10 MPa.

Varying level segment length's day produce oil and moisture content correlation curve, as shown in Figure 1.

Among Fig. 1, the oval tab area that represents, 1 represent one group day the produce oil curve, 2 represent one group of plot of water cut.

1000 meters of horizontal segment lengths horizontal well day produce oil apparently higher than 800 meters, 600 meters minimum, moisture content changes that then to be that 600 meters of horizontal segment lengths' horizontal well rises the slowest, secondly is 800 meters, 1000 meters risings are the fastest.The oil reservoir exploitation is after 30 years, and the recovery ratio of 800 meters horizontal wells is higher by 1.4% than 800 meters horizontal wells than the recovery ratio of 600 meters high 8.42%, 1000 meter horizontal wells.Because horizontal segment is longer, be subjected to horizontal segment frictional head loss etc., edge effect more serious, when horizontal segment surpasses 800 meters, continue to increase horizontal segment length, recovery ratio increases not obvious.In three-dimensional flooding pattern situation, increase with horizontal segment, the amplitude that crude output and recovery ratio increase reduces gradually.Consider from flow through oil reservoir and exploitation angle, horizontal section length should strengthen as far as possible; But should be taken into account simultaneously the restriction of drilling cost and technological level, net horizontal section is got about 800 meters and is advisable.

(2) the reasonable branch of fish-bone well angle research

According to actual oil deposit parameter, suppose that it is 3 that the fish-bone well divides number, each branch length is 280 meters.Test different branch's angles, be respectively 15 °, 25 °, 35 ° and 45 °, given injectionproduction pressure difference 10MPa simulation minings 30 years are seen Fishbone well type structure schematic diagram 2.

Among Fig. 2: 1 represents fish-bone well main hole, and length is l, and 2 represent fish-bone well branch, and length is l1, and l2 represents fish-bone well branch spacing; L3 represents the distance of fish-bone well main hole and branch's end points; θ represents the angle of fish-bone well main hole and branch; A represents fish-bone well well array distance,

A represents fish-bone well entrance; B represents fish-bone well end points.

The oil reservoir ultimate recovery correlation curve of the different branches of fish-bone well angle is such as Fig. 3.

Among Fig. 3, the rectangle pillar represents the oil reservoir ultimate recovery of the different branches of fish-bone well angle, and branches angle is respectively 15 °, 25 °, 35 ° and 45 °.

The branch of fish-bone well extends to the producing well below, compares with the horizontal flood well, annotates shape water from line and expands planar water filling to, has increased injection area, and planar water filling is more conducive to form the waterflooding extraction pattern that end hydrologic(al) budget holder is advanced.Branch's angle becomes 15 °～45 °, all can control whole bottom surface, therefore development effectiveness is more or less the same.Development effectiveness is best during 25 ° of branch's angles, secondly is 15 °.Because during 15 ° of angles, the disturbing effect between branch and the trunk section is obvious during than 25 °.When 35 ° of branch's angles and 45 °, the phase mutual interference affects flood effectiveness between the adjacent water injection well, and its development effectiveness is slightly poorer during with 25 ° than 15 ° of branch angles.And branch's angle increases, and drilling technology difficulty and drilling cost also can correspondingly increase, and the reasonable branch of Gu Yugujing angle should be got 15 °～25 °

(3) the fish-bone well rationally divides number and rationally branch length research

Keep the constant situation of branch's overall length:

According to actual oil deposit parameter, fish-bone well branch angle and total branch length are certain, test different minute number and branch length, are respectively 2 branches, 3 branches, 4 branches and 5 branches, given injectionproduction pressure difference 10MPa simulation minings 30 years.

The oil reservoir ultimate recovery correlation curve of the different minute numbers of fish-bone well and horizontal well is such as Fig. 4.

Among Fig. 4, the rectangle pillar represents the oil reservoir ultimate recovery of the different minute numbers of fish-bone well and horizontal well, and a minute number is respectively 2 branches, 3 branches, 4 branches and 5 branches.

The recovery ratio of fish-bone well water filling is better than water injection of horizontal well, because the fish-bone well is planar water filling, and injector producer distance is less than water injection of horizontal well, and producing well can be faster with the oily extraction in the oil reservoir.When between oil reservoir serious heterogeneity, injection-production well, having the hyposmosis band, adopt fish-bone well waterflooding extraction, guarantee development effectiveness.But in the same branches overall length situation, branch is more, and corresponding drilling cost is higher, therefore adopt the fish-bone well water filling of 3 branches.

Keep minute constant situation of number:

Fish-bone well branch angle and minute number are certain, test different branch length, are respectively 168 meters, 210 meters, 280 meters and 400 meters, given injectionproduction pressure difference 10 MPas,simulation mining 30 years.

The oil reservoir ultimate recovery correlation curve of the different branch head of fish-bone well and horizontal well is such as Fig. 5.

Among Fig. 5, the rectangle pillar represents the oil reservoir ultimate recovery of the different branch head of fish-bone well and horizontal well, and branch head is respectively 168 meters, 210 meters, 280 meters and 400 meters.

The recovery ratio of fish-bone well water filling is better than water injection of horizontal well, because the fish-bone well is planar water filling, and injector producer distance is less than water injection of horizontal well, and producing well can be faster with the oily extraction in the oil reservoir.280 meters development effectiveness of fish-bone well branch are best.Because during 280 meters of branch head, fish-bone well water filling branch just extends under the producing well, water injection well can be controlled whole bottom surface; 168 meters and 210 meters of branch head, water injection well control area less; And during 400 meters of branch head, have the phase mutual interference between the branch of adjacent water injection well, also can affect waterflooding development effect.Therefore when adopting the fish-bone well water filling of 3 branches, 280 meters of branch length are advisable.

Industrial applicibility:

Use technical scheme of the present invention, can effectively improve oil well output and oil recovery.

The MRC technology be from the well type preferably to the well Parameters Optimal Design, carried out successful test at the Xinglongtai buried hill oil pool and used.Take metamorphic rock as main, the interspersed Xinglongtai Archaean group buried hill oil pool that is distributed with magmatic rock, buried depth is at-2355～-4500 meters, the oil-containing amplitude surpasses 2000 meters, by many reverse fault clampings of the high angle normal fault in the north and south, have the oil reservoir of complicated inside story structure.In the research, determined minute band property of vertically upper oil reservoir according to lithology and oil reservoir distribution characteristics, pressure and production characteristics etc., in conjunction with the consideration of artificial recharge development scheme, proposed the MRC well pattern in the vertical with the plane on design.For the characteristics of straight well, horizontal well, high-inclination horizontal well and fish-bone well, propose in oil reservoir different development phases, diverse location optimizing well type, to reduce development risk, adapt to development scheme, to obtain the method for peak-production and longer stable production period.And the length of the MRC well horizontal segment after preferred, the branched angulation of fish-bone well, minute number, branch length are studied.76 mouthfuls of MRC test wells disposing wherein have 33 mouthfuls of wells to put into production.After test was gone into operation, the oil reservoir rate of oil production had improved 28 times, 80.5 tons/day of average individual well initial stage daily oil productioies, be 3.0 times of straight well output, wherein the initial production of fish-bone well reaches 97 tons/day, is 3.6 times of straight well output, the expense of drilling well has only increased by 68%, and operating cost has saved 75%.

The more important thing is, the exploration of Xinglongtai buried hill and reservoir evaluation stage are adopted straight well always, have played positive role at aspects such as abundant materials admission means, expansion oil reservoir scope of human knowledge, reduction exploration risks.Yet, along with the intensification to the oil reservoir awareness, for reservoir thickness surpass that 2000 meters, non-homogeneity are strong, the crack is take the high angle seam as main oil reservoir, continues to adopt the straight well exploitation will have following several respects problem:

(1) the well number is many, drill footage large, investment is high.Consider that straight well will adopt fracturing production, the perforation length general control is in 50 meters, and straight well is disposed in the leeway of returning production in the reservation, expectation can be disposed 221 mouthfuls, 2.6 times of MRC well number, corresponding drill footage straight well is 2.1 times (the upper strata straight well does not get into lower floor, to save drilling depth) of MRC well.

(2) single well controlled reserves is low, and straight well on average only has 14.3 ten thousand tons, and the MRC well on average reaches 600,000 tons.

(3) brill encountering rate in crack is low, rate of oil production is low.

Calculate according to theory take the netted seam of middle high angle as main in the crack, buried hill, and when identical fracture spacing, fracture aperture, brill chance equal length oil reservoir, straight well bores the number of meeting the crack and only has 1/3rd of MRC well, and output is also corresponding lower.9 mouthfuls of straight wells of statistics pilot production, average day at initial stage 26.9 tons/day of produce oils, and production declining is fast, drilling period is long, so the oil reservoir rate of oil production is always lower.And the MRC well has improved the crack and has bored encountering rate and core intersection, and crude output is high, average day at initial stage 88.8 tons/day of produce oils.

(4) production decline is fast.There is not primary pneumatic jack in oil reservoir, even exist end water below-4500 meters, natural energy is inadequate, the fast quick depletion of straight well oil production.The average year lapse rate up to 70.2%/year, and only have 1 mouthful of well to occur successively decreasing in 15 mouthfuls of wells that the stability test of MRC well is produced, annual decline rate is 25.4%/year, be much better than straight well.

Use maximum oil reservoir contact (MRC) well type exploitation method and well structure to address the above problem well.And solved straight well areal well pattern exploitation in the prior art, longitudinal difference causes producing degree of reservoir low, and required well number is many; Individual layer horizontal wells oil reservoir, the oil and gas reserves development degree is low; Straight well or the water filling of individual layer horizontal well patterns, the problem that the water drive sweep efficiency is low; Improve oil reservoir rate of oil production and recovery ratio, reduced simultaneously development cost.

As above-mentioned, known to have described the technical scheme that the present invention proposes in detail.Although the present invention is described and explained to the preferred embodiments of the present invention in detail, but this area those skilled in the art be appreciated that, in the situation of the spirit and scope of the present invention that do not deviate from the claims definition, can in form and details, make multiple modification.

Claims (4)

1. a maximum oil reservoir contacts (MRC) well type exploitation method, it uses maximum oil reservoir contact (MRC) well structure, this maximum oil reservoir contact (MRC) well structure is except straight well, comprise horizontal well, high-inclination horizontal well and fish-bone well, straight well is communicated with high-inclination horizontal well and fish-bone well, high-inclination horizontal well drills different intervals crack, the high-inclination horizontal well of many mouthfuls of layered arrangement, horizontal well all is arranged on the inside of bulk or thick-layer shape oil reservoir, and comprise many drainings horizontal well or high-inclination horizontal well in every layer of well, horizontal well among the adjacent row or high-inclination horizontal well well plane parallel interlaced arrangement, the horizontal well in the adjacent layer or the vertical interlaced arrangement of high-inclination horizontal well well; Many mouthfuls of fish-bone wells are distributed in the bottom oil reservoir and planar become to arrange shapes more and distribute, each the well plane parallel interlaced arrangement among the adjacent row, and be in the same level; Many mouthfuls of high-inclination horizontal wells and fish-bone well consist of that heave in the plane, vertical stacked staggered three-dimensional well pattern structure;

Wherein, adopt less than the injector producer distance of water injection of horizontal well and be the fish-bone well of planar water filling, described fish-bone well is distributed in the oil reservoir bottom, and is in the same level, every mouthful of fish-bone well to divide a number be 2～5; Each branch length of fish-bone well is identical or different, and each branch length is 150 meters～400 meters; Angle between the fish-bone branch of fish-bone well and the fish-bone well main pipe is for being 10 °～50 °;

Described maximum oil reservoir contact (MRC) well type exploitation method may further comprise the steps:

(1) early stage at oil reservoir development, for reducing development risk, oil reservoir adopts the straight well exploitation to be used for understanding and control oil reservoir; Well spacing mainly considers to belong to the plane well pattern design of two-dimentional well pattern structure design; Straight well is used for simultaneously the water filling early test and returns oil recovery on the later stage;

(2) oil reservoir enters the natural energy development phase, adopts horizontal well, high-inclination horizontal well to develop in the oil reservoir main body section, is used for improving crack brill encountering rate and oil reservoir and bores chance thickness, increases producing degree of reservoir and oil well output; Weakened planes contradiction, overcome interlayer contradiction, improve rate of oil production and recovery ratio;

(3) in the energy supplement stage, oil reservoir adopts the fish-bone well in the oil reservoir bottom, does the exploitation of water injection well type; The fish-bone well can further improve on the one hand the crack and bore encountering rate, and oil well output further improves; Second aspect is increased to the wire water filling of horizontal well from the spot flooding of straight well, further expand the pattern water flooding of fish-bone well to, increases the water drive swept volume, improves waterflood injection rate and water injection intensity; The third aspect, because water injection intensity strengthens, reservoir thermal crack(ing effect strengthens, thereby improves flood effectiveness.

2. according to method claimed in claim 1, minute number of wherein said fish-bone well is 3.

3. according to method claimed in claim 1, the fish-bone branch length of wherein said fish-bone well is 168 meters or 210 meters or 280 meters or 400 meters.

4. according to method claimed in claim 1, the fish-bone branch angle of wherein said fish-bone well is 15 ° or 25 ° or 35 ° or 45 °.

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