CN115596355A

CN115596355A - Borehole-while-drilling repairing tool and repairing method for easily-reduced stratum

Info

Publication number: CN115596355A
Application number: CN202211315808.XA
Authority: CN
Inventors: 秦春; 刘纯仁; 程智勇; 王委
Original assignee: Sinopec Oilfield Service Corp; Sinopec East China Petroleum Engineering Corp
Current assignee: Sinopec Oilfield Service Corp; Sinopec East China Petroleum Engineering Corp
Priority date: 2022-10-26
Filing date: 2022-10-26
Publication date: 2023-01-13

Abstract

The invention discloses a well-drilling repairing tool and a repairing method for an easily-reduced stratum, wherein a PDC (polycrystalline diamond compact) drill bit is upwards and sequentially screwed with a single-bent screw drilling tool, a drifting and drilling device, a non-magnetic drill collar, a spiral drill collar, a weighted drill rod, an eccentric reamer and a drill rod, a drilling jar is screwed above the next weighted drill rod, and the PDC drill bit is a five-blade anti-balling drill bit; the outer wall of the eccentric reamer is provided with an upper reaming blade and a lower reaming blade, the inclination directions of the upper reaming blade and the lower reaming blade are opposite, the heights of the blades are unequal, the upper reaming blade and the lower reaming blade are respectively and uniformly provided with a plurality of reaming cutting teeth on the respective circumferences and are respectively provided with reaming cutting teeth on the head-on side; and a drilling inclinometer is arranged in the non-magnetic drill collar. In the drilling process, drilling fluid is pushed through every 200 meters in the open hole section once, enters the hole-shrinkage well section, starts to scratch holes when meeting resistance of 20kN, and continues to drill after the scratches are not blocked. The invention can effectively prevent diameter shrinkage, and can greatly reduce the short take-off times and the complex failure rate caused by diameter shrinkage.

Description

Borehole-while-drilling repairing tool and repairing method for easily-reduced stratum

Technical Field

The invention relates to a borehole repairing tool, in particular to a borehole repairing tool while drilling for an easily-reduced stratum, and further relates to a borehole repairing method while drilling for the easily-reduced stratum, belonging to the technical field of borehole repairing while drilling.

Background

At present, the first party of each oil field saves the engineering investment, meets the requirement of reducing the cost, simplifies the well body structure of a construction well, reduces the running depth of a surface casing or a technical casing, and increases the number of long open hole wells year by year. The upper part of the sleeve is not used for sealing and fixing the expansive mudstone stratum and the soft mudstone stratum with creep property, so that the sleeve is very easy to hydrate and expand, the diameter shrinkage phenomenon is caused, the complex phenomena of tripping, hanging and clamping, drilling and stopping are caused sometimes, even accidents such as new well hole scratching, drilling clamping and the like are caused, and the serious economic loss is caused.

The following problems exist in the construction process: 1. the upper stratum is generally constructed by water-based drilling fluid, so that the hydration expansion speed of mudstone is increased, the hole shrinkage probability is greatly increased, and in order to inhibit hole shrinkage, a method for improving the density of the drilling fluid is generally adopted, so that the material cost is increased, and the high density can press and leak the soft mudstone stratum, so that the aggravation is complicated.

2. The existing diameter reduction prevention measure is to adopt a mode of hard taking down to repair a well wall, and a part of stratum easy to reduce is even a drilling mode of 'striking one and returning two', so that the construction period is greatly increased. Once the technical measures of drilling and cutting are not carried out in place, new well bores are easy to cut out or drilling tool jamming accidents happen.

3. A part of construction teams adopt large-size drill bits to construct a diameter-reduced stratum so as to drill out a hole larger than a standard hole size to resist stratum diameter reduction, and then drill up to replace the drill bits with the standard size to continue construction after drilling to a stable stratum, so that not only is the drill bit cost increased and the drilling times increased, but also a shaft is changed into a duplex structure shaft, and rock debris is easily accumulated on steps of large and small shafts, so that the problems of drilling, electrical measurement and casing running are caused to be blocked at the step positions.

Disclosure of Invention

The invention aims to provide a borehole repairing tool while drilling for a formation easy to shrink, which can solve the problems of continuous increase of drilling cost, construction period and complex failure rate caused by the fact that a casing cannot be set in a long open hole well to seal the formation easy to shrink.

In order to achieve the purpose, the borehole repairing tool while drilling for the easily-reduced stratum comprises a PDC drill bit, wherein a single-bent screw drilling tool, a drifting and drilling device, a non-magnetic drill collar, a spiral drill collar, an weighting drill rod, an eccentric reamer and a drill rod are sequentially screwed above the PDC drill bit from bottom to top; the outer wall of the eccentric reamer is provided with an upper reaming blade and a lower reaming blade, the upper reaming blade and the lower reaming blade are opposite in inclination direction and unequal in height, the upper reaming blade and the lower reaming blade are respectively and uniformly provided with a plurality of reaming cutting teeth on respective circumferences and are provided with reaming cutting teeth on the head-on side; and a drilling inclinometer is arranged in the non-magnetic drill collar.

Furthermore, five bit blades of the PDC bit are uniformly distributed on the outer arc surface of the bit crown, inter-blade water holes are respectively formed between the adjacent bit blades, a pair of central water holes are additionally formed in the central area of the bottom of the bit crown, and the inner ends of the two bit blades respectively extend between the two central water holes; the front of each drill wing is provided with a plurality of main cutting teeth, and the rear row of each main cutting tooth is provided with arc-shaped head alloy teeth.

Furthermore, the top of each drill bit wing is connected with the drill bit body through an arc convex surface respectively, and upper reaming teeth are distributed on the arc convex surface.

Further, the drifting and reaming device comprises a cylinder body, a cylinder body center hole is formed in the cylinder body along the axis, a plurality of spiral blades are evenly arranged on the outer wall of the middle section of the cylinder body, a plurality of hard alloy columns are embedded in righting edges of the spiral blades respectively, the upper end and the lower end of each spiral blade are connected with the cylinder body through taper slopes respectively, spiral overflowing grooves are formed between the adjacent spiral blades respectively, upper spraying holes which are sprayed upwards are formed in the upper portions of the spiral overflowing grooves respectively, a plurality of triangular cutting teeth are embedded in the facing surfaces of the spiral blades and the taper slopes respectively, and a plurality of conical cutting teeth are embedded in the edge of the back surfaces of the upper taper slope and the lower taper slope respectively.

The invention also aims to provide a borehole-while-drilling repairing method for a formation easy to shrink, which can solve the problems of continuous increase of drilling cost, construction period and complex failure rate caused by the fact that a casing cannot be set in a long open hole well to seal the formation easy to shrink.

In order to achieve the purpose, the borehole repairing method while drilling of the stratum easy to shrink in the invention adopts the borehole repairing tool while drilling of the stratum easy to shrink in any claim 1 to 4, the borehole repairing tool is placed at a constant speed in the drilling process, the drilling fluid is pushed through every 200 meters in the open hole section once, the shearing force of the drilling fluid is damaged, the position of a pump opening layer is selected at the stable part of the borehole, and a small-displacement top water through hole is adopted; entering a reducing well section, starting reaming when meeting 20kN of resistance, and continuing drilling after reaming is carried out till the hole is unobstructed; and (3) detecting the settled sand after the well is drilled and communicated to the bottom, then jacking the well with small discharge capacity, and after the circulation is normal, increasing the discharge capacity to the normal drilling discharge capacity to clean rock debris in the shaft.

Further, drilling parameters of the phi 311.1mm borehole are as follows: the bit pressure is 60-120 KN, the rotating speed is 60r/min, and the discharge capacity is 50-55L/s; drilling parameters of the phi 215.9mm borehole are as follows: the bit pressure is 40-100 KN, the rotating speed is 60r/min, and the discharge capacity is 32-34L/s.

Further, the drilling fluid comprises the following raw materials in parts by weight: 1000 parts, sodium bentonite: 3-5 parts of composite metal ion PMHA-II:0.2 part, emulsion polymer coating agent COATER:0.1 part, KCl: 5-7 parts of polyamine inhibitor PAIR:0.2 part, low-viscosity polyanionic fiber PAC-LV:1 part of modified asphalt FT-342:2 parts, cationic asphalt latex: 2 parts, sulfonate copolymer filtrate reducer DPS-2:1 part of micro-nano plugging agent: 1 part of amphiphilic pressure-bearing plugging agent: 0.5 part, extreme pressure lubricant LUB: 2-3 parts of superfine calcium carbonate QS-4: and 2, adding barite to adjust the density of the drilling fluid to 1.25-1.35 g/cm for high-speed harvest.

Compared with the prior art, the invention has the following beneficial effects: 1. the method can solve the problems of continuous increase of drilling cost, construction period and complex failure rate caused by failure of casing setting to seal the formation with easy shrinkage in the long open hole well, can effectively prevent shrinkage, and can greatly reduce short tripping times and complex failure rate caused by shrinkage, thereby shortening construction period and achieving the purposes of speed and efficiency improvement.

2. And the high-efficiency PDC drill bit is adopted for construction, so that the mechanical drilling speed of the upper stratum is improved, and the soaking time of the stratum easy to shrink is shortened. The five-blade anti-balling seven-water-hole drill bit can reduce the torque of the drill bit, reduce the probability of tooth breakage, improve the aggressivity of the drill bit and reduce the occurrence of balling. The arc convex surface at each drill bit wing top makes the top thing that drops be difficult to pile up, sets up the reaming tooth on the arc convex surface and can carry out the breakage to the thing that drops, meets when preventing to lift and hinders.

3. Two sets of reverse blades are arranged on the upper part and the lower part of the eccentric reamer, and the heights of the blades are different, so that the purpose of eccentricity is achieved; the cutting teeth are arranged at the head-on position of the blade, so that a borehole with a diameter larger than the actual drift diameter can be generated under the eccentric action during rotation, the real-time reaming of the reduced-diameter stratum is realized, the borehole wall can be cut by forward cutting and backward cutting, and the diameter reduction is prevented. The eccentric reamer has the advantages of simple structure, no movable part, no pressure loss, low cost and long service life.

4. The drifting and reaming device has the advantages of good reaming stability, easy passing of collapsed objects, good well wall repairing capability, increased upper jet holes, and improved down reaming effect and drifting quality. The well wall with the hole shrinkage, the steps and the collapsed well section is repaired, the well cleaning effect is improved, the well body quality is improved, the torque is small when the hole is scratched, the damage to a drilling tool is reduced, and the accident risk of the underground drilling tool is reduced.

Drawings

The invention will be described in further detail with reference to the following drawings and detailed description, which are provided for reference and illustration purposes only and are not intended to limit the invention.

FIG. 1 is a schematic structural diagram of a wellbore repair while drilling tool for a formation with a diameter that is easily reduced according to the present invention;

FIG. 2 is a front view of the present invention;

FIG. 3 is a cross-sectional view of a helical blade in the drift reamer;

FIG. 4 is a front view of the eccentric reamer of the present invention;

FIG. 5 is a front view of a PDC bit of the present invention;

fig. 6 is a bottom view of fig. 5.

In the figure: A.PDC drill bit; B. a single-bent screw drilling tool; C. a pigging and hole-cutting device; D. a non-magnetic drill collar; E. a helical drill collar; F. weighting the drill rod; G. a drilling jar; H. an eccentric reamer; J. drilling a rod; 1. a cylinder; 1a, conical female threads; 1b, a central hole of the cylinder; 1c, tapered male threads; 2. a spiral blade; 3. a taper slope; 3a, a first slope surface; 3b, a second slope surface; 4. a hard alloy post; 5. three-edged cutting teeth; 6. a tapered cutting tooth; 7. a spiral overflow groove; 8. an upper jet hole; 9. reaming the upper blade; 10. expanding the lower blade of the eye; 11. reaming the cutting teeth; 12. a drill blade; 13. an interwing water hole; 14. a central water hole; 15. a main cutting tooth; 16. the arc-shaped head alloy teeth; 17. an arc convex surface; 18. and (5) scratching the eye.

Detailed Description

In the following description of the present invention, the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not mean that the apparatus must have a specific orientation.

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further explained by combining the specific drawings.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

As shown in figure 1, the well repairing tool string while drilling is used for a stratum easy to reduce, a PDC drill bit A, a single-bent screw drilling tool B, a drifting and drilling device C, a non-magnetic drill collar D, a spiral drill collar E, an weighted drill rod F, an eccentric reamer H and a drill rod J are sequentially screwed from bottom to top, the weighted drill rod F comprises a plurality of mutually screwed and is screwed with a drilling jar G above the next weighted drill rod F, and a inclinometer while drilling is installed in the non-magnetic drill collar D. The method does not change the original drilling process, does not occupy extra time, is used for the easily-reduced well section, can effectively inhibit the reduction of the upper shale formation, solves the serious problem of the blockage during tripping, and prevents accidents such as new well marking, drill sticking and the like. The torque and the annular back velocity are little influenced, real-time reaming of the easily-reduced stratum can be realized in the drilling process, a large-size drill bit does not need to be specially put into the easily-reduced stratum, the easily-reduced section well wall does not need to be frequently and temporarily repaired, the tripping times are reduced, the construction period is saved, meanwhile, the high-efficiency PDC drill bit A is adopted, the mechanical drilling speed is high, and the construction period is further shortened.

As shown in fig. 2 and 3, the drifting and drilling device C comprises a cylinder 1, a cylinder center hole 1b is formed in the axis of the cylinder, a conical female thread 1a is formed in the upper end of the cylinder 1, a conical male thread 1C is formed in the lower end of the cylinder 1, a plurality of spiral blades 2 are uniformly arranged on the outer wall of the middle section of the cylinder, the number of the spiral blades 2 is three, the spiral blades are clockwise, the winding angle is 270-360 degrees, the drilling tool is favorable for rotation and rock debris return, and the drilling fluid circulation efficiency is favorably improved. The spiral blade 2 and the cylinder 1 are of an integrated structure, and the spiral blade is safe, reliable and high in durability.

A plurality of hard alloy columns 4 are respectively embedded on the righting edges of the spiral blades 2, and the upper end and the lower end of each spiral blade 2 are respectively connected with the column body 1 through the taper slope 3. The exposure height of the hard alloy columns 4 is 4mm, the top of each hard alloy column 4 is provided with an arc-shaped slope, the diameter of the bottom of each arc-shaped slope is 2mm, and the slope angle is 30-45 degrees. The arc-shaped slope surface structure enables the hard alloy column 4 to be in line smooth contact with a hard stratum, and the torque is small when the hole is scratched; the arranged teeth are all brazed at low temperature, so that the stability is enhanced.

The taper angle parts of the upper side and the lower side of the spiral blade 2 body, which are contacted with the drilling tool body, are designed into two sections of arc-shaped structures, namely, the taper slope surface 3 is a first slope surface 3a close to the cylinder 1, the taper slope surface 3 is a second slope surface 3b close to the spiral blade 2, and the two slope surfaces are in arc transition. The included angles between the starting point of the first slope 3a far away from the spiral blade 2 and the outer surface of the cylinder are respectively 30 degrees, the included angles between the starting point of the second slope 3b and the axis of the cylinder are respectively 20 degrees, and the smaller angle of the chamfer surface enables collapsed objects not to be easily accumulated on the slope, so that the risk of drill sticking is reduced.

Spiral overflow grooves 7 are respectively arranged between the adjacent spiral blades 2, in order to improve the reverse reaming and sand carrying effect of the reaming device, upper injection holes 8 which are upwards injected are respectively arranged at the upper parts of the spiral overflow grooves 7, outer ports of the upper injection holes 8 incline upwards, and an included angle between the axis of each upper injection hole 8 and the axis of the column body is 45 degrees. The upper injection holes 8 may be fitted with different sized nozzles depending on the particular downhole conditions to achieve different water horsepower requirements. The upper rock debris can be prevented from settling during the forward reaming, the upward injection holes 8 can perform secondary acceleration on upward returning rock debris during the backward reaming, the energy of rock debris migration is increased, the rock debris migration effect is guaranteed, the well hole purification effect is guaranteed to the maximum extent, mud bags are prevented from appearing, and the well dredging quality is guaranteed.

A plurality of triangular cutting teeth 5 are respectively embedded on the facing surfaces of the spiral blades 2 and the taper slope surface 3, and one triangular cutting tooth 5 is arranged at an interval of 10cm so as to improve the transverse grinding and cutting effects.

The edges of the back surfaces of the upper and lower tapered slopes 3 are respectively embedded with a plurality of tapered cutting teeth 6 so as to improve the stability of the cambered surface. The triangular cutting teeth 5 and the conical cutting teeth 6 with strong aggressivity and impact resistance are adopted on the two sides of the spiral blade 2 and are PDC cutting teeth, so that the tooth breaking probability is reduced, the rock breaking efficiency of the hole cutting device is improved, and the service life of the hole cutting device is prolonged.

The hard alloy columns 4 are arranged on the outer wall of each spiral blade 2 in one row or more than two rows, the two rows are usually distributed in a crossed manner, and the hard alloy columns 4 in each row are uniformly arranged along the spiral line of the spiral blade 2.

The outer diameter of the body of the spiral blade 2 is designed to be an underdimension, wherein when the diameter of the mineshaft is less than or equal to 8 bea inches, the outer diameter of the body of the spiral blade 2 is the diameter of the mineshaft minus 1/16 inch; when the wellbore diameter is >8 ZZ ″, the body outside diameter of the helical blades 2 is the wellbore diameter minus 1/8 inch or 1/16 inch; the width of the spiral blade 2 is 40-50mm to ensure that rock debris smoothly passes through the chip groove.

When a regular well hole is met, the hard alloy columns 4 on the spiral blade righting edges firstly contact the well wall, and tiny bulges, rock debris beds and the like on the well wall are repaired, so that the well hole quality is improved; when an irregular well wall is met, the triangular cutting teeth 5 on the face of the spiral blade contact the well wall for repair, the hard alloy columns 4 perform secondary repair on the well wall, damage to mud cakes of the well wall is reduced as much as possible, and the stability of the well wall is maintained.

When an underground collapsed object is encountered, the underground collapsed object firstly falls to the slope surface position at the tail end of the spiral blade, and the PDC cutting teeth on the spiral blade body and the PDC cutting teeth on the slope surface cut and crush the collapsed object by lifting, lowering or rotating the drilling tool forwards and backwards, so that the phenomenon that a large number of collapsed objects are accumulated to cause drill jamming is avoided, the phenomenon that a drill bit is jammed when the drilling tool is lifted is avoided, and the problem that the drill jamming is caused by underground collapse is solved. Meanwhile, the piled debris bed can be cleaned, the well quality is improved, and the occurrence of drilling sticking accidents is greatly reduced.

As shown in fig. 4, the outer wall of the eccentric reamer H is provided with an upper reaming blade 9 and a lower reaming blade 10, the inclination directions of the upper reaming blade 9 and the lower reaming blade 10 are opposite, the upper reaming blade 9 and the lower reaming blade 10 are respectively and uniformly provided with a plurality of reaming cutting teeth 11 on the respective circumferences and facing surfaces.

The eccentric reamer H adopts an upper group of spiral cutting blades and a lower group of spiral cutting blades which are in the upper and lower opposite directions, so that a borehole slightly larger than the theoretical diameter of a drill bit can be reamed while drilling, and the upper group of cutting blades and the lower group of cutting blades can realize conventional forward reaming in the normal drilling process and reverse reaming in the tripping process. The method can eliminate the underground micro dog legs, does not need to specially enter a reaming tool for reaming after drilling before casing or entering the expansion packer, is favorable for logging instruments to enter and exit the well, and improves the success rate of once electrical measurement.

The heights of the reaming upper blade 9 and the reaming lower blade 10 are unequal, micro-eccentricity is realized, the borehole can be subjected to micro-reaming in the drilling process, and during the sliding drilling, the tool cannot be influenced to smoothly pass through the borehole formed by the drill bit, so that the phenomena that the borehole is scratched when being drilled down and the piston is pulled out when the drill bit is pulled out are reduced.

The upper end and the lower end of the eccentric reamer H are standard 411 multiplied by 410 drill pipe buckles, the length is only 1m, and the eccentric reamer H is connected in a drill pipe upright post, so that the upright post placement and the racking platform operation are not influenced for most derricks;

as shown in fig. 5 and 6, the PDC drill a is a five-blade anti-balling drill, five drill blades 12 are uniformly distributed on the outer arc surface of a drill crown, inter-blade water holes 13 are respectively formed between adjacent drill blades 12, a pair of central water holes 14 are additionally formed in the central area of the bottom of the drill crown, and seven water holes and nozzles thereof are beneficial to washing and cooling the drill to the maximum extent, driving rock debris to rapidly wash away from the well bottom, and preventing the drill from being damaged due to repeated cutting of the rock debris accumulated in the well bottom. The inner ends of the two drill bit blades 12 respectively extend to the position between the two central water holes 14; a plurality of main cutting teeth 15 are respectively arranged on the head side of each drill blade 12, and arc-head alloy teeth 16 are respectively arranged on the rear row of each main cutting tooth 15.

The top of each drill bit wing 12 is connected with the drill bit body through the arc convex surface 17 respectively, and the objects falling from the top are not easy to be accumulated on the arc convex surface 17 to form clamping stagnation. The upper reaming teeth 18 are distributed on the arc convex surface 17, and can crush falling objects and prevent the falling objects from being blocked when being lifted.

Drilling operation: the tool string is placed at a constant speed in the drilling process, drilling fluid is pushed through every 200 meters in an open hole section once, the shearing force of the drilling fluid is damaged, the position of a pump opening layer is selected to be a stable position in a well, and a small-displacement top water through hole is adopted; entering a reducing well section, starting reaming with a resistance of 20kN, and continuing drilling after reaming is smooth; and (3) detecting settled sand after the well is drilled and communicated to the bottom, then jacking and communicating with a small displacement, after circulation is normal, increasing the displacement to the normal drilling displacement, adjusting the performance of the drilling fluid, and removing rock debris in the shaft.

The drilling fluid comprises the following raw materials in parts by weight: 1000 parts of water, sodium bentonite: 3-5 parts of composite metal ion PMHA-II:0.2 part, emulsion polymer coating agent COATER:0.1 part, KCl: 5-7 parts of polyamine inhibitor PAIR:0.2 part, low-viscosity polyanionic fiber PAC-LV:1 part of modified asphalt FT-342:2 parts, cationic asphalt latex: 2 parts, sulfonate copolymer filtrate reducer DPS-2:1 part of micro-nano plugging agent: 1 part of amphiphilic pressure-bearing plugging agent: 0.5 part, extreme pressure lubricant LUB: 2-3 parts of superfine calcium carbonate QS-4: and 2, adding barite to adjust the density of the drilling fluid to 1.25-1.35 g/cm for high-speed harvest.

The comprehensive performance evaluation experiment of the drilling fluid system is shown in the table 1:

TABLE 1

As can be seen from the data in the table 1, the viscosity and the shear of the drilling fluid before and after aging, the rheological property change is not large, the system has good temperature resistance and stability, no barite sedimentation exists before and after aging, and the suspension performance of the system is good.

2. The medium pressure filtration loss of the drilling fluid is 3.4mL at normal temperature, the medium pressure filtration loss of the drilling fluid is 3.8mL after the drilling fluid is aged for 16h at 120 ℃ by hot rolling, and the high temperature and high pressure filtration loss is 10mL, which shows that the medium pressure filtration loss and the high temperature and high pressure filtration loss of the drilling fluid system are good in performance, and can meet the construction requirement of a hole section easy to shrink.

3. The lubricating coefficient of the system is less than 0.1 at room temperature, and after the system is hot rolled for 16 hours at 120 ℃, the lubricating coefficient is slightly reduced, and the lubricating performance is better.

4. And (3) performing inhibition evaluation on the drilling fluid by adopting a Funing group shale rock core in Jiangsu region. The expansibility of the rock core in clear water is high, the expansibility after 8 hours is 5.57 percent, while the expansibility after 8 hours is only 0.46 percent, so that the inhibition is greatly improved, and the inhibition dispersion effect of the potassium chloride polyamine drilling fluid on the rock core is improved.

The polyamine drilling fluid system with low viscosity and strong inhibition starts from strong inhibition and low viscosity, and the polymer and the polyamine inhibitor are compounded to quantitatively control large and small molecular inhibitors, thereby practically improving the inhibition performance, preventing hydration dispersion of a mudstone stratum and ensuring smooth tripping.

The manufacturer and performance parameter requirements for the raw materials used in the drilling fluid system are shown in table 2:

TABLE 2

Drilling operation: the recommended parameters of the borehole of phi 311.1mm are weight on bit: 60-120 KN; rotating speed: 60r/min; discharge capacity: 50-55L/s; the recommended borehole parameter of phi 215.9mm is the weight on bit of 40-100 KN; the rotating speed is 60r/min; the discharge capacity is 32-34L/s; and (4) frequently moving the drilling tool in the drilling process, observing drilling parameters and rock debris return conditions, and confirming well bore conditions.

And (3) tripping operation: (1) Circularly treating the drilling fluid before tripping out, and cleaning rock debris in a shaft; (2) If the diameter-reduced well section meets the blockage during the tripping, lifting and reversely marking, after the underground condition is treated normally, drilling to the bottom, and circularly treating the drilling fluid; and (3) strengthening the post sitting. Drilling fluid is filled once every 3 columns of drill rods or 1 column of drill collars, so that the phenomenon of piston pulling is prevented.

And (3) maintenance treatment of the drilling fluid: (1) In the drilling process, a fine water long-flow mode is adopted to timely supplement the macromolecule inhibiting inhibitor, so that the drilling fluid is ensured to have good inhibition performance, and mud rock slurrying can be effectively inhibited; (2) The content of the main polymer is ensured, and the inhibition performance of the drilling fluid is enhanced by matching the emulsion coating agent and the filtrate reducer; and (3) ensuring the normal operation of the solid control equipment in the construction process. The utilization rate of the vibrating screen is not less than 100%, the utilization rate of the double-removing screen is not less than 80%, and the utilization rate of the centrifugal machine is not less than 40%.

The drilling fluid is applied to 12 wells such as 11-13 wells, 7-46 wells and the like, the shrinkage of the upper shale stratum is effectively improved, the average hole diameter expansion rate is 9.99 percent, one drill bit completes one-time construction, the average mechanical drilling speed is improved by 34 percent compared with that of an adjacent well, and the drilling fluid maintenance and use cost is reduced by 29.4 percent compared with that of the adjacent well.

Example 1: true 11-13 well

The true 11-13 well is completed with a drilling depth of 2506m, the adjacent well is generally pulled down for 5 times in a short time, the well is repaired by adopting the well hole while drilling, the electric measurement is successful once when the well is pulled down for 2 times in a short time after the completion of drilling, and the hole diameter expansion rate is increased to 9.72 percent compared with that of the adjacent well by 3.21 percent. And the drilling bit reaches 2154m in single trip, and the average mechanical drilling speed is improved by 26.9 percent compared with the same stratum well section of an adjacent well. The maintenance and use cost of the drilling fluid is reduced by 23.1 percent compared with that of an adjacent well.

Example 2: sand 7-46 well

The well completion depth of the sand 7-46 well is 2426m, the adjacent well is generally pulled out for 4 times in a short time, the well is repaired by adopting the well hole while drilling, only 1 time of short pulling out is carried out until the completion, the electric measurement is successful once, and the hole diameter expansion rate is increased to 8.72 percent compared with 2.17 percent of the adjacent well. And the drilling head has a single trip reaching 2026m, and the average mechanical drilling speed is increased by 31 percent compared with the same stratum well section of an adjacent well. Compared with the adjacent well, the maintenance and use cost of the drilling fluid is reduced by 26.4 percent.

Example 3: sand 20-89 well

The well completion depth 2412m of the sand 20-89 well is achieved, the adjacent well is generally dug for 4 times in a short time, the well is repaired by adopting the well hole while drilling, the electrical measurement is successful once when the well is dug for only 1 time in a short time, and the hole diameter expansion rate is increased to 10.72 percent compared with that of the adjacent well by 3.27 percent. And the drilling head has a single trip reaching 2170m, and the average mechanical drilling speed is improved by 29 percent compared with the same stratum well section of an adjacent well. The maintenance and use cost of the drilling fluid is reduced by 30.5 percent compared with that of an adjacent well.

Example 4: min 28-16 well

The Min 28-16 well is drilled with a depth of 1906m, the adjacent well is generally short-drilled at least 3 times, the well is repaired by a well-drilling well hole, the well is drilled successfully after short-drilled at 823.5m, the electrical logging is successful once, and the hole diameter expansion rate is increased to 8 percent compared with-1.12 percent of that of the adjacent well. And the drilling head has a single-trip drilling depth of 1687m, and the average mechanical drilling speed is improved by 32 percent compared with the same stratum well section of an adjacent well. The maintenance and use cost of the drilling fluid is reduced by 19.4 percent compared with that of an adjacent well.

Example 5: horse 46-01 inclined shaft

The completion drilling depth of 46-01 deviated well is 1767m, the adjacent well generally needs to be pulled out for at least 3 times in a short time, the well is repaired by a well hole while drilling, the short pulling-out is carried out only at 823.5m, the pulling-out is smooth, the electrical measurement is successful once, and the hole diameter expansion rate is increased to 8 percent compared with that of the adjacent well by 1.12 percent. And the drilling head has a single-trip drilling depth of 1682m, and the average mechanical drilling speed is improved by 48 percent compared with the same stratum well section of an adjacent well. The maintenance and use cost of the drilling fluid is reduced by 22.3 percent compared with that of an adjacent well.

Example 6: wer 2-133 well

The completion drilling depth of the Wei 2-133 well is 1697m, the adjacent well generally needs to be started and stopped for 3 times, the well is repaired by the well drilling, only 1 time of short start and stop is carried out until the completion drilling, the drilling cycle is only 3.75 days, the electric measurement is successful once, and the hole diameter expansion rate is increased to 12 percent compared with 2.13 percent of that of the adjacent well. And the drilling bit reaches 1517m in single trip, and the average mechanical drilling speed is improved by 35 percent compared with the same stratum well section of the adjacent well. The maintenance and use cost of the drilling fluid is reduced by 18.6 percent compared with that of an adjacent well.

While the foregoing is directed to the preferred embodiment of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. The utility model provides a borehole repair while drilling instrument in easy undergauge stratum, includes the PDC drill bit, its characterized in that: a single-bent screw drilling tool, a drifting and drilling device, a non-magnetic drill collar, a spiral drill collar, an aggravated drill rod, an eccentric reamer and a drill rod are sequentially screwed above the PDC drill bit from bottom to top, the aggravated drill rod comprises a plurality of mutually screwed and is screwed with a drilling jar above the next aggravated drill rod, and the PDC drill bit is a five-blade anti-balling drill bit; the outer wall of the eccentric reamer is provided with an upper reaming blade and a lower reaming blade, the upper reaming blade and the lower reaming blade are opposite in inclination direction and unequal in height, the upper reaming blade and the lower reaming blade are respectively and uniformly provided with a plurality of reaming cutting teeth on respective circumferences and are arranged on the head-on side; and a drilling inclinometer is arranged in the non-magnetic drill collar.

2. The wellbore repair while drilling tool for a reduced formation of claim 1, wherein: five bit blades of the PDC bit are uniformly distributed on the outer arc surface of the bit crown, inter-blade water holes are respectively formed between the adjacent bit blades, a pair of central water holes are additionally formed in the central area of the bottom of the bit crown, and the inner ends of the two bit blades respectively extend to the position between the two central water holes; the front of each drill wing is provided with a plurality of main cutting teeth, and the rear row of each main cutting tooth is provided with arc-shaped head alloy teeth.

3. The diameter-reducible formation while drilling wellbore remediation tool of claim 2, wherein: the top of each drill bit wing is connected with the drill bit body through an arc convex surface respectively, and upper reaming teeth are distributed on the arc convex surface.

4. The wellbore repair while drilling tool for a reduced formation of claim 1, wherein: the drifting hole-drawing device comprises a cylinder body, a cylinder body center hole is formed in the cylinder body along the axis of the cylinder body, a plurality of spiral blades are evenly arranged on the outer wall of the middle section of the cylinder body, a plurality of hard alloy columns are embedded on righting edges of the spiral blades respectively, the upper end and the lower end of each spiral blade are connected with the cylinder body through taper slopes respectively, spiral overflowing grooves are formed between every two adjacent spiral blades respectively, upper spraying holes which are sprayed upwards are formed in the upper portions of the spiral overflowing grooves respectively, a plurality of triangular cutting teeth are embedded in the facing surfaces of the spiral blades and the taper slopes respectively, and a plurality of conical cutting teeth are embedded in the edges of the upper and lower taper slope backs respectively.

5. A method for repairing a formation with a borehole while drilling is easy to reduce, and is characterized in that the method adopts the tool for repairing the formation with the borehole while drilling of the easy to reduce formation according to any one of claims 1 to 4, the tool is placed down at a constant speed in the drilling process, the shearing force of drilling fluid is destroyed when the drilling fluid is pushed through every 200 meters in an open hole section, the position of a pump is selected at a stable part of the borehole, and a small-displacement top water hole is adopted; entering a reducing well section, starting reaming with a resistance of 20kN, and continuing drilling after the reaming is unobstructed; and (3) detecting the settled sand after the well is drilled and communicated to the bottom, then jacking the well with small discharge capacity, and after the circulation is normal, increasing the discharge capacity to the normal drilling discharge capacity to clean rock debris in the shaft.

6. The method for wellbore repair while drilling of a reducible formation of claim 5, wherein: drilling parameters of the phi 311.1mm well are as follows: the bit pressure is 60-120 KN, the rotating speed is 60r/min, and the discharge capacity is 50-55L/s; drilling parameters of the phi 215.9mm borehole are as follows: the bit pressure is 40-100 KN, the rotating speed is 60r/min, and the discharge capacity is 32-34L/s.

7. The method for repairing a borehole while drilling of a diameter-reducing stratum as claimed in claim 5, wherein the drilling fluid is prepared from the following raw materials in percentage by weight: 1000 parts, sodium bentonite: 3-5 parts of composite metal ion PMHA-II:0.2 part, emulsion polymer coating agent COATER:0.1 part, KCl: 5-7 parts of polyamine inhibitor PAIR:0.2 part, low-viscosity polyanionic fiber PAC-LV:1 part of modified asphalt FT-342:2 parts, cationic asphalt latex: 2 parts, sulfonate copolymer filtrate reducer DPS-2:1 part of micro-nano plugging agent: 1 part of amphiphilic pressure-bearing plugging agent: 0.5 part, extreme pressure lubricant LUB: 2-3 parts of superfine calcium carbonate QS-4: and 2, adding barite to adjust the density of the drilling fluid to 1.25-1.35 g/cm for harvesting.