CN107722954B - Plugging agent for fractured leakage of drilling well, plugging slurry and plugging construction method - Google Patents

Abstract

The invention relates to a plugging agent, a plugging slurry and a plugging construction method for drilling fracture loss. The plugging agent comprises the following components in parts by weight: 80-85 parts of cement, 6-10 parts of floating beads, 6-10 parts of micro silicon and 1-3 parts of asbestos fibers. The plugging agent for the fractured leakage of the well drilling is a plugging agent main body formed by compounding cement, floating beads, micro silicon and asbestos fibers, wherein the asbestos fibers play a bridge plug bridging role on fractures, the floating beads and the micro silicon play a filling and plugging role on the fractures, the components coordinate to enable the plugging agent to easily enter a leakage layer, the bridge plug, the bridge and the filling and plugging combined action is achieved, and the plugging agent is particularly suitable for the comprehensive action of bridge plugs, bridging and filling and plugging, wherein the fracture width is 3-10mm, the leakage rate is 5-100m³The leakage stoppage has the advantages of quick leakage stoppage effect, short operation period and high success rate of leakage stoppage.

Description

Plugging agent for fractured leakage of drilling well, plugging slurry and plugging construction method

Technical Field

The invention belongs to the field of plugging of drilling leakage, and particularly relates to a plugging agent, a plugging slurry and a plugging construction method for drilling fractured leakage.

Background

When a drilling well encounters a stratum layer with geological structure characteristics such as faults, altitude angle connectivity cracks or mudstone broken zones, due to the fact that a window between leakage pressure and stratum pressure is narrow, if the density of drilling fluid is unreasonably controlled and excitation pressure is too large, drilling well leakage and even malignant leakage are prone to being caused. In addition, in the process of treating lost circulation, unstable collapse of well walls, blowout and drill tool jamming accidents are easily induced, and the well situation is complicated. The well drilling loss or the collapse of the well wall caused by the loss seriously affects the well drilling progress, prolongs the well drilling period and increases the well building cost.

Lost circulation can be classified into permeability, fracture and karst cave losses, depending on the nature of the lost circulation, the rate of leakage and the cause of the lost circulation. Fracture losses, caused by geological formation or well-drilling engineering factors, are widespread in both geographic areas and longitudinally in the formation. Geographical areas such as the domestic deldos basin, the Xinjiang Tahe and the northward areas; the stratum distribution is like Yanan group, extension group, Liujia ditch group, Shiqian Peak group and the like of the Hulusi flag block of Ordos, and the stratum of a two-fold system with the length of about 400m along the north section has serious crack loss. The patent with the application publication number of CN102443382A discloses a plugging agent suitable for large-scale leakage, which comprises the following components in percentage by mass: clear water: HSD: HD-1: HD-2: LD-102: DF-A: barite 100: (12-15): (4-5): (7-8): (4-5): 30, of a nitrogen-containing gas; the technology is mainly used for plugging large-scale leakage by using a bridge plug or after gel and the bridge plug, the leakage amount is relatively small, normal drilling cannot be performed or the cement injection effect is not good, and the leakage is plugged by adopting a composite structure plug body plugging process. In other words, the technique requires other lost circulation processes to pretreat the formation for large lost circulation situations.

For the fractured leakage loss with the fracture width of 3-10mm, large granular materials for plugging in the conventional drilling are attached to the well wall and are difficult to enter a leakage layer, and a blocking layer is quickly damaged after repeated drilling; although the small-particle plugging material can enter the stratum, the characteristics of quick plugging effect and short re-leakage period are shown due to insufficient cementing power with the stratum and insufficient self structural force.

Disclosure of Invention

The invention aims to provide a plugging agent for drilling fracture loss, so as to solve the problem of low success rate of plugging by the existing plugging agent.

The second object of the present invention is to provide a plugging slurry using the plugging agent.

The third purpose of the invention is to provide a matched leaking stoppage construction method of the leaking stoppage slurry.

In order to achieve the purpose, the technical scheme of the plugging agent for the drilling fracture leakage is as follows:

a plugging agent for drilling fracture loss comprises the following components in parts by weight:

80-85 parts of cement, 6-10 parts of floating beads, 6-10 parts of micro silicon and 1-3 parts of asbestos fibers.

The plugging agent for the fractured leakage of the well drilling is a plugging agent main body formed by compounding cement, floating beads, micro silicon and asbestos fibers, wherein the asbestos fibers play a bridge plug bridging role on fractures, the floating beads and the micro silicon play a filling and plugging role on the fractures, the components coordinate to enable the plugging agent to easily enter a leakage layer, the bridge plug, the bridge and the filling and plugging combined action is achieved, and the plugging agent is particularly suitable for the comprehensive action of bridge plugs, bridging and filling and plugging, wherein the fracture width is 3-10mm, the leakage rate is 5-100m³The leakage stoppage has the advantages of quick leakage stoppage effect, short operation period and high success rate of leakage stoppage.

The construction performance and the adaptability of the plugging agent can be optimized by further adding an auxiliary agent. Preferably, the plugging agent consists of the following components in parts by weight: 80-85 parts of cement, 6-10 parts of floating beads, 6-10 parts of micro-silicon, 1-3 parts of asbestos fiber, 1-2 parts of fluid loss additive, 0.5-1.5 parts of expanding agent, 0.2-0.3 part of retarder and 0.02-0.06 part of potassium polyacrylate.

Preferably, the particle size of the cement is 0.68-63 μm, the particle size of the micro-silicon is 0.04-0.68 μm, and the particle size of the floating bead is 0.063-0.256 mm.

Preferably, the length of the asbestos fiber is 1-6 mm. More preferably, the asbestos fiber is formed by compounding short asbestos fiber with the length being less than or equal to 1mm and less than or equal to 3mm and feldspar cotton fiber with the length being less than or equal to 3mm, and the mass ratio of the short asbestos fiber to the feldspar cotton fiber is (1.5-2.5): 1. The short asbestos fiber and the feldspar cotton fiber are compounded according to the proportion, so that the bridge plug and bridging effects can be further optimized, and a better plugging effect can be provided.

Furthermore, the plugging agent for the drilling fracture leakage of the invention optimizes the water loss reduction property and improves the flow pattern of the plugging agent by further adding an auxiliary agent, and can adapt to the changes of different leakage layer depths, temperatures and construction time; the cement stone has moderate strength, reduces the difficulty of sweeping the plug and avoids the formation of a new borehole; the cement stone also has crack-stopping and toughening properties, and the effect of stopping leakage due to the influence of stress, crushing and cracking of the cement stone during plug sweeping is prevented.

The technical scheme of the invention is as follows:

the plugging slurry using the plugging agent for the drilling fracture leakage comprises water and the plugging agent, wherein the water-cement ratio is 0.8-0.9.

The plugging slurry for the drilling fracture leakage is prepared by mixing cement, micro-silicon and floating beads according to a certain condition to realize the maximum dry mixture bulk percentage and obtain the density of 1.40-1.45 g/cm³The low-density cement slurry avoids the aggravation of the leakage degree caused by overlarge density of the plugging cement slurry; the plugging slurry has good construction performance, can be pumped for a long time, and can be quickly thickened after entering a leaking layer; meanwhile, the slurry has certain thixotropy, and assists the slurry to be retained in the crack.

The leaking stoppage slurry has the performance characteristics of short coagulation promotion, poor fluidity and thixotropy, and increases the flow resistance of the leaking stoppage slurry in a leaking layer; the early strength development is fast, the leaking layer can be rapidly solidified, and the plugging capability is improved.

The technical scheme of the leakage stoppage construction method is as follows:

a leaking stoppage construction method adopting the leaking stoppage slurry comprises the following steps: and (4) injecting plugging slurry into the position above a leak point, replacing the slurry, tripping the drill, closing the well, pushing and waiting for setting.

Preferably, the distance between the lower depth of the plugging pipe column and the top of the designed plugging section of the cement plug is 15m plus the length of the static leaking section before closing the well and pushing; wherein the length of the designed plugging section of the cement plug is not less than 150 m; length of static loss section is V_Loss/S₂×t₁In the formula V_LossFor static leak-off velocity after tripping, m³/min；S₂Is the cross-sectional area of the borehole in the open hole section, m²；t₁And (5) performing construction time from grouting to well closing and pushing in min.

Preferably, the injection amount of the plugging slurry is the volume corresponding to the length of a plugging section designed by the cement plug in the well, the leakage amount during the waiting setting period and 10m pushed to the stratum³The sum of the three components; wherein the leakage amount during waiting for coagulation is V_Loss×(T₂-T), wherein T is₂Thickening time, min; and t is the whole construction time of the plugging operation, and min.

Preferably, the front spacer fluid and the rear spacer fluid are respectively injected before and after the plugging slurry is injected; the front spacer fluid and the rear spacer fluid play roles in separating leakage-stopping slurry and drilling fluid, and the injection amount of the front spacer fluid is 2m³The injection amount of the rear flushing liquid is designed according to the principle of a cement plug formed by a balance method. The discharge amount of the injected plugging slurry is 400-700L/min.

Replacing the slurry to 100-150 m above the balance surface in the slurry replacing and drilling process; the displacement of the slurry replacement is 500-700L/min. And (4) pulling the drill until the theoretical height of the leaking stoppage slurry is increased by at least 100 m. After the drill is tripped, a pump is started to flush the drill rod, so that leaking stoppage slurry is prevented from being retained in the drill rod, and the safety is ensured; the flushing amount is the inner volume of the drill rod corresponding to the section length from the slurry replacing position to the bottom of the drill rod.

Preferably, the pushing amount Q of the well closing pushing_R＝Q_t+10-Q_Loss；Q_t＝S₂×(H_Loss-H_d)；Q_tThe annular volume m corresponding to the length from the lower depth position of the drill rod to the bottom section of the target leaking layer³(ii) a Wherein S is₂Is the cross-sectional area of the borehole in the open hole section, m²；H_LossThe depth of the layer where the leakage point is located is m; h_dThe lower depth of the leaking stoppage pipe column is m; q_LossIn order to actually measure the leakage loss during the period from the time when the plugging slurry is discharged from the drilling tool to the time when the pump injection is finished, the Q can be actually measured and calculated by combining the pump injection amount of a cement truck and the liquid level changes of the isolated drilling fluid replacement slurry tank and the recovery tank_Loss。

Construction time T and pumping time T of whole process of leakage stopping operation₁The relationship of (1): t is₁＝t+(20～30min)。

After waiting for setting, the drilling tool probes the plug to bear pressure, circulates for 20min according to the normal drilling displacement to check leakage, and records the top and the bottom of the plug; if no leakage is judged, normal drilling displacement is adopted for plug sweeping.

Further, the leakage stoppage construction method can be adjusted according to the leakage point or the leakage speed change, and specifically comprises the following steps:

(1) the leakage point is closed or the leakage speed is reduced in the leakage stopping operation. In this case, the top boundary of the plugging slurry moves upwards; the length of the short starting section of the drill rod is to follow the principle that the length of the theoretical short starting section is added with 100 m; the well closing pushing quantity is to reach the borehole volume from the bottom of the plugging slurry to the bottom of the leaking layer and enter the stratum by 10m³The total amount of (A);

(2) the leakage is completely lost in the leakage stopping operation. In this case, the bottom boundary moves downwards after the leaked slurry is discharged out of the drill rod, the operation is still performed in a full return state after the slurry is replaced and the drilling tool is only flushed after the drill rod is in place and is not pushed;

(3) and half returns to half leaks. Under the condition, the total leakage amount of the leakage-stopping slurry discharged from the drilling tool to the end stage of pump injection is accurately recorded, and the actual pushing total amount Q is obtained after the drilling rod is in place after being short-started_R＝S₂×(H_Loss-H_d)+10-Q_Loss。

The leaking stoppage construction method of the invention refines the lower depth of the leaking stoppage pipe column, the injection amount of the leaking stoppage slurry and the closing pushing amount, promotes most of the leaking stoppage slurry to enter the stratum, and leaves a small amount of the leaking stoppage slurry as a cement plug; when the leak point is judged wrongly, the lower leak point is automatically searched for secondarily in the pushing operation, so that the leak stoppage is realized.

The leakage stopping construction method is particularly suitable for the case that the width of a crack is 3-10mm and the leakage speed is 5-100m³Fracture loss per hour. After the drilling loss occurs, if the leakage rate is highAt 5m³Directly pulling out the drill without carrying out leakage layer pretreatment to replace the leakage stopping pipe column, lowering the drill to the designed well depth, and injecting leakage stopping slurry to stop leakage; the amount of the leaking stoppage slurry entering the leaking layer can be quantitatively controlled, and the condition that the leaking stoppage channel is deteriorated and the leaking is caused by the fact that the leaking stoppage slurry is extruded into the leaking layer at a too high speed is avoided; the plugging material has the advantages of quick plugging effect, short operation period, wide application range, high construction mechanization degree, simple and convenient procedure, simple and convenient operation, low cost of the plugging material, and no environmental pollution caused by the discharge of residual plugging slurry. The technology is suitable for the well drilling and leaking stoppage of fractured and lost strata of the Ordos basin, the Hangjinqi block on the north edge of the basin leaks the leakage for 72 times, the one-time leaking stoppage success rate reaches 87.5 percent, the underground safety is effectively ensured, the well drilling efficiency is obviously improved, and the well drilling cost is greatly reduced.

Drawings

FIG. 1 is a graph of the differential percentage of floating bead particle size;

FIG. 2 is a graph showing the cumulative percentage of floating bead particle sizes;

FIG. 3 is an external view of the cement paste of example 1 before crushing (a) and after crushing (b);

FIG. 4 is a schematic view showing the design of the lower depth of the plugging string in the plugging construction method of example 1;

FIG. 5 is a schematic view of grouting in the plugging construction method of example 1;

FIG. 6 is a schematic view showing the drill-out cleaning in the leak stoppage construction method of example 1;

fig. 7 is a schematic view of closing a well and pushing in the plugging construction method of embodiment 1.

Detailed Description

The following examples further illustrate embodiments of the present invention. The following examples relate to the main data and key parameters:

1) depth H of layer bottom where leakage point is located_Loss，m；

2) Designing a plugging well section L, m;

3) static leak-off velocity V after tripping_Loss，m³/min；

4) Actual measurement leakage rate Q from leaking stoppage slurry discharging to pump injection ending_Loss，m³；

5) Inner section area S of leaking stoppage drilling tool₁，m²；

6) Borehole section area S of open hole section₂，m²；

7) Time T for pumping leakage-stopping slurry₁Min; thickening time T₂，min；

8) The whole construction time t, min of the plugging operation; construction time t from grouting to well closing and pushing₁，min；

9) Lower depth H of leaking stoppage pipe column_d，m；

10) Annular volume Q corresponding to the length from the lower deep position of the drill rod to the bottom section of the target leaking layer_t，m³；

11) Actual pushing amount Q_R，m³。

The fluid loss agent is G309 fluid loss agent for oil well cement, and is purchased from Wei Hui city chemical industry Co., Ltd; the expanding agent is an XJP-1 oil well cement lattice expanding agent which is purchased from Xinxing building materials Co.Ltd in Henan; the retarder is XJH-1 oil well cement retarder, and is purchased from Xinxing building materials Co.

Example 1

The plugging agent of the embodiment comprises the following components in parts by weight: 84 parts of G-grade cement, 8 parts of floating beads, 8 parts of micro-silicon, 2 parts of asbestos fibers, 1.8 parts of fluid loss additive, 1 part of expanding agent, 0.22 part of retarder and 0.05 part of potassium polyacrylate (KPAM); the cumulative percentage of the cement in the particle size range of 0.68-63 mu m reaches 93.8%; the floating beads are power plant floating beads, and the cumulative percentage of the floating beads in the particle size range of 0.063-0.256 mm reaches 95.21% (as shown in figure 1 and figure 2); the cumulative percentage of the micro silicon in the particle size range of 0.04-0.68 μm reaches 97.4%; the asbestos fiber is formed by compounding short asbestos fiber with the length being more than or equal to 1mm and less than or equal to 3mm and feldspar cotton fiber with the length being more than or equal to 3mm and less than or equal to 6mm according to the mass ratio of 2:1, and the two types of fibers are mixtures with different lengths within respective length ranges.

The blocking effect of the asbestos fiber compounded by adopting the short asbestos fiber and the feldspar cotton fiber on cracks with different widths is shown in table 1.

TABLE 1 fiber length versus crack plugging for different widths

Width of crack	3.00	4.00	5.00	7.00	9.00	10.00
							Short asbestos fibres	Bridge plug and bridge	Bridge plug and bridge	Bridge plug	Bridge plug	Bridge plug	---
Long asbestos fibers	----	----	Bridge	Bridge plug and bridge	Bridge plug and bridge	Bridge plug

The plugging slurry of the present example was prepared by mixing the plugging agent of the present example with water, and the water-cement ratio was 0.85. The cement slurry solidified cement paste has a structural schematic diagram shown in fig. 3(a) and a good degree of compactness, and a broken structural schematic diagram shown in fig. 3(b) has good crack-stopping and toughening properties, so that the influence of stress, breakage and cracking on the plugging effect of the cement paste during plugging sweeping can be effectively prevented.

The leaking stoppage construction design of the embodiment comprises the following contents:

1) top leakage drilling: in order to fully expose the leaking layer and avoid repeated leaking stoppage of the same layer, drilling is continuously carried out with small displacement so as to drill through the leaking layer; during drilling, observing and measuring the liquid level at the wellhead to ensure the stability of the underground well;

2) a plugging pipe column (optical drill rod) is put in, and a plugging slurry column consisting of a preposed spacer fluid, a plugging slurry and a postposition spacer fluid is injected; the front spacer fluid consists of clear water and 5 percent XJCX-1, and the injection amount is 2m³The injection amount of the postposition spacer fluid is designed according to the principle of a cement plug by a balance method, and the composition of the postposition spacer fluid is 'clear water +2 percent XJG-1'; the grouting discharge capacity is 400-700L/min; XJCX-1 is a composite high-efficiency flushing fluid, XJG-1 is cellulose modified by high molecules, and the two additives are purchased from Xinxing building materials Co.Ltd of Henan;

the lower depth of the plugging pipe column is the sum of the length of a static leakage section above the top of a designed plugging section of the cement plug and before closing a well and pushing; before closing well and pushing, the length of static leakage section is equal to V_Loss/S₂×t₁The lower depth design is shown in fig. 4;

the injection amount of the plugging slurry is equal to the designed plugging section length corresponding volume of the cement plug in the well, the leakage amount during the waiting solidification period and the pushing to the stratum by 10m³The sum of the three components; designing the length of a plugging section to be not less than 150 m; the leakage during waiting for solidification is V_Loss×(T₂-t); the schematic diagram of the grouting process is shown in FIG. 5;

3) replacing the slurry to 100-150 m above the balance surface, wherein the discharge capacity of the replacing slurry is 500-700L/min;

4) the drilling is started in a short distance until the theoretical height of the leaking stoppage slurry is at least 100m above, a pump is started to flush the drill rod, the flushing amount is the inner volume of the drill rod corresponding to the length from the slurry replacing position to the bottom section of the drill rod, and the construction schematic diagram is shown in FIG. 6;

5) close the well and push after short rise, push quantity Q_R＝Q_t+10-Q_Loss；Q_t＝S₂×(H_Loss-H_d)；Q_LossThe measurement was carried out as follows: respectively isolating two mud tanks, wherein one tank is used as a replacement mud tank, and the other tank is used as a recovery tank; calculating the actual leakage amount of the leaking-stopping slurry out of the drill rod to the end of pump injection according to the volume change of the two slurry tanks and the pump injection amount of a cement truck before pushing; a schematic view of the shut-in push operation is shown in fig. 7;

construction time T and pumping time T of whole process of leakage stopping operation₁The relationship of (1) is: t is₁＝t+(20-30min)；

6) Waiting for setting not less than 8h, carrying out plug probing pressure bearing on the drilling tool, circulating for 20min according to normal drilling displacement, checking leakage, and recording the top and bottom of the plug; if no leakage is judged, normal drilling displacement is adopted for plug sweeping.

The construction design adopts a high-injection low-plugging principle, the lower part of the drilling tool is deeper than a leak point, and the leak point at the lower part is automatically searched for secondarily in the pushing operation when the leak point is judged wrongly, so that plugging is realized.

The construction design is applied to JPX-3Y1 wells of an Erdos Hangjin flag block, when the wells are drilled to 2699.6m, fracture leakage occurs, the leakage rate is checked at a small discharge capacity of 14L/min, and drilling fluid is lost. The construction method for plugging is adopted for construction, and the specific process is as follows:

1) adopting small-particle high-concentration conventional leakage-stopping slurry of 10m³Plugging section by section from the bottom of the well, judging the position of a leak point through well head grouting and pump pressure change, and determining the leak point to be the middle lower part of the Liujia ditch; liu Jia Trench group well depth 2513-2653 m;

2) adopting a 0:30 and 1:30 two-point grouting method to measure the static leak-off speed to be 0 m/h;

3) the light leakage blocking drill rod consists of an 2136.2m common drill rod and a 348.8m weighted drill rod; injecting plugging cement slurry 13m into the depth of 2585m below the smooth drill rod³Average density of 1.45g/cm³Replacement of 19.19m³(ii) a Leakage loss of 7.4m after the plugging slurry is discharged from the drilling tool³；

4) The well is tripped to a safe well section of 2182m, a blowout preventer of a brake plate is closed, and drilling fluid is pushed to 5.6m³(ii) a After waiting for setting for 8 hours, probing the plug surface, and plugging the top of 2593m with plugging slurry; the leakage is tested by circulating for 20 minutes at the normal drilling displacement,no loss; and (5) back-flushing the plug, wherein the displacement of the plug is 29L/s, the circulation in the well is normal after the plug is flushed, and the drilling is recovered.

By adopting the leakage stoppage construction method of the embodiment, 72 times of leakage stoppage is performed on the E.ltose Hangjin flag block, the success rate of one-time leakage stoppage reaches 87.5 percent, the underground safety is effectively ensured, the drilling efficiency is obviously improved, and the drilling cost is greatly reduced. Compared with the conventional plugging method, the plugging construction method has the characteristics of convenient field operation, short plugging operation time, quick plugging effect, long leak recovery period and low plugging cost, and can effectively reduce various underground complex conditions caused by long-term plugging; the plugging construction method can also be effectively applied to karst cave leakage loss after bridge plugging by stone mud balls, long fiber objects and the like.

Example 2

The plugging agent of the embodiment comprises the following components in parts by weight: 81 parts of G-grade cement, 7 parts of floating beads, 10 parts of micro-silicon, 1 part of asbestos fiber, 1 part of fluid loss additive, 0.8 part of expanding agent, 0.2 part of retarder and 0.03 part of potassium polyacrylate (KPAM); the asbestos fiber is formed by compounding short asbestos fiber with the length being less than or equal to 1mm and less than 3mm and feldspar cotton fiber with the length being less than or equal to 3mm and less than or equal to 6mm according to the mass ratio of 1.8: 1.

The plugging slurry of this example was prepared by mixing the plugging agent of this example with water, and the water-cement ratio was 0.82.

Example 3

The plugging agent of the embodiment comprises the following components in parts by weight: 85 parts of G-grade cement, 10 parts of floating beads, 7 parts of micro-silicon, 3 parts of asbestos fiber, 2 parts of fluid loss additive, 1.2 parts of expanding agent, 0.28 part of retarder and 0.06 part of potassium polyacrylate (KPAM); the asbestos fiber is formed by compounding short asbestos fiber with the length being less than or equal to 1mm and less than or equal to 3mm and feldspar cotton fiber with the length being less than or equal to 3mm according to the mass ratio of 2.2: 1.

The plugging slurry of the present example was prepared by mixing the plugging agent of the present example with water, and the water-cement ratio was 0.88.

The plugging slurry of the embodiment 2 and the embodiment 3 is adopted for plugging construction, the technical process can refer to the embodiment 1, and the plugging effect with equivalent effect can be obtained.

Claims (7)

1. A leaking stoppage construction method is characterized by comprising the following steps: injecting plugging slurry into the position above a leak point, replacing the slurry, tripping the drill, closing the well, pushing and waiting for setting;

the distance between the lower depth of the plugging pipe column and the top of the designed plugging section of the cement plug is =15m + the length of the static plugging section before closing the well and pushing; wherein the length of the designed plugging section of the cement plug is not less than 150 m; length of static loss section =V _Loss/S ₂×t ₁In the formulaV _LossFor static leak-off velocity after tripping, m³/min；S ₂Is the cross-sectional area of the borehole in the open hole section, m²；t ₁The construction time is min from the beginning of grouting to the time before closing the well and pushing;

the plugging slurry consists of water and a plugging agent, and the water-cement ratio is 0.8-0.9;

the plugging agent comprises the following components in parts by weight: 80-85 parts of cement, 6-10 parts of floating beads, 6-10 parts of micro silicon and 1-3 parts of asbestos fibers.

2. The plugging construction method according to claim 1, wherein the injection amount of the plugging slurry is the volume corresponding to the designed plugging section length of the cement plug in the well, the leakage amount during the waiting solidification period and 10m of the plugging slurry pushed to the stratum³The sum of the three components; wherein the leakage amount during the waiting period isV _Loss×（T ₂-t) of the formulaT ₂Thickening time, min; and t is the whole construction time of the plugging operation, and min.

3. Lost circulation construction method according to claim 1, wherein the pushing amount of the well closing pushing isQ _R =Q _t +10-Q _Loss；Q _t =S ₂×（H _Loss-H _d ) (ii) a Wherein,Q _t the annular volume m corresponding to the length from the lower depth position of the drill rod to the bottom section of the target leaking layer³；S ₂Is the cross-sectional area of the borehole in the open hole section, m²；H _LossIs the layer bottom of the leakage pointDepth, m;H _d the lower depth of the leaking stoppage pipe column is m;Q _Lossin order to actually measure the leakage loss during the period from the time when the plugging slurry is discharged from the drilling tool to the time when the pump injection is finished, the actual measurement can be carried out by combining the pump injection amount of the cement truck and the liquid level change of the isolated drilling fluid replacement slurry tank and the recovery tankQ _Loss。

4. The leak stoppage construction method as recited in claim 1, wherein the leak stoppage agent comprises the following components in parts by weight: 80-85 parts of cement, 6-10 parts of floating beads, 6-10 parts of micro-silicon, 1-3 parts of asbestos fiber, 1-2 parts of fluid loss additive, 0.5-1.5 parts of expanding agent, 0.2-0.3 part of retarder and 0.02-0.06 part of potassium polyacrylate.

5. A leak stoppage construction method according to claim 1 or 4, wherein the particle size of the cement is 0.68 to 63 μm, the particle size of the microsilica is 0.04 to 0.68 μm, and the particle size of the floating bead is 0.063 to 0.256 mm.

6. The leak stoppage construction method according to claim 1 or 4, wherein the length of the asbestos fiber is 1 to 6 mm.

7. The leakage stoppage construction method according to claim 6, wherein the asbestos fiber is formed by compounding short asbestos fiber with the length being less than or equal to 1mm and less than 3mm and feldspar cotton fiber with the length being less than or equal to 3mm and less than or equal to 6mm, and the mass ratio of the short asbestos fiber to the feldspar cotton fiber is (1.5-2.5): 1.

Images