Well drilling and cementing method for full-leakage stratum

Abstract

The invention provides a full-leakage stratum drilling well cementation method which comprises the steps that the quantity demanded of well cementation cement paste is calculated according to the section length of a full-leakage stratum drilling leakage section, double-liquid split-flow well cementation is utilized, a cement paste conveying pipeline is inserted into a drilling hole from one side of a full-leakage stratum drilling hole opening, an accelerator is injected into the other side of the full-leakage stratum drilling hole opening, and the full-leakage stratum drilling leakage section is formed. And the accelerator and the cement paste are alternately injected into the two sides, when the total mass of the accelerator and the cement paste which are injected is 1.5 times of the demanded quantity of the well cementation cement paste, injection of the accelerator and the cement paste into the full-leakage stratum drill hole is stopped, and after the accelerator and the cement paste are solidified, full-leakage stratum drill hole well cementation is completed. According to the drilling well cementation method for the full-leakage stratum, initial setting of the cement paste is accelerated by injecting the accelerator, fluidity is lost, and the strength is rapidly improved; the double-liquid split-flow well cementation time is short, and the time cost is saved; the material consumption is reduced, and the material cost is obviously reduced.

Description

Technical Field

[0001] This invention belongs to the field of drilling construction technology, specifically relating to a drilling and cementing method for fully leaky formations. Background Technology

[0002] In recent years, the number of gas drainage wells, pipeline wells, and large-diameter feed wells has shown a year-on-year upward trend. These wells all require casing installation and cementing operations. Pipeline wells and large-diameter feed wells, in particular, are typically directly connected to roadways. In contrast, gas wells may encounter losing circulation formations or need to traverse roadways, goafs, and other formations with special losing circulation characteristics. In these special cases, traditional cementing techniques are insufficient to meet practical needs, posing greater challenges to the time and material control of cementing.

[0003] With the continuous increase in the number of boreholes, the requirements for cementing technology are also constantly increasing. There is an urgent need to develop a cementing method and process to meet the special needs of lost circulation formations and to strictly control the time and material costs of cementing. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a drilling and cementing method for fully leaky formations, which addresses the shortcomings of the prior art. The present invention uses an injection of a quick-setting agent to accelerate the initial setting of the cement slurry, causing it to lose its fluidity and rapidly increase its strength; the two-liquid split cementing method is time-saving and saves time costs; and the material consumption is reduced, significantly reducing material costs.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for drilling and cementing in a completely leaky formation, the method being as follows: S1. Calculate the required amount of cement slurry based on the length of the lost section in the fully leaking formation borehole. S2. Using dual-liquid split cementing, quick-setting agent and cement slurry are injected alternately; The accelerator can speed up the initial setting of cement paste, causing it to lose its fluidity and rapidly increase its strength; S3. When the total mass of the quick-setting agent and the cement slurry injected in S2 is 1.5 times the amount of cement slurry required in S1, stop injecting the quick-setting agent and cement slurry into the fully leaky formation borehole. After the quick-setting agent and cement slurry solidify, the cementing of the fully leaky formation borehole is completed.

[0006] Preferably, the dual-liquid diversion in S2 refers to inserting the cement slurry delivery pipe 3m into the borehole from one side of the fully leaky formation borehole and injecting the quick-setting agent from the other side of the fully leaky formation borehole.

[0007] Preferably, the density of the cement slurry in S1, S2 and S3 is 1.8 g / cm³. 3 The quick-setting agent mentioned in S2 is liquid sodium silicate.

[0008] Preferably, the conditions for alternating injection of quick-setting agent and cement slurry in S2 are as follows: first inject quick-setting agent into the fully leaking formation borehole, then inject cement slurry into the fully leaking formation borehole, pause for 1 min to 2 min, and then repeat the above operation; the mass ratio of quick-setting agent to cement slurry is 0.37:1.

[0009] Preferably, the setting time of the quick-setting agent and cement slurry in S3 is 1h to 1.5h.

[0010] Compared with the prior art, the present invention has the following advantages: 1. In the fully leaky formation drilling cementing method of the present invention, the injection of a quick-setting agent can accelerate the initial setting of the cement slurry, causing it to lose its fluidity and rapidly increase its strength.

[0011] 2. The fully leaky formation drilling and cementing method of the present invention uses dual-liquid split cementing, which is time-saving and saves time costs.

[0012] 3. The dual-liquid split cementing method for drilling and cementing in fully leaky formations of the present invention reduces material consumption and significantly reduces material costs.

[0013] The present invention will be further described in detail below with reference to the embodiments. Detailed Implementation

[0014] Example 1 This embodiment describes a drilling and cementing method for completely leaky formations. The method is as follows: S1. Calculate the required amount of cement slurry based on the length of the lost section in the fully leaking formation borehole. S2. Using a dual-liquid split cementing method, accelerator and cement slurry are injected alternately. The cement slurry delivery pipe is inserted 3m into the borehole from one side of the fully leaky formation borehole, and accelerator is injected into the other side of the fully leaky formation borehole. The injection conditions are: first inject accelerator into the borehole, then inject cement slurry into the borehole, pause for 1 minute, and then repeat the above operation. The mass ratio of accelerator to cement slurry is 0.37:1. The accelerator can speed up the initial setting of cement paste, causing it to lose its fluidity and rapidly increase its strength; The density of the cement slurry is 1.8 g / cm³. 3 The quick-setting agent is liquid sodium silicate (Jichang Sodium Silicate Factory, Duji District, Huaibei City); S3. When the total mass of the quick-setting agent and the cement slurry injected in S2 is 1.5 times the amount of cement slurry required in S1, stop injecting the quick-setting agent and cement slurry into the fully leaky formation borehole. After the quick-setting agent and cement slurry solidify for 1.5 hours, their strength is sufficient to support the pressure of the cement slurry column in the upper non-leaking section, thus completing the cementing of the fully leaky formation borehole.

[0015] This embodiment also provides an application of the above-described drilling and cementing method for completely lost-circuit formations: In the drilling of seven C+ type gas boreholes through the goaf at the Tongting Coal Mine of Huaibei Mining Co., Ltd., by the Hydrological Exploration Team of Anhui Provincial Bureau of Coal Geology, the cementing method for drilling through the goaf leakage section was applied in Example 1 to address the cementing problem. The total cementing time was 1.5h, 3h, 1.5h, 1.5h, 3h, 3h, and 1.5h respectively, and the material consumption was only 1.1, 1.5, 1.2, 1.1, 1.5, 1.5, and 1.1 times that of the normal formation design.

[0016] Example 2 This embodiment describes a drilling and cementing method for completely leaky formations. The method is as follows: S1. Calculate the required amount of cement slurry based on the length of the lost section in the fully leaking formation borehole. S2. Using dual-liquid split cementing, the cement slurry delivery pipe is inserted 3m into the borehole from one side of the fully leaky formation borehole, and the quick-setting agent is injected into the other side of the fully leaky formation borehole. The injection conditions are: first inject the quick-setting agent into the borehole, then inject the cement slurry into the borehole, pause for 2 minutes, and then repeat the above operation. The mass ratio of the quick-setting agent to the cement slurry is 0.37:1. The accelerator can speed up the initial setting of cement paste, causing it to lose its fluidity and rapidly increase its strength; The density of the cement slurry is 1.8 g / cm³. 3 The quick-setting agent is liquid sodium silicate. S3. When the total mass of the quick-setting agent and the cement slurry injected in S2 is 1.5 times the amount of cement slurry required in S1, stop injecting the quick-setting agent and cement slurry into the fully leaky formation borehole. After the quick-setting agent and cement slurry solidify for 1 hour, their strength is sufficient to support the pressure of the cement slurry column in the upper non-leaking section, and the cementing of the fully leaky formation borehole is completed.

[0017] This embodiment also provides an application of the above-described drilling and cementing method for completely lost-circuit formations: During the drilling of seven pipeline wells through the goaf at the Xutuan Coal Mine of Huaibei Mining Co., Ltd., undertaken by the Hydrological Exploration Team of the Anhui Provincial Coalfield Geological Bureau, the cementing method for drilling through the goaf leakage section was used in Implementation Example 1 to address the cementing problem. The total cementing time was reduced to 8 hours. (Since the borehole directly connects to the underground working face roadway, for safety reasons, the intermittent cementing time during the cementing operation was intentionally extended to allow the lower cement slurry more time to solidify and achieve sufficient strength to support the pressure of subsequent injection of new pressure-reduced sections in the upper well section. This prevented the cement from being too strong after solidification, which could lead to insufficient cement strength and failure of the slurry to reach the roadway, causing an underground safety accident. Therefore, the cementing operation time was artificially extended.) The material consumption was consistent with the design consumption.

[0018] Example 3 This embodiment describes a drilling and cementing method for completely leaky formations. The method is as follows: S1. Calculate the required amount of cement slurry based on the length of the lost section in the fully leaking formation borehole. S2. Using dual-liquid split cementing, the cement slurry delivery pipe is inserted 3m into the borehole from one side of the fully leaky formation borehole, and the quick-setting agent is injected into the other side of the fully leaky formation borehole. The injection conditions are: first inject the quick-setting agent into the borehole, then inject the cement slurry into the borehole, pause for 1.5 minutes, and then repeat the above operation. The mass ratio of the quick-setting agent to the cement slurry is 0.37:1. The accelerator can speed up the initial setting of cement paste, causing it to lose its fluidity and rapidly increase its strength; The density of the cement slurry is 1.8 g / cm³. 3 The quick-setting agent is liquid sodium silicate. S3. When the total mass of the quick-setting agent and the cement slurry injected in S2 is 1.5 times the amount of cement slurry required in S1, stop injecting the quick-setting agent and cement slurry into the fully leaky formation borehole. After the quick-setting agent and cement slurry solidify for 75 minutes, their strength is sufficient to support the pressure of the cement slurry column in the upper non-leaking section, thus completing the cementing of the fully leaky formation borehole.

[0019] This embodiment also provides an application of the above-described drilling and cementing method for completely lost-circuit formations: In the 2025 Surface Geological Drilling Project (Phase III) of Yuandian No. 2 Coal Mine of Huaibei Mining Co., Ltd., the Hydrological Exploration Team of Anhui Provincial Coalfield Geological Bureau drilled three boreholes through the goaf. The cementing method of the fully perforated formation was adopted in Example 1. The total cementing time was shortened by 1.2h, 1.3h and 1h respectively, and the material consumption was only 1.1, 1.15 and 1.2 times that of the normal formation design consumption.

[0020] Comparative Example 1 This comparative example demonstrates the application of traditional cementing methods: (1) During the construction of a large-diameter gas hole project in a mine in Henan Province, the traditional internal cementing method was adopted to address the cementing problem in the leakage section of the goaf. Cement slurry was injected into the outer casing ring through a 50mm drill pipe. After five repeated cementing operations, the total time was 8 days and the material consumption exceeded the design amount by 5 times.

[0021] (2) In a pipeline well project in a mine in Anhui Province, due to the connection between the borehole and the roadway, leakage occurred in the second casing cementing. The project adopted the traditional single liquid slurry cementing method, and the total cementing time was 5 days, with material consumption exceeding the design amount by 3 times.

[0022] In summary, by comparing Example 1, Example 2, Example 3 and Comparative Example 1, it can be seen that the drilling and cementing methods for fully leaky formations in Example 1 and Example 2 are time-saving and save time costs; they also reduce material consumption and significantly reduce material costs.

[0023] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for drilling and cementing in a completely leaky formation, characterized in that, The method is as follows: S1. Calculate the required amount of cement slurry based on the length of the lost section in the fully leaking formation borehole. S2. Utilize dual-liquid split cementing, alternately injecting quick-setting agent and cement slurry; S3. When the total mass of the quick-setting agent and the cement slurry injected in S2 is 1.5 times the amount of cement slurry required in S1, stop injecting the quick-setting agent and cement slurry into the fully leaky formation borehole. After the quick-setting agent and cement slurry solidify, the cementing of the fully leaky formation borehole is completed.

2. The method for drilling and cementing in a completely leaky formation according to claim 1, characterized in that, The dual-liquid diversion mentioned in S2 refers to inserting the cement slurry delivery pipe 3m into the borehole from one side of the fully leaky formation borehole, and injecting the quick-setting agent from the other side of the fully leaky formation borehole.

3. The method for drilling and cementing in a completely leaky formation according to claim 1, characterized in that, The density of the cement paste described in S1, S2 and S3 is 1.8 g / cm³. 3 The quick-setting agent mentioned in S2 is liquid sodium silicate.

4. The method for drilling and cementing in a completely leaky formation according to claim 1, characterized in that, The conditions for alternating injection of quick-setting agent and cement slurry in S2 are as follows: first inject quick-setting agent into the fully leaking formation borehole, then inject cement slurry into the fully leaking formation borehole, pause for 1 min to 2 min, and then repeat the above operation; the mass ratio of quick-setting agent to cement slurry is 0.37:

1.

5. The method for drilling and cementing a completely leaky formation according to claim 1, characterized in that, The setting time of the quick-setting agent and cement grout mentioned in S3 is 1h to 1.5h.