Solid medicament filling method for shale oil horizontal well shaft

Abstract

The invention discloses a shale oil horizontal well shaft solid agent filling method which is specifically implemented according to the following steps that 1, after a shaft is treated to a well bottom pocket, a well is washed, and a drill is pulled out; 2, a plurality of soluble metal containers are selected according to needs, the soluble metal containers are connected in series, and each soluble metal container is filled with a plurality of solid medicament particles; 3, drilling is conducted, and the soluble metal container in the step 1 is pushed into a well bottom pocket through a pipe column; and 4, the pipe column is lifted to the operation section for operation, and well completion and commissioning are conducted. According to the method, the problem that in the prior art, the agent cannot be injected to the target position of a well bottom pocket from the position 1000 m below the shaft of the shale oil long horizontal well is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum extraction, and in particular relates to a method for injecting solid reagents into a shale oil horizontal wellbore. Background Art

[0002] my country is rich in shale oil and gas resources, which are mainly distributed in the Ordos, Sichuan, Songliao, Bohai Bay, Junggar and other basins. Exploration and evaluation show that the total shale oil resources alone amount to 11 to 13.5 billion tons. With the continuous advancement of exploration and development technology, especially the breakthrough of horizontal well volume fracturing technology, shale oil development has been piloted in Changqing Oilfield, Daqing Oilfield and Tuha Oilfield.

[0003] The proportion of horizontal wells in shale oil long horizontal sections is high, and most of the horizontal sections are 2000 meters to 3000 meters. During the production process, the sand produced by the oil wells accumulates and cements near the holes, accompanied by wellbore scaling. The proportion of pump inspection wells caused by scaling in shale oil horizontal wells is 7.5%, and the scaling location is concentrated in the pump and 300 meters above the pump, with a thickness of 0.5mm to 2.5mm. The scale type is mainly carbonate scale, and barium sulfate scale is also found in a few wells. The phenomenon of sand scale hardening is prominent, and 50% of the sand flushing operation wells have sand scale hardening. The scaling products are mainly FeCO3, CaCO3, and Fe2O3. The longer the horizontal section, the longer the scaling distance. The phenomenon of scale sand hardening has existed in the horizontal wells developed over the years, and the scaling products increase with the extension of the production time. Through the analysis of scaling products: with the increase of production time, the size of the cemented sand block increases (1-10cm), the density is strong, and the content of scaling products increases significantly. In the early stage, it is mainly FeCO3, and in the later stage, it is mainly CaCO3. The scaling mechanism is analyzed from the sources of the main scaling products CaCO3 and FeCO3 ions. CaCO3: It is the most common scaling type in oil fields. Under the formation water environment, calcium carbonate is in a saturated state. When the pressure drops during the production process, CO2 escapes and CaCO3 precipitates. FeCO3: Its CO3 2- The source is the same as CaCO3, from formation water, ferrous ion Fe 2+ There are several sources: casing corrosion, ball seat dissolution and dissolution of formation filling materials. 2+ The source is mainly liquid dissolution of formation filling materials, which is also confirmed by the core sampling results of North American fracturing wells. At present, there are mature anti-scaling agents such as PBTCA for calcium carbonate scale, but the shale oil horizontal wellbore 1000-1400 meters and perforation section are severely scaled, and conventional liquid and solid anti-scaling agents are difficult to reach.

[0004] China Patent Publication No. CN115559689A discloses a drug-adding plunger suitable for drainage, gas production and wax removal in horizontal wells of condensate gas reservoirs, which realizes the functions of drainage, gas production and wax removal at the same time; China Patent Publication No. CN210798939U discloses a drug-adding device for horizontal wells in oil fields, in which the drug is added between the casing and the oil pipe through the filling pipe, reducing the impact of the casing gas on the drug addition; China Patent Publication No. CN208152990U discloses a self-energy drug-adding device for horizontal wells, which adds liquid drugs to the annulus of the oil casing under normal pressure. However, none of these patent technologies mention how to add drugs to the target position of the bottom pocket below 1,000 meters in the wellbore of a long horizontal well of shale oil. Summary of the invention

[0005] The purpose of the present invention is to provide a method for injecting solid reagents into a shale oil horizontal wellbore, which solves the problem in the prior art that the reagents cannot be injected into a shale oil long horizontal wellbore below 1000 meters to a target position of a bottom pocket.

[0006] The technical solution adopted by the present invention is a method for injecting solid reagents into a shale oil horizontal wellbore, which is specifically implemented according to the following steps:

[0007] Step 1: After the wellbore is processed to the bottom pocket, the well is cleaned and the drill is pulled out;

[0008] Step 2, selecting a plurality of soluble metal containers as required, and arranging the plurality of soluble metal containers in series, each of the soluble metal containers containing a plurality of solid pharmaceutical particles;

[0009] Step 3, drilling down, pushing the soluble metal container in step 1 into the bottom pocket of the well through the pipe string;

[0010] Step 4: lift the tubing string to the operating section for operation and complete the well and put it into production.

[0011] The present invention is also characterized in that:

[0012] In step 2, two adjacent soluble metal containers are connected by ordinary threads of an oblong buckle.

[0013] In step 2, the soluble metal container is a cylinder, and the material is magnesium-aluminum alloy or zinc-magnesium alloy.

[0014] In step 2, the size of the soluble metal container is The wall thickness is 3mm~5mm.

[0015] In step 2, the solid pharmaceutical particles are spheres or cylinders, and the total amount of solid pharmaceutical particles added is 10ppm to 100ppm of the liquid production.

[0016] In step 2, the outer diameter of the solid pharmaceutical particles is 1 mm to 3 mm, and the volume density is 0.7 t / m 3 ~0.9t / m3 , compressive strength is not less than 28MPa.

[0017] In step 2, the solid pharmaceutical particles are composed of a main agent and a skeleton material, the main agent is one of PBTCA, EDTMP, and ATMP, and the skeleton material is EVA.

[0018] In step 3, the tubing string includes a tool tubing, and the bottom end of the tool tubing is connected to a bevel tip.

[0019] The beneficial effects of the present invention are:

[0020] (1) The solid reagent injection method for shale oil horizontal wellbore of the present invention can place solid reagents in the bottom pocket of the well, thereby improving the effect of the reagents, reducing the frequency of well repairs, and improving production time efficiency;

[0021] (2) The solid reagent filling method for shale oil horizontal wellbore of the present invention has a filling cycle that matches the shale oil wellbore operation cycle. The filling can be carried out by using the wellbore and measures operation, without the need for separate operations, thereby reducing costs;

[0022] (3) The method for injecting solid reagents into the wellbore of shale oil horizontal wells of the present invention fundamentally solves the problem that horizontal wells cannot be injected with reagents in a conventional manner, thus achieving wellbore management. It is also applicable to shale oil injection requirements such as anti-corrosion and anti-wax, without the need to adjust the production system, thus maximizing shale oil production. DETAILED DESCRIPTION

[0023] The present invention is described in detail below in conjunction with specific implementation modes.

[0024] The present invention provides a method for injecting solid reagents into a shale oil horizontal wellbore, which is specifically implemented according to the following steps:

[0025] Step 1: After the wellbore is treated to the bottom pocket, the well is washed for 1.5 well volumes and the drill is started;

[0026] Step 2, selecting a plurality of soluble metal containers as required, and arranging the plurality of soluble metal containers in series, each of the soluble metal containers containing a plurality of solid pharmaceutical particles;

[0027] The number of soluble metal containers is determined according to the amount of solid pharmaceutical particles, and each soluble metal container can hold 9 kg of solid pharmaceutical particles;

[0028] The soluble metal container is a cylindrical container with dimensions of The wall thickness is 3mm to 5mm, and it is made of magnesium-aluminum alloy or zinc-magnesium alloy;

[0029] Two adjacent soluble metal containers are connected by ordinary threads of long round buckles;

[0030] Solid pharmaceutical particles are spheres or cylinders with an outer diameter of 1mm to 3mm and a volume density of 0.7t / m 3 ~0.9t / m 3 , the effective period of dissolution is more than 600 days, the total amount of solid pharmaceutical particles added is 10ppm~100ppm of the liquid production, and the pressure resistance is not less than 28MPa;

[0031] The solid pharmaceutical particles are composed of a main agent and a skeleton material. The main agent is one of PBTCA, EDTMP, ATMP, etc., and the skeleton material is EVA, etc.

[0032] Step 3, drilling down, pushing the soluble metal container in step 1 into the bottom pocket of the well through the pipe string;

[0033] The tubing string includes a tool tubing, the bottom end of which is connected to an oblique tip;

[0034] The tubing string may also be an acidizing or fracturing operation tubing string, which can push the soluble metal container into the bottom hole pocket.

[0035] Step 4: lift the tubing string to the operating section for operation and complete the well and put it into production.

[0036] Example 1

[0037] The H7-A well has a horizontal section of 1,500 meters and a bottom pocket of 150 meters. After the wellbore is treated to the bottom pocket, the well is washed for 1.5 well volumes, the drill is pulled out, and 20 soluble metal containers are placed in series. The outer diameter of the solid agent particles is 1 mm and the volume density is 0.7 t / m 3 The total amount added is 180kg. The main agent of the solid reagent particles is PBTCA. After drilling, the pipe string is combined into a tool tubing + inclined tip. The soluble metal container is pushed into the bottom hole pocket and the well is completed and put into production.

[0038] After being put into production, the cumulative production in the first three years increased by 123% compared with the neighboring wells without adding chemicals. After two years, the soluble metal dissolved substances were washed out of the well, and the wellbore remained unobstructed, and there was no blockage due to scaling in the later period.

[0039] Example 2

[0040] Mu H21-A well, the horizontal section is 2300 meters long, the bottom pocket is 180 meters, after the wellbore is treated to the bottom pocket, the well is washed for 1.5 well volumes, the drill is pulled out, and 10 soluble metal containers are placed in series, of which the outer diameter of the solid agent particles is 3mm and the volume density is 0.9t / m 3 The total amount added is 90kg. The main agent of the solid reagent particles is EDTMP. After drilling, the pipe string is combined into a tool tubing + inclined tip. The soluble metal container is pushed into the bottom pocket of the well. After segmented acidification, the well is completed and put into production.

[0041] After being put into production, the cumulative production in the first three years increased by 166% compared with the neighboring wells without adding chemicals. After one year, the soluble metal dissolved substances were washed out of the well, and the wellbore remained unobstructed, and there was no blockage due to scaling in the later period.

[0042] Example 3

[0043] The H35-A well has a horizontal section of 1,800 meters and a bottom pocket of 80 meters. After the wellbore is treated to the bottom pocket, the well is washed for 1.5 well volumes, the drill is pulled out, and 20 soluble metal containers are placed in series. The outer diameter of the solid agent particles is 2 mm and the volume density is 0.8 t / m 3 The total amount added is 90kg. The main agent of the solid reagent particles is ATMP. After drilling, the pipe string is combined with a tool tubing + an inclined tip. The soluble metal container is pushed into the bottom hole pocket. After segmented acidification, the well is completed and put into production.

[0044] After being put into production, the cumulative production in the first three years increased by 189% compared with the neighboring wells without adding chemicals. After one and a half years, the soluble metal dissolved substances were washed out of the well, and the wellbore remained unobstructed, and there was no blockage due to scaling in the later period.

[0045] Example 4

[0046] Hua H70-A Well, the horizontal section is 3500 meters long, the bottom pocket is 280 meters, after the wellbore is treated to the bottom pocket, the well is washed for 1.5 well volumes, the drill is pulled out, and 6 soluble metal containers are placed in series, among which the outer diameter of the solid reagent particles is 1mm and the volume density is 0.8t / m 3 The total amount added is 180kg. The main agent of the solid reagent particles is PBTCA. After drilling, the pipe string is combined into a tool tubing + inclined tip. The soluble metal container is pushed into the bottom hole pocket. After staged fracturing, the well is completed and put into production.

[0047] After being put into production, the cumulative production in the first three years increased by 171% compared with the neighboring wells without adding chemicals. After one and a half years, the soluble metal dissolved substances were washed out of the well, and the wellbore remained unobstructed, and there was no blockage due to scaling in the later period.

[0048] The solid reagent filling method for shale oil horizontal wellbore of the present invention is to put the solid reagent into a soluble metal container, and use the downhole operation pipe string to push the soluble metal container into an artificial bottom pocket of the well. After the operation, the soluble metal container gradually dissolves, and the solid reagent gathers in the bottom pocket of the well. By dissolving and diffusing, the wellbore under the entire liquid surface is protected from scaling, the frequency of well repair is reduced, and the production time rate is improved. The filling method of the present invention is simple and can be completed through conventional oil pipe operations.

Claims

1. A method for injecting solid reagents into a shale oil horizontal wellbore, characterized in that: Follow the steps below to implement it: Step 1: After the wellbore is processed to the bottom pocket, the well is cleaned and the drill is pulled out; Step 2, selecting a plurality of soluble metal containers as required, and arranging the plurality of soluble metal containers in series, each of which contains a plurality of solid pharmaceutical particles; Step 3, drilling down, pushing the soluble metal container in step 1 into the bottom pocket of the well through the pipe string; Step 4: lift the tubing string to the operating section for operation and complete the well and put it into production.

2. The method for injecting solid reagents into a shale oil horizontal wellbore according to claim 1, characterized in that: In step 2, two adjacent soluble metal containers are connected by ordinary threads of an oblong buckle.

3. The method for injecting solid reagents into a shale oil horizontal wellbore according to claim 1, characterized in that: In step 2, the soluble metal container is a cylinder, and the material is magnesium-aluminum alloy or zinc-magnesium alloy.

4. The method for injecting solid reagents into a shale oil horizontal wellbore according to claim 3, characterized in that: In step 2, the size of the soluble metal container is φ89mm×2m, and the wall thickness is 3mm~5mm.

5. The method for injecting solid reagents into a shale oil horizontal wellbore according to claim 1, characterized in that: In step 2, the solid pharmaceutical particles are spheres or cylinders, and the total amount of solid pharmaceutical particles added is 10ppm to 100ppm of the liquid production.

6. The method for injecting solid reagents into a shale oil horizontal wellbore according to claim 5, characterized in that: In step 2, the outer diameter of the solid pharmaceutical particles is 1 mm to 3 mm, and the volume density is 0.7 t / m 3 ~0.9t / m 3 , compressive strength is not less than 28MPa.

7. The method for injecting solid reagents into a shale oil horizontal wellbore according to claim 5, characterized in that: In step 2, the solid pharmaceutical particles are composed of a main agent and a skeleton material, the main agent is one of PBTCA, EDTMP, and ATMP, and the skeleton material is EVA.

8. The method for injecting solid reagents into a shale oil horizontal wellbore according to claim 1, characterized in that: In step 3, the tubing string includes a tool tubing, and the bottom end of the tool tubing is connected to a bevel tip.