Oil-gas-water-invasion-resistant cement paste suitable for well cementation of adjusting well
By adding flocculant, permeable crystallization self-healing agent, oil-healing agent and gas-healing agent to the cement slurry, the water and micro-crack problems caused by no waterproof material in the cement slurry system are solved, and the cement slurry is realized The solidification stability and self-healing ability improve the long-term sealing and safety of oil and gas wells.
Patent Information
- Application Number
- CN202310977747.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-04
- Publication Date
- 2025-02-14
AI Technical Summary
In the prior art, since there is no waterproof material in the cement slurry system, water flows into the cement slurry and directly affects the solidification process of the cement slurry, destroys the structure and cementing quality of the cement ring, and has adverse effects on the mining of oil and gas wells. At the same time, the cement ring is later stage. Microcracks are generated and cannot be repaired automatically, resulting in oil, gas and water traversing.
Add flocculant, permeable crystallization self-healing agent, oil-healing agent and gas-healing agent to the cement slurry. Through the combined action of these components, the solidification stability and self-healing ability of the cement slurry are improved and water slurry is prevented from squirting. and the creation of micro-cracks.
It effectively improves the solidification stability and bonding quality of cement slurry, prevents water squirting and microcracking, maintains the long-term sealing and self-healing ability of the cement ring, and ensures the long-term, safe and effective operation of the oil and gas well.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of oil and gas well cementing engineering, and in particular to an oil, gas and water intrusion resistant cement slurry suitable for cementing an adjustment well. Background Art
[0002] Most of my country's onshore oil fields have entered the late stage of high water content development. Even newly developed oil reservoirs mostly use early water injection development to maintain formation productivity, which makes cementing operations face the problem of water channeling. At present, the water channeling problem of oil and gas wells, especially adjustment well cementing, is a technical problem that has not been well solved in various oil fields. At the same time, the formations with oil, gas and water in the same layer make it more difficult to ensure the sealing quality, which seriously restricts the implementation of oilfield development strategies and the improvement of oil and gas recovery. After the formation oil, gas and water channel into the cement slurry, it will directly affect the solidification process of the cement slurry, destroy the structure and bonding quality of the cement sheath, and have an adverse effect on the exploitation of oil and gas wells.
[0003] Domestic oil fields have conducted a lot of research on the problem of water channeling according to their own formation characteristics, and have also achieved some research results. However, due to the limitations of water channeling mechanism research and the characteristics of cement admixtures, the overall technical level of water channeling is still unsatisfactory. The research on anti-channeling materials is mostly focused on the research of anti-gas channeling materials. The lack of special anti-channeling materials leads to the direct impact of water channeling into cement slurry on the solidification process of cement slurry. Lu Haichuan has studied a kind of anti-channeling material for cementing and its preparation method, which can play a role in preventing water channeling during the waiting process of cement slurry, but after the cement stone is formed in the later stage, it cannot prevent water from invading and maintain the sealing integrity of the cement ring. Summary of the invention
[0004] The purpose of the present invention is to provide an oil, gas and water-resistant cement slurry suitable for cementing of adjustment wells, which solves the technical problem in the prior art that there is no anti-water intrusion material in the cement slurry system, which causes water to enter the cement slurry and directly affects the solidification process of the cement slurry, destroys the structure and bonding quality of the cement sheath, and has an adverse effect on the production of oil and gas wells. At the same time, it solves the technical problem that microcracks in the cement sheath cannot be automatically repaired after oil, gas and water intrusion in the later stage.
[0005] In order to solve the above technical problems, the technical solution provided by the present invention is:
[0006] The invention discloses an anti-oil, gas and water intrusion cement slurry suitable for adjusting well cementing, which comprises the following components in parts by mass: 100 parts by mass of cement, 1.5-2.5 parts by mass of fluid loss reducer, 0.2-1.0 parts by mass of drag reducer, 38-46 parts by mass of distilled water, 0.2-0.5 parts by mass of flocculant, 2-5 parts by mass of permeation crystallization self-healing agent, 5-7 parts by mass of oil-encountered self-healing agent, 10-12 parts by mass of gas-encountered self-healing agent, 0.1-0.3 parts by mass of retarder, 2-4 parts by mass of expansion agent and 0.1-0.5 parts by mass of defoamer.
[0007] Furthermore,
[0008] The cement is silicate cement.
[0009] Furthermore,
[0010] The fluid loss reducer is a 2-acrylamide-2-methylpropanesulfonic acid AMPS polymer.
[0011] Furthermore,
[0012] The drag reducer is an aldehyde-ketone condensate.
[0013] Furthermore,
[0014] The flocculant is one of anionic polyacrylamide, cationic polyacrylamide, neutral polyacrylamide and non-ionic polyacrylamide, and has a molecular weight of 8-12 million.
[0015] Furthermore,
[0016] The infiltration crystallization self-healing agent is a water-based self-healing agent, which can repair micro cracks below 0.4 mm.
[0017] Furthermore,
[0018] The oil-encountering self-healing agent can swell and heal when encountering oil.
[0019] Furthermore,
[0020] The self-healing agent can swell and heal when it encounters hydrocarbon gas.
[0021] Furthermore,
[0022] The retarder is a 2-acrylamide-2-methylpropanesulfonic acid AMPS polymer.
[0023] Furthermore,
[0024] The expansion agent is a lattice expansion agent.
[0025] Based on the above technical solutions, the technical effects that can be achieved by the present invention are:
[0026] The cement slurry provided by the invention is mixed with a flocculant, and the underwater loss rate of the system is less than 1.5%, so that the cement slurry does not disperse in water, the gelling substances in the system do not separate, and the strength and bonding quality of the cement stone are improved.
[0027] The cement slurry provided by the invention is mixed with an expansion agent, so that the expansion rate of cement stone is greater than 0.05%, which effectively offsets the volume shrinkage caused by cement hydration and prevents the generation of micro cracks in the underground annulus.
[0028] The cement slurry provided by the present invention is mixed with a permeable crystallization self-healing agent, which can repair micro cracks below 0.4 mm. The permeable crystallization self-healing agent is a waterproof material with automatic repairing properties formed by compounding active silicon, cement, active inorganic mixture, etc. The permeable crystallization self-healing agent is added so that when micro cracks are generated in the cement stone at a later stage, if formation water invades the cement stone matrix, the active ingredients in it will automatically recrystallize, repair micro cracks below 0.4 mm, and maintain the long-term sealing of the cement ring.
[0029] The cement slurry provided by the present invention is mixed with an oil- and gas-encountered self-healing agent, which can expand when exposed to oil and expand when exposed to hydrocarbon gas. The oil- and gas-encountered self-healing agent is added so that when microcracks are generated in the cement stone at a later stage, if formation oil or gas invades the cement stone matrix, the active ingredients therein will automatically expand to repair the microcracks and maintain the integrity of the cement ring.
[0030] The cement slurry provided by the present invention has good sedimentation stability under the joint stacking action of multiple components, and the cement stone has the characteristics of micro-expansion, high strength, low elastic modulus, anti-gas channeling, resistance to oil, gas and water invasion, self-healing when encountering water, oil and gas, etc. When sealing strata with oil and water in the same layer, gas and water in the same layer, or oil, gas and water in the same layer, the active ingredients in the cement slurry can intelligently repair cracks, which can avoid the phenomenon of "peaking" of cementing quality caused by oil, gas and water channeling after cementing of the adjustment well, as well as the generation of microcracks, microannular gaps and even ruptures in the cement ring, thereby achieving good interlayer isolation and providing technical support for the long-term, safe and effective operation of oil and gas wells. DETAILED DESCRIPTION
[0031] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.
[0032] The endpoints and any values of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, the endpoint values of each range and the individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in this article.
[0033] Therefore, the following detailed description is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0034] In order to solve the problem that cement slurry in the prior art is difficult to meet the requirements of on-site application, an embodiment of the present invention provides a cement slurry, which includes, in parts by mass, 100 parts by mass of cement, 1.5-2.5 parts by mass of fluid loss reducer, 0.2-1.0 parts by mass of drag reducer, 38-46 parts by mass of distilled water, 0.2-0.5 parts by mass of flocculant, 2-5 parts by mass of osmotic crystallization self-healing agent, 5-7 parts by mass of oil-involved self-healing agent, 10-12 parts by mass of air-involved self-healing agent, 0.1-0.3 parts by mass of retarder, 2-4 parts by mass of expansion agent, and 0.1-0.5 parts by mass of defoaming agent.
[0035] Preferably, the cement is Portland cement.
[0036] Preferably, the fluid loss agent is a 2-acrylamide-2-methylpropanesulfonic acid AMPS polymer.
[0037] Preferably, the drag reducer is an aldehyde-ketone condensate.
[0038] Preferably, the flocculant is anionic polyacrylamide with a molecular weight of 8-12 million.
[0039] Preferably, the penetrating crystallization self-healing agent is a water-based self-healing agent that can repair microcracks below 0.4 mm.
[0040] Preferably, the water-based self-healing agent is a mixture of silicone emulsion, potassium sulphoaluminate dodecahydrate, calcium hydroxide, bentonite and sodium silicate in a certain proportion.
[0041] Preferably, the oil-entraining self-healing agent is BCY-200S produced by PetroChina Boxing Engineering Technology Co., Ltd.
[0042] Preferably, the air-induced self-healing agent is BCY-201S produced by China National Petroleum Corporation Boxing Engineering Technology Co., Ltd.
[0043] Preferably, the retarder is 2-acrylamide-2-methylpropanesulfonic acid AMPS polymer.
[0044] Preferably, the expansion agent is a lattice expansion agent.
[0045] In the following specific embodiments, relevant performance data of cement slurries with different component contents and relevant performance data after hardening are provided. Experiments have proved that the above-mentioned cement slurries have the various advantages described above.
[0046] Table 1 includes experimental formula data of cement slurries in multiple examples, and Comparative Example 1 is an existing formula of cement slurry for resisting oil, gas and water intrusion. The components in the examples and comparative examples are all measured in parts by mass.
[0047] Table 1:
[0048] In Example 1, a water-based self-healing agent, an oil-based self-healing agent, and an air-based self-healing agent are added at the same time. In Comparative Example 1, a water-based self-healing agent is added. In Comparative Example 2, an oil-based self-healing agent is added. In Comparative Example 3, an air-based self-healing agent is added. In Comparative Example 4, a water-based self-healing agent and an oil-based self-healing agent are added. In Comparative Example 5, a water-based self-healing agent and an air-based self-healing agent are added. In Comparative Example 6, an oil-based self-healing agent and an air-based self-healing agent are added. In Comparative Example 7, no self-healing agent is added.
[0049] This embodiment provides performance test experiments of cementing slurry in Examples 1 to 6 and Comparative Examples 1 to 7, wherein the density measurement, fluidity measurement, API water loss measurement, free liquid measurement, and thickening time measurement are carried out according to the GB / T19139 oil well cement test method; the underwater loss rate is carried out according to the test method of the Q / CNPC underwater non-dispersible concrete construction technical specification. The results of the above performance tests are shown in Table 2.
[0050] Table 2:
[0051] As can be seen from Table 2, compared with the comparative example, the cementing cement slurry provided in this embodiment has the advantages of good adjustability of thickening time, good fluidity, low water loss, zero free liquid, etc., which can effectively improve the field adaptability of cement slurry, ensure the safety of cementing construction, and ensure the quality of cementing. The basic performance of the cement slurry in comparative examples 1-6 is not much different from that of Example 1. The existing anti-oil, gas and water intrusion cement slurry, such as comparative example 7, does not add flocculants and self-healing agents for oil, gas and water in the cement slurry system. The cement slurry has some free liquid, the underwater loss rate is relatively large, and the cement slurry matrix has poor cohesion, which cannot prevent the invasion of high-temperature and high-pressure oil, gas and water in the well, and cannot meet the construction needs of adjusting well cementing.
[0052] This embodiment provides a performance test experiment of cement stone obtained after the cementing cement slurry in Examples 1 to 6 and Comparative Examples 1 to 7 is hardened, wherein the measurement of elastic modulus, compressive strength, volume expansion rate, and permeability are carried out in accordance with the GB / T19139 oil well cement test method; the degree of repair of 0.4 mm cracks is observed by scanning electron microscopy.
[0053] The test method for breakthrough pressure is as follows: (1) Seam making. The cylindrical test seam is made by the Brazilian splitting method; first, the cylindrical specimen is placed in a splitting mold, placed on the pressure head of the triaxial testing machine, and the mold blade is aligned with the center of the cylinder. The splitting seam is made at a loading speed of 0.5 mm / min. Pay attention to the load change. When the load suddenly drops, stop loading immediately and take out the cylindrical specimen. (2) Sample processing. After filling the indentation or damaged part of the splitting blade position of the sample after seam making with room temperature curing AB glue, carefully transfer the sample to a heat shrink tube with a diameter of 30±2 mm, and use a hair dryer to heat the heat shrink tube to wrap the sample after seam making. Leave it at room temperature for at least 12 hours to ensure that the AB glue is cured and set aside. (3) Breakthrough pressure test. Place the treated sample in the core holder of the core flow instrument and apply a confining pressure of 7MPa. Fill the piston container with kerosene, keep the core holder and piston container constant temperature at 40°C, and connect the end of the core holder to the glass receiving container. According to the core flow instrument operation steps, set the injection flow rate of the constant flow pump to 0.20mL / min. After turning on the constant flow pump, observe the injection pressure at the inlet of the core holder and whether there is continuous liquid outflow at the outlet of the core holder. Record the injection pressure at the inlet when liquid outflows from the outlet of the core holder, which is the breakthrough pressure, and stop the test.
[0054] The results of the above performance tests are shown in Table 3.
[0055] Table 3:
[0056] It can be seen from Table 3 that, compared with Comparative Example 7 in which no self-healing agent was added, Comparative Examples 1-3 in which only one self-healing agent was added, and Comparative Examples 4-6 in which two self-healing agents were added, the cement slurry of Example 1 has good sedimentation stability, a lower elastic modulus of cement stone, higher compressive strength, and stronger self-healing ability against oil, gas and water invasion, water, oil and gas; compared with the comparative example, the cement slurry provided in this embodiment has good sedimentation stability, and the cement stone has the characteristics of micro-expansion, high strength, low elastic modulus, anti-gas channeling, anti-oil, gas and water invasion, and self-healing when encountering water, oil and gas. It can avoid the phenomenon of "peaking" of cementing quality caused by oil, gas and water channeling after cementing of the adjustment well, as well as the generation of microcracks, microannular gaps and even ruptures in the cement ring, achieve good interlayer isolation, and provide technical support for the long-term, safe and effective operation of oil and gas wells. The existing anti-oil, gas and water invasion cement slurry such as comparative examples 1-7 shows that the elastic modulus of the cement slurry increases, the compressive strength decreases, the volume expansion rate decreases, the permeability increases, the crack healing ability decreases, and the overall performance cannot meet the construction needs of the adjustment well cementing.
[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. An oil, gas and water intrusion resistant cement slurry suitable for cementing an adjustment well, characterized in that: The invention comprises the following components in parts by mass: 100 parts by mass of cement, 1.5-2.5 parts by mass of fluid loss reducer, 0.2-1.0 parts by mass of drag reducer, 38-46 parts by mass of distilled water, 0.2-0.5 parts by mass of flocculant, 2-5 parts by mass of osmotic crystallization self-healing agent, 5-7 parts by mass of oil-exposed self-healing agent, 10-12 parts by mass of air-exposed self-healing agent, 0.1-0.3 parts by mass of retarder, 2-4 parts by mass of expansion agent and 0.1-0.5 parts by mass of defoaming agent.
2. The oil-gas-water intrusion resistant cement slurry for adjusting well cementing according to claim 1 is characterized in that: The cement is silicate cement.
3. The oil-gas-water intrusion resistant cement slurry for cementing an adjustment well according to claim 1, characterized in that: The fluid loss reducer is a 2-acrylamide-2-methylpropanesulfonic acid AMPS polymer.
4. The oil-gas-water intrusion resistant cement slurry for adjusting well cementing according to claim 1, characterized in that: The drag reducer is an aldehyde-ketone condensate.
5. The oil-gas-water intrusion resistant cement slurry for adjusting well cementing according to claim 1, characterized in that: The flocculant is one of anionic polyacrylamide, cationic polyacrylamide, neutral polyacrylamide and non-ionic polyacrylamide, and has a molecular weight of 8-12 million.
6. The oil-gas-water intrusion resistant cement slurry for adjusting well cementing according to claim 1, characterized in that: The infiltration crystallization self-healing agent is a water-based self-healing agent, which can repair micro cracks below 0.4 mm.
7. The oil, gas and water intrusion resistant cement slurry for adjusting well cementing according to claim 1 is characterized in that: The oil-encountering self-healing agent can swell and heal when encountering oil.
8. The oil, gas and water intrusion resistant cement slurry for adjusting well cementing according to claim 1 is characterized in that: The self-healing agent can swell and heal when it encounters hydrocarbon gas.
9. The oil-gas-water intrusion resistant cement slurry for adjusting well cementing according to claim 1, characterized in that: The retarder is a 2-acrylamide-2-methylpropanesulfonic acid AMPS polymer.
10. The oil, gas and water intrusion resistant cement slurry for adjusting well cementing according to claim 1, characterized in that: The expansion agent is a lattice expansion agent.