Leaking stoppage spacer fluid as well as preparation method and application thereof

Abstract

The invention discloses leaking stoppage spacer fluid as well as a preparation method and application thereof. The leaking stoppage spacer fluid is prepared from the following components in parts by mass: 290 to 310 parts of silicon powder, 150 to 170 parts of ferromanganese ore powder, 40 to 60 parts of micro silicon, 100 to 120 parts of rubber particles Flex medium, 34 to 36 parts of a suspending agent bod2, 40 to 60 parts of a leaking stoppage agent Plus and 600 to 800 parts of water. According to the plugging spacer fluid disclosed by the invention, if leakage occurs in a well during cementing, the plugging spacer fluid can quickly plug 1-2mm pores and cracks, so that a stratum can be quickly plugged when cement paste flows through the plugging spacer fluid, the leakage of the cement paste is avoided, the well cementation quality of the stratum prone to leakage is improved, and the plugging spacer fluid can be compatible with drilling fluid and the cement paste; the problem of leakage of a stratum in the cementing process can be effectively prevented, the requirement for leaking stoppage of the stratum at the high temperature of 120 DEG C is met, the pressure bearing capacity can reach 750 PSI, and a guarantee is provided for follow-up operation of an oil and gas well.

Description

Technical Field

[0001] The present invention relates to the technical field of drilling plugging isolation fluids, and more specifically, to a plugging isolation fluid, a preparation method thereof, and an application thereof. Background Art

[0002] During the process of oil drilling, the problem of lost circulation often occurs. Lost circulation is one of the most common complex phenomena. Especially in micro-fractured formations, permeable formations, shale formations and reservoirs, the risk of wellbore instability and lost circulation increases greatly. Wellbore instability usually causes the collapse of the wellbore, leading to the risks of stuck pipe and burying drill tools. The occurrence of lost circulation greatly increases reservoir damage, the cost of drilling fluid preparation, prolongs the drilling cycle, and even brings well control risks, resulting in the abandonment of the wellbore and causing significant economic losses.

[0003] In drilling operations, when the hydrostatic pressure of the drilling fluid is too high, it will fracture the formation and form artificial secondary fractures. The drilling fluid will leak into the formation along the fractures under the pressure difference between the wellbore and the formation, resulting in lost circulation. Especially the lost circulation occurring in low-pressure formations is more complex to handle, and the common plugging measures are difficult to meet its special requirements.

[0004] The conventional methods for solving the problem of lost circulation at home and abroad are to add plugging materials. According to the action principle of the plugging agent, the current methods for treating lost circulation are mainly divided into two categories: chemical plugging and physical plugging.

[0005] Chemical plugging technology mainly achieves the purpose of plugging through the chemical reactions of polymers, involving various methods such as cross-linking reactions of polymers and curing of resins. However, due to the relatively intense chemical reactions occurring in the wellbore, the controllability of the reaction is affected by various underground factors, with high risks, and the construction and configuration are complex, greatly prolonging the drilling time.

[0006] Physical plugging relies on the bridging, reinforcing and stuffing effects of inert particles in the throats of the lost circulation channels to mechanically block the lost circulation formation, thereby achieving the purpose of eliminating lost circulation, such as lost circulation drilling fluid, lost circulation cement slurry, etc.

[0007] During the drilling process, adding lost circulation materials can usually seal the formation. However, during the cementing process, since the density of the spacer fluid and cement slurry is greater than that of the drilling fluid, and the plastic viscosity is also higher than that of the drilling fluid, when injecting cement, the annular space between the casing and the formation is smaller than the annular space between the drill string and the formation when injecting the spacer fluid and cement slurry into the wellbore, resulting in a large frictional resistance during fluid flow. At the same time, the hydrostatic pressure generated by the spacer fluid and cement slurry is higher than that of the drilling fluid. In addition, the circulation frictional resistance generated by the circulation of the spacer fluid and cement slurry during the cement injection process is also higher than that of the drilling fluid. Then, under the dual action of the hydrostatic pressure and circulation frictional resistance of the spacer fluid and cement slurry, the annular pressure during cement injection is higher than that during the drilling process, which easily leads to leakage during the cement injection process, causing the cement slurry not to reach the preset return depth, and further resulting in poor cementing quality.

[0008] In view of this, the present application is specifically proposed. Summary of the Invention

[0009] The problem existing in the prior art is that the existing lost circulation materials will cause leakage during the cement injection process, resulting in the cement slurry not reaching the preset return depth, and further leading to poor cementing quality. The purpose of the present invention is to provide a lost circulation spacer fluid and its preparation method and application. If leakage occurs in the well during cement injection, the lost circulation spacer fluid can quickly seal pores and cracks with a size of 1 - 2 mm, thereby ensuring that the cement slurry can quickly seal the formation when flowing through, avoiding the leakage of the cement slurry, improving the cementing quality of leaky formations, being compatible with the drilling fluid and cement slurry, effectively preventing the problem of formation leakage during the cement injection process, meeting the lost circulation requirements of high-temperature formations at 120 °C, and having a pressure-bearing capacity of 750 PSI, providing a guarantee for the subsequent operations of oil and gas wells.

[0010] The present invention is realized through the following technical solutions:

[0011] On the one hand, the present invention provides a lost circulation spacer fluid, which comprises the following components in parts by mass:

[0012] 290 - 310 parts of silica powder, 150 - 170 parts of ferromanganese ore powder, 40 - 60 parts of microsilica, 100 - 120 parts of rubber particles Flex medium, 34 - 36 parts of suspending agent bond2, 40 - 60 parts of lost circulation agent Plus, and 600 - 800 parts of water.

[0013] The lost circulation isolation fluid of the present invention can quickly plug pores and cracks of 1-2 mm when lost circulation occurs in the well during cementing, thereby ensuring that the cement slurry can quickly plug the formation when flowing through, avoiding the loss of the cement slurry, improving the cementing quality of the lost circulation prone formation, being compatible with drilling fluid and cement slurry, effectively preventing the problem of formation loss during cementing, meeting the lost circulation plugging requirements of high-temperature formations of 120 °C, with a pressure-bearing capacity reaching 750 PSI, providing guarantee for the subsequent operations of oil and gas wells.

[0014] The lost circulation isolation fluid of the present invention is used before the cement slurry. When it reaches the annulus, the isolation fluid flows in front of the cement slurry. At this time, the isolation fluid can well plug the lost circulation layer of the 1-2 mm crack / pore formation. When the subsequent cement slurry flows through, the loss of the cement slurry is avoided, thereby improving the displacement efficiency and effectively sealing off the lost circulation formation. And the lost circulation isolation fluid has good rheology and can effectively enter the lost circulation crack channel to complete lost circulation plugging.

[0015] In one embodiment, the mass parts of each component are as follows: 300 parts of silica powder, 160 parts of ferromanganese ore powder, 50 parts of microsilica, 110 parts of rubber particle Flex medium, 35 parts of suspending agent bond2, 50 parts of lost circulation plugging agent Plus, and 700 parts of water.

[0016] In one embodiment, the density of the ferromanganese ore powder is 4.8 g / cm 3 , and the particle size of the ferromanganese ore powder is 5 μm.

[0017] In one embodiment, the density of the silica powder is 2.32 g / cm 3 , and the particle size of the silica powder is 74 μm to 125 μm.

[0018] In one embodiment, the density of the microsilica is 2.2 g / cm 3 , and the particle size of the microsilica is 0.1 μm to 0.3 μm.

[0019] In one embodiment, the particle size of the rubber particle is 500 μm to 2000 μm.

[0020] In one embodiment, the lost circulation plugging agent Plus uses nano calcium carbonate powder with a particle size of 1 μm to 10 μm.

[0021] In one embodiment, the suspending agent bond2 uses sodium alginate.

[0022] Compared with conventional physical plugging agents, the present invention utilizes large-particle substances to bridge at narrow cracks, takes into account the particle size distribution factor, and uses particles of each level for filling. Through continuous leakage to filtration loss, a dense plugging layer can be formed. Among them, sodium alginate can increase the viscosity of the liquid phase, improve the suspension stability of solid-phase particles, and can act together with rubber particles, microsilica, silica powder, manganese iron ore powder and plugging agent Plus to form a filter cake. The particle size of the plugging agent Plus is matched according to the particle size distribution, and it can effectively plug holes and cracks with a size of ≤1 mm. When used in combination with Flex medium, it can effectively plug large holes and cracks.

[0023] In a second aspect, the present invention also provides a preparation method of a plugging isolation fluid, comprising the following steps:

[0024] Introduce silica powder, manganese iron ore powder, microsilica, rubber particles Flex medium, suspending agent bond, and plugging agent Plus into fresh water, and stir at a rotation speed of 4000 r / min for 2 min to obtain the plugging isolation fluid.

[0025] In a third aspect, the present invention also provides the application of the plugging isolation fluid or the plugging isolation fluid prepared by the above method in low-pressure and easily leaky formations.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0027] 1. The plugging isolation fluid, its preparation method and application provided by the embodiment of the present invention can quickly plug pores and cracks with a size of 1-2 mm when leakage occurs in the well during cement injection, thereby ensuring that the cement slurry can quickly plug the formation when flowing through, avoiding the leakage of the cement slurry, and improving the cementing quality of easily leaky formations.

[0028] 2. The plugging isolation fluid, its preparation method and application provided by the embodiment of the present invention have good compatibility with drilling fluid and cement slurry, can effectively prevent the problem of formation leakage during cement injection, meet the formation plugging requirements under high-temperature conditions of 120 °C, can effectively plug cracks, solve the technical problem of cement slurry leakage during cementing, and its pressure-bearing capacity reaches 750 PSI, providing guarantee for subsequent operations of oil and gas wells.

[0029] 3. The plugging isolation fluid, its preparation method and application provided by the embodiment of the present invention utilize large-particle substances to bridge at narrow cracks, take into account the particle size distribution factor, and use particles of each level for filling. Through continuous leakage to filtration loss, a dense plugging layer can be formed, thereby achieving good plugging.

[0030] 4. A plugging isolation fluid provided by an embodiment of the present invention, its preparation method, and application. Sodium alginate can increase the viscosity of the liquid phase, improve the suspension stability of solid-phase particles, and can act together with rubber particles, microsilica, silica powder, manganese iron ore powder, and plugging agent Plus to form a filter cake; among them, the particle size of the plugging agent Plus is matched according to the particle size distribution, and it can effectively plug holes and cracks ≤ 1 mm. When used in combination with Flex medium, it can effectively plug large holes and cracks. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0032] Figure 1 It is a particle size distribution diagram of rubber particles Flex medium provided by an embodiment of the present invention;

[0033] Figure 2 It is a "leakage volume - time" curve graph of seam plate plugging provided by Embodiment 1 of the present invention;

[0034] Figure 3 It is a "leakage volume - time" curve graph of orifice plate plugging provided by Embodiment 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the embodiments. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0036] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is obvious to those of ordinary skill in the art that the present invention does not have to be practiced with these specific details. In other embodiments, well-known structures, circuits, or methods are not specifically described in order to avoid obscuring the present invention.

[0037] Throughout the specification, references to "one embodiment", "an embodiment", "an example" or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Thus, the phrases "one embodiment", "an embodiment", "an example" or "an example" appearing throughout the specification do not necessarily all refer to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in any suitable combination and / or sub-combination in one or more embodiments or examples. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0038] In the description of the present invention, the orientation or positional relationship indicated by terms such as "front", "rear", "left", "right", "upper", "lower", "vertical", "horizontal", "high", "low", "inner", "outer", etc. is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the protection scope of the present invention.

[0039] Example 1

[0040] A method for preparing a plugging isolation fluid provided by an embodiment of the present invention comprises the following specific steps:

[0041] Introduce silicon powder, manganese iron ore powder, microsilica, rubber particles Flex medium, suspending agent bond, and plugging agent Plus into fresh water, and stir at a speed of 4000 r / min for 2 min to obtain the plugging isolation fluid;

[0042] Among them, the mass parts of each component are: 300 parts of silicon powder, 160 parts of manganese iron ore powder, 50 parts of microsilica, 110 parts of rubber particles Flexmedium, 235 parts of suspending agent bond, 50 parts of plugging agent Plus, and 700 parts of water;

[0043] Among them, the density of the manganese iron ore powder is 4.8 g / cm 3 , and the particle size of the manganese iron ore powder is 5 μm; the density of the silicon powder is 2.32 g / cm 3 , and the particle size of the silicon powder is 74 μm to 125 μm; the density of the microsilica is 2.2 g / cm 3 , and the particle size of the microsilica is 0.1 μm to 0.3 μm; the particle size of the rubber particles is 500 μm to 2000 μm, and its particle size distribution is as Figure 1 shown; the plugging agent Plus uses nano calcium carbonate powder with a particle size of 1 μm to 10 μm; the suspending agent bond2 uses sodium alginate.

[0044] Example 2

[0045] A preparation method of a plugging isolation fluid provided by an embodiment of the present invention is as follows:

[0046] Introduce silicon powder, manganese iron ore powder, microsilica, rubber particles Flex medium, suspending agent bond, and plugging agent Plus into fresh water, and stir at a speed of 4000 r / min for 2 min to obtain the plugging isolation fluid;

[0047] Among them, the mass parts of each component are: 290 parts of silicon powder, 150 parts of manganese iron ore powder, 40 parts of microsilica, 100 parts of rubber particles Flexmedium, 234 parts of suspending agent bond2, 40 parts of plugging agent Plus, and 600 parts of water;

[0048] Among them, the density of the manganese iron ore powder is 4.8 g / cm 3 , the particle size of the manganese iron ore powder is 5 μm; the density of the silicon powder is 2.32 g / cm 3 , the particle size of the silicon powder is 74 μm - 125 μm; the density of the microsilica is 2.2 g / cm 3 , the particle size of the microsilica is 0.1 μm - 0.3 μm; the particle size of the rubber particles is 500 μm - 2000 μm; the plugging agent Plus uses nano calcium carbonate powder, and the particle size is 1 μm - 10 μm; the suspending agent bond2 uses sodium alginate; among them, the particle size distribution of Flex medium is as Figure 1 shown.

[0049] Example 3

[0050] A preparation method of a plugging isolation fluid provided by an embodiment of the present invention is as follows:

[0051] Introduce silicon powder, manganese iron ore powder, microsilica, rubber particles Flex medium, suspending agent bond, and plugging agent Plus into fresh water, and stir at a speed of 4000 r / min for 2 min to obtain the plugging isolation fluid;

[0052] Among them, the mass parts of each component are: 310 parts of silicon powder, 170 parts of manganese iron ore powder, 60 parts of microsilica, 120 parts of rubber particles Flexmedium, 36 parts of suspending agent bond2, 60 parts of plugging agent Plus, and 800 parts of water;

[0053] Among them, the density of the manganese iron ore powder is 4.8 g / cm 3 , the particle size of the manganese iron ore powder is 5 μm; the density of the silicon powder is 2.32 g / cm 3 , the particle size of the silicon powder is 74 μm - 125 μm; the density of the microsilica is 2.2 g / cm 3, the particle size of microsilica is 0.1 μm to 0.3 μm; the particle size of the rubber particles is 500 μm to 2000 μm; the plugging agent Plus uses nano calcium carbonate powder with a particle size of 1 μm to 10 μm; the suspending agent bond2 uses sodium alginate; among them, the particle size distribution of Flex medium is as Figure 1 shown.

[0054] Comparative Example 1

[0055] A preparation method of a plugging isolation fluid provided in this comparative example is as follows:

[0056] Introduce silicon powder, manganese iron ore powder, microsilica, suspending agent bond, and plugging agent Plus into fresh water, and stir at a speed of 4000 r / min for 2 min to obtain a plugging isolation fluid;

[0057] Among them, the mass parts of each component are: 300 parts of silicon powder, 160 parts of manganese iron ore powder, 50 parts of microsilica, 235 parts of suspending agent bond, 50 parts of plugging agent Plus, and 700 parts of water;

[0058] Among them, the density of the manganese iron ore powder is 4.8 g / cm 3 , the particle size of the manganese iron ore powder is 5 μm; the density of the silicon powder is 2.32 g / cm 3 , the particle size of the silicon powder is 74 μm to 125 μm; the density of the microsilica is 2.2 g / cm 3 , the particle size of the microsilica is 0.1 μm to 0.3 μm; the plugging agent Plus uses nano calcium carbonate powder with a particle size of 1 μm to 10 μm; the suspending agent bond2 uses sodium alginate.

[0059] Comparative Example 2

[0060] A preparation method of a plugging isolation fluid provided in this comparative example is as follows:

[0061] Introduce silicon powder, manganese iron ore powder, microsilica, rubber particles Flex medium, and plugging agent Plus into fresh water, and stir at a speed of 4000 r / min for 2 min to obtain a plugging isolation fluid;

[0062] Among them, the mass parts of each component are: 300 parts of silicon powder, 160 parts of manganese iron ore powder, 50 parts of microsilica, 110 parts of rubber particles Flexmedium, 50 parts of plugging agent Plus, and 700 parts of water;

[0063] Among them, the density of the manganese iron ore powder is 4.8 g / cm 3 , the particle size of the manganese iron ore powder is 5 μm; the density of the silicon powder is 2.32 g / cm 3, the particle size of the silicon powder is 74 μm to 125 μm; the density of the microsilica is 2.2 g / cm 3 , the particle size of the microsilica is 0.1 μm to 0.3 μm; the particle size of the rubber particles is 500 μm to 2000 μm; the plugging agent Plus uses nano calcium carbonate powder with a particle size of 1 μm to 10 μm.

[0064] Comparative Example 3

[0065] A preparation method of a plugging isolation fluid provided by this comparative example is as follows:

[0066] Put silicon powder, manganese iron ore powder, microsilica, rubber particles Flex medium, suspending agent bond into fresh water, and stir at a speed of 4000 r / min for 2 min to obtain a plugging isolation fluid;

[0067] Among them, the mass parts of each component are: 300 parts of silicon powder, 160 parts of manganese iron ore powder, 50 parts of microsilica, 110 parts of rubber particles Flexmedium, 235 parts of suspending agent bond and 700 parts of water;

[0068] Among them, the density of the manganese iron ore powder is 4.8 g / cm 3 , the particle size of the manganese iron ore powder is 5 μm; the density of the silicon powder is 2.32 g / cm 3 , the particle size of the silicon powder is 74 μm to 125 μm; the density of the microsilica is 2.2 g / cm 3 , the particle size of the microsilica is 0.1 μm to 0.3 μm; the particle size of the rubber particles is 500 μm to 2000 μm; the suspending agent bond2 uses sodium alginate.

[0069] Comparative Example 4

[0070] A preparation method of a plugging isolation fluid provided by this comparative example is as follows:

[0071] Put silicon powder, manganese iron ore powder, rubber particles Flex medium, suspending agent bond, plugging agent Plus into fresh water, and stir at a speed of 4000 r / min for 2 min to obtain a plugging isolation fluid;

[0072] Among them, the mass parts of each component are: 300 parts of silicon powder, 160 parts of manganese iron ore powder, 110 parts of rubber particles Flexmedium, 235 parts of suspending agent bond, 50 parts of plugging agent Plus and 700 parts of water;

[0073] Among them, the density of the manganese iron ore powder is 4.8 g / cm 3 , the particle size of the manganese iron ore powder is 5 μm; the density of the silicon powder is 2.32 g / cm 3, the particle size of the silicon powder is 74 μm to 125 μm; the particle size of the rubber particles is 500 μm to 2000 μm; the plugging agent Plus uses nano calcium carbonate powder with a particle size of 1 μm to 10 μm; the suspending agent bond2 uses sodium alginate.

[0074] Comparative Example 5

[0075] A preparation method of a plugging isolation fluid provided by this comparative example is as follows:

[0076] Stir the silicon powder and manganese iron ore powder at a rotation speed of 4000 r / min for 2 min to obtain the plugging isolation fluid;

[0077] Among them, the mass parts of each component are: 300 parts of silicon powder, 160 parts of manganese iron ore powder, and 700 parts of water;

[0078] Among them, the density of the manganese iron ore powder is 4.8 g / cm 3 , the particle size of the manganese iron ore powder is 5 μm; the density of the silicon powder is 2.32 g / cm 3 , the particle size of the silicon powder is 74 μm to 125 μm.

[0079] Performance test

[0080] Use a plugging experiment device to evaluate the leak prevention and plugging of the plugging isolation fluids of the above-mentioned examples and comparative examples. The plugging experiment device mainly consists of an intake valve, a temperature sensor, a lost circulation slurry barrel, a lost circulation medium, a heating jacket, a nitrogen cylinder, and a high-precision data acquisition system. Use this experimental device to simulate the leak prevention and plugging evaluation of the isolation fluid for a complex formation with pores and fractures, and record the relevant data of "lost circulation volume - time" in real time.

[0081] Among them, Figure 2 and Figure 3 are the "lost circulation volume - time" curves of the plugging of the seam plate and orifice plate by the plugging isolation fluid of Example 1. Table 1 shows the experimental results of the plugging effects of the plugging isolation fluids of Examples 1 - 3 and Comparative Examples 1 - 4 on the seam plate and orifice plate.

[0082] Table 1

[0083]

[0084] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above description is only the specific embodiments of the present invention and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A plugging and isolating fluid, characterized in that: Includes the following mass components: 290-310 parts of silicon powder, 150-170 parts of manganese iron ore powder, 40-60 parts of microsilicon, 100-120 parts of rubber particles Flex medium, 34-36 parts of suspending agent bond2, 40-60 parts of plugging agent Plus and 600-800 parts of water.

2. A plugging and isolating fluid according to claim 1, characterized in that: The mass proportions of each component are as follows: 300 parts of silicon powder, 160 parts of manganese iron ore powder, 50 parts of micro silicon, 110 parts of rubber particles Flex medium, 35 parts of suspending agent bond2, 50 parts of plugging agent Plus and 700 parts of water.

3. A plugging and isolating fluid according to claim 1, characterized in that: The density of the manganese iron ore powder is 4.8 g / cm 3 The particle size of the manganese iron ore powder is 5μm.

4. A plugging and isolating fluid according to claim 1, characterized in that: The density of the silicon powder is 2.32 g / cm 3 The particle size of silicon powder is 74μm~125μm.

5. A plugging and isolating fluid according to claim 1, characterized in that: The density of the microsilicon is 2.2 g / cm 3 The particle size of micro silicon is 0.1μm~0.3μm.

6. A plugging and isolating fluid according to claim 1, characterized in that: The particle size of the rubber particles is 500 μm to 2000 μm.

7. The plugging and isolation fluid according to claim 1, characterized in that: The plugging agent Plus is made of nano-calcium carbonate powder with a particle size of 1 μm to 10 μm.

8. The plugging and isolating fluid according to claim 1, characterized in that: The suspending agent bond2 is sodium alginate.

9. A method for preparing the plugging and isolation fluid according to any one of claims 1 to 8, characterized in that: The steps include: Silica powder, manganese iron ore powder, microsilica, rubber particles Flex medium, suspending agent bond, and plugging agent Plus were introduced into fresh water, and stirred at a speed of 4000r / min for 2 minutes to prepare a plugging isolation fluid.

10. Use of the plugging and spacing fluid according to any one of claims 1 to 8 or the plugging and spacing fluid prepared by the method according to claim 9 in low-pressure formations prone to leakage.

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