阅读说明：本技术 深水固井用隔离液及其制备方法 (Isolating fluid for deepwater well cementation and preparation method thereof ) 是由 谢飞燕 夏元博 涂思琪 王翀 张其滨 宋有胜 赵宝辉 石凌龙 王建瑶 邹建龙 于 2018-06-11 设计创作，主要内容包括：本发明公开了一种深水固井用隔离液及其制备方法,属于固井作业领域。该深水固井用隔离液包括以下重量份数的各组分：悬浮稳定剂2～8份、稀释剂1～4份、1～190重量份的加重剂、水100份。其中,悬浮稳定剂选自凹凸棒土、膨润土、羧甲基纤维素、温轮胶、改性瓜尔胶、聚丙烯酰胺、硅酸钠中的至少一种。该隔离液具有如下效果：与钻井液和水泥浆之间的相溶性良好,相溶后的流变性良好,不会引起水泥浆絮凝、稠化时间缩短等问题。隔离钻井液和水泥浆的效果好,能够有效防止水泥浆和钻井液之间的相互污染。能够有效地稀释钻井液,提高隔离液对钻井液的顶替效率。能够应用于0～30℃的深水固井作业中,利于深水固井作业的施工。(The invention discloses a spacer fluid for deep water well cementation and a preparation method thereof, and belongs to the field of well cementation operation. The spacer fluid for deep water well cementation comprises the following components in parts by weight: 2-8 parts of suspension stabilizer, 1-4 parts of diluent, 1-190 parts of weighting agent and 100 parts of water. Wherein the suspension stabilizer is at least one selected from attapulgite, bentonite, carboxymethyl cellulose, welan gum, modified guar gum, polyacrylamide and sodium silicate. The spacer fluid has the following effects: the drilling fluid has good intermiscibility with the drilling fluid and the cement paste, and the rheological property after intermiscibility is good, so that the problems of cement paste flocculation, thickening time shortening and the like can not be caused. The effect of isolating the drilling fluid and the cement paste is good, and mutual pollution between the cement paste and the drilling fluid can be effectively prevented. The drilling fluid can be effectively diluted, and the displacement efficiency of the spacer fluid to the drilling fluid is improved. The method can be applied to the deepwater cementing operation at 0-30 ℃, and is beneficial to the construction of the deepwater cementing operation.)

1. The spacer fluid for deepwater well cementation is characterized by comprising the following components in parts by weight:

2-8 parts of suspension stabilizer, 1-4 parts of diluent, 1-190 parts of weighting agent and 100 parts of water;

Wherein the suspension stabilizer is at least one selected from attapulgite, bentonite, carboxymethyl cellulose, welan gum, modified guar gum, polyacrylamide and sodium silicate.

2. The spacer fluid as claimed in claim 1, wherein the suspension stabilizer comprises the attapulgite, the bentonite, the carboxymethyl cellulose and the modified guar gum in a mass ratio of 58-62: 28-32: 6-10: 1-3.

3. the spacer fluid of claim 2, wherein the suspension stabilizer comprises the attapulgite, the bentonite, the carboxymethyl cellulose, and the modified guar gum in a mass ratio of 60:30:8: 2.

4. The spacer fluid of claim 3, wherein the diluent is selected from at least one of sodium tripolyphosphate, polyethylene glycol, sodium lignosulfonate, sulfonated tannin, sodium chloride, calcium chloride, potassium chloride, and further comprises water.

5. The spacer fluid as claimed in claim 4, wherein the diluent comprises the following components in percentage by mass:

40% of sodium lignosulfonate, 10% of sulfonated tannin, 5% of sodium chloride, 5% of calcium chloride and 40% of water.

6. The spacer fluid of any one of claims 1 to 5, wherein the weighting agent is barite.

7. a preparation method of the spacer fluid for deepwater well cementation, which is applied to the spacer fluid for deepwater well cementation according to any one of claims 1 to 6, and comprises the following steps:

Adding a suspension stabilizer into water according to the weight parts of the components, carrying out first stirring, and dissolving to obtain a first mixed solution;

adding a diluent into the first mixed solution, carrying out second stirring, adding a weighting agent after dissolution, carrying out third stirring, and obtaining the spacer fluid for deep water well cementation after uniform mixing;

Wherein the suspension stabilizer is at least one selected from attapulgite, bentonite, carboxymethyl cellulose, welan gum, modified guar gum, polyacrylamide and sodium silicate.

8. The preparation method according to claim 7, wherein the first stirring time is 2-5 min, and the rotation speed is 3800-4200 rpm;

the time of the second stirring and the third stirring is 8-12 min, and the rotating speed is 3800-4200 rpm.

Technical Field

The invention relates to the field of well cementation operation, in particular to a spacer fluid for deep water well cementation and a preparation method thereof.

Background

Deepwater field hydrocarbon resources represent a large proportion of the total hydrocarbon reserves, such as hydrate layers (e.g., methane) deposited at the bottom of deepwater bodies. However, the deepwater environmental temperature is low, the stratum is soft, the fracture pressure is low, and the fluid movement is easy to occur, so the deepwater cementing operation is a key link of oil and gas exploitation. In deep water cementing operation, cement slurry is required to be used for displacing drilling fluid so as to play a role in supporting a casing and sealing a stratum between a well wall and the casing. However, the compatibility between cement slurry and drilling fluid is poor, and during the displacement process, the cement slurry and drilling fluid mixed section is easy to form a cement structure, which is not beneficial to the smooth operation of deepwater well cementation. The above problems can be solved by pumping spacer fluid between the cement slurry and the drilling fluid. Therefore, it is necessary to provide a spacer fluid for deep water cementing.

disclosure of Invention

The embodiment of the invention provides a spacer fluid for deep water well cementation and a preparation method thereof, which can solve the technical problems. The specific technical scheme is as follows:

On one hand, the embodiment of the invention provides a spacer fluid for deepwater cementing, which comprises the following components in parts by weight:

2-8 parts of suspension stabilizer, 1-4 parts of diluent, 1-190 parts of weighting agent and 100 parts of water;

wherein the suspension stabilizer is at least one selected from attapulgite, bentonite, carboxymethyl cellulose, welan gum, modified guar gum, polyacrylamide and sodium silicate.

in one possible design, the suspension stabilizer comprises the attapulgite, the bentonite, the carboxymethyl cellulose and the modified guar gum in a mass ratio of 58-62: 28-32: 6-10: 1-3.

in one possible design, the suspension stabilizer includes the attapulgite, the bentonite, the carboxymethyl cellulose, the modified guar gum in a mass ratio of 60:30:8: 2.

in one possible design, the diluent is selected from at least one of sodium tripolyphosphate, polyethylene glycol, sodium lignosulfonate, sulfonated tannin, sodium chloride, calcium chloride, potassium chloride, and the diluent also includes water.

In one possible design, the diluent comprises the following components in percentage by mass:

40% of sodium lignosulfonate, 10% of sulfonated tannin, 5% of sodium chloride, 5% of calcium chloride and 40% of water.

In one possible design, the weighting agent is barite.

In another aspect, an embodiment of the present invention provides a preparation method of a spacer fluid for deep water well cementation, where the preparation method is applied to any one of the above mentioned spacer fluids for deep water well cementation, and the preparation method includes:

Adding a suspension stabilizer into water according to the weight parts of the components, carrying out first stirring, and dissolving to obtain a first mixed solution;

Adding a diluent into the first mixed solution, carrying out second stirring, adding a weighting agent after dissolution, carrying out third stirring, and obtaining the spacer fluid for deep water well cementation after uniform mixing;

Wherein the suspension stabilizer is at least one selected from attapulgite, bentonite, carboxymethyl cellulose, welan gum, modified guar gum, polyacrylamide and sodium silicate.

in one possible design, the first stirring time is 2-5 min, and the rotating speed is 3800-4200 rpm;

The time of the second stirring and the third stirring is 8-12 min, and the rotating speed is 3800-4200 rpm.

The technical scheme provided by the embodiment of the invention has the following beneficial effects:

According to the spacer fluid for deep water well cementation provided by the embodiment of the invention, each component in the spacer fluid is stably and uniformly dispersed by adding the suspension stabilizer comprising the components and cooperating with the diluent. The good rheological property of the spacer fluid is kept by adding the diluent and cooperating with the suspension stabilizer. By adding the weighting agent and cooperating with other components, the density of the spacer fluid can be adjusted, and the density of the spacer fluid is ensured to be between the drilling fluid and the cement slurry so as to meet the isolation effect. When the spacer fluid is used, the following effects are achieved: (1) the drilling fluid has good intermiscibility with the drilling fluid and the cement paste, and the rheological property after intermiscibility is good, so that the problems of cement paste flocculation, thickening time shortening and the like can not be caused. (2) The effect of isolating the drilling fluid and the cement paste is good, and mutual pollution between the cement paste and the drilling fluid can be effectively prevented. (3) The drilling fluid can be effectively diluted, and the displacement efficiency of the spacer fluid to the drilling fluid is improved. (4) The method can be applied to the deepwater cementing operation at 0-30 ℃, and is beneficial to the construction of the deepwater cementing operation.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a graph of cement slurry thickening provided in application example 3;

FIG. 2 is a graph of the thickening of a mixed slurry at a drilling fluid to cement slurry volume ratio of 10:90 provided in application example 3;

FIG. 3 is a graph showing the thickening of a mixed slurry when the volume ratio of the drilling fluid, the spacer fluid and the cement slurry provided in application example 3 is 20:10: 70.

Detailed Description

Unless defined otherwise, all technical terms used in the examples of the present invention have the same meaning as commonly understood by one of ordinary skill in the art. In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in further detail below.

In a first aspect, an embodiment of the present invention provides a spacer fluid for deep water well cementation, where the spacer fluid includes the following components in parts by weight:

2-8 parts of suspension stabilizer, 1-4 parts of diluent, 1-190 parts of weighting agent and 100 parts of water. Wherein the suspension stabilizer is at least one selected from attapulgite, bentonite, carboxymethyl cellulose, welan gum, modified guar gum, polyacrylamide and sodium silicate.

According to the spacer fluid for deep water well cementation provided by the embodiment of the invention, each component in the spacer fluid is stably and uniformly dispersed by adding the suspension stabilizer comprising the components and cooperating with the diluent. The good rheological property of the spacer fluid is kept by adding the diluent and cooperating with the suspension stabilizer. By adding the weighting agent and cooperating with other components, the density of the spacer fluid can be adjusted, and the density of the spacer fluid is ensured to be between the drilling fluid and the cement slurry so as to meet the isolation effect. When the spacer fluid is used, the following effects are achieved: (1) the drilling fluid has good intermiscibility with the drilling fluid and the cement paste, and the rheological property after intermiscibility is good, so that the problems of cement paste flocculation, thickening time shortening and the like can not be caused. (2) The effect of isolating the drilling fluid and the cement paste is good, and mutual pollution between the cement paste and the drilling fluid can be effectively prevented. (3) The drilling fluid can be effectively diluted, and the displacement efficiency of the spacer fluid to the drilling fluid is improved. (4) The method can be applied to the deepwater cementing operation at 0-30 ℃, and is beneficial to the construction of the deepwater cementing operation.

wherein, the parts by weight of the suspension stabilizer can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts and the like. The diluent may be present in 1 part, 2 parts, 3 parts, 4 parts, etc.

The density of the spacer fluid is controlled between the drilling fluid and the cement slurry, so that the effects of isolation and displacement can be effectively improved. Wherein, the weight portions of the weighting agent can be 1 portion, 10 portions, 20 portions, 23 portions, 40 portions, 60 portions, 77 portions, 80 portions, 100 portions, 110 portions, 113 portions, 130 portions, 150 portions, 162 portions, 170 portions, 183 portions, 190 portions and the like.

The weighting agent is added and is cooperated with the suspension stabilizer and the diluent to adjust the density of the spacer fluid conveniently. In addition, the suspension stabilizer has a suspension stabilizing effect on the weighting agent, and the uniformity and stability of the isolation liquid provided by the embodiment of the invention are ensured.

As an example, the spacer fluid comprises the following components in parts by weight:

4-6 parts of suspension stabilizer, 2-3 parts of diluent, 30-160 parts of weighting agent and 100 parts of water.

The weight parts of the components are set, so that the effect of the components can be fully exerted, the isolation fluid has a good isolation effect, the displacement efficiency of the isolation fluid on the drilling fluid is improved, and the requirements of deepwater well cementation operation are met.

In the embodiment of the invention, the suspension stabilizer, the diluent and the weighting agent are compounded, so that the weighting agent and the diluent can be stably and uniformly dispersed in water, and the stability and the uniformity of the spacer fluid are ensured. In order to provide the above-mentioned effects excellent after the suspension stabilizer synergistically acts with other components, the following examples are given:

The suspension stabilizer comprises attapulgite, bentonite, carboxymethyl cellulose and modified guar gum in a mass ratio of 58-62: 28-32: 6-10: 1-3.

The attapulgite, the carboxymethyl cellulose, the modified guar gum and the bentonite have good suspension and stability, and the four components are compounded according to the mass percentage, so that the suspension stabilizer has excellent suspension property and stability, and the weighting agent and the diluent are favorably dispersed stably and uniformly. Moreover, the components are low in price and easy to obtain.

The attapulgite and the bentonite belong to inorganic minerals, can be hydrated and uniformly dispersed in water, and form a bridged network structure through the interaction of layer bonds. The attapulgite has good saline-alkali resistance, is beneficial to seawater slurry preparation, has strong rapid hydration capability, and reduces free water in slurry through adsorption. Carboxymethyl cellulose and modified guar gum belong to high molecular materials, are dissolved and stretched in water to form molecular coils, and the carboxymethyl cellulose is completely dissolved in water in a low-temperature environment and increases the viscosity of the solution, so that the modified guar gum has good alkali resistance; the modified guar gum solution has the shearing and diluting characteristics, and the flow performance of the solution is ensured while the suspension effect of the solution is realized. The attapulgite, the carboxymethyl cellulose, the guar gum and the bentonite are compounded for use, so that the synergistic effect of a network bridge and a molecular coil is realized, the suspension stability of the solution is efficiently improved, the isolation liquid is suspended to weight solid-phase particles in a low-temperature environment, and the drilling fluid is displaced through density difference.

wherein the mass ratio of the attapulgite, the bentonite, the carboxymethyl cellulose and the modified guar gum can be 57:32:10:1, 58:32:9:1, 62:28:7:3, 60:30:8:2 and the like.

As an example, the suspension stabilizer includes attapulgite, bentonite, carboxymethyl cellulose, modified guar gum in a mass ratio of 60:30:8: 2.

The suspension stabilizer is prepared by mixing the components in percentage by mass, so that the suspension and stability performance can be fully exerted after the attapulgite, the bentonite, the carboxymethyl cellulose and the modified guar gum are compounded.

In the embodiment of the invention, the diluent can play a role in diluting the suspension stabilizer and the weighting agent, so that the spacer fluid has good rheological property. After the spacer fluid is mixed with the drilling fluid and the cement slurry, the diluent can ensure that the mixing section is not too thick, and the fluidity of the mixing section of the spacer fluid, the drilling fluid and the cement slurry is ensured, so that the deepwater well cementation operation is smoothly carried out.

The diluent is at least one selected from sodium tripolyphosphate, polyethylene glycol, sodium lignosulfonate, sulfonated tannin, sodium chloride, calcium chloride and potassium chloride, and the diluent also comprises water.

I.e., the diluent is selected from any one, two, three, or a mixture of all of the foregoing.

As an example, the diluent comprises the following components in percentage by mass:

37-42% of sodium lignosulphonate, 8-12% of sulfonated tannin, 4-6% of sodium chloride, 4-6% of calcium chloride and the balance of water.

The components of the diluent are arranged in such a way, so that the components are conveniently cooperated with one another to achieve a good diluting effect. Moreover, the components are low in price and easy to obtain.

The ionic sulfonic acid group, the sulfonated group, the sodium ion, the calcium ion and the chloride ion in the diluent can be adsorbed on attapulgite, bentonite, carboxymethyl cellulose and modified guar gum in the suspension stabilizer, electric double layers of the attapulgite, the bentonite and other ions are properly adjusted, the extending length of a carboxymethyl cellulose molecular chain and a guar gum molecular chain is changed, cementation, flocculation and the like between the attapulgite, the bentonite, the carboxymethyl cellulose and the modified guar gum and between the ionic modified guar gum and other molecules, ions and suspended matters in drilling fluid and cement paste are avoided, and the mixed slurry has good rheological property.

The mass percentage of the sodium lignin sulfonate can be 37%, 38%, 39%, 40%, 41%, 42% and the like. The mass percentage of the sulfonated tannin can be 8%, 9%, 10%, 11%, 12% and the like. The mass percentage of sodium chloride may be 4%, 5%, 6%, etc. The calcium chloride may be present in an amount of 4%, 5%, 6%, etc.

As an example, the diluent comprises the following components in percentage by mass:

40% of sodium lignosulphonate, 10% of sulfonated tannin, 5% of sodium chloride, 5% of calcium chloride and 40% of water.

the mass percentages of the components are set in such a way, so that the components can fully play a role after being compounded, the diluent has an excellent diluting effect, and the problems of cement paste flocculation, thickening time shortening and the like can not be caused after the spacer fluid is mixed with the drilling fluid and the cement paste. Besides, the spacer fluid can effectively dilute the drilling fluid and improve the displacement efficiency of the spacer fluid to the drilling fluid.

In the embodiment of the invention, the weighting agent and other components are cooperated to adjust the density of the isolation fluid, so that the density of the isolation fluid is ensured to be between the drilling fluid and the cement slurry, and the isolation effect is met. As one example, the weighting agent is barite.

after the barite is compounded with the suspension stabilizer and the diluent, the barite can be stably and uniformly dispersed in the spacer fluid, so that the stability of the spacer fluid is ensured. In addition, the barite is low in price and easy to obtain.

In a second aspect, an embodiment of the present invention further provides a preparation method of a spacer fluid for deepwater well cementation, where the method is applied to any one of the above mentioned spacer fluids for deepwater well cementation, and the method includes:

adding the suspension stabilizer into water according to the parts by weight of the components, carrying out first stirring, and dissolving to obtain a first mixed solution.

and adding a diluent into the first mixed solution, carrying out second stirring, adding a weighting agent after dissolution, carrying out third stirring, and uniformly stirring to obtain the spacer fluid for deep water well cementation.

wherein the suspension stabilizer is at least one selected from attapulgite, bentonite, carboxymethyl cellulose, welan gum, modified guar gum, polyacrylamide and sodium silicate.

The preparation method is simple, can be prepared on site, and is beneficial to deepwater well cementation operation. In addition, the prepared spacer fluid for deep water well cementation can be applied to deep water well cementation operation at 0-30 ℃, and has good isolation and displacement effects.

Wherein the first stirring time is 2-5 min, such as 2min, 3min, 4min, 5 min. The number of revolutions is 3800 to 4200rpm, and may be 3800rpm, 3850rpm, 3900rpm, 3950rpm, 4000rpm, 4050rpm, 4100rpm, 4150rpm, 4200rpm, or the like.

the time of the second stirring and the third stirring is 8-12 min, such as 8min, 9min, 10min, 11min, 12min, etc., and the rotation speed is 3800-4200 rpm, such as 3800rpm, 3850rpm, 3900rpm, 3950rpm, 4000rpm, 4050rpm, 4100rpm, 4150rpm, 4200rpm, etc.

The time and the rotating speed of the first stirring, the second stirring and the third stirring are set, so that the components are fully dissolved or mixed, and the effect of each component can be fully exerted.

The present invention will be further described below by way of specific examples.

In the following examples, those whose operations are not subject to the conditions indicated, are carried out according to the conventional conditions or conditions recommended by the manufacturer. The raw materials are conventional products which can be obtained commercially by manufacturers and specifications.

The drilling fluid is purchased from Bohai star engineering science and technology Limited in Tianjin.

Oil well G-grade cement in the cement paste is purchased from Shandong Lin' 26384victoria Special Cement Co., Ltd, and other component materials are purchased from oil Bohai Star engineering technology Co., Ltd in Tianjin. The cement slurry has a conventional density water cement ratio of 0.44.