阅读说明：本技术 阳离子水基钻井液体系及其制备方法 (Cationic water-based drilling fluid system and preparation method thereof ) 是由 逯贵广 袁俊秀 徐冬梅 于 2018-07-31 设计创作，主要内容包括：本发明公开了一种阳离子水基钻井液体系及其制备方法,阳离子水基钻井液包括基浆、抑制剂、包被剂、降滤失剂、润滑剂、流型调节剂。其中以基浆为基准,抑制剂的用量为0.05-0.5%(w/v),包被剂的用量为0.5-1%(w/v),降滤失剂的用量为0.5-2%(w/v),润滑剂的用量为1-5%(w/v)、流型调节剂的用量为0.05-0.3%(w/v)。本发明的水基钻井液具有良好的抑制性能、润滑性能、降滤失性能,有利于井壁加固,减少井壁失稳、掉块、垮塌、及卡钻的发生。(The invention discloses a cation water-based drilling fluid system and a preparation method thereof. Wherein the dosage of the inhibitor is 0.05-0.5% (w/v), the dosage of the coating agent is 0.5-1% (w/v), the dosage of the fluid loss additive is 0.5-2% (w/v), the dosage of the lubricant is 1-5% (w/v), and the dosage of the flow pattern regulator is 0.05-0.3% (w/v) based on the base slurry. The water-based drilling fluid disclosed by the invention has good inhibition performance, lubricating performance and filtration loss reduction performance, is beneficial to reinforcing the well wall, and reduces the occurrence of well wall instability, block falling, collapse and drill sticking.)

1. A cationic water-based drilling fluid system is characterized in that the cationic water-based drilling fluid system comprises a base slurry, an inhibitor, a coating agent, a fluid loss additive, a lubricant, a flow pattern regulator and a weighting agent; taking the base pulp as a reference: the dosage of the flow pattern regulator is 0.05-0.3% (w/v); the dosage of the inhibitor is 0.05-0.5% (w/v); the dosage of the coating agent is 0.5-1% (w/v); the dosage of the filtrate reducer is 0.5-2% (w/v); the amount of the lubricant is 1-5% (w/v); the adding amount of the weighting agent is adjusted according to the density of the drilling fluid.

2. The cationic water-based drilling fluid system according to claim 1, characterized in that the flow pattern modifier is one or both of xanthan gum, guar gum.

3. The cationic water-based drilling fluid system according to claim 1, wherein the fluid loss additive is one or both of sodium carboxymethyl cellulose (CMC) for drilling fluids and polyanionic cellulose (PAC).

4. The cationic water-based drilling fluid system according to claim 1, characterized in that the inhibitor is a polyamine inhibitor.

5. The cationic water-based drilling fluid system according to claim 1, characterized in that the coating agent is a low molecular weight cationic polyacrylamide having a coating flocculating effect.

6. The cationic water-based drilling fluid system according to claim 1, wherein the lubricant is a vegetable oil ester lubricant.

7. The cationic water-based drilling fluid system according to claim 1, wherein the weighting agent is one or more of barite, limestone, hematite, wustite, and iron oxide.

8. The cationic water-based drilling fluid system according to claim 5, wherein the relative molecular mass of the cationic polyacrylamide is less than or equal to 250 ten thousand, and the cationic degree is greater than or equal to 5%.

9. A method for preparing the cationic water-based drilling fluid system according to any one of claims 1 to 8, wherein the cationic water-based drilling fluid is obtained by adding a flow regulator, a fluid loss additive, an inhibitor, a coating agent and a lubricant into a base slurry in sequence under sufficient stirring, and finally adding a proper amount of weighting agent according to the density requirement of the water-based drilling fluid.

Technical Field

The invention belongs to the technical field of petroleum drilling, and particularly relates to a cationic water-based drilling fluid system and a preparation method thereof.

Background

With the development of petroleum exploration and development, drilling of stratums is more and more complex, and the number of special process wells such as directional wells, horizontal wells and the like is gradually increased. This makes the drilling engineering put forward higher requirements for the use performance of the drilling fluid. At present, the water-based drilling fluid system commonly used at home and abroad uses most of anionic treating agents which are adsorbed on the surface of clay through hydrogen bonds and Van der Waals force. The treating agents have anionic groups, the main action mechanism is to increase the negative charge of clay particles, strengthen the negative charge hydration effect, increase the thickness of the hydration film on the surfaces of the clay particles, and avoid agglomeration through charge repulsion so as to achieve the aim of stabilizing colloid. However, this electronegative water-based drilling fluid system is a disadvantage for clay minerals in the well walls and formations. Because all the factors capable of dispersing the clay in the drilling fluid also inevitably cause hydration, expansion and dispersion of clay minerals in the well wall and the stratum, the well wall is unstable, and complex conditions such as well wall collapse, drill sticking and the like are caused. In order to solve the above problems, it is necessary to improve the performance of the drilling fluid, and to add a cationic treating agent to the drilling fluid system to improve the stability of the drilling fluid system, inhibit clay dispersion, and stabilize the well wall.

Disclosure of Invention

The invention aims to provide a cationic water-based drilling fluid system and a preparation method thereof.

The invention achieves the above object by the following technical scheme.

The invention provides a cation water-based drilling fluid system and a preparation method thereof, wherein the cation water-based drilling fluid system comprises base slurry, an inhibitor, a coating agent, a filtrate reducer, a lubricant, a flow pattern regulator and a weighting agent; wherein the base pulp is used as a benchmark:

the flow pattern modifier is used in an amount of 0.05-0.3% (w/v).

The inhibitor is used in an amount of 0.05-0.5% (w/v).

The coating agent is used in an amount of 0.5-1% (w/v).

The dosage of the filtrate reducer is 0.5-2% (w/v).

The amount of the lubricant is 1-5% (w/v).

The adding amount of the weighting agent is adjusted according to the density of the drilling fluid.

The flow pattern regulator is one of xanthan gum and guar gum or a mixture of the xanthan gum and the guar gum in any proportion.

The fluid loss additive is one of sodium carboxymethyl cellulose (CMC) or polyanion cellulose (PAC) for drilling fluid, or a mixture of the two in any proportion.

The inhibitor is a polyamine inhibitor, has the functions of enhancing the inhibitive performance of the water-based drilling fluid, inhibiting the hydration and dispersion of the shale and is beneficial to well wall reinforcement. The polyamine inhibitor is preferably a polyamine inhibitor for NH type drilling fluid produced by southern chemical group research institute.

The coating agent is low-molecular-weight cationic polyacrylamide, has a coating flocculation effect, can play a coating role on the shale, can inhibit the hydration expansion of the shale, and is helpful for preventing the borehole wall from collapsing.

The lubricant is vegetable oil ester lubricant which is used for enhancing the lubricity of the water-based drilling fluid, and the vegetable oil ester lubricant is preferably used for NH-EPL type drilling fluid produced by Ministry of chemistry research.

The weighting agent is one or more of barite, limestone, hematite, wustite and iron oxide, and the adding amount can be determined according to the requirement of the density of the drilling fluid.

The preparation method of the water-based drilling fluid comprises the following steps: sequentially adding an inflow type regulator, a filtrate reducer, an inhibitor, a coating agent and a lubricant into the base slurry under the fully-stirred state, and finally adding a proper amount of weighting agent according to the density requirement of the water-based drilling fluid to obtain the cationic water-based drilling fluid.

The invention has the advantages and characteristics that:

(1) the drilling fluid has strong inhibition, and can inhibit the dispersion of the shale during drilling;

(2) the drilling fluid has good lubricity, can effectively improve the drilling efficiency and reduce the occurrence of underground accidents;

(3) the drilling fluid has good filtration loss reduction;

(4) the drilling fluid system of the invention has good temperature resistance and temperature resistance of 160 ℃, and well solves the defect of weak temperature resistance of water-based drilling fluid.

Detailed Description

In order to better understand the present invention, the following examples are further provided to illustrate the content of the present invention, but the content of the present invention is not limited to the following examples.