A kind of ultra-high temperature salt-resistant drilling fluid and preparation method thereof

Abstract

The present invention provides an ultra-high temperature salt-resistant drilling fluid for ultra-deep well and ultra-high temperature stratum drilling, and a preparation method thereof, wherein the ultra-high temperature salt-resistant drilling fluid comprises, by weight, 100 parts of water, 1-5 parts of clay, 0.3-6 parts of a filtrate loss reducer PFL-L, 0.3-6 parts of a filtrate loss reducer PFL-M, 0.3-6 parts of a filtrate loss reducer PFL-H, 2-8 parts of a sulfonated phenol formaldehyde resin, 2-8 parts of sulfonated lignite, 0.5-4 parts of a solid-phase chemical cleaning agent, 1-6 parts of a high temperature anti-collapse blocking agent, 1-6 parts of a lubricant, 0-35 parts of salt, 0.3-2 parts of a surfactant, 1.0-4 parts of a pH value adjusting agent, and 0-200 parts of a weighting agent. According to the present invention, the ultra-high temperature salt-resistant drilling fluid is not thickened at a high temperature of more than or equal to 240 DEG C, has easily-controlled rheology and low high-temperature and high-pressure filtrate loss, can be used for bottom hole drilling construction in the high temperature (more than or equal to 240 DEG C) and high salt (saturated salt) environments, and has the good application effect.

Description

technical field [0001] The invention relates to a water-based drilling fluid in the field of petroleum and natural gas exploration and development, in particular to an ultra-high-temperature salt-resistant drilling fluid for drilling ultra-deep wells and ultra-high-temperature formations and a preparation method thereof. Background technique [0002] In the process of drilling deep wells, ultra-deep wells or formations with high geothermal gradients, the temperature at the bottom of the well can reach 200-250°C or higher. The failure of the chemical agent in the drilling fluid, serious thickening or dilution of the drilling fluid, and difficulty in controlling the high-temperature and high-pressure filtration volume will cause complex well conditions such as well wall collapse, block loss, wellbore diameter shrinkage, and irregularities, which will affect the construction quality and construction cost. [0003] At the beginning of the 21st century, high-temperature resistant...

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Problems solved by technology

[0002] In the process of drilling deep wells, ultra-deep wells or formations with high geothermal gradients, the temperature at the bottom of the well can reach 200-250°C or higher. The failure of the chemical agent in the drilling fluid, serious thickening or dilution of the drilling fluid, difficulty in controlling the high-temperature and high-pressure filtration volume, etc., lead to complex well conditions such as well wall collapse, block loss, wellbore diameter shrinkage, and irregularities, which affect the construction quality and construction cost

[0003] At the beginning of the 21st century, high-temperature resistant drilling fluid technology developed rapidly at home and abroad, and a large number of drilling fluid treatment agents with a temperature resistance above 200°C were developed, and a large number of high-temperature resistant drilling fluid formulations also appeared: (1) sepiolite drilling fluid, made of Composed of saponite, sepiolite, high relative molecular mass polymer fluid loss reducer, low relative molecular mass polymer deflocculant, etc., the temperature resistance can be increased to 260 °C; (2) organic salt drilling fluid, composed of sodium formate, Potassium formate, cesium formate and other preparations are a new type of solid-free water-based drilling fluid developed in recent years. It has good compatibility with existing high-temperature treatment agents, but the disadvantage is that the cost is high

Therefore, judging from the current application of high temperature resistant drilling fluids, it is still difficult to meet the needs of drilling in high temperature saline formations.

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