Marine high-temperature high-pressure water-based drilling fluid

Abstract

The invention discloses a marine high-temperature high-pressure water-based drilling fluid, which comprises the following components by weight: 2.5% of bentonite slurry, 0.6% of polyanionic cellulose,2% of sulfonated asphalt, 2-3% of a sulfonated resin, 3-4% of sulfonated poly-coal, 2% of a high-temperature-resistant polymer, 1-2% of a high-temperature-resistant diluent, 0.5-0.9% of caustic soda,7.5-8.2% of barite, 10% of potassium formate, 1.5% of a lubricant, and the balance of water, wherein the pH value of the drilling fluid is 10-11, the total filter loss is less than 8 mL / 30 min at a temperature of 150 DEG C under a pressure of 100 MPa, and the filter loss is less than 0.7 mL / min after 15 min. According to the invention, the water-based drilling fluid has low high-temperature and high-pressure filtration loss, the formed filter cake is thin and tough, good in rheological property and good in reservoir protection effect, and the problems of high-temperature and high-pressure drilling and pre-control of downhole accidents can be well solved in the drilling process so as to provide a certain reference significance and popularization value in subsequent similar well operation.

Description

technical field [0001] The invention belongs to the technical field of offshore oil drilling, and in particular relates to an ocean high-temperature, high-pressure water-based drilling fluid. Background technique [0002] The Ying-Qiong block, located in the western part of the South China Sea, is one of the world's three major high-temperature and high-pressure oil and gas accumulation areas, with a formation pressure coefficient as high as 2.40g / cm 3 , the safe operating density window is as small as 0.08g / cm 3 , the maximum downhole temperature reaches 246°C, and the maximum drilling fluid density is 2.8g / cm 3 . In high-temperature and high-pressure wells that have been drilled, the rheology of the drilling fluid is often easily damaged at high temperatures, resulting in the downhole wall easily collapsing, causing complex problems such as downhole vicious leakage and drilling tool stuck. Entering the operation has buried a great potential safety hazard. At the same t...

AI Technical Summary

Problems solved by technology

In high-temperature and high-pressure wells that have been drilled, the rheology of the drilling fluid is often easily damaged at high temperatures, resulting in the downhole wall easily collapsing, causing complex problems such as downhole vicious leakage and drilling tool stuck. Entering the operation has buried a great safety hazard

At the same time, under the complex conditions of high temperature and high pressure, problems such as wireline logging and reservoir protection become more and more severe

Images