Confining liquid system beneficial for stability of barefoot well wall of high temperature and high pressure well

Abstract

The invention discloses a confining liquid system beneficial for the stability of a barefoot well wall of a high temperature and high pressure well. The confining liquid system is prepared from the following components in parts by weight: 100 parts of fresh water, 10-20 parts of sodium bentonite, 2-4 parts of potassium chloride, 5-7 parts of caustic soda, 2-4 parts of low-viscosity polyanionic cellulose, 2-6 parts of a high temperature-resistant filtrate reducer, 10-20 parts of organic resin, 6-8 parts of a diluent, 7-9 parts of sulfonated lignite, 30-40 parts of sulfonated gilsonite, 2-4 parts of calcium oxide and 1-300 parts of barite. The confining liquid system is relatively good in rheological property, low in filter loss property and well in wall stability, and the problem that an electrical logging tool encounters resistance due to the situation that visual and thick mud cakes easily form on the well wall as the open hole section is exposed to well mud for a long time in the electrical logging operation period during the process of high temperature and high pressure well drilling can be solved; the confining liquid is applicable to the high temperature and high pressure well with the temperature of 150-220 DEG C, the long-term stability can reach 3 days, and the confining liquid has no special demand for well depth and is good in adaptability.

Description

technical field [0001] The invention relates to a sealing fluid system, in particular to a high-temperature and high-pressure sealing fluid system, and belongs to the technical field of oil field drilling. Background technique [0002] Sealing fluid is a measure taken during the tripping of offshore exploration wells to reduce the damage to the wellbore in the case of open holes after tripping. Generally, high-viscosity, high-shear performance drilling fluid is used as the sealing fluid, and the density is slightly higher than that normally required. There is a certain density of sealing fluid in the drill string, which can make the drilling fluid pressure in the drill string greater than the annular pressure, and reduce the possibility of drilling fluid ejecting from the drill string during the drilling process. [0003] In offshore high-temperature and high-pressure exploration wells, in order to meet the requirements for data acquisition, multiple electrical survey opera...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a sealing fluid system suitable for long-term electrical surveying operations, which is beneficial to the stability of the open-hole wall of high-temperature and high-pressure wells. Problems such as the thickness of the well wall mud cake and the instability of the well wall caused by the well mud make the electrical measurement operation go smoothly and improve the work stability, safety and work efficiency