Preparation method of potassium magnesium salt mine drilling fluid

Abstract

The invention relates to a preparation method of potassium magnesium salt mine drilling fluid, which includes the following steps: (1) weighing and taking raw materials according to the following proportion by weight 50-70% of water, 20-30% of magnesium chloride, 0.1-4% of potassium chloride, 0.1-3% of sodium chloride, 4-15% of bentonite and 0-1% of carboxymethylcellulose; (2) adding water into a stirring tank, adding magnesium chloride, and stirring to enable the magnesium chloride to be dissolved completely; (3) adding potassium chloride and sodium chloride sequentially into the stirring tank and stirring to enable the potassium chloride and sodium chloride to be dissolved; and (4) adding the bentonite and the carboxymethylcellulose into the stirring tank, stirring evenly, and obtaining the potassium magnesium salt mine drilling fluid. The preparation method is simple in process, low in cost and capable of effectively avoiding corrosion of a wall of a well. Compared with the prior art, salt mine core extracting rate can be effectively improved, and an improving effect of core extracting rate for a sylvine layer, especially for a carnallite mineral layer is remarkable.

Description

technical field [0001] The invention relates to the technical field of salt mine exploration, in particular to a preparation method of drilling fluid for potassium-magnesium salt mines. Background technique [0002] Drilling fluid technology is the key technology for the success of drilling in salt deposits. There are many successful precedents in China for drilling protection holes with potassium chloride and sodium chloride, but there is no experience for drilling protection holes with carnallite (potassium-magnesium salt mine). The traditional salt mine drilling fluid is a saturated brine solution, which can prevent fresh water from dissolving the salt mine wall and core, but when drilling into the carnallite (potassium, magnesium chloride) layer, regardless of the Saturated brine solution or saturated potassium salt solution cannot effectively prevent the drilling fluid from dissolving the wall and core of the carnallite mine, and often the core cannot be mined or the co...

AI Technical Summary

Problems solved by technology

The traditional salt mine drilling fluid is a saturated brine solution, which can prevent fresh water from dissolving the salt mine wall and core, but when drilling into the carnallite (potassium, magnesium chloride) layer, regardless of the Neither saturated brine solution nor saturated potassium salt solution can effectively prevent the drilling fluid from dissolving the wall and core of the carnallite mine, and often the core cannot be mined, or the core is dissolved, which fails to meet the coring requirements

[0003] In the process of carnallite exploration in Laos, diesel oil is also used as drilling fluid, which has a very good effect on the protection of the mine wall and salt core. However, due to the low density of the drilling fluid, the sand in the hole (cuttings, Rock dust) cannot be eliminated in time, and buried drilling accidents are prone to occur when the thickness of the ore layer is large, and on the other hand, the economic cost is high; so this method does not fundamentally solve the drilling fluid problem of carnallite ore

[0004] According to the analysis of the phase diagram of the NaCl-KCl-MgCl2-H2O quaternary system, the composition of the solution at point E of the halite precipitation point at 25°C is 3.35% for KCl, 1.80% for NaCl, and 25.85% for MgCl2. It is not difficult to find that the traditional drilling fluid The reason why carnallite is dissolved is that magnesium chloride is unsaturated, and there is not enough magnesium chloride added to the traditional drilling fluid, so carnallite is dissolved; in addition, traditional salt mine drilling fluid-saturated brine solution has no viscosity, often cuttings and Rock powder cannot be brought out of the drill hole in time, and buried drilling accidents often occur