1. Selection of mud material

(1) Clay: Use high-quality bentonite, and its technical requirements are as follows: 1. Particle size: above 200 mesh. 2. Moisture content: not more than 10% 3. Pulping rate: not less than 10m3/ton. 4. Water loss: no more than 20ml/min.
(2) Water selection: The water should be tested for water quality. Generally, the soft water should not exceed 15 degrees. If it exceeds, it must be softened.

(3) Hydrolyzed polyacrylamide: The choice of hydrolyzed polyacrylamide should be dry powder, anionic, with a molecular weight of not less than 5 million and a degree of hydrolysis of 30%.

(4) Hydrolyzed polyacrylonitrile: The choice of hydrolyzed polyacrylonitrile should be dry powder, anionic, molecular weight 100,000-200,000, and degree of hydrolysis 55-65%.

(5) Soda ash (Na2CO3): Decalcify bentonite to improve its performance (6) Potassium humate: Black powder 20-100 mesh is the best

2. Preparation and use

(1) Basic ingredients in each cubic mud: 1. Bentonite: 5%-8%, 50-80kg. 2. Soda ash (NaCO3): 3% to 5% of the soil volume, 1.5 to 4kg of soda ash. 3. Hydrolyzed polyacrylamide: 0.015% to 0.03%, 0.15 to 0.3kg. 4. Hydrolyzed polyacrylonitrile dry powder: 0.2% to 0.5%, 2 to 5kg of hydrolyzed polyacrylonitrile dry powder.
In addition, according to the formation conditions, add 0.5 to 3 kg of anti-slumping agent, plugging agent and fluid loss reducing agent per cubic meter of mud. If the Quaternary formation is easy to collapse and expand, add about 1% anti-collapse agent and about 1% potassium humate.
(2) Preparation process: Under normal circumstances, about 50m3 of mud is needed to drill a 1000m borehole. Taking the preparation of 20m3 mud as an example, the preparation process of “double polymer mud” is as follows:
1. Put 30-80kg of soda ash (NaCO3) into 4m3 water and mix well, then add 1000-1600kg of bentonite, mix well, and soak for more than two days before use. 2. Before use, add the stuffed mud into clean water to dilute it to make a 20m3 base slurry. 3. Dissolve 3-6kg of hydrolyzed polyacrylamide dry powder with water and add it to the base slurry; dilute and dissolve 40-100kg of hydrolyzed polyacrylonitrile dry powder with water and add it to the base slurry. 4. Stir well after adding all the ingredients

(3) Performance test The various properties of the mud should be tested and checked before use, and each parameter should meet the following standards: solid phase content: less than 4% specific gravity (r): less than 1.06 funnel viscosity (T): 17 to 21 seconds Water volume (B): less than 15ml/30 minutes Mud cake (K): <1mm Sand content: <1% PH value: 7.5～8.5

Ingredients of drilling mud per kilometer

1. Clay:
Select high-quality bentonite, and its technical requirements are as follows: 1. Particle size: above 200 mesh 2. Moisture content: no more than 10% 3. Pulping rate: no less than 10 m3/ton 4. Water loss: no more than 20ml/min5. Dosage : 3000～4000kg
2. Soda ash (NaCO3): 150kg
3. Water selection: The water should be tested for water quality. Generally, the soft water should not exceed 15 degrees. If it exceeds, it must be softened.
4. Hydrolyzed polyacrylamide: 1. The choice of hydrolyzed polyacrylamide should be dry powder, anionic, molecular weight not less than 5 million, and hydrolysis degree 30%. 2. Dosage: 25kg.
5. Hydrolyzed polyacrylonitrile: 1. The choice of hydrolyzed polyacrylonitrile should be dry powder, anionic, molecular weight 100,000-200,000, and degree of hydrolysis 55-65%. 2. Dosage: 300kg.
6. Other spare materials: 1. ST-1 anti-slump agent: 25kg. 2. 801 plugging agent: 50kg. 3. Potassium humate (KHm): 50kg. 4. NaOH (caustic soda): 10kg. 5. Inert materials for plugging (saw foam, cottonseed husk, etc.): 250kg.

Composite low solid phase anti-collapse mud

1. Features
1. Good fluidity and strong ability to carry rock powder. 2. Simple mud treatment, convenient maintenance, stable performance and long service life. 3. Wide applicability, it can be used not only in loose, broken and collapsed strata, but also in muddy broken rock stratum and water-sensitive rock stratum. It can meet the wall protection requirements of different rock formations.
4. It is easy to prepare, without heating or pre-soaking, just simply mix the two low-solid phase slurries and stir well. 5. This kind of compound anti-slump mud not only has anti-slump function, but also has the function of anti-slump.

2. Preparation of composite low-solid anti-slump mud A liquid: polyacrylamide (PAM)─potassium chloride (KCl) low-solid anti-slump mud 1. Bentonite 20%. 2. Soda ash (Na2CO3) 0.5%. 3. Sodium carboxypotassium cellulose (Na-CMC) 0.4%. 4. Polyacrylamide (PAM molecular weight is 12 million units) 0.1%. 5. Potassium chloride (KCl) 1%. Liquid B: Potassium humate (KHm) low solid phase anti-slump mud
1. Bentonite 3%. 2. Soda ash (Na2CO3) 0.5%. 3. Potassium humate (KHm) 2.0% to 3.0%. 4. Polyacrylamide (PAM molecular weight is 12 million units) 0.1%. When using, mix the prepared liquid A and liquid B at a volume ratio of 1:1 and stir thoroughly.
3. Mechanism Analysis of Composite Low Solids Anti-slump Mud Wall Protection

Liquid A is polyacrylamide (PAM)-potassium chloride (KCl) low-solid anti-slump mud, which is a high-quality mud with good anti-slump performance. The combined effect of PAM and KCl can effectively inhibit the hydration expansion of water-sensitive formations, and has a very good protective effect on drilling into water-sensitive formations. It effectively inhibits the hydration expansion of this type of rock formation in the first time when the water-sensitive formation is exposed, thereby preventing the collapse of the hole wall.
Liquid B is potassium humate (KHm) low-solid anti-slump mud, which is a high-quality mud with good anti-slump performance. KHm is a high-quality mud treatment agent, which has the functions of reducing water loss, diluting and dispersing, preventing hole wall collapse, and reducing and preventing mud scaling in drilling tools.
First of all, during the circulation process of potassium humate (KHm) low-solid phase anti-collapse mud in the hole, through the high-speed rotation of the drill pipe in the hole, the potassium humate and clay in the mud can seep into the loose and broken rock formation under the action of centrifugal force. The loose and broken rock strata play a role of cementation and reinforcement, and prevent moisture from penetrating and immersing the hole wall in the first place. Secondly, where there are gaps and depressions in the hole wall, the clay and KHm in the mud will be filled into the gaps and depressions under the action of centrifugal force, and then the hole wall will be strengthened and repaired. Finally, potassium humate (KHm) low-solid phase anti-collapse mud circulates in the hole for a certain period of time, and can gradually form a thin, tough, dense, and smooth mud skin on the hole wall, which further prevents It prevents the seepage and erosion of water on the pore wall, and at the same time plays the role of strengthening the pore wall. The smooth mud skin has the effect of reducing drag on the drill, preventing mechanical damage to the hole wall caused by the vibration of the drilling tool due to excessive resistance.
When liquid A and liquid B are mixed in the same mud system at a volume ratio of 1:1, liquid A can inhibit the hydration expansion of the “structurally broken muddy” rock formation in the first time, and liquid B can be used in the first time It plays a role in dialysis and cementation of “loose and broken” rock formations. As the mixed liquid circulates in the hole for a long time, liquid B will gradually form a mud skin in the whole hole section, thereby gradually playing the main role of protecting the wall and preventing collapse.

Potassium humate + CMC mud

1. Mud formula (1), bentonite 5% to 7.5%. (2), Soda ash (Na2CO3) 3% to 5% of the soil amount. (3) Potassium humate 0.15% to 0.25%. (4), CMC 0.3% to 0.6%.

2. Mud performance (1), funnel viscosity 22-24. (2), the water loss is 8-12. (3), specific gravity 1.15 ~ 1.2. (4), pH value 9-10.

Broad Spectrum Protective Mud

1. Mud formula (1), 5% to 10% bentonite. (2), Soda ash (Na2CO3) 4% to 6% of the soil amount. (3) 0.3% to 0.6% broad-spectrum protective agent.

2. Mud performance (1), funnel viscosity 22-26. (2) The water loss is 10-15. (3), specific gravity 1.15 ~ 1.25. (4), pH value 9-10.

plugging agent mud

1. Mud formula (1), bentonite 5% to 7.5%. (2), Soda ash (Na2CO3) 3% to 5% of the soil amount. (3), plugging agent 0.3% to 0.7%.

2. Mud performance (1), funnel viscosity 20-22. (2) The water loss is 10-15. (3) The specific gravity is 1.15-1.20. 4. The pH value is 9-10.