Tianjin Chemical Mud Manufacturer
Viscosity: A measure of the internal frictional resistance between layers as they flow. Commonly measured using a funnel viscometer and a six-speed rotational viscometer. A. Funnel viscometer: The time it takes for 500ml of fluid to leak out of a standard funnel after 700ml is added is the funnel viscosity, measured in seconds; water takes 15 seconds.
2. Loss Volume and Mud Cake Thickness: Loss Volume: The free water in the mud, under the action of pressure difference, will渗透 into the porous formation, causing water loss, also known as the size of water loss, which describes the quality of the mud. The commonly used on-site pressure loss tester is set at 7 kg/cm² pressure and room temperature, with a normal water loss of 13-18 ml within 30 minutes.
High mud water loss can cause the filtrate to渗透 and erode the borehole walls and rock formations, leading to accidents such as wall contraction, slippage, and collapse. Therefore, the mud water loss should generally be controlled at 10-25ml per 30 minutes; if this value is exceeded, the mud should be replaced.
The mud cake thickness: The mud cake, formed by the accumulation of clay particles during the dehydration process, is thin and dense, which is beneficial for drilling. A thick and loose mud cake can lead to downhole accidents such as mud packing on the drill bit. Generally, the mud cake thickness should be less than 1mm.
3. Specific Gravity: The ratio of the weight of mud to the weight of an equal volume of water. Measurement is typically done using a lever balance, with the normal specific gravity of low solid-phase muds ranging between 103-105. The specific gravity of muds formulated for different strata varies as well.
4. Sand Content: The percentage of sand weight to mud volume through a 200-mesh sieve. High sand content in mud can significantly wear equipment, drill bits, drilling tools, and mud pumps, and is prone to issues such as sedimentary rock powder buildup and drill sticking. For high solid-phase muds, the sand content should be less than 4%, and for low solid-phase muds, less than 1%. When exceeding the specified limit, use sand removal equipment (a sand separator or a vibratory screen) to purify the mud.
5. pH Level: Refers to the acidity or alkalinity of drilling mud, easily measurable and adjustable, yet often overlooked. Its pH level has a significant impact on the mud, including the dispersion and stability of clay, the solubility and viscosity of additives, equipment corrosion, and the inhibition of calcium treatment mud, all of which are related to the pH level. The pH level of drilling mud is generally greater than 7, meaning it operates in an alkaline environment.
Section 3: Slurry Preparation
1. Raw Materials: Clay, also known as bentonite, primarily consists of aluminum silicate. The requirement is for a slurry yield of more than 15 m3 per ton. Water: Generally, water is sourced locally, such as from rivers, lakes, streams, or wells. Clear water from these sources can be used for slurry preparation. However, water with high hardness or turbidity should be pre-treated before use. Soda Ash: Industrial or food-grade soda ash is sufficient. If there are no special requirements for the slurry's density, the mixture should be prepared by adding 50kg of clay per cubic meter of water, with soda ash at 5% of the clay weight (calcium-based clay requires soda ash, while sodium-based clay does not). Mix the soda ash and clay together, then let it sit for 30 minutes before use.
