With the continuous development of drilling fluid technology, there are more and more types of drilling fluids. At present, there are various classification methods for drilling fluids at home and abroad. The simpler classification methods are as follows:
According to its density, it can be divided into non-weighted drilling fluid and heavy drilling fluid.
According to the strength of hydration with clay, it can be divided into non-inhibiting drilling fluid and inhibiting drilling fluid.
According to the difference of its solid phase content, the drilling fluid with low solid phase content is called low solid phase drilling fluid, and the drilling fluid with basically no solid phase is called solid phase free drilling fluid.
However, the classification method generally refers to the classification according to the composition characteristics of the fluid medium and system in the drilling fluid. According to different fluid media, it is generally divided into three types: water-based drilling fluid, oil-based drilling fluid and gas-based drilling fluid. Recently, a type of synthetic-based drilling fluid has emerged.
Since water-based drilling fluids have always occupied a dominant position in practical applications, they can be divided into several types according to the composition of the system.
Water-based drilling fluid is a multiphase dispersion system composed of bentonite, water (or brine), various treatment agents, weighting materials and drilling cuttings. Among them, the average density of bentonite and drilling cuttings is 2.6 g/cm3, which are usually called low-density solid phases; while weighted materials are often called high-density solid phases. The most commonly used weighting material is API barite, which has a density of 4.2 g/cm3. Since bentonite is the most commonly used slurry mixing material in water-based drilling fluids, it mainly plays the role of viscosities and shears, fluid loss reduction and wall building, so it and barite and other weighting materials are called useful solid phases. Instead, cuttings are referred to as useless solid phase. In the drilling fluid, the content of cuttings should be minimized through various solid control measures. The amount of bentonite should also be sufficient, and should not be too large, otherwise it will cause excessive viscosity and shear of the drilling fluid, seriously affect the ROP, and have an adverse effect on the protection of oil and gas layers.
Oil-based drilling fluid is a emulsion formed by adding water droplets as the dispersed phase and oil as the continuous phase, adding an appropriate amount of emulsifiers, wetting agents, lipophilic solid treatment agents (organic soil, oxidized asphalt, etc.), lime and weighting materials. liquid system.
KOSUN- China Solids Control Leader&Drilling Waste Management Expert
WhatsApp/Wechat:+86 18792396268
Contact person: Lily Wang
Online consulting:
