The mud fluid formulated with petroleum-grade polyanionic cellulose (PAC for short) has good water loss reduction, high temperature resistance and salt resistance, whose pulping rate is high in fresh water, 4% salt water and saturated salt water; when the dosage is 35-40% of traditional CMC, its viscosity-increasing and fluid loss-reducing capabilities are similar in freshwater drilling fluids, and is better in 4% salt water and saturated salt water drilling fluids, that is, it has stronger resistance to salt paste and is widely used for oil drilling, especially suitable for deep wells, high temperature wells, salt water wells and offshore oil drilling.
1. It is suitable for any mud from fresh water to saturated salt water.
2. The pulping rate is high, and the pulping volume of petroleum-grade polyanionic cellulose (PAC) can reach 2-3 times that of ordinary CMC.
3. The low-viscosity petroleum-grade PAC can effectively reduce the fluid loss, and the high-viscosity PAC has a high pulping volume and has an obvious effect on reducing fluid loss. The mud fluid can prevent the dispersion and expansion of clay and shale in the high-salt medium, so that the pollution of the well wall can be controlled, and the time of clay hydration, expansion and dispersion can be delayed.
4. With good protective colloid ability, petroleum-grade PAC can be used in many complex formations such as salt, gypsum, high temperature, and difficult drilling conditions such as oceans and deserts.
5. It is ideal for petroleum-grade polyanionic cellulose (PAC) to be used as a fluid loss agent. The mud fluid formulated by PAC can prevent the dispersion and expansion of clay and shale in high-salt media, so that the pollution of the well wall can be controlled.
6. The workover fluid formulated by petroleum-grade PAC is low in solids, which will not block the permeability of the production layer due to solids, and will not damage the production layer; and has a low water loss, which reduces the amount of water entering the production layer, while the incoming water will be blocked by the emulsion and form a water-suppression phenomenon.
1. It protects the production layer from damage.
2. It has the collateral ability to clean the wellbore, which reduces the workload of maintaining the wellbore.
3. It has the ability to resist the infiltration of water and sediment, and rarely foams.
4. It can be stored or transferred from well to well, and its cost is lower than that of ordinary mud workover fluid.
The fracturing fluid formulated with petroleum-grade PAC can withstand 2% KCI solution (to be added when preparing the fracturing fluid). It has good solubility, which is easy to use and can be formulated on-site, and has fast gelling speed and strong sand carrying capacity. When used in formations with low osmotic pressure, its fracturing effect is better.