Application of Petroleum-grade Polyanionic Cellulose (PAC) in Petroleum Cementing Fluid and Fracturing Fluid

Application of Petroleum-grade Polyanionic Cellulose (PAC) in Petroleum Cementing Fluid and Fracturing Fluid

1. What is polyanionic cellulose?

Polyanionic cellulose (PAC for short) is a water-soluble cellulose ether derivative prepared by chemically modifying natural cellulose. It is an important water-soluble cellulose ether, often used in oil drilling, especially salt wells and offshore oil drilling.

2. Wide application of polyanionic cellulose (PAC) in petroleum cementing fluid (completion fluid)

(1) The cement slurry configured with petroleum-grade PAC can improve the fluidity of the cementing fluid, make it have a suitable initial viscosity, and a lower fluid loss, while protecting the well wall and preventing the fluid from entering the pores and cracks.

(2) Packing fluid configured with polyanionic cellulose can adjust the fluidity, thixotropy and ability of the suspended solid phase of the liquid. Because the product has better salt resistance (especially monovalent metal ions),  the product has obvious effect on cleaning brine type packer fluid.

(3) The workover fluid prepared with polyanionic cellulose (PAC) is low solid, 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, so that the amount of water is reduced, and the incoming water will be blocked by the emulsion and form a water town phenomenon. The workover fluid formulated with PAC provides advantages that other workover fluids do not have. Protect the production layer from permanent damage; have the ability to clean the wellbore, and reduce the workload of maintaining the wellbore; have the ability to resist the infiltration of water and sediment, and rarely foam; can be stored or transferred from well to well, lower cost than ordinary mud workover fluid.

3. Application of polyanionic cellulose (PAC) in fracturing fluid

(1) The fracturing fluid formulated with polyanionic cellulose can quickly increase the viscosity of the fracturing fluid, can efficiently carry proppant into the fractures of the oil well, establish a permeation channel, quickly reduce the fluid loss, and make the formation pressure rise rapidly to achieve the function of high efficiency transmitting pressure, the product has no residue, no damage to the bottom layer, high pumpability, low friction, and has a certain ability to carry proppant.

(2) The fracturing fluid prepared with petroleum-grade PAC can withstand 2% KCI solution (must be added when preparing fracturing fluid) and has good solubility, small addition amount, no residue, and can effectively reduce the fluid loss of fracturing fluid, and It has good salt resistance and temperature resistance, is easy to use, can be prepared on-site, and has fast gelling speed and strong sand carrying capacity. When used in formations with low osmotic pressure, the fracturing effect is more excellent, which can be used instead of guar gum.