Application of hydroxyethyl cellulose in oilfield industry
Publication time:2018.04.26 10:30
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Application of hydroxyethyl cellulose in oilfield industry
HEC HEC in oilfield is mainly used as thickening stabilizer of treatment process, it has good thickening effect, suspended sand ability strong and stable, heat resistant, high capacity salt, small, less liquid loss in pipelines, fast break, low residue, is a kind of good oilfield chemicals, widely used in oil drilling, well completion, cementing operation.
In the process of oil drilling, mud treatment is the key to a very important working procedure, the sixties of the 20th century, our country mud treatment technology is quite backward, and in fine dispersed slurry phase, for example, in the clay mud is widely accepted to join tannins, mimosa extract, coal alkali dispersants, and increase the stability, reducing filter loss, and make the cuttings and increase is expected to get better suspension action, but due to the dispersed clay particles extremely, causes this kind of system of mud pollution resistance is extremely low, in salt, gypsum, nitrate and clay under the condition of pollutants such as immersed, mud change is very big, therefore, in the middle of the '60 s, Dagang oilfield development in our country when they met with difficulties, the data reported, because the region at the shore of the bohai sea, the enrichment of ground brine pond spores, surface water salinity in parts per million, in such a high salinity drilling area, only the mimosa extract, materials such as alkali agent for coal slurry additives, high viscosity, high shear force, mud property change is big, and as the downhole complex accidents, make the drilling work affected, in order to change this situation, must search for and application of new mud additives, to improve the mud, and meet the requirements of geological drilling with mud.
Specific application of hydroxyethyl cellulose in oil fields:
Drilling fluid: the drilling fluid with hydroxyethyl cellulose is usually used for hard rock drilling as well as for special conditions such as control of circulating water leakage, excessive water loss, abnormal pressure and uneven shale. The application effect is also very good in the process of drilling and big hole drilling.
HEC hydroxyethyl cellulose can also be used as non-fermentable protective glue in drilling mud for oil well treatment and the determination of high pressure (atmospheric pressure) and temperature. It is the thickening agent and cementing agent of well workover fluid. It helps to provide a clear solution of low fixed content, which greatly reduces damage to the well structure. "Fuying" hydroxyethyl-cellulose HEC can be used as an additive in non-dispersed bentonite mud, which can reduce water loss and increase viscosity without increasing gel strength. At the same time, the application of HEC in drilling mud can disperse clay in the well and prevent well collapse
Hydroxyethylcellulose HEC has the properties of thickening, suspension and lubrication, and is used in drilling mud. It can cool iron filings and drilling debris, bring the cutting pests to the surface and improve the rock-carrying capacity of the mud. Shengli oilfield has used it as sand-carrying fluid for well expansion, which is effective and put into practice. The filtration performance of the mud can be greatly improved by using hydroxyethyl cellulose. Greatly improve the stability of mud.
Completion and workover: low solid completion fluid prepared with hydroxyethylcellulose HEC prevents clogging of interstices by soil particles as it approaches the reservoir. The reduced water loss property also prevents large amounts of water from entering the reservoir from the mud to ensure the production capacity of the reservoir. Hydroxyethylcellulose HEC reduces mud friction, thus reducing pump pressure and power consumption. Its excellent salt solubility also ensures no precipitation during acidification treatment.
In cementing process, hydroxyethyl cellulose has dual functions: first, it can reduce hydraulic friction, pump pressure and speed by reducing hydraulic friction. More importantly, hydroxyethyl cellulose HEC has excellent water loss protection effect, which can effectively prevent water from flowing to rock formations and keep well cementing alive, as well as protect the mechanical properties of cement. China's daqing oilfield and shengli oilfield use hydroxyethylcellulose HEC to successfully complete well cementing above meters.
Liaohe oilfield USES hydroxyethylcellulose to do without solid - phase workover fluid, in sand control workover, acidification, well test, steam stimulation, well kill all aspects of significant results. They argue that such workover fluids, which are clean, do not interact with the reservoir, cause swelling and migration of clay and cause little damage to the core permeability, can be used in heavy oil Wells and heavily leaking Wells, and can be recycled.
After fracturing fluid with HEC concentration of 0.6% and copper-sulfate crosslinking agent in daqing oil field, it is concluded that compared with other natural gels, HEC of hydroxyethylcellulose is used in fracturing fluid. Compared with other natural gels, HEC of hydroxyethylcellulose in fracturing fluid is less prone to corruption and deterioration and can be placed for a longer time. The residue is low." The latter is the key to the wide application of HEC in oil well fracturing in foreign countries.
Hydroxyethylcellulose can coexist well with some commonly used oil field chemical additives, such as pesticides, deoxidizers, control agents for mud loss and defoaming agents.
Fracturing fluid: in fracturing fluid, hydroxyethyl cellulose can improve its adhesion, and hydroxyethylcellulose itself has no influence on the oil layer, and will not block crack glume, which can be used to fracture the oil well. At the same time, it has the general characteristics of water-based fracturing fluid, such as strong suspension capacity and low friction. Water base fracturing fluid made of hydroxyethyl cellulose HEC is basically free of residue after liquefaction, especially suitable for the formation with low permeability and unable to reverse discharge residue. Under alkaline conditions, it forms complex with solutions such as manganese chloride, copper chloride, copper nitrate, copper sulfate and bichromate, and is used for fracturing fluid with supporting agent. Fuying hydroxyethyl-cellulose HEC is less prone to corruption and deterioration in underground conditions, with low residue, and basically will not block oil roads and cause underground pollution. In terms of performance, it is much better than the commonly used glue in fracturing,