The role of drilling mud

Thickener:controls the specific gravity of the mud,coagulates the clay and drilling cuttings in the drilling fluid,

carries out the drilling cuttings,and polyacrylamide can be used to increase the viscosity of the mud when drilling is  stopped.During this period,the drilling cuttings will not sink in the mud and cause sticking.

Lubricant: Polyacrylamideadsorbs on metal or clay particles to form a liquid film,which changes from solid surface   friction to liquid friction,thereby lubricating drill bits and tools,reducing mud cake friction coefficient,and

reducing downhole accidents.

Sealing agent: This product can undergo cross-linking under the action of AL3+,Fe3+,and Ca2+plasma,and some

polymer compounds change from linear to body shape.They are insoluble in water and adsorb on the wellbore wall,  blocking formation pores and preventing the loss of drilling fluid.

Application of water plugging and profile control(Water blocking and profile control agents)

The chemical water plugging technology in oilfields in China has been applied on site since the 1950s and has a history of more than 50 years.Water soluble polymers and their gel have been used in oilfields since the 1970s.In the middle and later stages of development,the rate of water content increase is accelerating,and currently the        average water content in oil well production has exceeded 80%.Therefore,the workload of water plugging and profile control has been increasing year by year,and the difficulty of the work has increased.

At present,water-soluble polymers represented by polyacrylamide are the most widely used and effective water plugging materials both domestically and internationally.Due to the fact that polyacrylamide is soluble in water but not in oil,after injection into the formation,it is necessary to limit the internal and external water production without affecting oil and gas production.When processing,there is no need to measure the water source or sealing layer section,and the processing cost is low.Polyacrylamide has unique water blocking selectivity and is easy to crosslink,making it suitable for formations with different permeability.

Application in tertiary oil recovery(oil recovery performance)

When the oilfield enters the third oil recovery period,using a single water injection to drive oil,due to its flow rate   being higher than the flow rate of the underground crude oil,the result will greatly reduce its sweep efficiency and  increase water consumption,greatly increasing the water content of the extracted crude oil.In addition,the

uniformity of reservoir geology can reduce sweep efficiency.The upper part of the special oil layer leaves a large amount of oil that has not been swept away.If the single water flooding method is changed to adding polyacrylamide,which can increase water viscosity,it will help to increase the sweep frequency,reduce the water content of oil recovery,and increase the production of crude oil.