Pumping system for oil production

A pumping system for oil production, comprising:

• a hydraulic unit set on the ground and adapted to send out a high-pressure oil having a viscosity lower than that of crude oil to be drawn up;
• and
• a pump unit set in an oil well and adapted to draw up crude oil, said pump unit including,
• a pump cylinder,
• a plunger adapted for reciprocating movement in said pump cylinder, said plunger being provided with an oil reservoir adapted to receive the high-pressure oil sent from said hydraulic unit thereto,
• a sucker rod attached to said plunger, said sucker rod also being atached to a reciprocating mechanism set on the ground, said plunger being reciprocatingly moved in response to the reciprocating motion of said reciprocating mechanism,
• a clearance formed between that portion of the outer circumferential surface of said plunger which is on the side of a cylinder chamber and the inner circumferential surface of said pump cylinder, said clearance communicating with said oil reservoir, the high-pressure oil being ejected from said clearance along the inner surface of said pump cylinder into said cylinder chamber while said plunger is reciprocatingly moved in said pump cylinder,
• a hydraulic piston provided in said plunger and adapted for reciprocating movement between a pair of opposing oil chambers, such that said high-pressure oil is received in each of said opposing oil chambers, and
• a pair of communicating lower chambers formed within said plunger, said lower chambers containing a slider adapted for reciprocating movement therebetween in response to said high-pressure oil from said oil chambers, the reciprocating movement of said slider causing the high-pressure oil to be pumped into said oil reservoir.