Well construction for sand protection of electrical submersible pump

Abstract

The paper deals with the complications associated with the sand production occurring while operation of oil wells with electric submersible pumps. Due to the fact that electrical submersible pumps are related to those, which pump the fluid with high rotating ability under the effect of centrifugal force, the impact of the composition of pumped fluid on its working parts is great. Long-term performance and endurance of the pumps depend on the quantity and granulometric composition of pumped mechanical impurities. The principal protection of electrical submersible pump from sand is based on the scheme according to which the sand and other mechanical impurities in the composition of reservoir product are separated from the fluid in the context of the pumps, and in the form of solution are replaced towards the electrical submersible pump and mixed with pumped fluid in its upper part (at the pump outlet) again. To solve the problem, consistent connection of the pump is offered. The equipment unit consists of the electrical submersible pump, the ejector and sand separator, the operation principle of which is based on the centrifugal force. While starting the electrical submersible pump, the sand separator connected to the engine axis starts rotating as well. Due to the occurred turbulent flow, the sand particles in product acquire centrifugal acceleration and replaced towards production casing. Thus, sucking the fluid cleaned from sand, the electrical submersible pump transfers it to the ejector under the pressure, providing it with the energy necessary for lifting general fluid. The ejector, in its turn, sucking the mixture with sand particles flowing near the electrical submersible pump, mixes it with cleaned fluid and lifts to the surface. The major purpose of offered well scheme is to decrease to the minimum the probability of pump corrosion due to the prevention of physical contact of operating parts of the electrical submersible pump with mechanical impurities.