CN104818972A - Offshore thick oil heat injection and oil extraction pipe column and method - Google Patents

Abstract

The invention relates to a offshore heavy oil heat injection and production pipe string and its method. The sand control screen is divided into a heat injection chamber and an oil production production chamber. A check valve is installed on the top of the heat injection chamber and the top of the oil production production chamber. The central pipe string can be lifted and lowered repeatedly. The oil pipe is connected to the electric submersible pump unit and connected to the ground power supply equipment through cables. The oil pipe is equipped with a downhole safety valve and connected to the ground hydraulic supply equipment through the hydraulic control pipeline; stage, after the heat medium is injected from the central pipe string, the check valve that can flow into the screen is opened, and the check valve that can flow out of the screen is closed, and the heat medium flows into the reservoir through the heat injection cavity; , the check valve that can flow out of the screen is opened, the check valve that can flow into the screen is closed, and the reservoir fluid flows from the reservoir into the oil production chamber; this string reduces the impact of two-way flow and temperature changes on the sand control screen. Corrosion effects, reducing the damage to sand control screens in thermal recovery operations, prolonging the production life of oil wells.

Description

An offshore heavy oil heat injection and production string and method

technical field

The invention relates to an offshore heavy oil heat injection and oil recovery pipe string and a method thereof.

Background technique

Thermal huff and puff oil recovery is the leading technology in the development of heavy oil fields. Due to the shallow burial of heavy oil reservoirs, relatively loose reservoirs and easy sand production, it is necessary to use sand control screens for well completion. In the process of thermal stimulation, heat medium such as steam flows from the wellbore to the reservoir through the sand control screen in the heat injection stage, and the reservoir fluid flows from the reservoir to the wellbore through the sand control screen in the oil production stage. The two stages of production are subject to erosion in different directions, which will accelerate the destruction of the sand control screen. At the same time, due to the large temperature changes in the two stages of heat injection and oil production, the stress of the sand-retaining metal screen of the sand control screen will change, and the risk of failure of the sand control screen will also increase.

The failure of the sand control screen will cause the screen to lose its sand-retaining function, resulting in sand production in the oil well and shutdown. Usually, overhaul operations or re-sidetracking are used to solve the problem of sand production, and the later investment costs are very high.

Therefore, in the case of high cost of offshore drilling and completion and overhaul operation, it is very important to invent a heat injection and production string to reduce the damage of thermal recovery operation to the sand control screen and prolong the production life of the oil well.

Contents of the invention

The object of the present invention is to provide an offshore heavy oil heat injection and oil production string and its method, so that the fluids in the two stages of heat injection and oil production can pass through different parts of the sand control screen, which not only reduces the two-way erosion, but also reduces the temperature change zone. The application changes in the future, thereby reducing the risk of sand control screen damage and extending the life of the production well.

The offshore heavy oil heat injection and production string of the present invention includes a sand control screen and a central string; the sand control screen is divided into a heat injection chamber and an oil recovery production chamber by an inner partition of the sand control screen, and There is a check valve that can flow into the sand control screen, and the top of the oil production chamber is equipped with a check valve that can flow out of the sand control screen, and the sand control screen is connected to the oil layer casing through a blind pipe and a sand control packer;

The central pipe string is located in the lower part of the oil layer casing and can be lifted and lowered repeatedly. The oil pipe is fixed in the center of the oil layer casing by the bottom packer and the cable packer; the oil pipe is connected to the electric submersible pump unit through the Y joint, and the electric submersible pump unit passes through The cable is connected to the ground power supply equipment, the upper half of the oil pipe is equipped with a downhole safety valve, and the downhole safety valve is connected to the ground hydraulic supply equipment through the hydraulic control pipeline.

In the offshore heavy oil heat injection and production pipe string described in the present invention, in the heat injection stage, after the heat medium is injected from the oil pipe of the central pipe string, the check valve that can flow into the screen pipe is opened, and the single flow valve that can flow out of the screen pipe is opened. When the flow valve is closed, the heat medium can flow into the reservoir through the heat injection chamber; in the stage of oil production, the check valve that can flow out of the screen is opened, and the check valve that can flow into the screen is closed, and the reservoir fluid flows from the oil The reservoir flows into the oil production cavity.

According to the present invention, different parts of the screen are used in the two stages of offshore heavy oil heat injection and oil production string, which not only reduces the impact of bidirectional flow on sand control screen erosion, but also reduces the influence of temperature changes on the screen, thereby Reduce the damage to sand control screens in thermal recovery operations and prolong the production life of oil wells

Description of drawings

Fig. 1 Schematic diagram of offshore heavy oil heat injection and production string structure

1 Sand control screen, 2 Center string, 3 Blind pipe, 4 Sand control packer, 5 Oil layer casing, 11 Internal partition of sand control tube, 12 Heat injection cavity, 13 Oil recovery production cavity, 14 Single unit that can flow into the screen tube flow valve, 15 check valve that can flow out of the screen pipe, 21 oil pipe, 22 bottom packer, 23 cable packer, 24Y joint, 25 electric submersible pump unit, 26 cable, 27, safety valve 28, safety valve Valve hydraulic control line.

Detailed ways

The offshore heavy oil heat injection and production string of the present invention at least includes a sand control screen 1 and a central string 2; the sand control screen 1 is divided into a heat injection chamber 12 and an oil recovery production chamber by an internal partition 11 of the sand control screen 13. The top of the heating chamber is equipped with a check valve 14 that can flow into the sand control screen, and the top of the oil production chamber is equipped with a check valve 15 that can flow out of the sand control screen. The sand control screen passes through the blind pipe 3 and the sand control pack The device 4 is connected with the oil layer casing 5; the central string 2 is located in the lower part of the oil layer casing 5, and can be lifted and lowered repeatedly; the oil pipe 21 is fixed in the center of the oil layer casing 5 by the bottom packer 22 and the cable packer 23; 21 is connected to the electric submersible pump unit 25 through the Y joint 24, and the electric submersible pump unit is connected to the surface power supply equipment through the cable 26. The upper half of the oil pipe 21 is equipped with a downhole safety valve 27, and the downhole safety valve is connected through the hydraulic control pipeline 28. to surface hydraulic supply equipment.

Claims (2)

1. Offshore Heavy Oil Field heat injection and a flow string, comprises a sand control screen and a center tubing string; It is characterized in that: sand control screen is divided into heat injection chamber and oil recovery production chamber by sand control screen internal partition, heat injection top of chamber is equipped with the ball-and-seat that can flow in sand control screen, the ball-and-seat that can flow out outside sand control screen is equipped with at oil recovery production chamber top, and sand control screen is connected with production string by blind pipe and sand control packer;

Center tubing string is positioned at production string bottom, can repeat to remove, and oil pipe is fixed on production string center by bottom packer and cable-passing packer; Oil pipe is connected with electric submersible pump unit by Y-shaped connector, and electric submersible pump unit is connected to surface power supply equipment by cable, and in oil pipe, upper semisection is equipped with storm valve, and storm valve is connected to ground hydraulic supply arrangement by liquid controling pipe line.

2. an Offshore Heavy Oil Field heat injection and oil production method, it is characterized in that: application rights requires Offshore Heavy Oil Field heat injection described in 1 and flow string, in the heat injection stage, after thermal medium injects from the oil pipe of central tube post, the ball-and-seat that the ball-and-seat that can flow in screen casing is opened, can flow out outside screen casing is closed, and thermal medium flows into oil reservoir by heat injection chamber; In the oil recovery production phase, the ball-and-seat that can flow out outside screen casing is opened, and the ball-and-seat that can flow in screen casing is closed, and reservoir fluid flows into oil recovery production chamber from oil reservoir.