A three-dimensional layout, reduce the ground viscosity shear loss of offshore platform polymer flooding preparation system

Abstract

The application discloses a kind of offshore platform polymer flooding preparation systems with three-dimensional layout and reduced ground viscosity shear loss.The polymer flooding preparation system includes polymer dry powder feeding system, forced stretching system, forced dispersion system and injection polymer pump connected in sequence;Polymer dry powder feeding system and forced stretching system are arranged on the top deck of offshore platform;Forced dispersion system is arranged on the middle deck of offshore platform;Injection polymer pump is arranged on the lower deck of offshore platform.The application uses the gravity potential difference formed by the height difference generated by the multi-deck structure of offshore platform, replaces the feeding pump, conveying pump and other devices in the conventional offshore polymer flooding ground injection preparation system to overcome the flow friction resistance of high-viscosity polymer mother liquor, and maintains the necessary flow operation pressure;Using conventional nitrogen inert seal cover system or offshore platform common membrane nitrogen system, through increasing pressure control device, the pressure supplement or adjustment of each node of polymer flooding ground preparation process system is completed, and the normal operation of ground system is maintained.

Description

Technical Field

[0001] This invention relates to a three-dimensional layout polymer flooding formulation system for offshore platforms that reduces surface viscosity shear loss, belonging to the field of petroleum engineering technology. Background Technology

[0002] Polymer flooding, as an important technology for enhancing oil recovery, has been successfully applied to offshore oilfield development and exploitation. However, the unique characteristics of offshore platforms also pose significant challenges to the large-scale application of polymer flooding.

[0003] Offshore platforms have limited space, and the efficient development and production enhancement of offshore oil fields, along with the massive amount of various construction operations, leave very little deck space available for polymer flooding preparation. However, conventional chemical flooding surface preparation processes require a large footprint and are heavy, such as... Figure 1 As shown. The limited output power of the main power station of the offshore platform restricts the expansion of the scale of the existing polymer flooding surface injection system; with the application of various new processes and technologies of offshore platforms, the support legs of the offshore platform have approached the load-bearing limit and cannot support the weight of large-scale polymer surface process systems (Chen Wenjuan, Zhao Wensen, Zhang Jian. Research on efficient preparation method of polymer solution in offshore oilfield. [J] Oil and Gas Field Surface Engineering, 2017, 3(5): 20-23. Liu Liwei, Zhang Jian. Research on a rapid dissolution method of hydrophobic associative polymer. [J]. Journal of Southwest Petroleum University (Natural Science Edition), 2012, 34(03): 157-162.).

[0004] In recent years, considering the special characteristics of offshore oilfields, polymer surface preparation process equipment has been developing towards high integration, lightweighting, and skid-mounting to minimize the footprint of the offshore platform's top deck. In polymer curing process equipment, devices such as high-strength stretching and high-strength curing have been developed to reduce polymer curing time, thereby reducing the volume of curing tanks (buffer tanks) and the area of ​​the offshore platform's top deck. However, under the existing surface process system design, in order to maintain the normal operation of the process system, a large number of moving equipment such as transfer pumps and feed pumps are required (Liu Min, Zou Minghua, Wu Huaxiao, Zou Wanqin, Zhao Boxin. Polymer flooding platform injection technology in offshore oilfields [J]. China Offshore Oil & Gas, 2010, 22(04):259-261.), which increases the system's power load, occupies a large amount of deck area, and increases the shear viscosity loss of the polymer solution.

[0005] Therefore, it is necessary to study a novel polymer-driven ground-based dispensing system that combines the characteristics of multi-deck structures on offshore platforms to solve problems such as large footprint and viscosity loss in existing dispensing systems. Summary of the Invention

[0006] The purpose of this invention is to provide a high-efficiency polymer formulation system with a three-dimensional layout suitable for the structural characteristics of offshore platforms. It features a small footprint, fewer moving parts, low power consumption, large throughput, and low polymer viscosity shear loss. This invention can effectively reduce shear loss within the system and reduce the system's footprint.

[0007] The polymer flooding formulation system for offshore platforms provided by this invention includes a polymer dry powder feeding system, a forced stretching system, a forced dispersion system, and a polymer injection pump connected in sequence; wherein:

[0008] The polymer dry powder feeding system and the forced stretching system are located on the top deck of the offshore platform;

[0009] The forced dispersion system is located on the middle deck of the offshore platform;

[0010] The polymer injection pump is located on the lower deck of the offshore platform;

[0011] An inertial seal pressurization compensation system with pressure control function can be installed on any deck of an offshore platform.

[0012] Preferably, the polymer dry powder feeding system is a water jet powder suction device.

[0013] Preferably, both the forced stretching system and the forced dispersion system are provided with a gas connection interface at the top, and the gas connection interface is connected to a nitrogen system.

[0014] Preferably, the nitrogen system is a membrane nitrogen generation system or a shared nitrogen system attached to an offshore platform. The nitrogen system is equipped with a pressure regulating valve for pressure adjustment; the pressure regulating valve can be a self-operated valve or a pneumatic or electric pressure regulating valve.

[0015] Preferably, a pressure transmitter is provided at the inlet of the polymer injection pump, and a pressure regulating valve is provided at the top of the forced dispersion system. The pressure transmitter is connected to the pressure regulating valve. When the suction pressure of the polymer injection pump is at a low pressure level, the pressure regulating valve at the top of the forced dispersion system should be in the open state to supplement the pressure of the forced dispersion system and increase the suction inlet of the polymer injection pump on the wellhead deck. When the suction inlet of the polymer injection pump is at a high pressure level, the pressure regulating valve at the top of the forced dispersion system should be in the closed state to stop consuming nitrogen.

[0016] Preferably, the forced dispersion system is equipped with a level transmitter, and both the level transmitter and the polymer injection pump are connected to a PLC electronic control system. When the liquid level supply system of the forced dispersion system malfunctions or the process is abnormal and the liquid level is extremely low, the polymer injection pump can be shut down by an electronic control signal to prevent the polymer injection pump from running dry.

[0017] The present invention provides a three-dimensional layout for a polymer flooding preparation system for offshore platforms that reduces surface shear viscosity loss. It utilizes the gravitational potential energy difference created by the elevation differences of the multi-deck structure of the offshore platform to replace feed pumps and transfer pumps in conventional offshore polymer flooding surface preparation systems. This overcomes the flow friction resistance of high-viscosity polymer mother liquor and maintains the necessary process operating pressure. It employs a conventional nitrogen inertization system or a membrane nitrogen generation system common to offshore platforms, and adds a pressure control device to replenish or adjust the pressure at each stage of the polymer flooding surface preparation process system, maintaining normal operation of the surface system. It utilizes existing rapid dissolution technologies, including but not limited to forced stretching and strong dispersion technology modules, combined with the necessary pipeline space formed by the three-dimensional space between the decks, to achieve a polymer flooding surface preparation system design without curing tanks or buffer tanks. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a conventional offshore platform polymer ground filling process system.

[0019] Figure 2 This is a schematic diagram of the polymer drive formulation system for offshore platforms with a three-dimensional layout that reduces viscosity shear loss at ground surfaces, as described in this invention.

[0020] Figure 3 This is a schematic diagram of the pressure compensation and adjustment control of the polymer drive formulation system for offshore platforms according to the present invention. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings, but the present invention is not limited to the following embodiments.

[0022] like Figure 2 The diagram above illustrates a three-dimensional layout of a polymer flooding formulation system for offshore platforms that reduces surface viscosity shear loss, as provided by the present invention. The system includes a polymer dry powder feeding system, a forced stretching system, a forced dispersion system, and a polymer injection pump connected in sequence. The polymer dry powder feeding system is a waterjet powder suction device located on the top deck of the offshore platform. The forced stretching system is also located on the top deck, the forced dispersion system on the middle deck, and the polymer injection pump on the lower deck. An inertial seal pressurization compensation system with pressure control function is arranged on any deck of the offshore platform.

[0023] In the polymer flooding formulation system for offshore platforms of the present invention, both the forced stretching system and the forced dispersion system are equipped with gas connection interfaces at their tops, which are connected to a nitrogen system. Preferably, the nitrogen system is a membrane nitrogen generation system or a shared nitrogen system attached to the offshore platform. The nitrogen system is equipped with a pressure regulating valve for pressure adjustment, which can be a self-operated regulating valve or a pneumatic or electric pressure regulating valve.

[0024] In the polymer drive formulation system for offshore platforms of the present invention, such as Figure 3 As shown, a pressure transmitter is installed at the inlet of the polymer injection pump, and a pressure regulating valve is installed at the top of the forced dispersion system. The pressure transmitter is connected to the pressure regulating valve. When the suction pressure of the polymer injection pump is at a low pressure level, the pressure regulating valve at the top of the forced dispersion system should be in the open state to supplement the pressure of the forced dispersion system and increase the suction inlet of the polymer injection pump on the wellhead deck. When the suction pressure of the polymer injection pump is at a high pressure level, the pressure regulating valve at the top of the forced dispersion system should be in the closed state to stop consuming nitrogen.

[0025] In the polymer drive formulation system for offshore platforms of the present invention, such as Figure 3 As shown, the forced dispersion system is equipped with a level transmitter, and both the level transmitter and the polymer injection pump are connected to the PLC electrical control system. When the forced dispersion system's level supply system malfunctions or there is an abnormal process problem, and the level is in an extremely low state, the polymer injection pump can be shut down via a signal to prevent the pump from running dry.

[0026] Application Example 1: Ground Formulation of Functional Polymers

[0027] (1) Functional polymer (AP-P4, viscosity-average molecular weight approximately 1.06 × 10⁻⁶) 7 The dry powder is fed into the screw feeder from the storage tank. The amount of dry powder is controlled by the screw feeder. The dry powder enters the water jet negative pressure suction port. The inlet of the water jet pipe is equipped with a flow meter and a flow control valve. By controlling the amount of dry powder fed into the screw feeder and the water jet negative pressure suction pipe, a polymer mother liquor of a predetermined concentration of 5000 mg / L is prepared.

[0028] (2) The initially mixed polymer solution enters the forced stretching system to begin further pre-dispersion. This process is a continuous stretching state, and the viscosity of the polymer solution at the outlet is 7500 mPa·s.

[0029] (3) The pre-dispersed polymer solution enters the forced dispersion system for further solid-liquid mass transfer. This process is continuous, and the viscosity of the polymer solution at the outlet is 5100 mPa·s.

[0030] (4) The polymer solution after maturation is diluted with high pressure water to the target concentration of 1000 mg / L, at which point the viscosity is 42 mPa·s.

[0031] go through Figure 1 The AP-P4 solution prepared by the conventional marine curing tank process shown has a concentration of 1000 mg / L and a viscosity of 45 mPa·s.

[0032] Application Example 2: Formulation of Functional Polymer I-type Ground

[0033] (1) The functional polymer (the heavy oil activator shown in Formula I) was prepared according to the method described in the following literature (Zhang Jian, Hua Chao, Zhu Yuejun, et al. Performance of high molecular weight activator and its disintegration, viscosity reduction and desorption effect on heavy oil [J]. China Offshore Oil & Gas, 2018, 30(4):93-101.)) dry powder was fed into the screw feeder from the storage tank. The amount of functional polymer I dry powder was controlled by the screw feeder. The dry powder was fed into the water jet negative pressure suction port. The inlet of the water jet pipe was equipped with a flow meter and a flow control valve. By controlling the amount of dry powder fed into the screw feeder and the water jet negative pressure suction pipe, a mother liquor of functional polymer I with a predetermined concentration of 5000 mg / L was prepared.

[0034]

[0035] (2) The initially mixed functional polymer I solution enters the forced stretching system to begin further pre-dispersion. This process is a continuous stretching state, and the viscosity of the outlet functional polymer I solution is 1500 mPa·s.

[0036] (3) The pre-dispersed polymer solution enters the forced dispersion system for further solid-liquid mass transfer. This process is continuous, and the viscosity of the outlet functional polymer I solution is 430 mPa·s.

[0037] (4) The polymer solution after maturation is diluted with high pressure water to the target concentration of 1000 mg / L, at which point the viscosity is 19.5 mPa·s.

[0038] go through Figure 1 The functional polymer I solution prepared by the conventional marine curing tank process shown has a concentration of 1000 mg / L and a viscosity of 20 mPa·s.

[0039] Comparing the viscosities of the functional polymer solutions prepared by the two methods, it can be seen that the viscosity of the polymer solution (heavy oil activator) prepared by the liquid preparation system of the present invention is almost equal to that of the conventional aging tank process.

[0040] By comparing the viscosities of the two polymer solutions, it can be seen that the solution preparation system of the present invention can reduce the footprint and optimize the platform space while maintaining a high viscosity retention rate, thereby ensuring the implementation of chemical flooding applications.

Claims

1. A polymer flooding formulation system for offshore platforms, comprising a polymer dry powder feeding system, a forced stretching system, a forced dispersion system, and a polymer injection pump connected in sequence; characterized in that: The polymer dry powder feeding system and the forced stretching system are located on the top deck of the offshore platform; The forced dispersion system is located on the middle deck of the offshore platform; The polymer injection pump is located on the lower deck of the offshore platform. It utilizes the gravitational potential energy difference generated by the height difference of the multi-deck structure of the offshore platform to replace the feed pump and transfer pump in the conventional offshore polymer flooding ground injection system. The forced dispersion system is provided with a gas connection interface at the top, which is connected to a nitrogen system, and the nitrogen system is provided with a pressure regulating valve. The top of the forced stretching system is also provided with a gas connection interface, which is connected to the nitrogen system. A pressure transmitter is provided at the inlet of the polymer injection pump. The pressure transmitter is connected to the pressure regulating valve and is used to adjust the gas phase pressure of the forced dispersion system according to the inlet pressure of the polymer injection pump.

2. The offshore platform polymer drive formulation system according to claim 1, characterized in that: The polymer dry powder feeding system is a water jet powder suction device.

3. The offshore platform polymer drive formulation system according to claim 1 or 2, characterized in that: The nitrogen system is a membrane nitrogen generation system.

4. The offshore platform polymer drive formulation system according to claim 1 or 2, characterized in that: The forced dispersion system is equipped with a level transmitter. Both the level transmitter and the polymer injection pump are connected to a PLC electronic control system and are used to shut down the polymer injection pump when the forced dispersion system is at a low level.

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