Closed-loop controlled-pressure well drilling system

Abstract

The invention discloses a closed-loop controlled-pressure well drilling system, which comprises an annular pressure monitoring system, a rotary control head, a liquid-gas separation system, a monitoring and controlling system, an automatic throttle control system and a back pressure compensation system, wherein the monitoring and controlling system is respectively connected with the automatic throttle control system and the back pressure compensation system; the monitoring and controlling system comprises a superior industrial control detection mechanism, an automatic throttle system monitoring unit and a back pressure compensation system monitoring unit; and the superior industrial control detection mechanism is respectively connected with the automatic throttle system monitoring unit and the back pressure compensation system monitoring unit. Through precise pressure control, bottom-hole pressure is precisely controlled to reach a target pressure.

Description

technical field [0001] The invention relates to a closed-loop pressure-controlled drilling system, which is used for precise control of wellbore pressure to ensure that the annular pressure profile of the wellbore is at a set value, and belongs to the field of drilling pressure control in oil and gas fields. Background technique [0002] In recent years, with the intensification of oil and gas exploration and development, drilling in various complex areas is increasing, and the application of conventional overbalance pressure control technology can no longer meet the needs of complex areas in piedmont, safe drilling in narrow density windows, and H-containing areas. 2 Production requirements such as drilling in S gas layers, shrinkage sticking caused by high-density mud leakage, and well control risks, because the bottomhole pressure control mainly depends on the traditional method, that is, the adjustment of drilling parameters such as controlling the performance of drilling...

AI Technical Summary

Problems solved by technology

[0005] 1. There are two ways to obtain the engineering data (such as pumping flow rate, vertical pressure, well depth and other process parameters) required by the existing MPD system. One is from the reinstalled sensors on the well site equipment, which will lead to The well site sensors are installed repeatedly, and the well site has an integrated mud logging system, or the drilling rig itself has a data acquisition system, so there is no need for repeated wasteful installation; the second is to manually input the key engineering parameters required, such as well depth, etc., which cannot be achieved For the purpose of real-time, the wellhead control pressure calculated by hydraulics is inaccurate, and requires personnel to input data from time to time, which is labor-intensive, and may cause wrong instructions to control casing pressure due to human error, which may lead to drilling accidents. Even if the managed pressure drilling system of some companies is compatible with the integrated mud logging system, it can only be compatible with the integrated mud logging system of a specific data format. application

[0006] 2. At present, if there is a problem with the upper computer, transmission data line or communication of the managed pressure drilling system, the ground pressure execution equipment (back pressure compensation, automatic throttle manifold) will lose the automatic control signal and cannot be automatically controlled, which may cause control failure. Increased well control and equipment risk;

[0007] 3. The surface pressure automatic control system cannot be split into independent units for on-site application. The whole set of equipment must be put on the well site, including back pressure compensation, automatic choke manifold, numerical control room, etc., which is selective for the size of the well site and limits the Its application range; and the on-site debugging after the equipment is manufactured also needs to go to the site, which increases the cost and is inconvenient for equipment debugging; and the current high cost of the managed pressure drilling system limits its popularization and application

[0008] 4. At present, the control of the automatic choke manifold of the domestic and foreign MPD systems adopts the hydraulic control method. The main problems are: 1. The hydraulic choke control can realize automatic control, although the labor of personnel is reduced to a certain extent. strength, but the hydraulic control cannot be improved on the original choke manifold, and the choke manifold must be redesigned and manufactured, resulting in a lot of waste of the existing manual choke manifold; 2. If a foreign hydraulic control choke system is used , the cost is high, and each valve is as high as more than 1 million yuan, which is not conducive to domestic promotion and application; 3. The current domestic hydraulic control throttling system has slow response speed and large pressure control fluctuations, which cannot meet the technical requirements of fine MPD; 4. The existing automatic control choke manifold only has manual control near the ground and remote control through the CNC room, or only has the function of remote control, and cannot realize automatic control near the ground. After the failure of the communication room (for example, the on-site communication cable is damaged, the communication network is disturbed), data exchange cannot be performed, and automatic control cannot be realized, resulting in wellhead pressure control that cannot meet the requirements of drilling and well control

[0009] 5. In the fine pressure control drilling process, the casing pressure compensation mainly depends on the back pressure pump system when the circulation is stopped. The current field application of this system mainly has the following problems: 1. In order to meet a certain outlet displacement and pressure , the rated power of the motor of the back pressure pump system is large, and the well team needs to provide a 400KW generator dedicated power supply, which makes the field application highly selective and dependent on the equipment of the well team, and some well teams cannot provide corresponding power generation Machine, need additional equipment, and high energy consumption

2. The characteristics of the site installation location of the system determine that the distance between the mud tank of the well team and the inlet of the back pressure pump unit is long, and the water supply efficiency of the back pressure pump is not good, which makes the outlet flow unstable, and it is difficult to accurately control the wellhead casing pressure, and it is difficult to achieve The goal of stable and fine control of wellbore pressure

3. At present, in order to solve the problem of water supply, a mud storage tank is specially installed in the back pressure pump unit manufactured in China. However, in terms of the supply of drilling fluid in this tank, it is necessary to use a special sand pump to pump the drilling fluid tank of the drilling team. From the inner mud to the mud storage tank, often the drilling fluid cannot be poured into the well in time due to insufficient drilling fluid, or too much drilling fluid is supplied, resulting in the failure of the mud storage tank and causing environmental pollution; several people are required to cooperate Reversing the valve is labor-intensive

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