RU2670311C1 - Method of utilizing oil gas from well to system of oil collection - Google Patents

Abstract

FIELD: technological processes.SUBSTANCE: invention relates to a technology for reducing associated petroleum gas emissions from oil producing wells. By the method, the accumulated oil gas in the intertubular space during the operation of the well is completely transferred to the oil collection system by its displacement with highly mineralized water. To do this, two valves are installed above the deep pump first: reverse one is closer to the pump and the bypass one of KOT-93 type. In the TS tubing string, a high-mineralized water is injected from the wellhead with a mobile pumping unit or the nearest injection well of the reservoir pressure maintenance system. If the pressure exceeds a certain value, the bypass valve is opened. High-mineralized water fills the intertube space and displaces the oil gas into the oil collection system. Water injection process is carried out until high-mineralized water appears from the sampler on the branch pipe connecting the annular space at the wellhead with the oil collection system.EFFECT: exclusion of associated petroleum gas from entering the atmosphere, increasing the safety of work carried out on wells.1 cl, 1 dwg

Description

The invention relates to the oil industry and is intended to reduce the loss of gaseous hydrocarbons in oil producing wells. The technology is applicable for wells equipped with additional underground equipment in advance.

Before repairing wellhead equipment or underground equipment of an oil producing well, it is necessary to reduce the pressure in the annular space (MP) of the well to the atmospheric value, since the lifting of the deep equipment can be carried out only in the absence of excessive pressure in the well.

As a rule, the annular space in the MP is filled with a significant amount of associated petroleum gas, including light hydrocarbons, such as methane, ethane, propane and butane.

The second reason for the need to reduce the pressure in the annular space is due to the fact that the process of oil degassing in the MP is constantly, therefore the gas pressure in the MP is constantly increasing, and the dynamic level is gradually approaching the inlet holes of the deep well pump. This leads to an increase in the proportion of free gas in the fluid supplied to the intake of a submersible pump and to a failure in the supply of the latter.

In this regard, in many oil-producing fields, periodically gas from the annulus releases into the atmosphere partially or completely. This practice is unseemly for three reasons. First, the company loses a certain amount of valuable hydrocarbons from methane to propane-butane fractions and higher (hexane, octane, etc.).

Secondly, methane released into the atmosphere accelerates the greenhouse effect of the planet, leading to global climate change on all continents. Thirdly, the release of gas into the atmosphere is a gas-hazardous and fire-hazardous procedure and requires the implementation of enhanced security measures.

To reduce or completely eliminate the release of APG to the atmosphere can be achieved by using a compressor unit, which takes gas from wells, increases the gas pressure and pumps it into the pipeline of the oil gathering system. These devices are not purchased by oil companies because of their high initial cost and the need for constant maintenance.

A technical solution is known for the selection and injection of associated petroleum gas from oil producing wells into an oil collection system using ejector devices (the article “Calculation and selection of wellhead ejector for wells equipped with electric centrifugal devices” / K. R. Urazakov et al. // Oil and Gas Business: Electr. scientific research papers - 2013. - № 4. - p. 212-224. http://www.ogbus.ru. Ejector devices are not used in oil producing wells due to the fact that for their operational operation stable fluid supply is necessary. and gas, which is impossible in a complex system c-well-pump ".

The presence of an overflow valve at the wellhead solves the problem of APG utilization before the depressurization of the well is only partially - the passage of gas from the annulus into the oil collection system is stopped when the pressure in the MP and in the discharge line connected to the oil collection system is equalized.

Today, for oil companies, a technical solution is relevant that would satisfy the conditions of operation of all oil wells, regardless of the method of oil production and the presence of adjacent wells. A technology that is known by increasing the gas pressure in the annular space is required - to take all the gas from the well into the oil collection system before it is depressurized so that associated petroleum gas does not enter the atmosphere.

The technical problem of the invention is solved as follows. Prior to the start of operation of the well, two valves are installed in the tubing string: a check valve above the submersible pump and above it in close proximity - the three-position valve KOT-93, which acts as a bypass valve towards the annular space (annular space between tubing and well casing). For utilization of petroleum gas, the annular space of a well at the wellhead is connected to the oil collection system by a branch pipe with an oil collection system, and highly mineralized water is pumped into the tubing string through a three-position valve through an inter-pipe valve under pressure. the space (MP) will not be filled with highly mineralized water to the wellhead, displacing oil gas and oil from the MP into the oil collection system. The displacement of gas and oil into the oil-collecting system is carried out until a highly mineralized water appears from the sampler at the pipe connecting the MP and the oil-collecting system.

In the absence of a mobile pumping unit, water is pumped into the tubing string from the nearest injection well using a high-pressure conduit and pressure reduction at the wellhead to the required level by covering the valve or using an adjustable choke.

A diagram of the standard and additional deep and wellhead equipment of the well is shown in the drawing, where the numbers indicate the elements of the well: 1 - casing string; 2 - tubing string; 3 - submersible pump; 4 - check valve; 5 - three-position valve of KOT-93 type; 6 - angle valve MP at the wellhead; 7 - pipe connection MP with oil collection system; 8 - sampler; 9 - collector of the oil collection system; 10 - mobile pumping unit or injection well for injection of highly mineralized water into the tubing string; 11, 12, 13 - gate valves; 14 - annulus of a gas well; 15 - bypass valve in the mouth area.

The method is implemented by performing sequential actions: 1. Downhole on the tubing tubing 2 downhole pump 3 with a check valve 4 and a three-position valve of the COT-93 type (position 5) is lowered into the well. The source of information on the valve is the Packer product catalog. -2011.- №10 - p. 106-107; http: //www.npf@paker.ru.

2. Over time, a significant amount of associated petroleum gas accumulates in the annular space of the well 14, which must be transported to the oil collection system before depressurizing the well.

3. The operation of the pump 3 is stopped, part of the gas from the well MP is transferred to the oil collection system via the wellhead bypass valve 15 in automatic or manual mode until the pressure in the MP decreases to the pressure in the oil collection system.

3. The annular space of the well with the help of pipe 7 is connected to the collector of the oil gathering system 9, the valve 12 is closed.

4. Through the valve 11 with the help of a mobile pumping unit 10 or the nearest injection well, saline water is pumped into the tubing string. According to the passport data, when a pressure of a certain size is exceeded (approximately 9–15 MPa), a KOT-93 type valve opens in the direction of the MP, and the saline water enters the annular space.

5. The liquid level in the MP rises to the mouth, displacing all of the oil gas into the oil collecting system. At the first stage of water injection, only gas is released from sampler 8, then oil, and mineralized water appears at the final stage.

6. The appearance of water from the sampler 8 will indicate that both gas and oil with dissolved gas are removed from the well.

According to the invention, it has been proposed to transport the entire APG from the annular space to the oil collection system without a compressor by delivering saline water to the wellhead in the MP. The stated technical task is performed without attracting additional energy and with the necessary efficiency - light hydrocarbons are prevented from entering the atmosphere during depressurization of the well.

According to the invention, it is proposed to use the annular space of a well as a giant piston pump, in which highly mineralized water plays the role of a piston, in which, as is well known, associated petroleum gas dissolves least of all. The method is not applicable to wells that tend to absorb fluids from the reservoir. Such wells in the oil fields, as a rule, are not more than 5%, therefore, the use of this technology in the remaining wells should improve the environmental situation around the well oil production.

Claims (2)

1. The method of utilization of petroleum gas from the well into the oil gathering system, which consists in transferring gas from the annular space of the well to the oil gathering system by increasing the gas pressure, which is different in that two valves are installed in the tubing string - the tubing before the well starts up: valve above the submersible pump and above it in close proximity - a three-position valve of the type KOT-93, which acts as a bypass valve towards the annulus, annulus spaces wells at the wellhead are connected to the oil collection system by a branch pipe, and high-mineralized water is pumped into the tubing string using a mobile pumping unit with subsequent transfer under the pressure of this water into the annular space through a three-position valve until the intertubular space - MP is filled with highly mineralized water to the mouth wells, displacing oil gas and oil from the MP into the oil collecting system, and gas and oil being forced into the oil collecting system until the sampler is atrubke connecting the MP and oil gathering system, not highly mineralized water appears. 2. The method according to p. 1, characterized in that the water in the tubing string is pumped from the nearest injection well using a high-pressure conduit and reducing the pressure at the wellhead to the required level by covering the valve or using an adjustable choke.

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