Well head gas multi-stage combined recovery process method

Abstract

A multistage combined recovery process method for well head gas relates to the technical field of petroleum equipment and comprises produced liquid, the produced liquid is connected with a two-phase separator through a pipeline, the two-phase separator is connected with a first-stage cyclone separator, the first-stage cyclone separator is connected with a second-stage cyclone separator, the second-stage cyclone separator is connected with a first-stage cyclone dissolved air flotation device, and the first-stage cyclone dissolved air flotation device is connected with a second-stage cyclone dissolved air flotation device. The first-stage dissolved air flotation is connected with the second-stage dissolved air flotation, the second-stage rotational flow dissolved air flotation is connected with the first-stage filter, the first-stage filter is connected with the second-stage filter, the second-stage filter is connected with the reinjection water tank, the reinjection water tank is respectively connected with the second-stage filter and the first-stage filter, the second-stage filter and the first-stage filter are respectively connected with the backwashing water collecting tank, and the backwashing water collecting tank is connected with the backwashing water collecting tank. The backwashing water collecting tank is connected with the sludge dewatering equipment, and the sludge dewatering equipment is connected with the primary filter. The multistage combined recovery process method for the well head gas is advanced in filtering technology, high in filtering precision, good in effect, high in impact resistance and long in service life of a filter material, and ensures that the water quality is stable and reaches the standard.

Description

Technical field:

[0001] The invention relates to the technical field of petroleum equipment, and in particular to a multi-stage combined recovery process for wellhead gas. Background technology:

[0002] The traditional oilfield produced fluid treatment mode is: the high-water produced fluid from each single well is transported to the joint station for centralized treatment. After oil and water separation, the crude oil is transported out after meeting the standards, and the produced water is deoiled and purified at the water station. After the water quality meets the standards, it is transported to various water injection stations and water distribution rooms for reinjection. This centralized treatment mode with the joint station as the core is mainly built for the treatment of medium and low water produced fluids.

[0003] As oil fields enter the high water content and ultra-high water content development stage, the unsuitability of the previous centralized treatment model has become increasingly prominent:

[0004] First, the amount of produced fluid in the oil field is large and the water content is high. A large amount of electricity is consumed in the ineffective round-trip transportation of produced water, which seriously affects the overall development benefits of the oil field.

[0005] Second, as the amount of produced fluid continues to increase, the existing joint stations are facing the problem of insufficient processing capacity. Some joint stations can improve their processing capacity by expanding their capacity, but the investment in capacity expansion is huge. With the development of the city, some joint stations are already in or near the center of the city, and there is no room for expansion. The insufficient processing capacity of the joint stations has gradually become a major contradiction restricting the development of oilfield benefits. Therefore, it is urgent to find a produced fluid treatment mode suitable for the high water cut period.

[0006] Usually, a pre-water separation device is added to the gathering and transportation station or the front end of the gathering and transportation station (wellhead, metering station, transfer station) to pre-separate most of the water in the high-water-content produced fluid, thereby reducing the load of the subsequent oil-water treatment device. At present, the commonly used pre-water separation technology is mainly achieved through single technologies such as gravity sedimentation, cyclone, flotation, thermochemistry, or a combination of two or more of the above technologies. Representative technologies mainly include elevation oil-water separation technology, series hydrocyclone separation technology, high-efficiency three-phase separation technology, and low-temperature demulsification technology. There is still a lack of systematic research on the combination of columnar cyclone separators and hydrocyclone separators, and there is also a lack of design methods for parameter matching between integrated devices. Summary of the invention:

[0007] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and to provide a multi-stage combined recovery process for wellhead gas, which has advanced filtering technology, high filtering accuracy, good effect, strong impact resistance, long filter material life, and ensures that the water quality is stable and meets the standards.

[0008] In order to solve the problems existing in the background technology, the present invention adopts the following technical scheme: comprising produced liquid, the produced liquid is connected to the two-phase separator through a pipeline, the two-phase separator is connected to the first-level cyclone separator through a liquid phase pipeline, the first-level cyclone separator is connected to the second-level cyclone separator through a water outlet pipeline, the second-level cyclone separator is connected to the first-level cyclone dissolved air flotation through the water outlet pipeline, the first-level dissolved air flotation is connected to the second-level dissolved air flotation through the water outlet pipeline, the first-level cyclone separator, the second-level cyclone separator, the first-level cyclone dissolved air flotation and the second-level cyclone dissolved air flotation are respectively connected to the waste oil collection tank through the waste oil pipeline, the waste oil collection tank is connected to the oil pipeline, the first-level cyclone dissolved air flotation The flotation and secondary cyclone dissolved air flotation are respectively connected to the flare or natural gas pipeline through the waste pipeline, the secondary cyclone dissolved air flotation is connected to the primary filter through the outlet pipe, the primary filter is connected to the secondary filter through the outlet pipe, the secondary filter is connected to the reinjection water tank through the outlet pipe, the reinjection water tank is respectively connected to the secondary filter and the primary filter through the backwash inlet pipe, the secondary filter and the primary filter are respectively connected to the backwash water collecting tank through the backwash outlet pipe, the backwash water collecting tank is connected to the sludge dewatering equipment through the inlet pipe, the sludge dewatering equipment is connected to the primary filter through the outlet pipe, and the sludge dewatering equipment is connected to the mud cake bagging and external transportation through the pipeline.

[0009] The two-phase separator is connected to the gas phase pipeline.

[0010] The primary dissolved air flotation and the secondary dissolved air flotation are respectively connected to nitrogen or pure natural gas pipelines.

[0011] The sludge dewatering equipment is connected to the PAC / PAM pipeline.

[0012] The beneficial effects of the present invention are:

[0013] 1. Short process, high efficiency, strong impact resistance, stable water output meets water quality requirements;

[0014] 2. No chemicals, pure physical demulsification and separation technology, no aging oil, no secondary pollution, good environmental benefits;

[0015] 3. Two-stage cyclone separator + two-stage cyclone dissolved air flotation is used for pre-treatment, which has strong impact resistance and ensures stable and reliable operation of subsequent processes; advanced filtration technology, high filtration accuracy, good effect, strong impact resistance, long filter material life, ensure stable water quality and meet standards;

[0016] 4. Skid-mounted, small footprint, suitable for occasions with high space requirements such as offshore platforms;

[0017] 5. Fully automated and information-based operation, remote monitoring, less manpower, convenient operation and maintenance with low cost. Description of the drawings:

[0018] Figure 1 It is a schematic diagram of the structure of the present invention. Specific implementation method:

[0019] Reference Figure 1 The present invention specifically adopts the following implementation mode: it includes produced liquid, the produced liquid is connected to the two-phase separator through a pipeline, the two-phase separator is connected to the first-level cyclone separator through a liquid phase pipeline, the first-level cyclone separator is connected to the second-level cyclone separator through a water outlet pipeline, the second-level cyclone separator is connected to the first-level cyclone dissolved air flotation through the water outlet pipeline, the first-level dissolved air flotation is connected to the second-level dissolved air flotation through the water outlet pipeline, the first-level cyclone separator, the second-level cyclone separator, the first-level cyclone dissolved air flotation and the second-level cyclone dissolved air flotation are respectively connected to the dirty oil collection tank through the dirty oil pipeline, the dirty oil collection tank is connected to the oil pipeline ... first-level cyclone dissolved air flotation and the second-level cyclone dissolved air flotation are respectively connected to the dirty oil collection tank through the dirty oil pipeline, the dirty oil collection tank is connected to the oil pipeline, the first-level cyclone dissolved air flotation and the second-level cyclone dissolved air flotation are respectively connected to the dirty The gas flotation is connected to the flare or natural gas pipeline through the waste pipeline, the secondary cyclone dissolved air flotation is connected to the primary filter through the outlet pipe, the primary filter is connected to the secondary filter through the outlet pipe, the secondary filter is connected to the reinjection water tank through the outlet pipe, the reinjection water tank is connected to the secondary filter and the primary filter through the backwash inlet pipe, the secondary filter and the primary filter are connected to the backwash water collection tank through the backwash outlet pipe, the backwash water collection tank is connected to the sludge dewatering equipment through the inlet pipe, the sludge dewatering equipment is connected to the primary filter through the outlet pipe, and the sludge dewatering equipment is connected to the mud cake bagging and transportation through the pipeline. The two-phase separator is connected to the gas phase pipeline. The primary dissolved air flotation and the secondary dissolved air flotation are connected to the nitrogen or pure natural gas pipeline respectively. The sludge dewatering equipment is connected to the PAC / PAM pipeline.

[0020] In this multi-stage combined recovery process of wellhead gas, after the produced liquid is pretreated by a two-phase separator, the water phase discharges the oily wastewater and enters a two-stage cyclone separator and a two-stage cyclone dissolved air flotation to remove oil and suspended solids, the waste oil enters a waste oil collection tank, the waste gas goes to a flare or a natural gas pipeline network, the effluent enters a two-stage active filter filter for filtration, and after the effluent reaches the reinjection water standard, it enters a reinjection water tank, the filter backwash water uses the water from the reinjection water tank, the effluent is filtered through a sludge dehydration device, and the mud cake is bagged and transported out.

[0021] In summary, the multi-stage combined recovery process of wellhead gas has the advantages of short process, high efficiency, strong impact resistance, and stable effluent that meets water quality requirements; no chemicals, pure physical demulsification and separation technology, no aging oil, no secondary pollution, and good environmental benefits; two-stage cyclone separator + two-stage cyclone dissolved air flotation are used as pre-treatment, which has strong impact resistance and ensures stable and reliable operation of subsequent processes; advanced filtration technology, high filtration accuracy, good effect, strong impact resistance, long filter material life, ensuring stable water quality that meets standards; skid-mounted, small footprint, suitable for occasions with high space requirements such as offshore platforms; fully automated and information-based operation, remote monitoring, less manpower, convenient operation and maintenance, and low cost.

Claims

1. A multi-stage combined recovery process for wellhead gas, characterized in that: The invention comprises a produced liquid, wherein the produced liquid is connected to a two-phase separator through a pipeline, the two-phase separator is connected to a primary cyclone separator through a liquid phase pipeline, the primary cyclone separator is connected to a secondary cyclone separator through a water outlet pipeline, the secondary cyclone separator is connected to a primary cyclone dissolved air flotation through a water outlet pipeline, the primary dissolved air flotation is connected to a secondary dissolved air flotation through a water outlet pipeline, the primary cyclone separator, the secondary cyclone separator, the primary cyclone dissolved air flotation and the secondary cyclone dissolved air flotation are connected to a waste oil collection tank through a waste oil pipeline respectively, the waste oil collection tank is connected to an oil pipeline, the primary cyclone dissolved air flotation and the secondary cyclone dissolved air flotation are connected to a waste oil collection tank through a waste oil pipeline respectively, the waste oil collection tank is connected to an oil pipeline, the primary cyclone dissolved air flotation and the secondary cyclone dissolved air flotation are connected to a waste oil collection tank through a waste oil pipeline respectively, The waste pipeline is connected to the flare or natural gas pipeline, the secondary cyclone dissolved air flotation is connected to the primary filter through the outlet pipe, the primary filter is connected to the secondary filter through the outlet pipe, the secondary filter is connected to the reinjection water tank through the outlet pipe, the reinjection water tank is respectively connected to the secondary filter and the primary filter through the backwash inlet pipe, the secondary filter and the primary filter are respectively connected to the backwash water collecting tank through the backwash outlet pipe, the backwash water collecting tank is connected to the sludge dewatering equipment through the inlet pipe, the sludge dewatering equipment is connected to the primary filter through the outlet pipe, and the sludge dewatering equipment is connected to the mud cake bagging and external transportation through the pipeline.

2. The multi-stage combined recovery process of wellhead gas according to claim 1 is characterized in that: The two-phase separator is connected to the gas phase pipeline.

3. The multi-stage combined recovery process of wellhead gas according to claim 1 is characterized in that: The primary dissolved air flotation and the secondary dissolved air flotation are respectively connected to nitrogen or pure natural gas pipelines.

4. The multi-stage combined recovery process of wellhead gas according to claim 1 is characterized in that: The sludge dewatering equipment is connected to the PAC / PAM pipeline.

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