Process Introduction

Through coiled tubing and supporting downhole tools, such as disconnectors, single flow valves, motors, shoe grinding, salvage tools, cutting tools, etc., liquid or chemical agents are pumped to accomplish the purpose of workover or production increase. Types include: sand washing, scraping and washing, salvage, drilling and grinding, cutting, switch sliding sleeve, acidification, fracturing, cement injection, etc.

Technical indicators

It can effectively solve the problems of wellbore sand production, falling objects and scaling in oil, water and gas wells, and a series of functional measures.

Technical applicability

Minimum inner diameter of production string: 4mm greater than the maximum outer diameter of coiled tubing downhole tool.

Supporting systems, software and tools

Sand washing liquid system: fresh water, seawater, dilute glue, foam, etc.

Supporting software: Cerberus, Orion Unit

Supporting tools: single flow valve, motor, shoe grinding, switch sliding sleeve tool, salvage tool, packer, cutter, lead print, centralizer, weighting rod, accelerator, jar, oscillator, etc

Method of Use

Connect the coiled tubing equipment, carry out functional testing, lower the coiled tubing, and pump liquid to make the downhole tool reach the rated working pressure or displacement, so as to complete functional measures to achieve the purpose of workover or stimulation.

Application

The conventional service of coiled tubing has more than 1000 well operations experience.

Process Introduction

Concentric coiled tubing (double-layer tubing) is used, and the sand in the wellbore is washed/pumped by special downhole tools, pumped from the inner coiled tubing, and the annulus of double-layer coiled tubing is returned, and the small annulus is easier to return gravel out of the wellbore.

Technical indicators

It can effectively solve the serious sand production problem of oil and water wells, especially the sand production problem of horizontal wells.

Technical applicability

Large production string or casing size, horizontal wells, extended reach wells

Supporting systems, software and tools

Sand washing liquid system: water, thin glue, foam, etc.

Supporting software: Cerberus, Orion Unit

Supporting tools: double-pipe sand washing tool

Method of Use

Connecting the coiled tubing equipment, carrying out functional testing, lowering the coiled tubing, and carrying out sand exploration;

After the sand surface is proved, according to the designed displacement, inject sand washing liquid, start coiled tubing sand washing, and switch sand washing, sand washing + sand pumping, and sand pumping modes of downhole tools under different working conditions, so as to better Return the sand in the wellbore to the ground, and take samples at the return port for observation during the sand washing/pumping process;

After sand washing/pumping to the design position, lift the coiled tubing up to the wellhead and stop the pump;

Note: During sand washing/pumping, special personnel should be arranged to observe the return situation. If the return is smaller or there is no return, the coiled tubing should be lifted immediately to prevent the accident of sand burying coiled tubing.

Application

Coiled tubing sand flushing/pumping services have been serviced in areas such as Southwest Gas field.

Process Introduction

A small diameter coiled tube is lowered into the original production column to speed up the gas flow speed and improve the gas liquid carrying capacity by reducing the flow area. At the same time, operating parameters such as layer pressure, liquid-gas production, coiled tubing diameter, operating depth, wellhead and bottom-hole flow pressure affect the production of velocity string.

Technical indicators

Through the design of reasonable pipe diameter, wall thickness and operation depth, coiled tubing is used instead of conventional coupling tubing, and the flow speed of natural gas in coiled tubing can be improved, which can effectively avoid or slow down water inflow, reduce bottom hole liquid accumulation, and implement the construction operation technology of secondary completion without killing the well or moving the pipe string in the well.

Technical applicability

The fluid accumulation in gas well leads to the increase of bottom hole flow pressure, the decrease of production pressure, and the substantial decrease of production, resulting in production suspension

Supporting systems, software and tools

Supporting system: supporting wellhead equipment, operation window, hanging tools, etc.

Supporting software: Cerberus, Orion Unit

Supporting tools: hanging packer, unsealing tool, plugger, recovery tool, etc

Method of Use

After the velocity string is lowered into place by coiled tubing, the suspension packer is sealed and inspected. After the inspection is qualified; Suppress and knock out the blocker to establish a circulation; Pitching and suppressing, hydraulic pressure dropped hands and dropped hands, and coiled tubing was proposed to realize production.

In the later stage, coiled tubing is used to enter the recovery tool or GS salvage tool. After unsealing the suspension packer, the suspension packer can be lifted out of the ground.

Application

Velocity String Services has implemented dozens of well operations offshore.

Case Study

In a gas field of an offshore platform, the downhole safety valve is 2.813 ", the size of the upper return tubing is 3-1/2", and the inner diameter is 2.992 ". The 1.5" coiled tubing is suspended twice by downhole velocity string suspension + surface velocity string suspension. After operation, the effect is remarkable and the gas production increases significantly. According to the comparison of the production situation before and after the operation, it can be seen that the liquid carrying capacity after the operation increases obviously (the liquid-gas ratio increases from 0.002 m3/m3 to an average of 0.004 m3/m3, and the production situation is relatively stable.

Process Introduction

By using special downhole tools, such as crawlers, oscillators, the coiled tubing is sent to the deeper bottom of the hole.

Technical indicators

It can effectively solve the problem of difficult downhole entry in extended reach wells, horizontal wells and serious self-locking wells, and make the coiled tubing go down to the target position.

Technical applicability

Extended reach wells, horizontal wells, and wellbores with severe self-locking.

Supporting systems, software and tools

Supporting software: Cerberus, Orion Unit Unit

Supporting tools: crawler, hydraulic oscillator

Process Introduction

Coiled tubing pumps nitrogen or low density liquid to replace high density liquid in the well, reduces the pressure of liquid column in the wellbore, and at the same time forms a certain negative pressure in the production interval, so that oil and gas wells can achieve the ability of self-injection. Coiled tubing gas lift operation is a mechanical oil production method that restores self-injection by manual method after oil and gas wells stop injection.

Technical indicators

Nitrogen purity: 99.999%

Liquid nitrogen pump model: 90K, 180K, 1000K

Technical applicability

Production, acidification and fracturing flowback operation of self-injected oil and gas wells

Wellbore cleaning operation of oil and gas wells with sufficient formation energy

Supporting systems, software and tools

Supporting software: Cerberus, Orion Unit

Method of Use

Connect the coiled tubing equipment, carry out functional test, start lowering the coiled tubing, start the liquid nitrogen equipment at the same time, and pump nitrogen according to the designed displacement;

After reaching the returned liquid volume required by self-injection or design, keep the pump nitrogen displacement, lift the coiled tubing to the wellhead at a constant speed, disassemble the coiled tubing equipment, and restore the wellhead.

Application

Coiled tubing gas lift service has hundreds of well operation experience.

Case Study

In an offshore gas field, the reservoir depth is 4000 ~ 4500m, and the typical self-blowing production string. During the production and development process, the formation pressure coefficient drops to 0.6 ~ 0.7, and the wellbore gradually accumulates liquid. Wells Y-Ax1, Y-Ax2 and Y-Ax3 stop blowing one after another. Therefore, the coiled tubing gas lift operation was carried out, and the self-blowing production of wells Y-Ax1, Y-Ax2 and Y-Ax3 was successfully restored.

Process Introduction

Nitrogen airtightness technology mainly refers to the use of nitrogen to conduct airtightness tests on process equipment and pipelines during the commissioning of the platform. Its purpose is to verify the strength of the entire pipeline, and at the same time replace the remaining flammable and explosive gases in the process pipeline to prevent future gathering and transportation. System leakage during the production process brings harm to platform safety.

Technical indicators

Test Pressure/System Operating Pressure = 1.1

Purity of test medium nitrogen ≥ 95%

Technical applicability

Air tightness testing of process equipment and pipelines in the platform or gathering and transportation process.

Supporting systems, software and tools

Nitrogen gas tightness is mainly to generate nitrogen through membrane nitrogen production, and inject nitrogen into the container or pipeline to be tested for air tightness test.

Method of Use

Connect nitrogen equipment for equipment debugging;

Connect the platform process that needs airtightness and conduct pipeline pressure test;

Carry out airtightness test according to design requirements.

Application

At present, the nitrogen airtight process has been applied on multiple offshore platforms, with a cumulative application of more than 100 wells, and the equipment is running well.