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Coiled Tubing Technology

Introduction of Dragon coiled tubing Service Center
DOT currently has 5  sets Coiled Tubing units ,can provide a full range service both in conventional and sour gas wells, such as gas lift, clean out, muti-stage CoilFRAC  milling, fishing, perforating, well test and velocity etc. With the help of our experienced professional team, we have created remarkable achievements both in China and overseas. all of which have been highly recognized by our clients.   
 
The Scope Of DOT
Coiled Tubing Service Center 
Conventional well operation
1.Gas-lift
2.Wellbore Cleanout
3.Muti-Stage CoilFRAC
4.Acidizing 
5.Plug Milling
6.Cutting
7.Fishing
8.Horizontal well testing and perforation
9.Set Bridge Plug
10.Completion pipe string
Sour Gas Filed Operation 
1.Gas lift
2.Scale Removal
3.Water Shut off
4.Horizontal well testing
 
 
Brief Introduction to Coiled Tubing Unit (CTU) 
Equipment advantages
Currently DOT have 5 sets of advance Coiled Tubing Units with the following aspects:
1.Advanced HR680&ZRT-100K injector;
2.Can easily switch from 1" to 2-3/8" system ;
3.Tripping speed of coiled tubing is extensively controlled from min 0.06m/min to max 60m/min;
4.Full-featured BOP;
5.The maximal pull up force is 45 tons and the maximal set-down force is 22.5 tons ;
6.Equipment meet NACE MR-0175 for HS Services
 
Simulation design
(1)Fatigue life tracking
The degree of fatigue of the coiled tubing by every ten inches and the life of each coiled tubing can be calculated by using the data collected from the Orion data acquisition system.
(2)Tubing forces
To measure the pressure and gravity of coiled tubing;
To calculate how much weight can be borne;
To calculate the force of pulling up coiled tubing in the horizontal well;
To calculate the force needed for fishing job. 

(3)Stress
To calculate the construction safety limit in the well;
To take safety precautions when necessary according to the tubing conditions.



(4) Hydraulic simulation
To design solid particle flowback volume, tubing speed, cutting speed and fishing speed.


(5)Downhole tools configuration
In configuration downhole tools with the existing tool database or by creating specific database, users can not only manipulate the tools completely but can also save, print, input and output these downhole data.


Data acquisition
The following parameters can be collected, displayed, saved, copied and printed in the form of curves: tubing depth, tubing tripping speed, tubing weight, annulus pressure, inlet pressure, discharge volume of the injection and the cumulative injection volume at two bypass orifices.
(1)Real-time tubing forces monitoring
(2)Real-time detection over limits of tubing operation conditions
(3)Real-time tubing fatigue condition monitoring

Coiled tubing parameters

Coiled tubing specification

1.5″Coiled tubing

7000m 

Two reels 

1.75″ Coiled tubing

6500

One reel 

2″ Coiled tubing

5000

Three reels 

2.375″ Coiled tubing

3800

One reel

 

Matching operation tools
(1)Standard tools
  ①Tubing connectors: “external slip” type, “dimple-on” type and “roll-on” type.
 


  ② Motorhead assembly: double flapper check valve, releasing sub and circulating sub.


 

(2)Auxiliary tools
  ①Centralizer: bow spring, hydraulic centralizer

 

②Torque through knuckle joint


③Special joints: rotating joint


Operating and cleaning tools



⑤Bumping tools

⑥Milling tools
 

⑦Fishing tools

Technical Support
The company has built strategic partnerships with several large oil service enterprises and research institutions through in-depth cooperation with them, so as to supply guarantees for the company to quickly master the world’s advanced technologies and provide high quality and efficient technologies and services.
 
 
Standardized Management

Various management systems have been established, including: QHSE Management System, Equipment Maintenance and Operations Procedure, Post Responsibility System and Quality and Safety Supervision and Management System.

(1)Working procedure specification: detailed operation procedures have been established to standardize the admission of the materials, construction design, construction quality management and control as well as construction safety management.

(2)“THREE-STANDARDIZATION” management specification: standardized site, standardized operation and standardized management.

The Operating Performance of Coiled Tubing
From 2013 to 2014 in the JiaoShiBa area, we have done nearly 40 wells continuous tubing drilled plug operation, more than 50 wells in coiled tubing perforating operation, more than 20 wells in coiled tubing salvage operation, more than 10 wells in the coiled tubing bridge plug operation, 3 wells in coiled tubing horizontal well testing operations and 3 wells in coiled tubing completion string operations. The construction success rate is 100%. Among them, the JY 12-X well drilled plug created 2100m longest horizontal segment, 26 maximum number of drill stopper construction records in domestic shale gas wells. Also 2014, multiple oil wells in Puguang Gas Field were finished with one hundred percent successful rate by using coiled tubing equipment in this year, including 7 wells flushing de-plugging operation of high sulfur content gas well, 4 wells gas lift operation of high sulfur content gas well, 3 well water plugging operation of high sulfur content gas well. Among above deeds, both of gas lift operation and water plugging operation used in high sulfur content gas wells were implemented for the first time in Puguang gas filed area.