“Longest Crossing In China”——Ningbo-Taizhou-Wenzhou Product Oil Pipeline Crossing Feiyun River Project Case

1.Project introduction:

• Ningbo-Taizhou-Wenzhou product oil pipeline and matched oil depot project is the major construction project of SINOPEC and Zhejiang Province Government, which consists of three super directional drilling project, that is, A line(north branch of Ou River), B line(south branch of Ou River) and C line(Feiyun River).The C line(Feiyun River) drilling project is the most important part among three lines, which is located in the Gexiang Town, Ruian City, Zhejiang Province, with crossing length of 3360 meters, the main pipe adopts L415 longitudinal high frequency welded steel pipe φ323.9×12.5mm, accompanied with φ140×9.5mm optical cable steel sleeve, the crossing depth is 55 meters, crossing bend radius is 1500D. The C line project is the dominant part of Ningbo-Taizhou-Wenzhou product oil pipeline project.

• Owner party: Sinopec Engineering Incorporation

• Construction contractor: Sinopec Petroleum Engineering & Construction Zhongyuan CorporationProject feature: It has been officially confirmed that steel pipeφ323.9mm×3360m directional crossing Feiyun River project has established a new longest crossing record in China.

• Soil condition: The crossing soil condition is mainly river sludge and quicksand.Terrain condition: Crossing the Feiyun River which is 35m in depth and 2300m in width with 55m directional drilling depth.

• Project difficulties: This project has established the historically long crossing record while the soil condition along the crossing line is sticky clay stratum, which is likely to collapse with high possibility, meanwhile, the erosion of mud and water to the pilot and reaming hole may cause the problem of drilling getting stuck or hole collapsing. Therefore,  many special techniques were employed to ensure the success of the directional drilling.

 

  

 

Pic 1：Feiyun River in Ruian City

2.Construction equipment: two sets of “Goodeng Machine” GD6000-L（S）rig

 

Pic 2： Goodeng Machine GD6000-L（S）rig

Pic 3： Goodeng Machine GD6000-L（S）rig

Pic 4： Goodeng Machine GD6000-L（S）rig

 

Pic 5：Goodeng Machine GD6000-L（S）rig

 

3. Technique support

Risk precaution: seamless working procedure to reduce the construction period.

Locating challenge: employed the most advanced end-to-end connection locating technique with buckle and drill bit to overcome the challenge of super-length drilling.

Tow-level reaming: 18inch（450mm）,24inch（600mm）tow-level reaming.

Pulling pipe: 24inch（600mm）barrel reamer to pull back the pipe.

 

4.  Construction process

Locating: taking 46 days, the average locating speed is 1 rod/15min, mud displacement 600L/min, torque 10-15Mpa, thrust&pull force 5-7Mpa;

First level reaming: 18inch（450mm） barrel reamer, in sludge and quicksand stratum the reaming speed is 1 rod/20min, mud displacement 800L/min，torque 15-18Mpa, thrust&pull force 6-10Mpa;

Second level reaming: 24inch（600mm） barrel reamer, in sludge and quicksand stratum the reaming speed is 1 rod/24min, mud displacement 1000L/min，torque 17-22Mpa, thrust&pull force 11-15Mpa;

Cleaning hole: 24inch（600mm） barrel reamer, the cleaning speed is 1 rod/18min, mud displacement 1500-1800L/min，torque 18-25Mpa, thrust&pull force 15-23Mpa;

Pulling pipe: the pulling started at 8am on Dec.30th, 2016 with starting pullback force 31Mpa，torque 21Mpa, pullback speed 3m/min,mud displacement 1800L/min. During the pullback process, the pullback force and torque remained at 19-28Mpa and 18-23Mpa respectively. The process finished at 6am on Jau.2nd, 2017, taking about 70 hours in total.

Pic 6：pilot drilling

 

Pic 7：18inch（450mm）reaming

Pic 8：preparation for pulling pipe

Pic 9：start pulling pipe

 

5.  Ancillary slurry

Bentonite consumption: 1000 tons

Slurry proportion: 4% ordinary bentonite, 0.15% salt-resistance tackifier, 0.15% lubricant

Slurry parameters: Marsh funnel viscosity 55S-65S, apparent viscosity 26mpa.s, plastic viscosity 12mpa.s, yield point 8pa.

 

Pic 10：pulling pipe succeeded

 

6. Ancillary slurry

Bentonite consumption: 1000 tons

Slurry proportion: 4% ordinary bentonite, 0.15% salt-resistance tackifier, 0.15% lubricant.

Slurry parameters: Marsh funnel viscosity 55S-65S, apparent viscosity 26mpa.s, plastic viscosity 12mpa.s, yield point 8pa.

Pic 11：celebrating the success

 

Pic 12：Sinopec Zhejiang general manager coming to celebrate

 

Pic 13、14：reported by news media

Pic 15：owner party, construction party, “Goodeng Machine” party and reporters witnessed the birth of longest crossing

7.  Project summary

The success of the crossing demonstrates that it is crucial to apply slurry in sludge and quicksand conditions as well as to reduce the reaming times and keep constant working in such highly compressible stratum. There is a certain angle between drilling track and axis of pipeline, therefore the dispatching groove is an effective to solve the difficulty in entering the hole and to lighten the weight of pipe.

The crossing Feiyun River project in the whole Ningbo-Taizhou-Wenzhou product oil pipeline and matched oil depot project was accomplished by “Goodeng Machine” GD6000-L（S） HDD rig, as most difficult and longest trenchless pipe laying project of similar diameter in recent years, the success of the project set the example for complicated and long-distance directional drilling.