Typical Heavy Oil Blocks in China

Heavy oil exists in many oil fields in China. The following are a shortlist of heavy oil blocks in China.

Oilfield Block Dept(m) Oil Density  (kg/m3) Viscosit(cP)
Liaohe Du 1-7-5 950 – 1090 980 30000 – 40000 (50 oC)
Du 84 650 – 750 1003 2963 (100 oC)
Karamay D-9 160 – 230 924 – 950 2300- 15000 (23 oC)
Fengcheng 150 – 500 938 – 962 50000 – 170000 (30 oC)
Shengli Shanjiasi 1100 – 1200 980 – 990 8984 – 55800 (50 oC)
Caoqiao 820 – 960 967 – 1061 10163 – 47223 (50 oC)
Gudao 1200 – 1430 950 – 990 250 – 5700 (50 oC)
Dagang Caosanmu 1220 – 1430 950 – 960 289 – 1073 (50 oC)
Zaobei 1736 – 2036 925 2262 (50 oC)

R& D for Heavy Oil Production Chemicals

VECO works with professional laboratory in University to develop, screen and test the chemical agents for promoting heavy oil production for different heavy oil blocks. Our researches are focus on the following two types of chemicals.

  • Chemical agent for viscosity reduction
  • Water blocking agent

Principles of Viscosity Reduction by Chemical Agents

Heavy oil exists as aggregated clusters of oil, asphaltene, aromatics, colloids and resins. It exhibits poor flowability, high viscosity and high density. Heavy oil is very difficult to produce from underground.

The chemicals used for viscosity reduction consists of hydrophobic groups

which have a hyperbranched carbon chain and nested benzene ring. They have  the following characteristics

  • Easily insert into the thick oil and strengthen their affinity with crude oil
  • The hydrophobic group introduces the strong electronegative elements N and O to break the internal hydrogen bond of the heavy oil and realize the low dynamic disaggregation of the heavy oil

Dedicated chemicals are developed to reduce viscosity of heavy oil and much

more diluted in water. This treatment will help to increase productivity with less energy for heavy oil production.

Evaluation of Chemical Agents

The chemical agents can diffuse rapidly in the heavy oil solution. Aggregation

structure of the heavy oil are destroyed and achieves in self-osmotic depolymerization and viscosity reduction.

After the chemical agent comes into contact with the heavy oil in the capillary

tube, it spontaneously reverses the tube wall in contact with the heavy oil from oil-wet to water-wet. Capillary resistance becomes the driving force, and the heavy oil is displaced from the capillary without external energy.

Experiment demonstrated that the heavy oil production can be increased by  23 . 26 % with chemical agent injection.

Successful Projects

VECO with our partner chemical agents have been successfully used in Shengli oilfield to promote heavy oil production. Oil production is increased with lower cost compared steam injection.

Data f rom another two blocks

Blocks Oil viscosity Start Date Production before  (m3/day) Production after  (m3/day) Production duration
(cP)
Liquid Oil Liquid Oil
CJC17-XX 16000 2020/6/26 55.7 1.5 44.8 1.8 131 (continue production)
CJC25-XX 22000 2020/7/21 37.1 0.9 34.6 2.1 127 (continue production)

CJ25 – XX Production Record

Chemicals was injected after stop steam
injection.

After 27 days for water discharge, oil
production increased
1 . 1 ton/ day. Water – cut
is reduced to 93 . 4 %
from 97 . 5 %.

Solution Chemical q’ty (t) Water injected  (m3)
2.5% chemical-A, 70-80 oC 10 400
2.2% chemical-B, 70-80 oC 6.6 300
合计 16.6 700