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 | Depth (m) | Oil Density (kg/m3) | Viscosity (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 |
