Hydrate Formation Conditions of Natural Gas with High Content of Carbon Dioxide and the Calculation Model
- Ruiyan Sun | Changjun Li (Southwest Petroleum Uninversity) | Sheng Yu (PetroChina JiLin Oilfield Company) | Shigang Wang | Ouyang Sun | Enbin Liu (Southwest Petroleum Uninversity)
- Document ID
- Society of Petroleum Engineers
- International Oil and Gas Conference and Exhibition in China, 8-10 June, Beijing, China
- Publication Date
- Document Type
- Conference Paper
- 2010. Society of Petroleum Engineers
- 0 in the last 30 days
- 343 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 8.50|
|SPE Non-Member Price:||USD 25.00|
In view of the natural gas with high content of carbon dioxide in Jilin oil field, this paper carried out experiments on hydrate formation conditions and studied the calculation model. Hydrate formation conditions of natural gas with high content of carbon dioxide were measured by using DBR device, and the formation temperatures of hydrate were obtained in the pressure range 0.5~15MPa. The molarity of carbon dioxide was 10% ~ 90%. Hydrate formation conditions of natural gas with high content of carbon dioxide were calculated by using vdW-P model and Chen-Guo model. The results show that: the calculation error of both models were more than ±2. With the increasing CO2 concentration in the natural gas, the calculation error of vdW-P model increased,but the Chen-Guo model's reduced. In general, the Chen-Guo model is superior to the vdW-P model. Based on the experimental data, the Chen-Guo model was improved. The results of improved Chen-Guo model agreed well with experimental result. The improved Chen-Guo model has high prediction accuracy, satisfies the engineering calculation, and has value popularized and applied.
The exploiture of the natural gas with high content of carbon dioxide in Jilin oil field needs to solve hydrate plugging problem of the well and the gathering & transportation facilities on the ground, and compared to other gases (such as CH4), it can form hydrate at a relatively low pressure and high temperatures. Therefore, to determine the hydrate formation conditions of natural gas with high content of carbon dioxide becomes very important. However, there is little literature reported such experimental data. Adisasmito, etc. measured the hydrate formation conditions of the (CH4+CO2) binary system in the pure water. Robinson and Hutton measured the hydrate formation conditions of the (CH4+CO2+H2S) ternary system. But in their experiments, the concentration range of carbon dioxide was narrow and the types of components were very few, so it couldn't satisfy the engineering calculation and the improvement of associated models. The thermodynamic models, which are used to predict the conditions for the forming of natural gas hydrate, developed from the vdW-P model. Both the Parrish-Pransnitz model and the Du-Guo model belong to the improved vdW-P models. The Chen-Guo model is a new thermodynamic model which is completely different from the vdW-P model. However, the deviation is large by using the above models. Therefore, in view of the natural gas with high content of carbon dioxide in Jilin oil field, prepares five groups of high CO2-containing solutions and systematically measures the hydrate formation conditions. To calculate their hydrate formation conditions by using of vdW-P model and Chen-Guo model. The various models' prediction precision is determined by comparing the predicted value and the experimental value. And based on the experimental data, the Chen-Guo model was improved.
Formation Condition Experiment of Hydrate
The experimental sample is prepared by mixing natural gas with pure carbon dioxide in the laboratory. The molarity of carbon dioxide in the five groups of gas samples are 10%, 30%, 50%, 70% and 90%. By using the gas chromatograph, measures the gas composition of the five samples (see table 1).
|File Size||380 KB||Number of Pages||8|