Gas Circle News, Sinopec's Northwest Oilfield Branch's “Three Nitrogen Injections” low-cost development replacement technology was successfully applied in the fracture-cavity reservoir of the Tahe Oilfield. By May 2018, cumulative gas injection volume was 880 million square meters and the number of wells exceeded 1,000. Well times, more than 2.1 million tons of oil increase.
In 2012, the first case of gas well TK404 in Tahe was successfully opened to the northwest oil field. “Three nitrogen injection routes were used. After the gas injection, more than 5,000 tons of oil was added. In that year, 9 gas injections were performed, and the cumulative gas injection volume was 497 thousand square meters. The 0.28 million tons oil increase was achieved through technical research. In the shortest 6 years, the “three nitrogen injection technologies” was used as the replacement technology for water injection development in the Tahe Oilfield to achieve scale expansion. In 2017, 264 well injections were cumulatively accumulated. The gas injection volume is 220 million square meters, and the annual oil increase amount is 617,000 tons.
Innovation incited cost reduction, cost reduction supported scale, and the promotion of scale was achieved thanks to the continuous optimization of key technology nodes by the gas-fired development team of the Institute of Petroleum Exploration in the Institute for 6 years. The four key cost-reduction technologies of gas-liquid simultaneous injection and pressure reduction method, ultra-deep well gas injection oil recovery technology, armored pressure swing adsorption nitrogen production technology, and removable armored 50 MPa electric drive technology are also benefitted from international crude oil Under the situation of falling prices, technicians have conducted in-depth studies and repeatedly demonstrated the cost of gas injection.
The innovation has formed a gas-liquid simultaneous injection and pressure injection method to realize the safe and stable injection of injection pressure control within 40 MPa, which has laid the foundation for the large-scale application of gas injection in Tahe Oilfield. The gas injection construction cost is covered by liquid nitrogen. 550 million yuan / well times, down to 800,000 yuan / well times.
High gas injection pressure in ultra-deep wells, post-injection gas transfer, and production problems require frequent replacement of the string. The innovative injection-production integrated wellhead, thick oil well, dilute oil well gas injection-production integrated column and associated tools have been implemented. Gas injection, oil recovery, and mixed rare-pipeline drilling, the cost of single-well completion and completion completion reduction has reached 56%.
Low-purity nitrogen corrodes the tubing string, leading to increased gas injection costs. The original membrane separation method is nitrogen pressure swing adsorption. Nitrogen purity is increased from 97% to 99%, and the proportion of corrosion scale wells is reduced by 20%.
Innovated to form a 50MPa armored flooded nitrogen injection technology, energy utilization rate increased by 40% compared with diesel flooding, after the field application, the gas cost decreased by 40%, for the first time the domestically produced 50MPa compressor armored, electric drive in the field Applications.
With the large-scale application of the "three nitrogen injection techniques", the cumulative cost reduction for the branch company has exceeded 100 million yuan. The gas injection team has experienced the entire development process. They feel deeply responsible and at the same time look forward to the bright future. They are moving forward. Going further, we are working on a series of technologies such as nitrogen well foam flooding technology and single-well gas injection viscosity reducing agent boosting technology. They will use the power of knowledge to once again promote the “improvement” wheel. At the same time, the "three nitrogen-injection injection technologies" have significant social and economic benefits, which is another major breakthrough in the theory of carbonate rock development and has effectively promoted China's development and technical level of fracture-cavity reservoirs.http://www.wxytgas.com/