Field application of a modular multiple thermal fluid generator for heavy oil recovery

Abstract

A modular multiple thermal fluid generator is introduced to enhance heavy oil production, which consists of water treatment system, fuel injection system, air compressor, central burning and heat exchanging system, and measuring and controlling system. All the components are mounted in three separated light shelters, which are easy to be lifted and installed, especially on the offshore production platform. It could be operated under 350 ℃ and 20 MPa, and the temperature and GWR (ratio of the volume of gas to the equivalent water volume of steam under standard conditions) could be adjusted by the water injection rate under the given heating capability of the central burning chamber. The temperature of the generated fluid is usually 200–300 ℃ with GWR of 200–300 m3/m3. Compared to conventional steam generator, such compact multiple thermal fluid generator is easy to be installed on the offshore oil production platform, and the generated multiple thermal fluid is potential to enhance heavy oil production in mechanisms of reducing heavy oil viscosity by both heating and injected gas, enlarging the heating reservoir chamber, and pressure by injected gas. In the past 10 years, the multiple thermal fluid generator has been applied to more than 40 wells in Bohai Offshore Oilfield and Xinjiang Oilfield in cyclic multiple thermal fluid stimulation (CMTFS in short) process. As a result, the multiple thermal fluid generators were operated soundly, and the heavy oil production of these wells was enhanced remarkably. (The oil production rate was 2–3 times more than cold production.)

Combining Steam and Flue Gas as a Strategy to Support Energy Efficiency: A Comprehensive Review of the Associated Mechanisms

“…Due to the size and weight of conventional steam generators, their installation in offshore fields is complex and limited, so China has been searching for alternatives that allow the exploitation of heavy crude oil resources offshore. To this end, they have implemented a new technique called multi-thermal fluid stimulation (MTFS), which consists of the coinjection of flue gas and steam at high temperatures and pressures . The injected fluids are produced by a portable generator, and according to the developers, it differs from the injection of steam and noncondensable gases in three points: (a) the fluids are always coinjected, (b) the composition of the gas flows with other gases in the composition (CO and CH 4 ), and (c) the injection pressures and temperatures are high, which represents savings associated with the treatment and cooling of the combustion gas stream.…”

“…Theoretically, each portable generator can produce 166 tons of steam at 300 °C and 4.82 × 10 4 m 3 /day of flue gas, and the enthalpy of this combination is equivalent, to 2.6 × 10 8 kJ according to manufacturers. 92 Bohai Field. This system has been applied in the NB35-2 field in the western Bohai area; the first MTFS pilot was conducted in 2009 as a cyclic injection process in more than 15 offshore horizontal wells.…”

“…Updated reports indicate that more than 15 wells have been intervened with high rates of incremental oil production, averaging 291 tons per well. 92 Shengli Project. Since 2011, this heavy crude oil field had been cyclically steam injected; in 2020, a well that had previously been subjected to 10 steam stimulation cycles was injected with the hybrid technology of steam and flue gas.…”

“…In 2016, the field also carried out multithermal fluid injection in 4 blocks with different heavy oils. Updated reports indicate that more than 15 wells have been intervened with high rates of incremental oil production, averaging 291 tons per well …”

“…To this end, they have implemented a new technique called multi-thermal fluid stimulation (MTFS), which consists of the coinjection of flue gas and steam at high temperatures and pressures. 92 The injected fluids are produced by a portable generator, and according to the developers, it differs from the injection of steam and noncondensable gases in three points: (a) the fluids are always coinjected, (b) the composition of the gas flows with other gases in the composition (CO and CH 4 ), and (c) the injection pressures and temperatures are high, which represents savings associated with the treatment and cooling of the combustion gas stream. Theoretically, each portable generator can produce 166 tons of steam at 300 °C and 4.82 × 10 4 m 3 /day of flue gas, and the enthalpy of this combination is equivalent, to 2.6 × 10 8 kJ according to manufacturers.…”