High pressure differential labyrinth steam flow regulator research
Heavy oil gather steam injection process on thermal regulator are basic requirements should in the small flow has large step-down function, and in big flow to get small pressure drop. Existing steam flow regulator are difficult to travel in the whole range efficiently regulate steam flow and exists in vibration and erosion problems. In the analysis of domestic and international high-pressure differential flow regulator structure, working principle and questions basis, developed new high-pressure difference labyrinth steam flow regulator. When regulator opening degree is from 0% to 100% percentage (travel is changing), flow percentage is from 0% up to 100%, Conversely, dropped, the whole trip nearly 100mm can be convenient adjusted, and realized the high-pressure differential low flow. The valve inlet Pin = 9.4 MPa, Outlet Pout = 320 MPa, measured valve noise 70dB (ordinary regulator noise achieves to above 84dB), fundamentally relieve the erosion and noise.
1. basic requirements
After heavy oil heating mining into steam driving mining, forming a fixed steam injection pipeline, steam distribution and measured typical processes. Heavy oil development steam injection process crucial in three problems is steam assign, measurement and adjustable control. Reasonable steam regulation can realize scientific steam injection, improving the heat collected oil vapor ratio and crude oil recovery, so as to achieve satisfactory economic benefits. Heavy oil heat mining have single well stimulation and steam driving two stages. In the whole block all over the hot mining process, in addition to early only single well stimulation, general is single well stimulation and steam driving simultaneously. Therefore steam station at the same time give throughput wells and steam driving well injection allocation. In xinjiang kelamayi oilfield hot mining site, throughput wells pressure is high (5 ~ 10MPa), steam injection flow is large (6 ~ 10t/h), while steam driving well steam injection pressure is low (2 ~ 5MPa), steam injection flow is small (1.5 ~ 5-ton/h). This means that allocator to each steam
injection well pressure differential is different, a difference of 3MPa or more, must on the dispenser and steam injection wells added between a resistance to flow link to absorb the rest of the pressure. Obviously, this used flow regulator should be able to in a small flow with large step-down function, and in large flow with small pressure drop. This is heavy hot steam injection process to adopt the special requirements.
2. Existing steam flow regulator and high-pressure difference flow regulator existing problems
At present thermal mining process, in order to reducing pressure, the used regulator works in narrowest opening, inside steam flow is very high, adjustable performance is poor, it is difficult to reach the predetermined flow value. Together with a splitter corresponding multi-port steam injection wells, adjust one well flow will affect other wells flow, this adds flow adjusting difficulty. The shengli oilfield and Xi'an high-pressure valve factory jointly developed JT65y250V type high-pressure steam adjusting globe valve resistance pieces as piston via type adjustment structure. According to the hot mining field running test data flow percentage and drawing the opening percentage relation curves as shown in figure 1. From the curve that opening degree is from 0% ~ 10% and flow percentage is over 60%, sensitivity adjustment is too big, the handwheel moves, steam flow is too large, or too small. While above 10% opening, sensitivity adjustment is too low, at 40% ~ 100% opening scope projects without regulatory function. Therefore difficult to travel in the whole range efficiently regulate steam flow. Meanwhile valve opening is smaller, the fluid reach the critical velocity, consequential vibration and erosion etc, serious problem.
flow percentage
Figure 1 JT65y250V type high-pressure steam adjusting globe valves with flow percentage opening percentage relation curves
Xi 'an jiaotong university researchers designed GYY high-pressure difference regulator (figure 2), realized the high pressure drop, and make flow adjusting properties has been improved, but the critical velocity exorbitant makes erosion, vibration and noise issues more serious, had to use high strength and wear resistance materials. So, not only improves the valve cost and flow with the variation is still very big, adjusting performance have not been improved obviously. In addition, critical flow general required inlet pressure and back pressure ratio is greater than 2, this has limited its application scope. For example, some hot gather steam injection wells need pressure 8 ~ 12MPa or higher, and boiler outlet maximal pressure is 18MPa, cannot form critical flow. In the spot usage, the regulator can't effectively realize high temperature and high pressure, big scope flow regulating and pressure drop adjustment, its flow adjusting mainly depends on the last level channel area. This regulation method is no fundamental distinction with common valve, still very hard to through adjusting valve opening to ensure is expected to flow. Existing high-pressure difference flow regulator is a characteristic of high-pressure difference will inevitably lead to high velocity, high velocity will bring vibration, erosion and noise etc serious problems. How to solve these problems are placed in front of scientific and technological personnel is an important research topic.
