Drilling fluid forced-cooling device and low-temperature circulatory drilling method

Abstract

The invention discloses a drilling fluid forced-cooling device and a low-temperature circulatory drilling method. The drilling fluid forced-cooling device comprises a refrigerating medium cooling system and a convection heat exchange system, wherein the refrigerating medium cooling system and the convection heat exchange system are connected in the device in series. The low-temperature circulatory drilling method for the drilling fluid forced-cooling device adopts the drilling fluid forced-cooling device to control an inside temperature of drilling fluid to be 40-50 DEG C, and comprises drilling fluid cooling cycle and refrigerating medium cooling cycle. The drilling technology can solve the technical bottleneck that a drilling fluid circulating temperature caused by an ultra-high underground temperature exceeds temperature-resistant limit of an underground tool, can effectively reduce the drilling fluid circulating temperature by reducing the inside temperature of the drilling fluid, prolongs the service life of the underground tool, is an effective means for safe and efficient well drilling of a high-temperature well, and is a key technology for deeper development of drilling operation. Process and equipment related can independently operate, so that normal drilling operation is not affected.

Description

technical field [0001] The invention relates to the field of exploration drilling, in particular to a forced cooling device for drilling fluid and a low-temperature circulation drilling method. Background technique [0002] With the increase of energy demand, the drilling workload of deep geothermal resources (hot dry rock) and oil and gas resources is increasing, and high temperature drilling technology has become a restrictive factor for the development of the drilling industry. In the process of geothermal drilling and ultra-deep well drilling, the formation temperature increases with the depth, and the bottom hole temperature can reach 240℃~260℃ or higher. At 180°C to 200°C, the organic additives in the drilling fluid will gradually degrade and fail, and at the same time cause the passivation of the clay, resulting in the deterioration of the performance of the drilling fluid. High temperature not only affects the performance of drilling fluid, but also affects the serv...

AI Technical Summary

Problems solved by technology

[0003] like Figure 4 As shown, taking typical high-temperature wells such as hot dry rock and deep geothermal wells: during the drilling process, the formation temperature increases with depth. As shown in L1, the bottomhole temperature at 4000m may reach 250°C. According to experience, when the bottom hole temperature reaches 250°C, in the conventional mode, the temperature change curve of the drilling fluid from the surface to the bottom of the hole is shown in L2. The temperature of the surface entering the well is about 80°C. The drilling fluid in the annular gap conducts heat exchange, and the temperature reaching the bottom of the well is about 190°C. The temperature change of the drilling fluid from the bottom of the well to the surface along the annular gap is shown in L3. The temperature returning to the surface is about 90°C. From the drilling fluid circulation temperature curves L2 and L3, it can be seen that the maximum working temperature of downhole tools must reach 190°C, which exceeds the temperature limit of 150°C for general downhole tools, resulting in the problem that downhole tools cannot work or have a very short life. A drilling fluid forced cooling device and a low-temperature circulation drilling method, thereby reducing the entry temperature of the drilling fluid and stabilizing the entry temperature at 40°C to 50°C. Under the low-temperature circulation mode, the temperature change of the drilling fluid from the surface to the bottom of the well is as shown in L4 It is predicted that the temperature reaching the bottom of the well is about 140 ℃ ~ 150 ℃; the temperature change of the drilling fluid from the bottom of the well to the surface along the annular gap is shown in L5, and the temperature returning to the surface is about 60 ℃; From the temperature curves L4 and L5, it can be seen that the maximum working temperature of the downhole tool does not exceed 150°C, which does not exceed the temperature resistance limit of the downhole tool. The downhole tool can work normally, safely and efficiently, effectively solving the technical problems of high temperature drilling

Images