Research And Application Of Geothermal Drilling Technology For Bedrock In Mountainous Area Of Western Henan

Geothermal,a kind of sustainable and renewable energy hidden inside the earth,is known a huge “treasure house for green energy”.At present,with the severe resource and environmental situation in China,searching for new clean energy,actively adjusting and optimizing energy resource consumption structure,geothermal energy has received unprecedented attention from the top management and industry.Various ministries have issued a number ofpolicies and documents to support geothermal energy development.The geothermal energy industry has ushered in tremendous development opportunities.For a long time,the main development and utilization of geothermal resources is drilling,which directly determines the cost of geothermal resources and the success of development.The western region of Henan province is rich in geothermal resources.However,due to its complex geological structure in evolution and poor natural geographical environment,geothermal drilling costs are high,efficiency is low,and accidents occur frequently.It became a high risk area where people are afraid to talk about.Through literature review and investigation,this paper analyzes the problems of geothermal drilling,such as poor equipment and process foundation,low drilling efficiency and long construction period.It is expected that there will be petroleum equipment technology,green intelligent drilling and multi-process composite drilling,high-deep high-temperature and high-pressure drilling and other development directions in the future.It summarizes the occurrence of geothermal resources in western Henan,analyzes characteristics and causes of complex strata,lists the main influences of local conditions on drilling engineering,also proposes corresponding countermeasures.At the same time,based on production practice,the three-hole geothermal well drilling project is completed by the combination of air DTH hammer + gas lift reverse circulation drilling technologyunder the complicated conditions of “hard,broken and leaking” in the igneous rock-deficient mountainous area of Jiulongshan,Suichuan.The conclusion is as follows: the combined process improves the drilling efficiency,reduces the construction period and cost,solves the leakage problem,and avoids the pollution of the aquifer by the mud;the air DTH hammer can effectively target more than 200 m in the area,where is characterized of hard and partial crushing seriously loses the formation and can maintain a high drilling speed;the gas lift reverse circulation technology can effectively solve the problems of deep hole drilling and leakage,and the drilling efficiency is 1.5 to 3 times that of the conventional positive circulation drilling method.Combined with the problem of small amount of hot water in Jiulongshan No.1 well,the hydraulic fracturing stimulation technology was applied for the first time in the geothermal wells and hydrological wells in the bedrock area of Henan Province,which increased the geothermal water production by three times,which provides demonstration and technical support for geothermal and groundwater resources increase in bedrock areas.