Cases and understandings on the drilling of horizontal well with horizontal section of 3 000 m long in China

The horizontal well technology with ultra-long horizontal section has already become the important technological guarantee for the development of low permeability and unconventional oil and gas resources. And many horizontal wells with the horizontal section at least 3 000 m long have been completed in China. Long horizontal section results in a series of problems, such as large torque and drag, difficult hole trajectory control, difficult hole cleaning, difficult WOB application and poor well stability. To deal with these difficulties, this paper analyzed the key technologies for drilling the horizontal wells whose horizontal sections are at least 3 000 m long, including hole trajectory optimization design, drilling fluid performance improvement, friction reduction and “one-trip drilling”. Then, the development direction of the horizontal wells with horizontal section of 3 000 m long was put forward, so as to improve its application effect and overall level.