Difficulties and countermeasures for drilling long lateral-section horizontal wells

Long lateral-section horizontal wells play an important role in exploiting oil and gas reservoir. Compared with vertical well and general horizontal well, it has unparalleled technical advantages. However, because of some factors such as long lateral-section, complex rock lithology, and long contacting time by drilling liquids or drilling tools and formation, many technical problems rise in the process of drilling and cementing. To raise the drilling level of long lateral-section horizontal wells, the paper summarizes these problems firstly, and analyses the reasons of drilling and cementing difficulties secondly. It concludes that the drilling difficulties of long lateral-section horizontal wells are caused by the long lateral-section, and the cementing difficulties are mainly caused by the status of horizontal-section being vertical or approximately vertical to the gravity direction of pipe and slurry. Finally the paper proposes some measures such as optimizing well trajectory, optimizing the performance of drilling liquids and cement liquids, optimizing drilling and cementing tools, and optimizing the tripping method of casing, which raises the quality of drilling and cementing and brings some guidance on the drilling and cementing of long lateral-section horizontal wells.