A Experimental Study Of The Buckling Of Drilling Strings In Horizontal Wellbores

With shale gas and other unconventional oil and gas exploration technology developed rapidly in recent years, in order to reduce drilling costs and improve reservoir development efforts, horizontal wells as an effective method for mining and oil and gas production efficiency in drilling engineering design increasingly the more is used. Research shows that the primary factor is the drillstring to continue drilling the drill string in the borehole of the steady state. The drill string in the wellbore stress state is complex, imposed WOB top, inside and outside the fluid pressure of the drilling fluid and viscous friction resistance, drill a reverse effect, top drive or torsional force caused by rotation of the turntable, drill string and wellbore friction resistance, and so will have a significant impact on the stability of the state of the drill string. When the drill string larger force will make the drill string buckling affect normal drilling and drill string and drilling drilling accidents caused by card, so a deep understanding of the drill string in the horizontal wellbore buckling state security drill efficient use of the reservoir and reduce drilling costs are a very important role.Design and build a large indoor displacement horizontal well drilling string dynamics simulation equipment, took a lot of experimental research work and got many research results. On the horizontal borehole drill string axial force transfer efficiency experimentally analyzed and the variation of frictional resistance in the eyes of the drillstring horizontal wells. Given the complexity of the drill string buckling form of horizontal wells in the eyes of proposed two methods of determining the state of the drillstring buckling analysis from the perspective of innovative experiments, can provide a reference for related research. Through extensive experimental study of critical loads on different horizontal borehole drill string, the critical load on the existing theoretical models were evaluated preferred, and established a more accurate calculation of critical loads. There are connectors for analog drillstring studied experimentally investigate the joint impact of horizontal wells in the eyes of the drillstring axial force transfer efficiency and critical buckling load. By changing the wellbore annulus between the drill string and drill string RPM, the drill string and the borehole wall friction coefficient, experimental studies were carried out to explore the effect of different external conditions buckling of the drill string.