Long open hole and long-immersion formation deepen drilling technology in Well Xinsudi-2

Abstract:

Well Xinsudi-2 is an oil and gas geological survey well deployed in the Xinjiang Tarim Basin. The well was drilled to 2468.50m with an open hole section of 2009.24m. After geological assessment， it was designed to be deepen drilling to 3168m. This article takes the 500~600m well section as an example to analyze the wellbore stability. The wellbore is soaked in drilling fluid for a long time， which causes the water content of the wellbore to increase. The cohesion and internal friction angle of the mudstone and other strength indicators decrease， resulting in the wellbore not having pressure-bearing capacity， slight disturbance will cause the well wall to become unstable. The project team adopted a new anti-pollution polymer anti-collapse drilling fluid system， a drilling tool assembly with a drill-while-drilling jar to relieve stuck conditions under complex well conditions， and the target layer was drilled using low drilling pressure\low rotational speed\low-displacement parameter combination drilling and other technical methods has solved a series of complex situations caused by long open-hole sections and long time soaked formations， ensured the smooth completion of the project and achieved the geological purpose， and accumulated the experience and technology of drilling long open hole and long-immersion formations.