Summary Managed pressure drilling (MPD) is a form of drilling that allows greater and more precise wellbore pressure control than conventional drilling. In addition, the mud weight used will be lower than for the conventional mud weight, and a secondary choke or frictional pressure will be applied on the surface to create a combined annular pressure profile within the well. For this paper, we investigated the effect of high power fiber laser heat tension on the carbonate rock body of the Kangan Formation during the irradiation process with accurate simulation work and by comparing the model with experimental results. First, the enforced stress by heat from the laser source was analyzed, and then the fracture propagation pattern in the rock body throughout the entire irradiation process was obtained. This research presented the weakening and fracturing mechanism that was generated from heat exposure during laser irradiation and determined numerical results for fracture pressure before and after laser irradiation. Also, MPD as an effective technology to control this induced anomaly was proposed during the laser-assisted drilling (LAD) operation to prevent any loss, gain, hole instability, or other drilling problem related to this fracturing and weakening.

SUMMARYDrilling is an expensive industry these days which consist of tools, services, rig and etc. so it's important for drilling engineers to optimum drilling parameters to reduce costs and avoid problems. In this paper an integrated drilling system with specific focus on BHA design which has been used to improve drilling performance in the world's largest offshore gas field will be discussed. The effect of this optimization was reduction of actual drilling time to more than half of the budget time.

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