Drilling technology with simplified casing program in Block Mo116

The geological condition of Block Mo116 is complex, with drilling depth of 4300 m. The intermediate casing was run in all the drilling wells in the appraisal period. For reducing the integrated drilling cost and improving the development benefit, drilling with simplified casing program in Mo116 Block was studied in 2011. By analyzing the logging and testing materials of the drilled well, the three-pressure profile was determined and the well casing program was simplified. The single pendulum assembly was determined to be used according to the mechanics analysis of the drilling tools and the actual early drilling results. The optimum type of drilling bit was recommended according to the drillable parameters of the formation rock in Block Mo116 obtained from the clustering analysis of the logging materials. and the potassium calcium based organic salt drilling fluid was taken to overcome the wellbore instability in long open hole section caused by strong water sensitivity of the mud shale formation. The achievements above were successfully used in Block Mo116 to realize the safety and efficiency with simplified casing program.