Key Techniques for Drilling and Efficiency Improvement of Offshore Exploration Wells in the Beibu Gulf Basin

The offshore Paleogene strata in the Beibu Gulf Basin in the western South China Sea are characterized by strong tectonic movement,large dip angle,frequent interlayer and strong water sensitivity.There is a high probability of borehole instability,difficulty in controlling the well trajectory,experiencing low steering drilling efficiency and low ROP while drilling.Therefore,based on the traditional four-section casing program of exploration wells in this region and the conventional drilling technologies,combined with the regional engineering geological features,the key factors restricting drilling efficiency were systematically analyzed.,This resulted in a simplified casing program.It also resulted in the development of a high-performance strong sealing drilling fluid system,which is suitable for the Paleogene strata of Beibu Gulf Basin in the western South China Sea,Further,the study optimized high-efficiency PDC bit and BHA design,so as to form the key technologies for drilling and efficiency improvement of offshore exploration wells in the Beibu Gulf Basin.These technologies have been applied in several exploration wells in the Beibu Gulf Basin,and the drilling period was reduced by 36.1% compared with conventional drilling operation under similar depths and drilling difficulties.These key technologies would provide a technical basis for the efficient exploration and development of oil and gas resources in the Beibu Gulf Basin.