An Integrated Drilling and Geomechanics Approach Helps to Successfully Drill Wells along the Minimum Horizontal Stress Direction in Khuff Reservoirs

摘要

Saudi Aramco is drilling horizontal wells along the minimum horizontal stress direction in an attempt to generate multiple transverse fractures during stimulation to increase gas production and enhance recovery. However,drilling operations in these wells are difficult due to wellbore instability because of the higher mud weights required to minimize formation breakout due to prevailing in-situ stress conditions. Increased mud weight also led to higher differential pressure across the variably depleted reservoir layers, which when coupled with formation instability,created greater challenges for the drilling team.These conditions resulted in a significantly increased number of stuck pipe incidents,incurring noticeably high nonproductive time including loss of bottomhole assemblies in the hole.To address these problems,an integrated approach between drilling expertise,applied geomechanics,and advanced mud logging technology was applied to successfully overcome stuck pipe events arising from wellbore instability and differential sticking.Additionally,the drilling and tripping practices were customized to confront borehole instability issues.Further,to account for formation heterogeneity and varying in-situ stresses,the predrill Mechanical-Earth-Model(MEM)was updated during drilling using Real-Time Drilling Geomechanics (RTDG).In addition,advanced cutting return-monitoring technology was used,which helped hole cleaning to minimize the risk of stuck pipe due to formation failure(excessive cuttings).An insight into the planning,challenges encountered,and procedures implemented to successfully drill the planned horizontal wells will be presented.