|Authors||E. DeNinno (Fortiori) | M. Molina (Newpark Drilling Fluids) | J. Shipman (Newpark Drilling Fluids) | H. Dearing (Newpark Drilling Fluids) | F. Arpini (Newpark-AVA) | L. Bussaglia (Newpark-AVA)|
|Publisher||Society of Petroleum Engineers|
|Source||SPE/IADC Middle East Drilling Technology Conference and Exhibition, 26-28 January, Abu Dhabi, UAE|
In Southern Europe, a field known to have extremely unstable formations was drilled successfully with a specialized high- performance water-based fluid (HPWBF). Prior to formulating the HPWBF, laboratory analyses were performed on the formation using x-ray diffraction (XRD). The formation was found to be high in calcite, quartz and clays. The relative concentrations of the aforementioned minerals were variable; therefore, the samples' reactivities (measured by cation exchange capacities (CECs)) were also variable, increasing the difficulty of predicting reactivities when planning an appropriate drilling fluid. Previously, wells in this area endured costly and untimely sidetracks caused by stuck pipes and collapsing wellbores. The financial impact of lost time and equipment greatly reduced the profitability of the wells.
During the drilling program a drill pipe failure and subsequent fishing operations involved a successful recovery of the lost string and bit after nine days without circulation. Based off of previous experiences1,2, the laboratory formulated and piloted a HPWBF to solve these challenges. Using various shale inhibitors and a high-performance drilling enhancer (HPDE), the fluid stabilized the wellbore and delivered a low coefficient of friction for torque reduction. The HPWBF was also customized with a unique blend of viscosifying agents to maintain rheological properties for optimum hole cleaning.
The HPWBF stabilized the wellbore, allowing the pipe and bit to be retrieved and pulled out of the hole without any issues after the nine days without circulation. This discussion will include the formation's XRD and CEC findings, general drilling fluid measurements such as lubricity coefficients, rheologies, wellbore stability, lab tests on corrosion and cement contamination, and a comprehensive overview of the well data including torque drilling days.