Nanotechnology Improves Wellbore Strengthening and Minimizes Differential Sticking Problems in Highly Depleted Formation

Abstract

It is a challenge to drill in highly deviated or horizontal holes across the highly depleted formations. Wellbore instability, differential sticking and mud loss are frequently encountered problems while drilling a depleted reservoir in deep HTHP wells in Kuwait. Long-term production caused formation pressures to be highly depleted, and drilling became more challenging with considerable non-productive time. Therefore, it is necessary to identify a fluid’s solution when other options with casing zone isolation are not viable. Traditionally, oil-based mud (OBM) was used while drilling these formations with limited success. A customized fluid system was designed to overcome the issue of high overburden pressure in depleted formations targeting effective bridging, minimizing pore pressure transmission and strengthening the wellbore. A nano-size deformable synthetic polymer, along with sized calcium carbonate and graphite, was identified to effectively plug the pore throats and minimized the fluid invasion, which was confirmed by particle plugging tests. A well section was identified to comingle the highly depleted and pressurized formations. This was the first attempt on a high-angle well with deep drilling operations in Kuwait and was performed to facilitate the successful drilling of the reservoir. Traditional OBM was converted to a customized fluid system using a nano-size polymer and sized bridging additives based on proprietary software selection and series of laboratory tests. Drilling, coring and logging were successfully performed for the first time in the commingle section without incident. There was no wellbore instability or differential sticking tendencies, less torque and drag, as well as enhanced wellbore cleaning in the high-angle sections. This paper also presents the some of the successful applications of the nano-size deformable polymer in OBM to drill highly depleted formations in HTHP wells managing upto 3500 psi overbalalnceacross highly permeable formations.

Investigating and Enhancing Mud Cake Reduction Using Smart Nano Clay Based WBM

“…Al-Baghli introduced nanosized polymer to substitute for the conventional oil based mud (OBM). Using a specially synthesized nanoparticles combining with graphite, the experiments conducted by Contreras et al [7] demonstrates the possibility of wellbore strengthening in sandstone formation, which is similar to the literature presented by Al-Baghli et al [6]. The molecular size of nanoparticles exhibits significantly high surface area to volume ratio.…”

“…Paper published by Al-Baghli et al [6] presented the first successfully drilled well on high angled well in Kuwait. Al-Baghli introduced nanosized polymer to substitute for the conventional oil based mud (OBM).…”

Modified Nanopolystyrene as a Plugging Agent for Oil-Based Drilling Fluids Applied in Shale Formation

“…The plugging performance of NS was determined by a Fann-389 permeability plugging apparatus (PPA), which could simulate the downhole static filtration using a specific permeability disc as a filtration medium. The permeability of the disc was 400 millidarcy, the temperature was 150 °C, the differential pressure was 3500 psi, and the filtration time was 30 min. , …”

“…The permeability of the disc was 400 millidarcy, the temperature was 150 °C, the differential pressure was 3500 psi, and the filtration time was 30 min. 42,43 2% NS, NX, and lipophilic nanosilica were each added into the base mud and mixed at 11,000 r/min for 20 min. Then, PPA filtration losses (FLs) before and after aging were determined.…”