Vertechs engineers at the worksite

The RWSS allowed the operator to successfully drill to the designed depth of 19,307.7 ft and extend another 1,610.9 ft further without any pressure-induced losses and wellbore instability issues, says a company spokesman

In Southwest China, after drilling began at an exploration well in a new block in a dolomite formation, the operator frequently observed pressure-induced leakages, first at 328.08 ft.

This meant a resultant formation damage and which could lead to non-productive time (NPT), especially since the depth of the well was nearly 20,000 ft.

The designed mud density for the well was 9.76-10.43 pounds per gallon (ppg), and it recorded a well temperature of 334.4 deg (168 deg C).

To protect the reservoir and prevent NPT, wellbore isolation specialist company Vertechs’ real-time wellbore strengthening solution (RWSS) was implemented to help the client prevent frequent leakage at this well.

After adjusting the mud density to 9.85 ppg, a 12 ppb ULIA ultra-low invasion additive was added into the active mud system to strengthen the wellbore and minimise mud losses to protect the reservoir.

Three shale shakers were equipped with API 160 mesh and 120 mesh screens. Vertechs also used the High-Pressure Invasion Tester (eHPIT) on-site to provide a real-time reference for drilling fluid invasion management and optimization of ULIA concentration.

As a result of the procedure, the operator successfully drilled to the designed depth of 19307.7 ft and extended another 1610.9 ft further without any pressure-induced losses and wellbore instability issues, protecting the reservoir and preventing NPT.

After the acidification test, the gas production reached 42.36 MMSCFD.

Based on the results of the successful application, the operator decided to use RWSS for the other upcoming exploration wells as well.