Several wells have been drilled recently by Arctic LNG 2 at the Salmanovskoye (Utrenneye) field. Horizontal drilling at this field is challenging because of an inclination angle up to 52° in the intermediate section, drilled with a 311.2 mm bit. Drilling of large (311.2 mm) intermediate sections with significant vertical offset is not common for this area. The production wellbore section was drilled at an angle of 86°. Solutions suggested for complex wellbore sections drilling, included the use of oil based mud.

Multiple tests were conducted in order to select the best drilling fluids formulation and an action plan was developed to maintain stability of the wellbore and to optimize wellbore cleaning.

Nevertheless, multiple issues were encountered during the first well drilling, which resulted in a significant extension of the construction period. Lessons learned during the first well were studied thoroughly and included into risk assessments made for drilling of subsequent wells. This contributed to the overall success of drilling these wells and to the significant reduction of their construction periods.

Drilling practices and fluids properties were optimized as follows:

  • The whole volume of mud was mixed as required for intermediate section drilling.

  • Dedicated software was used for the continuous modeling of wellbore cleaning efficiency and drilling parameters were adjusted promptly in accordance with the modelling results.

  • HPHT filtration rate was reduced to 2 ml/30 min in challenging wellbore sections.

  • The decision tree was revised as required for the efficient response in case of lost circulation.

Newly prepared OBM, combined with the developed and optimized action plan, contributed to the incident-free drilling of complex wells at the Salmanovskoye field.

Located remotely, requirements for proper logistical solutions was vital for success. This is discussed in details below.

With the success of these messures, it is expected that these practices will be implemented at two other fields on the Gydan peninsula and in other areas where traditional drilling practices may be ineffective due to challenging lithology, geological conditions and logistics and HSE risks

Keywords:
drilling fluid selection and formulation, drilling fluid property, drilling operation, upstream oil & gas, simulation, information, reservoir characterization, wellbore integrity, drilling fluid chemistry, drilling fluid management & disposal
Subjects:
Wellbore Design, Drilling Operations, Pressure Management, Drilling Fluids and Materials, Reservoir Characterization, Wellbore integrity, Directional drilling, Well control, Drilling fluid selection and formulation (chemistry, properties), Drilling fluid management & disposal
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