Successful Implementation of Innovative Open Hole Completion Technologies for the Longest ERD Well in India's Western Offshore Field
Authors: Bharati P. K. , Ranjan A. , Misra A. , Ranjan A. , Bhosale S. , Kumar V. , Kanakarajan K. , Sadare J. 
Published: February 2024

Designing and executing open hole completions in extended reach wells pose challenges, especially with the multiple-zone isolation requirement and subnormal reservoir pressure. Successfully implementing correct and innovative technology and optimizing the completion design is instrumental in achieving well objectives. The design scope included pressure-activated gas-lift valves (GLVs) enabled without intervention and the in-situ auto gas lift (AGL) using formation gas to aid the lifting of bottom oil sands.

The open hole lower completion design included multiple sand screens with integrated sliding sleeve doors (SSDs), slim swell packers for isolation, and a fluid loss control device. Unlike the historic upper completion, which had conventional GLVs requiring intervention for changeovers, the novel approach used casing pressure-activated shearable GLVs. This eliminated the need for electric-line (E-line) based tractor stroker intervention during installations/changeovers of GLVs from dummy valves at higher angles (greater than 65°). The design process involved a gas-lift design simulation for depth placement of pressure-activated GLVs (unloader and orifice) and orifice size selection. In addition, it included AGL solutions with variable choke positions and an integral screen for sand control in the upper completion, enhancing oil production.

The casing pressure-activated shearable GLVs, initially installed as dummy valves in the upper completion, facilitated the completion test through the annulus against the packer. The fracture rod broke at the predetermined pressure, and the valves operated/converted as unloader/orifice valves. The innovative upper completion design provided the option to use the existing shallow gas zone behind the production casing by deploying AGL solutions between the liner hanger packer and production packer. This allowed flexibility by manipulating variable choke positions for gas-rate control, featuring its unique shroud-and-screen design that best fit sand control needs. The design optimization involved applying slim swell packers (reduced stop-ring diameter) to minimize drag forces and enable completion through an unstable shale section. The production borehole enlargement technique was adopted, with acceptable differential pressure across the swell packers to reduce equivalent circulating densities (ECDs) and ensure smoother conveyance. The completion rig time was reduced by eliminating the E-line tractor operation for GLV changeovers in the upper completion. The deployment of this technology and design optimization enabled the successful completion of three zones in an approximately 3,000-ft lateral section.

The well was successfully completed, activated, and hooked up for production, resulting in a significant increase in incremental production in the field. This design, featuring multiple innovative solutions, is one of the most unique completion designs deployed in the field over the previous 20 years. It represents an innovative approach where flow assurance for later well life can be planned by using AGLs, which leverage existing shallow gas to sustain production. The AGLs can be activated through rigless tractor intervention when needed.