Julia Case History of the Stimulation and Lower Completion to Meet the 10kpsi Drawdown Tertiary Challenge

Abstract

Abstract The Lower Tertiary Wilcox Julia field is a large resource with low permeability (average 10 mD) and 20 cP in-situ viscosity oil. In order to achieve optimum production rates and ultimate recovery, ultra-high 10,000 psi drawdown is required from a multi-zone fracture stimulated lower completion. This paper will review design and execution details of the 4-well Phase 1 lower completion and fracture stimulation design. Results from Phase 1 will be used in future reservoir studies to determine the ultimate development plan for the Julia Field. The Julia reservoir and geology were studied and a single well simulation model developed to determine the optimal fracture geometries required to deliver low skin completions. A "clean sheet of paper" approach was taken to brainstorm all possible completion options to achieve these fracture geometries. Further study concluded a multi-zone fractured completion was needed to cover the typical ~2000ft vertical gross pay with 4-5 zones. The fracture gel, proppant and fracture designs were then developed to meet the fracture length and conductivity requirements. Four wells were completed with excellent results yielding initial skins of −4 to −6 when skins of −2 to −3 were expected. Four multi-zone, ultra-deep (~31000'+ TVD), ultra high reservoir pressure (~21000-22,000 psi) wells were completed successfully with initial production rates better than expected on a per well basis The completions were executed without sticking a frac tool and without loss or abandonment of any zones. Each aspect of the completion, multi-zone, fractures, proppant, fracture design and implementation was key in achieving the ability to drawdown the wells up to 10,000 psi and optimize the Julia production for Phase 1. This development shows the team's approach across multiple disciplines of geology, reservoir, and sub-surface to meet the Lower Tertiary challenge. Results from Phase 1 will allow further reservoir studies to be conducted over the next several years to determine the best ultimate development plan for Julia. Well operability limits to define the allowable drawdown and depletion were calculated. Initial production curves with drawdowns are shown.