Is Single Stage Vertical Well the Only Option for Khazzan/Ghazeer? Hydraulic Fracturing Design Optimization Coupled with Production Simulations Provide Insights on Different Completion Approaches to Maximize Recovery, Production and Economics

Abstract

Abstract Barik Sandstone is a well know condensate reservoir developed in several fields across Central Oman between Ghaba Salt Basin and Fahud Salt Basin. Its particularity lays in the vertical and lateral heterogeneity resulting from the fluvial-deltaic depositional environment and an associated quite unusually high stress differential across the different mudstone and sandstone members. Barik Sandstone is classified as Unconventional Tight Gas due to the low average permeability and requires hydraulic fracturing (HF) to economically exploit the natural resources. Over the years, operators have applied different completion strategies, all including HF, spanning form vertical wells with multiple stages to vertical wells with single massive HF treatments and horizontal multistage wells, the paper will contain a literature review covering all these solutions including the rationale and areas overlapping. However, the common denominator to the success of the stimulation and completion strategy applied is the identification of an optimized HF design that maximizes recovery and economics, increases deliverability and reliability, while efficiently deploy capital expenditure. This paper is focusing on the work done in the Khazzan and Ghazeer fields to optimize the HF through a full circle process that start from reservoir and Mechanical Earth Model descriptions to hydraulic fracturing modeling and sensitivities on different options, then exporting frac geometries to reservoir model and run production predictions, to compare economic analysis, and finally applying the findings to field operations. In condensate gas reservoir, both length (geometry of fracture) and conductivity of fracture play important roles in gas rate and recovery. This study shows how dimensionless fracture conductivity design and increase in fracture length can be balanced to improve gas rate and recovery. Additionally, it provides guidance and sensitivities on the effect of permeability and number of frac stages on recovery and production uplift. This paper presents a method integrating different disciplines including geology, petrophysics, stimulation, petroleum, and reservoir engineering, while using static and dynamic data. Static data such as vertical heterogeneity and stress profile and dynamic data such as HF treatment rate and pressure, well production data (rate and BHP), pressure build up data are integrated to provide the optimal stimulation approach with different optionality depending on project specific objective and constrains.