Comprehensive Screening of Available Technologies to Improve Productivity of Complex Undeveloped Carbonate Reservoir for Optimizing Field Development Plan Abu Dhabi UAE

Abstract

Abstract "M" is an undeveloped thin and tight carbonate reservoir consisting of four porous bodies isolated by the presence of intra-dense layers. The prominent layer is four feet of thickness. Applying conventional acid stimulation in "M" has been ineffective to increase wells productivity and sustainability. Therefore, the objective is to evaluate different technologies to optimize wells design and improve productivity, overcoming the reservoir challenges with cost efficiency for full-field implementation. It took the outcome of integrated reservoir analysis for helping in the selection of the best technology based on the results and lessons learnt, that had been applied in different development reservoirs, chasing analogy and comparing similarities in rock-fluid properties such as: composition, architecture, porosity, permeability, water saturation, and PVT, from core, logs, and production test analysis. Thus, induced hydrofracking, fishbone, abrasive jetting and limited entry liner were screened for feasibility. Once the technology qualified, the economic analysis and detailed design was established for planning purpose to be implemented in the first horizontal producer in "M" reservoir. A horizontal well was drilled in a sheet-like carbonate reservoir (pancake stratigraphy) with the advantage of having geosteering technology. It vanquished the structural complexities and the well remained in contact with the reservoir 3500 ft out of 4000 ft in four ft of thickness, nevertheless, two anomalies such as detected shear zones while drilling tried to put the well outside the target. The multidisciplinary team and real time analysis made the well always to come back on target without compromising time efficiency. The well was completed as producer with electrical semisubmersible pump as artificial lift method. According to the feasibility and screening of the technologies, abrasive jetting resulted in the most effective technique, for production enhancement as cost-effective alternative to induce hydrofracking and other applications in "M" reservoir as a trial. Abrasive Jetting is conducted with 28% HCL, and the distance between stages is designed ~ 20 - 30 ft. to create the channels for maximum production. The expected average wormhole and skin reduction are 1.3 ft and 2.3 respectively. The production testing will be executed to evaluate the well performance, pre and post abrasive jetting job. Based on the successful application of abrasive jetting technology in the first horizontal producer well in "M" reservoir, the technology will be deployed in the marginal reservoir for full field development plan.