Strategic Engineering Application for Long Lateral Wells

Abstract

A new vision with new techniques of wells’ upper and lower completions have been applied successfully throughout a giant offshore multi-reservoir oilfield. Wells with long to very-long laterals have been completed successfully following a systematic strategy based applications and showed tremendous success. This paper will present the various techniques used completing wells in different reservoirs considering well-integrity and HSE regulations in order to achieve the maximum wells’ deliverability’s at their lowest costs throughout the well life. Many challenges were faced and overcame in order to reach the optimum completion that suits each well. A complete journey from reservoir simulation to well and network models, well performance to reservoir management studies, from geological models and interpretation to geo-science and seismic inputs, in addition to actual production data, all helped to achieve the over-all target. From the phase of design to the phase of implementation and beyond to the production phase, each piece of information yielded a certain potential that led to a certain completion design based on available data and expectations. This paper will discuss the new innovative upper and lower completion designs’ strategies along with the execution and performance from production engineering perspective in order to reach the maximum productivity for the life cycle from these long horizontal wells at the lowest possible cost. The extended lateral length in these wells warrants innovative designs in upper and lower completions, as the traditional completion designs no longer suite to address the challenges in these wells. The key well design and planning process involves designing the upper completion including suitable tubing size with the most effective and durable gas-lift system, and lower completion liner designs for different wells’ cases. Efficient initial strategies to start-up wells including some protocols with well-performance monitoring and reservoir surveillance. The paper will also address and discuss the challenges in long horizontal wells such as accessibility, production/injection conformance, and effective stimulations of these laterals. This paper will discuss and show many examples of the completed wells with different types of completions and a comparison of their performances after initial startup and during the back-flow period in addition to the extended performance during normal flowing conditions. Some LEL wells were logged and stimulated showing excellent results; these results will be shared in the paper. It is concluded that the LEL completion proved itself to be the future for lower completion to be widely used in the field. The novelty of such new applications were that they were designed in-house and applied on considerable number of long lateral wells showing excellent results that is changing the completion future strategy in the field and may be in the region or even worldwide.