This paper discusses the first Smart in-situ gas lift systems that were installed in three Saudi Arabia offshore wells. These Smart in-situ gas lift systems have proven to work in an offshore development environment for production enhancement. Implementation of this technology will extend the well life by allowing high water cut wells to produce, rather than become inactive, due to high hydrostatic back pressure in the wellbore. The selection of this system, which uses reservoir gas cap energy as compared to other artificial lift methods, resulted from economic considerations and operation simplicity in a non-electrified offshore field. The primary focus of this paper will be to discuss the first in-situ gas lift equipment, completion installation procedures, field test results, operation principles utilizing the gas cap energy, production strategy and well performance using an online monitoring system, and reservoir management considerations for future installations within the field. Initially, five conventional in-situ gas lift systems were installed in the field with problematic downhole sliding sleeve assemblies that required wireline intervention. As a result, Smart in-situ gas lift systems were recommended to allow auto opening of the downhole gas lift orifice valves from surface. These Smart systems have proven their durability over conventional systems, and will extend well life at a relatively higher water cut and maximize reservoir sweep efficiency. Introduction The Z-field is located in the Arabian Gulf and covers an area of approximately 20 km x 8 km. The main producing reservoir lies in an anticlinal trap with a northeast-southwest trending axis. The central part of the accumulation is overlain by a gas cap. As indicated by the cross-section shown in Fig. 1, the oil column consists of a massive, clean highly permeable (3–5 Darcy) sandstone unit overlain by 1–3 Darcy stringer sands interspersed with shales. The reservoir consists of sandstones, siltstones and shales with minor limestones and coals deposited in a complex, fluvial dominated delta system. The overlying gas cap is in direct communication with the stringer sands on the flanks of the anticline and with the Main sand in the central dome of the reservoir. Below the oil reservoir lies a strong aquifer that has maintained reservoir pressure over the past 10 years. The primary drive mechanism for the Main sand is from natural aquifer influx with limited support from gas cap expansion. The main driving mechanisms for the stringer sands is primarily gas cap, fluid and rock expansion, and moderate aquifer support at the flanks. Historically, all vertical wells have been free-flowing to the surface without any artificial lift method.
The design of solid management systems (SMS) facilities for offshore big bore HP/HT sour gas well cleanup is an industry challenge, mainly it is due to solid erosion (sand), potential high pressure H2S release, heat radiation from flare, SO2 exposure, vibration, noise, including risk of piping or facilities blockage, and corrosion (facility integrity) that might hinder safety, operability and environmental issues. The objective of this paper is to develop a solid handling management decision making process especially during early facilities development, identify the merit and limitation on each handling option. As methodology; firstly, technology screening and benchmarking will be performed. Then characterize solid composition, determine the expected solid/ mud flow back during well clean up, erosion and deposition study, hydraulic flow assurance and heat impact mapping. The next process is, develop a decision-making workflow based on solid handling option scenarios including offshore, onshore or a combination of them. Moreover, a hydrocyclone solid removal simulation is performed, and for the onshore application; flow loop experimental work is carried out on a small scale to prove the solid removal efficiency. Various flow rate, pressure and mud with different particle size and concentration from 7% to 15% with mixture of base fluid component are tested during the flow loop test. It is found that factors such as safety (operability), reservoir, well type, solid mud properties, the availability of infrastructure and footprint are playing important roles in the decision of well clean up strategy. Having offshore and onshore SMS will help solid management further robust. Based on the flow loop test study, solids management system with multi-stage separation process has a capability to remove more than 90% solids separation and in addition, differential pressure across stage need to be maintained.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.