LEAN concepts have been applied in a wide range of industrial areas to identify and eliminate the waste in every stage of different processes, currently improve efficiency and lower production costs has become popular among Oil and Gas senior-level management. Minimizing waste is the base on which LEAN concepts are built. A LEAN endeavor seeks to eliminate activities or processes that consume resources, add cost or require unproductive time without creating value. The concepts can be described as striving for excellence in operations in which each employee seeks to eliminate waste and participates in the smooth flow of value to the customer. As part of a complete new strategy to ensure permanent improvements within the whole operational environment Petroleum Development Oman (PDO) has applied LEAN on drilling and other corporate core areas. This paper presents a LEAN application to optimize the Snubbing Interventions in order to ensure a significant CAPEX and OPEX reduction in an extensive deliquification campaign for gas wells thru the implementation of high end Velocity String (VS) completions. The projects involve the application of LEAN methodology from the early planning stages using in many cases re-engineering to the functional specifications, material selection and operational procedures. This re-engineering includes a deep review of every intervention activity, the application of new technologies and the analysis of major issues during previous snubbing interventions, followed by the measurement of the real operational times and deep technical brainstorming on every stage of the intervention process. All those factors have contributed with a significant amount of improvements along the intervention campaign.

Velocity strings are routinely installed to remediate liquid loading of gas wells. However, besides restoring stable production, velocity strings also reduce well capacity, easily by up to 50%. In PDO, a sliding side door (SSD) was introduced as part of the velocity string completion to reduce the loss of capacity by facilitating additional gas flow via the new annulus created between velocity string and original tubing. This paper documents different field cases that demonstrate how the SSD is manipulated to maximize well capacity, which in some cases was doubled for more than 1 year. The paper also presents modelling of gas production via velocity string, annulus or both (concurrent). Commercial software was not able to accurately predict the instability of concurrent gas production.

Following second stage depletion compression, more than 100 deep onshore gas wells operated by PDO in the Sultanate of Oman started suffering from downhole halite deposition. Halite scale blocks part of production and reduces well capacity by 20-80% depending on well specific conditions. Fresh water bullheading treatments were introduced to periodically dissolve the halite scale but in many cases treatments were applied too late or are not effective in preventing permanent blockage. In those cases, a cleanout using a work string is required to restore wellbore access and production. Historically, coiled tubing was used to remove halite scale via milling and fresh water jetting. Recently, 1/4" and 3/8" capillary strings were successfully deployed to reduce the cleanout cost and the volume of water lost to formation. This paper describes the experience with fresh water bulheading and the novel use of capillary string to clean wells that suffer from halite scale.

Petroleum Development Oman operates large amount of gas wells in Sultanate of Oman. Due to the liquid loading occurring in these ageing assets, PDO has already installed 110+ Velocity String completions in the various gas fields across the concession area. In the 2015–2019 period, 39 wells in the Saih Rawl field were retrofitted with Velocity Strings. This paper presents the integrated and standardized approach to Velocity String candidate selection and compares the production performance post-installation against the forecast.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractAn integrated study on a cluster of 23 fields in South Oman was performed in the Petroleum Development Oman (PDO) Study Center, in order to derive a coherent view on the cluster development as well as to write (waterflood) FPDs for the individual fields. The study combined conventional and stateof-the-art workflows and was conducted by a large integrated team over a period of three years. The study was conducted in four phases: screening, full field modelling, infra-structure development and FDPs for the 6 large fields and the writing of appraisal / development plans for the remaining 17 fields. This paper describes the workflow and learnings of the study.