Dry Tree Unit Research Articles

Strength check for production riser during dry tree unit coil tubing operations under different environmental conditions

In this paper, we introduce the modelling, loads, result evaluation method and boundary for production riser strength analysis. We investigated the different result evaluation method and different boundary condition based on a real project. The strength checks for the riser coil tubing stack up system in different environmental conditions was performed by SACS Software, calculate the most critical members UC and the maximum loads at critical flange locations of the riser during the whole dry tree unit coil tubing operations. According to the corresponding specification, the analysis results show that all the values of UC less than 1 and the project meet design requirements.

A Parametric Study on the Innovative Coupling Arm Connecting the Coupled TAD-TLP

Two body marine systems, like a Tender Assisted Drilling (TAD) vessel coupled with a floating Dry-Tree Unit (DTU), have become very common in offshore operations. One of the unavoidable challenge we have to cope with is the connection between the TAD and DTU should make sure the TAD does not drift away from the platform and also avoid the possible collision in case of a harsher environment. The objective of this study is to understand the hydrodynamic interactions between the two coupled floating bodies and improve the devising of the innovative connection system. In this study, an innovative rigid connection system, the coupling arm is applied to connect the TAD and a DTU, in this case, a Tension Leg Platform (TLP). The whole system is modelled by the commercial software HARP. A comprehensive parametric study on the pretension and the nominal length of the coupling arm is carried out. The hydrodynamic analysis of the coupled TAD-TLP system elucidates the interactions between the two bodies. The chosen combination of the coupling arm pretension and the nominal length will determine the required stroke range and maximum forces needed to design the innovative coupling arm for safe operations.

Upgrade of Spar Topside With Comprehensive Sand-Management System

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 24705, ’Upgrade of Spar Topside With Comprehensive Facilities Sand- Management System,’ by Y. Loong, Murphy Sabah Oil, and H. Rawlins and D. Goo, eProcess Technologies, prepared for the 2014 Offshore Technology Conference Asia, Kuala Lumpur, 25-28 March. The paper has not been peer reviewed. A deepwater field located offshore Sabah, east Malaysia, features a spar dry-tree unit (DTU) and multiple subsea-hub tiebacks to a floating production, storage, and offloading vessel (FPSO). In early 2011, several of the wells began producing solid fines that affected production. It was decided that a long-term solution would be to recomplete the affected wells with enhanced downhole sand control on the lower completions. The short-term solution consisted of installing a topside sand-management system on the spar and sand-sparging equipment on the FPSO separators. Project Overview The Kikeh field is located 120 km northwest of the island of Labuan at approximately 1300-m water depth. The field was developed using a standalone facility, with hydrocarbons being produced from both subsea and dry-tree wells from a spar/DTU facility. The oil is processed, stored, and exported from an FPSO. Fig. 1 shows the layout of the field. In December 2008, the Kikeh field began to produce solids at varying rates, and by January 2010, after the failure of a sand-screen completion on one of the wells, the process facilities on the FPSO started to receive approximately 1 t/d of sand. Once it became apparent that solids production would be experienced throughout the life of the field, a program had to be developed to address the challenge.