Integration Technology of Workover Equipment with Production Platform in Offshore Oilfield

Abstract

Abstract This paper presents the integration technology of workover equipment with production platform in offshore areas. The environmental conditions, the structure style and the characteristics of the platform are described in the paper. It belongs to the conventional jacket platform. The production control facilities, the work-over rig, triplex pump, watch cabin and living accommodation are installed on the deck, which are all movable and disassembling parts. They can be moved to other similar platforms to perform work-over or remedial work, which will reduce the platform operation cost. Although the cost of the platform is 30% higher than that of the conventional platform, it is 50% cheaper than that of a movable work-over platform and the construction method is simple. As a new type platform, it can be used for production in offshore areas with a water depth of 5-18 m. As more and more oil wells put into production in Chengdao island area, Shengli oilfield, Shandong province, oil testing water injection, well repair and work-over increases greatly. There are only two workover platforms in Shengli oilfield. Most oil testing and workover job is completed by the "Zuo Ye No.1" platform in the area where the water depth is more than 4m, it also need to perform the workover in offshore area in Liaohe oilfield. The "Zuo Ye No.2" platform can only work in the area where the water depth is less than 4m. Many work-over and remedial work especially oil testing after completion must be completed by drilling rig, which is a kind of waste to the drilling rig. The lack of the workover facility severely affected the production of offshore oilfield in Shengli and Bohai Bay. Movable production platform is not suitable for the exploitation of offshore oilfield because of its long design and construction period, high expenses, and high engineering difficulty. In addition, the towing and jacking are complicated and its workover costs are very high with an average price of 2.5 million Renminbi Yuan each time. The research on the integration technology of workover equipment with production platform in offshore field is started in 1997 so as to exploit effectively the marginal offshore field. For an offshore marginal field with a production less than 30-50 t/d per well or per well cluster in initial days and 10-20 t/d later, it is not commercial to use current conventional production technology. It is important for the exploitation of offshore oilfield in Shengli and Bohai Bay to find out a new kind of platform. The platform can meet production requirements not only at present but also in the future, be competent to not only production but also work-over, can not only fixed on the production and workover platform but also move flexibly among production platforms.