Offshore oil production platforms are mainly used to extract oil and gas and perform preliminary treatment of oil and gas (such as oil and gas, oil-water separation), and it must become the basis for multiple production wells and oil and gas processing facilities. Therefore, there must be a corresponding deck area and load capacity, but the displacement limit is not as strict as that of a drilling platform.
Because this type of platform is fixed at one positioning point for a long time, generally fixed platforms, such as jacket platforms or gravity platforms, are generally used. In shallow water areas, fixed platforms are also more economical. But in deep water, or in early production, it is more economical to use a mobile platform.
A part of the oil and gas produced by the mining platform can be stored by itself, while a large amount needs to be stored on another oil storage platform, and the platform can be transported to the land through fixed pipelines or shuttle tankers. This is especially necessary when there are several mining platforms in the same area. From a safety standpoint, it is more beneficial to separate the mining platform from the storage platform.
The steps of drilling oil on the ocean are as follows:
Build a platform – use a tugboat to fix the FPSO on the sea with STP – double-layer thermal insulation pipeline for oil and gas water mixed transportation is linked with the FPSO – the recovered crude oil is filtered and processed and stored in the FPSO – the tugboat comes from the land to take oil in a planned way
This is the “Christmas tree”, the most important part of the production equipment in the import platform.
The Christmas tree is composed of various gate valves, nozzle covers, tee, cross and so on. It is installed on the top of the tubing head to control oil and gas flow, carry out safe and planned production, and complete the work of testing, liquid injection, well killing, and wax removal.
FPSO (floating production storage & offloading) looks like a big ship, but in fact it is indeed a material energy exchange device. That is to say, it floats on the sea where the typhoon is constant along the coast, and supplies power to the platform and takes oil from the platform, and transports oil to and take water from the tugboat, so that the supply and demand of crude oil can be balanced. Crude oil is processed during its input to the FPSO in order to remove associated gas and water from the oil stream produced from the production well, so that the water content in the crude oil is less than 0.5% (weight ratio), and it is sufficiently stabilized, and at 55C, the true vapor pressure (TVP) at is 70-90kPa.
The Wellhead and Christmas tree is composed of four kinds of parts, valves, tubing head adapter, nozzles and pipe fittings. So what is the role of the Christmas tree? It can be used to control production, and it also provides good conditions for wellhead wireline operations, production logging operations, wellhead pressure sensors, production pressure measurement operations, wellhead sampling, and temperature sensors.
The offshore platform Christmas tree can be divided into integral type and split type according to the structural form. The integral type is mainly discussed here, so you know why the integral structure of the Christmas tree is suitable for oil and gas wells on offshore platforms? Because the integral type mainly assembles the main valve, safety valve, wing valve and swab valve into a whole-components, and the distance between the valve and the valve is very small, which saves space and is also resistant to high pressure.
In addition to the split type and the integral type, the single-tubing tree is divided into single-wing and double-wing, which is installed on the wellhead device of the single-tubing completion. The different forms of the single-tubing Christmas tree can be composed of valves and short joints. The single-tubing Christmas tree has three different connection methods: flange type, thread type and clamp type.
The dual-tubing Christmas tree is installed on the wellhead device of the dual-tubing completion. The dual-tubing completion separates the two oil and gas interval pairs by the dual-tubing packer and the single-tubing packer. The dual-tubing tree is used for the control of two reservoirs and independent production.
With the increasing demand for convenient on-site operations, integral wellheads are gradually being accepted. At present, oil production wellhead devices are mostly single-valve structure, flange connection, big height, large space, and on-site installation and maintenance are very inconvenient. When used in cluster wells and offshore platforms with narrow space, single-valve wellhead devices cannot meet the requirements of the site.
Therefore, Sanjack Company provides an integral oil production wellhead device, which is suitable for the use of small spacing cluster wells and offshore platforms with small spaces.
The wellhead is composed of pressure gauge, check valve (1), Swab valve (2), bore(3), side outlet valve(4), choke valve (5), safety valve (6), integral combination valve (7), Master Valve (8), Body(9), cable penetrator device (10), flange(11),hanger (12), tubing head (13), etc.。
Working principle: The upper end of the tubing head is connected to an integral combination valve. The body of the integral combination valve is equipped with a swab valve, a safety valve and a master valve. There is a vertical through hole between the swab valve and the safety valve. There is a side wing valve at both sides, and the lower end of the body is a flange, and the flange is connected with the tubing head to realize compact structure, low height, small volume, convenient on-site maintenance and installation, and safe operation.
The integral wellhead developed by Sanjack has a compact structure, low height, small size, convenient installation, safety and reliability, and is especially suitable for use in cluster wells with small spacing and narrow offshore platforms.