What is solids control system in the oil drilling?

Oil solids control system is mainly for solids control and separation of oil drilling fluid, and can make drilling fluid recycling, also called mud purification system.

Oil solids control system is mainly for solids control and separation of oil drilling fluid, and can make drilling fluid recycling, also called mud purification system. It is suitable for drilling process of 2000-7000m oil wells. The oil solids control system is composed of 3 to 7 modular combination tanks; the bottom of the purification tank adopts new cone bottom structure, and the mud mixing system is not easy to sink sand at the edge; the tanks of the whole circulation system can be separated from each other and connected with each other to meet the needs of drilling operation, in which the bottom valve of the suction pipe sink is flexible to open and close. The bottom valve of the suction pipe is flexible in opening and reliable in closing. The whole circulating system is equipped with 5 levels of purification equipment, supporting equipment such as vibrating sieve, sand and mud cleaner, vacuum degasser and mixer, etc. The use of the new oil drilling mud purification system reduces mud discharge and has obvious environmental protection effects.

The oil solids control system is used to separate and treat rock chips, mud and sand particles in the drilling fluid, maintain the performance of the drilling fluid and store the circulating drilling fluid. It is equipped with weighted mixing device, filling device and chemical injection device. It is used to improve the physical and chemical properties of drilling fluid to meet the needs of drilling work.

Foreign solid control equipment to the United States BRANDT, SWACO, DERRICK and other companies as representatives, they produce solid control equipment not only good performance, stable work, long life, and are the realization of the standardization of equipment, series and specialization. Quality and performance in the world’s first. Foreign configuration of solid control system equipment, focusing on optimal configuration and efficiency evaluation, thus developing an expert system for solid phase control of drilling fluid. Such as the United States of a solid control system consisting of four vibrating screens and two dryers, the processing capacity increased by 70%, not easy to block, and the separated solid phase particles by the dryer for dehydration, dry particles are drained off, off the liquid recovery, the effect is very good.

With the deepening of oil and gas resources exploration and development, the definition of deep well is also changing, and the current well depth of 6000-9000 meters is the category of deep well. Here, for deep well drilling rigs for oil and gas well exploration and development within 7000 meters of land drilling depth, a set of solid control system for 7000 meters drilling rigs is studied from several aspects, including the main technical parameters of solid control system, configuration of solid control equipment, and process flow of solid control system.

1.Main technical parameters

(1.1) Determination of the effective volume of the drilling fluid circulation tank

The effective volume of the drilling fluid circulation tank is the main technical parameter of the rig’s solid control system, which is explained below by the completion borehole volume method. The completion borehole volume method uses the volume of drilling fluid required to fill the borehole after drilling as the minimum volume required for the drilling fluid system. This method assumes that no mud collection device is used and that all drilling fluid is lost from the drilling tool.

Nominal drilling depth capacity of 7000m, with Ф127mm (5in) drill pipe and 36T drilling tappet combination drilling to the bottom of the drilling rig with the volume of the drilling fluid system. 7000m × O.O127m3/m = 88.9m³36000kg ÷ 7754kg/m3 = 4.6m388.9m³ + 4.6m3 = 93.5m。7754kg / m³ – density of drilling tools O.O127m3 / m – Ф127mm (5in) drill pipe per meter of the external volume of the minimum volume of drilling fluid required to fill the borehole is 93.5m3, plus 50% as a safety volume, that is, 46.75m3, the minimum volume in use of about 140m3. Adding the reserve volume, which is usually similar to the in-use volume, the effective volume of the complete drilling fluid system is about 280m3, and adding the weighted bin of 20m3, the total effective volume is 300m³.

(1.2) Main technical parameters:

Total volume: 353m3 Effective volume: 300m3 (excluding sediment bin, etc.) Mud tank tank size (L×W×H): 11000×2800×2300mm (including 300mm high skid seat) Mud tank transport size (L×W×H): 13500×3000×2800mm Number of mud tanks: 6 (bottom inclined structure) Drug tank: 1 Total installed power: ~650kw

2 Solids control system process flow

(2.1)Drilling fluid purification process flow chart.

In the drilling process, drilling fluid purification treatment is carried out by purification equipment to separate solids and liquids at one stage of drilling fluid, which is currently divided into five stages, usually called five-stage purification: vibrating screen → sand remover → mud remover → centrifuge → gas remover. For deep well drilling rigs, the drilling fluid is purified in five stages. The mud returned from the wellhead is purified by the five-stage purification equipment and then repeatedly pumped into the well by the drilling pump for recycling.

(2.2)Main supporting solids control equipment.

The mud returned from the wellhead is transferred from the elevated mud tank to 3 vibrating screens through the mud distributor; the mud treated by the vibrating screens is de-aerated by the vacuum de-aerator and discharged into the de-sanding bin; then it is sent to the de-sanding and de-muding cyclone by 2 55KW sand pumps in turn, and the treated mud is treated by the centrifuge in tank 2#, which can be further sheared or weighted before being pumped into the well by the drilling pump. In the process of mud treatment, the number of units of purification equipment and treatment time can be selected so that the solid phase content and viscosity of the mud can be controlled within the ideal range to meet the requirements of the drilling process.

(2.2.1)Drilling pump suction process.

 During the drilling process, the two drilling pumps have 2 types of suction methods: self-suction and perfusion: they can self-suction the mud in tank No. 5; through the two perfusion pumps, they can suction the mud in tanks No. 3 (no suction centrifuge supply bin), No. 4 (no suction shear bin), No. 5 and No. 6. There are filters and mud filters installed on the drilling pump suction line with quick-fit filtration devices. When the drilling pump adopts infusion inhalation, 2 infusion pumps can force mud infusion to 2 mud pumps respectively through the gate set, and standby each other, that is, when any 1 infusion pump fails, the other one can work instead of it.

(2.2.2)Slurry replenishment process.

The replenishment bin is located at the end of tank No. 1, and one replenishment pump is installed below the sand sink bin. The mud in the replenishment bin comes from the mud gun pipeline, which is purified and treated mud. The mud in the recharge bin comes from the mud gun pipeline and is purified mud. The recharge pump can be used to replenish the mud in the well at any time during the drilling process.

(2.2.3)Aggravation process.

A special mud weighting system is set up at the right end of No.6 tank for mud preparation and weighting. Mud weighting system consists of 2 weighting pumps, 2 mixing funnels, inhalation sinks, can pump the mud of each bin of tank 3-6, discharge sinks – can transport the mud to each bin of tank 3-6. 2 weighting pumps and mixing funnels as a backup, that is, when either one of the filling pump and mixing funnel failure, the other one can replace it to work. In addition to weighting and configuration of mud, the low pressure weighting system can also supply liquid to the mud gun pipeline, and through the

The mud gun pipeline is connected to the replenishment tank, so that the purified mud can be used in the mud tank.

(2.2.4)Shear mixing process.

For the mud materials that are difficult to decompose, hydrate and mix such as polymers, they can be mixed quickly and evenly by shear pumps and mixing funnels. The shear pump draws in the treatment liquid from the shear bin separated from tank No. 4 for repeated shear mixing, and the shear mixed medicine can be transported to the medicine tank located on the surface of tank No. 2 through the conveying line, and the medicine in the medicine tank can flow into mud tanks No. 2-4 through the output line and mud tank.

(2.2.5)Clear water pipeline flow. The clean water pipeline is set up on the side of each mud tank, which is conveyed to each mud tank through the rectangular steel pipe on the edge of the tank wall, and its outlet is installed with galvanized joint and 3/4″ stainless steel ball valve to inject water into each tank to dilute the mud, flush the equipment and use it for other purposes. Drain valves are installed at appropriate locations. A 3½” inlet valve is installed at the end of tank 4, and a 3½” return valve is installed at the front of tank 1.

(2.2.6)Mud gun piping flow.

Mud gun piping is set up on the other side of each mud tank, which is delivered to each mud tank through the rectangular steel pipe on the edge of the tank wall. The drilling pump and the weighted pump can both supply liquid to the mud gun. The medium pressure mud gun pipeline has a pressure-bearing capacity of 6.4Mpa and is connected to the high pressure pipe sink gate group with a 3″ high pressure hose. There is one high-pressure mud gun for each compartment in the mud tank with high-pressure gate valve and steerable coupling (can be rotated 360°).

The equipment and use of purification equipment is a critical piece of equipment in the drilling process. It directly affects the safety, speed and efficiency of drilling, or the morale of the team, and the purification equipment is equipped as an indispensable part of the complete rig.

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