Oil well sand control and sand cleaning

Oil well sand control and sand cleaning

The loose oil layer is cemented in the layer, and the lower screen in the wellbore prevents the oil sand from entering the well to ensure the normal production of the oil well and the water injection well, which is called sand control. Oil well sand control and sand cleaning chemical sand control points a certain amount of chemical cement into the sand oil layer to glue the oil layer sand together.

Coated loose sandstone particles enter the wellbore or carry to the ground with oil and water, which will erode, wear, block deep well pumps and pipelines and ground equipment, or deposit at the bottom of the well, block the oil layer, reduce or stop production of oil wells; even the oil layer collapses. The casing is crushed, causing the well to be overhauled or scrapped. When oil is produced, according to the production dynamics, sand sample analysis and sonic logging, the sand cause, horizon and nature should be known in time, and effective sand control measures should be taken. There are two types of sand control measures: screen filter and chemical cement. The former is suitable for various completion methods and is widely used. The latter is mainly used for wells completed by casing perforation. Sand test oil reservoirs have been confirmed through oil testing and test mining, and sand control completion should be considered.

Screen filter sand control is also called mechanical sand control. The multi-slot screen is fixed on the steel pipe with holes, down to the sand layer and the sand with a certain particle size is recycled to the outside of the screen by the sand carrying liquid. The bridge arch formed, the oil layer of the filter oil is sanded. Single, waterless, gas clamp on the oil layer

For the wells of the layer, the pre-stage sand control can be used. That is, the oil layer portion is reamed with a reaming drill, and then the screen is filled with sand (see figure). For wells with multiple layers or with water and gas interlayers, perforation completion. After cleaning the casing and the blasthole, fill the screen under the casing. The structure of the screen, from kerf to over-clad metal mesh or pre-filled gravel, to the development of pre-made filter tubes with organic or inorganic materials. At present, the stainless steel wire with trapezoidal section is used for spot welding to a metal wire-wound filter tube with high strength, large percolation surface and corrosion resistance. This method requires the sieve width and the diameter of the sand to be selected according to the sand particle size analysis data.

Commonly used binders are resins (such as phenolic resins, epoxy resins, etc.), and sometimes cement materials. It is required that the cement shrinks in volume when it is consolidated, or a pore-enlarging agent is added to cause a certain permeability to minimize the influence on the yield. For the oil layer which has been sanded a lot, the permeable artificial well wall is formed by the following method: 1 the sand and the cement are mixed in proportion, and then squeezed into the ground; 2 pre-filling the sand layer, and then raw materials such as formaldehyde and Phenol and curing agent are extruded into the formation in sequence, and the resin is synthesized under the conditions of the formation; 3 quartz sand is covered with a layer of resin, which is extruded into the formation before being completely cured, and solidified under the temperature of the oil layer; 4, using N as a carrier to introduce SiCl vapor The oil layer is decomposed, and the precipitated Si acts as a cement for the loose sand. The advantage of chemical sand control is that it can be used for sand control in multiple oil layers in the same well without shrinking the wellbore; the disadvantage is that the cost is high, and the production capacity of the sand layer is easy to be reduced. The effect is good for the sand control of the oil well or the sand prevention of the water injection well.

Remove the sand at the bottom of the well, generally enter the oil pipe, rinse it with the washing fluid, and take it out of the ground. The sand is accumulated in the blasthole and is washed in sections with a special well-washing packer. The sand in the underground deep well pump and other equipment must be taken out of the ground and inspected and cleaned.