Sieve tube free composite fracturing fibre sand prevention process

Abstract

The invention provides a novel oil well sand prevention technology and an implementation method. The technology is characterized in that: on the one hand, no sieve tubes is arranged in the oil well; on the other hand, no chemical cementing agent is injected into the oil layer; instead, the oil layer is filled by a method of injecting two kinds of pad fluids and filling a mixture of glass fiber and sands mixed by sand carrying fluid, which can prevent sands with a size of more than 0.07mm. The first pad fluid injected in advance is an oil layer pretreatment agent and is prepared by micro latex, hydrochloride and water; then the injected second pad fluid is sand carrying fluid used for the oil well fracturing, the viscosity of which is strictly controlled, and the injected second pad fluid plays a role of joint forming; next, the filling agent mixed by fiber and sands through the sand carrying fluid used for the oil well fracturing is injected into the oil layer. The technology has no damage on oil layer permeability, maintains higher flow conductivity, and meanwhile reduces partial oil viscosity; moreover, the construction is relatively simple, labor- and time-saving and is easy to carry out. The technology has a sand prevention validity period of more than 1-3 years as well as significant integrated yield-increasing effect.

Description

(1) Technical field [0001] The present invention relates to a new oil production process, in particular to a process and method for preventing sand production in oil and gas wells during oil field production. (2) Background technology [0002] The currently widely used sand control technology can be roughly divided into two categories: mechanical sand control technology and chemical sand control technology. These sand control technologies have many shortcomings in terms of practical effects. For example, mechanical sand control technology includes gravel packing sand control technology of wire-wound screen, gravel packing sand control technology of slotted liner, sand control technology of sand filter pipe and so on. Their common feature is that after the wire-wrapped screen (or slotted liner, sand filter pipe, etc.) Sand filter pipe, etc.) and the annular space between the casing and the part of the oil layer that is deficient around the wellbore. Their basic principle is...

AI Technical Summary

Problems solved by technology

Their common defect is that the scope of gravel packing is limited, and the slots or meshes of the screen pipes cannot be too small (if it is too small, the resistance will be large and the oil will come out less), so usually the silt and fine sand cannot be blocked at all, and Under a large production pressure difference, even the filled sand is easy to flow back out; in addition, the process is cumbersome and complicated. If you are not careful during operation, there will be more falling objects in the well, requiring major repairs, and the workover is complicated and expensive. Moreover, the validity period is short, and some have high costs. Sometimes, the salvage fails, and the situation of scrapped wells often occurs.

[0003] As another example, chemical sand control technology can be roughly divided into three categories: one is resin-coated sand control technology, which is to coat sand with resin and then dry it as a proppant, and inject it into the oil layer by fracturing for sand control. , its disadvantages are: (1) it needs a specific condition to meet the resin curing requirements, such as strict downhole temperature and pressure environmental conditions, etc.; Chemical reaction reduces the resin coating effect; (3) When the well is closed and opened, the cured resin is easy to break due to the change of the closing pressure, which causes the resin coating effect to drop greatly; (4) Resin coated sand treatment Finally, although it can play the role of sand control, the permeability loss of the filling layer is very serious. Within 48 hours after construction, the well temperature of many wells can only reach 50-60 ℃

The ensuing problem is: during the summer construction, the dried resin sand will re-agglomerate due to its own softening, which increases the construction difficulty; It is more complicated to carry out technical measures such as re-drilling and perforating

The second is resin sand consolidation and sand control technology, which is to inject resin into the oil layer and make the resin consolidate the sand in the oil layer to achieve the purpose of sand control. The biggest disadvantage is that the permeability of the oil layer is greatly reduced, the cost is high, and it is poisonous.

The third is artificial well wall sand control technology. There are many types of artificial well walls. For example, pre-coated gravel, resin mortar, water belt dry lime sand, cement mortar, emulsified cement, resin walnut shell, etc. are pumped to the oil layer through the pipe string. And squeeze into the cavity outside the casing to form a dense filling layer. After solidification, the excess filling in the wellbore is drilled and milled, perforated, and put into production. The biggest defect is that it will cause great damage to the oil layer and the permeability The loss is huge, the construction is cumbersome and time-consuming, and the actual effect is not very obvious

Images