CN1364211A - Method for injecting dense additive into drilling wells and composition therefor - Google Patents

Abstract

The present invention discloses method and composition of improved additives for use in control of lost circulation, fluid loss and/or seepage loss of drilling fluid during drilling operations. In particular, the additive is created from lost circulation and seepage control material for use in drilling operations. The steps to create this dense additive include grinding of the lost circulation and seepage control material to produce a small particle size, heating the lost circulation and seepage control material and applying pressure to the lost circulation and seepage control material such that it densifies and is forced through apertures creating a pelletized dense additive. Heating the ground lost circulation and seepage control material, which can release oils or other binding components, is a typical byproduct of the process of forcing the ground product through the apertures.

Description

Method and mixture thereof for injecting high density additive into wellbore

technical field

The present invention relates to an improved additive for controlling loss of circulation, fluid loss and/or drilling fluid seepage during drilling operations. In particular, an additive is provided that can be mixed into a drilling fluid at a rate greater than that of a powdered or ground additive of similar composition.

current technology

Various additives are known in the art to control loss of circulation or seepage in drilling operations. Although the types of additives used for this purpose range from organics to minerals to plastics, most additives are mixed into drilling fluids in powder form. There are a number of disadvantages to using these additives in powder form. The main disadvantage is that the additive is very light, which results in slower mixing of the additive with highly viscous drilling fluids. In drilling operations, rapid mixing of additives into the mud and circulation down the wellbore is necessary and affects the profitability and sometimes safety of the drilling operation. To overcome the slow mixing speed, funnels have been designed with cyclones, venturis and jets to enhance the mixing process and draw additives from the funnel into the drilling fluid at a faster rate. Despite improvements in the prior art, mixing speeds are still relatively low. Due to the low flow velocity through the cyclone, clogging often occurs and dust is also a problem. Dust is a particular problem in certain parts of the world where zero radiation is required. Even disregarding the requirements of radiation standards, dust poses a danger to workers.

Another problem with the use of traditional powder additives arises from general variations in drilling operations. There is a trend in drilling operations to use larger rigs for drilling in deep water, which requires the use of higher volumes of mud. The slurries used are usually more expensive slurries and synthetic oils, which place particular emphasis on the control of loss of circulation and seepage. These factors also lead to the need to use large amounts of additives. But storage space, especially for offshore rigs, is another limiting factor.

In the search for good additives, a large number of organic additives have been tested for their efficiency against circulation loss and seepage control agents. According to the disclosure of US Patent No. 4,217,965 issued to Jim G. Cremeans, waste cattle feed can be used as an additive. This organic material is made from cottonseed hulls with cottonseed meal, bentonite, certain lint, and a surfactant. To make the seeds into cattle feed, the components are heated and compressed, piling up into pellets. Cremeans believes that the advantage of using waste cattle feed is that it avoids the grinding, shredding and pre-processing steps required when using other organic waste products. The surfactant in the pellet acts as a wetting agent, improving mixing time without the need for other chemical additives. Cattle feed pellets are relatively dense and therefore require less storage space. The disadvantage of these cattle feeds is that they do not burst immediately after contact with the drilling fluid, but continue to retain their shape and structure after being added to the mud. Only when they are fully downhole do they begin to rupture.

There is a need to provide an additive which requires the least amount of space required for storage and/or transport. There is also a need to provide an additive that can be mixed with the drilling fluid at a faster rate. It would be desirable to provide a low or no dust alternative for delivering additives to drilling fluids. It is an object and object of the present invention to provide an additive which, once introduced into the drilling fluid, can be quickly and efficiently distributed throughout the drilling fluid. These and other objects of the present invention will be apparent to those of ordinary skill in the art with reference to the description of the specification that follows.

Contents of the invention

The invention discloses a method for manufacturing a high-density additive for drilling fluid and the additive formula. A method for producing a high density additive from a loss of circulation and seepage control material used in drilling operations comprising: grinding said loss of circulation and seepage control material to form particles of smaller size, heating the loss of circulation and seepage control material, and applying pressure to the loss-of-circulation and seepage control material such that the loss-of-circulation seepage material densifies through the small openings used to form pellets of high density additive. While many loss of circulation and seepage control materials are suitable, preferred embodiments include organic materials for use as loss of circulation and seepage control materials. The prilled high density additives for drilling operations made from ground loss circulation and leakage control materials compressed into pellets have a density greater than the density of the loss circulation and leakage control materials prior to compression.

Of the available organic cycle loss seepage materials for the production of high density additives, a preferred embodiment comprises a cellulosic material, in particular one or more of the following: groundwood pulp, pine bark , fruit pomace, vegetable pomace, ponderosa pine, pine bark, corn cob, peanut shell, hickory pith, almond shell, corn cob husk, tartar, cotton burr, oat husk, rice husk, seed husk, sunflower, Flax, linseed, cocoa beans, feathers, peat moss, jute, flax, mohair, wool, paper, sugar cane, bagasse, sawdust, bamboo, cork, popcorn, tapioca, and sorghum.

Although high density pellets are dense, they are 1/8 to 3/4 inch in diameter and 1/8 to 1 inch in length. The density of the additive can vary depending on the circulation loss and seepage control material, the preferred density is based on the highest compression ratio of the material properties. Many organic materials can be compressed to a density 2 to 3 times the density of the ground material.

The present invention also includes a method of performing drilling operations in which drilling fluid is circulated within a wellbore in an earth formation, the method comprising: grinding said loss of circulation and seepage control material to form particles, heating the particles to liquefy thereby Naturally occurring binders, compressed heated particles are passed through to form pellets with a density greater than that of the loss of circulation and seepage control material, which are added to the drilling fluid for circulation in the wellbore. Heating is usually the result of friction during compression. The grinding process also generates a small amount of heat. Additional heating is required for some loss of circulation and seepage control materials. In cases where a binding agent cannot naturally occur within the loss of circulation and seepage control material, preferred embodiments include minimizing the heat generated during the process and adding a suitable binding agent.

Fibrous materials such as sawdust, which are used as loss-of-circulation and seepage control materials, are often in a ground state. A method of making a high density additive for circulation and lost seepage control includes obtaining milled fibers and compressing the milled fibers into pellets such that the pellets have a greater density than the milled fibers prior to compaction.

The structures and methods of the present invention, as well as other characteristics, advantages, benefits and objects over prior art additives, will be more readily understood with reference to the following description.

Implementation

The present invention has many advantages over the prior art. These advantages include increased speed at which the additive is mixed into the drilling fluid, reduced space required for storage and transportation, and reduced or eliminated dust emissions. A feature of the present invention is that the high density additive begins to hydrate upon contact with the drilling fluid. With rapid hydration, the high density additive disperses quickly, allowing the additive to be evenly distributed throughout the drilling fluid as it is pumped down the wellbore. A preferred embodiment involves distributing the high density additive into the drilling fluid using a prior art hopper for mixing non-high density or conventional additives. A typical funnel has an outside diameter of 4-6 inches. The size of the pellet allows easy and compact flow through the outlet of the funnel. As with prior art non-dense additives, the funnel creates a mixing effect whereby the dense additive contacts the drilling fluid. Where appropriate, pellets can be added to the drilling fluid without the use of a funnel. In this case, the pellets hydrate as soon as they come into contact with the drilling fluid and immediately break into fibers or other lost circulation and seepage control materials, but this will take a long time to pump the drilling fluid into the wellbore. The mixing action distributes the fibers evenly into the drilling fluid. Although added in this way it cannot be evenly distributed into the drilling fluid, the additive can easily perform its function after mixing with the drilling fluid at the surface, and the rheology of the fluid at the surface is the same as that downhole.

One advantage of using densified additives is to substantially or completely reduce the amount of dust generated when the additives are added to the drilling fluid. Conventional powdered materials will generate dust when added through the hopper, which poses a danger to the environment and workers. Certain regions, such as the North Sea, have strict regulations regarding dust. The use of densified additives is basically a non-dusting cycle loss seepage control additive.

Conventional powder or finely ground additives (especially fiber additives) have a maximum rate of introduction into the mud or drilling fluid. The rate of addition is related to the stack angle of the additive, which determines the speed at which the additive can be expelled. While previous efforts to increase the rate of introduction have focused on the design of the funnel (including changing the size of the outlet, using cyclones and other physical means), the present invention is directed at reducing the stack angle of the additives thereby allowing these materials to flow more quick. The pile angle is related to any buildup of material and therefore the speed at which it is flowing. By increasing the density of the additive, the build-up can be reduced allowing the same amount of material to be added to the drilling fluid in less time.

Pellets can be made in a variety of properties and sizes. The preferred size of the pellets depends on the particular application, such as the size of the funnel, the material used to form the pellets and the specific shape and size of the stack. Pellets can range from very small dense particles to dense flakes of several inches. The best size balls are 1/8 to 3/4 inch in diameter and 1/8 to 1 inch long. Any device that can be used to force material through a small opening can be used in the present invention. A preferred embodiment includes a belt driven pellet mill (such as the Ace Pellet Mill commercially available from Koppers of Muncy, Pennsylvania). This conventional pellet mill includes a feed roll for accumulating material into a Air-conditioned interior. Steam can be injected into the feed section or into the conditioned chamber if necessary. A roller unit forces the material through a die at each end of the conditioned chamber. The power depends in part on the hole size of the small ball die. The forces generated by such a ball mill are usually sufficient to achieve maximum compression of the ground material. Also, without additional heating, the heat generated by friction is usually sufficient to release the oil or oil-containing binder from these materials. Other methods for compressing the abrasive material may also be used. Similarly, in the present invention the milling and compacting process can be done on one device.

Loss of circulation and leakage control materials useful in the present invention include any additives and/or leakage control agents that can accomplish a loss of circulation. At least one loss of circulation and leakage control material should be somewhat compressible to allow the density of the pellets actuated by the material to be greater than the density of the loss of circulation and leakage control material prior to compression. In the present invention, certain organic materials useful in the circulation loss and seepage control materials include cellulosic materials such as groundwood pulp, pine bark, fruit pomace, vegetable pomace, ponderosa pine, pine bark, corn cobs, peanut shells, Hickory pith, almond husks, corn cob husks, tartar, cotton burrs, oat husks, rice husks, seed husks, sunflower, flax, linseed, cocoa beans, feathers, peat moss, jute, flax, mohair , wool, paper, sugar cane, bagasse, sawdust, bamboo, cork, popcorn, tapioca and sorghum. A wide variety of organic materials useful as cycle loss additives are also suitable for the present invention, including carrageenan, guar gum, and other soluble gums.

Frequently used organic materials include natural binders such as lignosulfonates, xylose, oils or other binders. Since organic materials can form high-density additives when used as additives, these materials generate fine material by friction during the grinding process. The ground material is then subjected to pressure which forces the oil containing material through small openings or orifices forming pellets. In turn, the heat generated by the backlog process releases oil and other easily liquefied parts of the material. These oils and other materials are used to bind the loss of circulation and seepage control material so that the material remains as a pellet. Oil or other loss of circulation and seepage control materials can be added when inorganic materials are used alone or when there is not enough oil to bind the pellets. Similarly, when the oil in the material has a higher melting point, additional heat input is required.

The pellets may consist of one or more additives that are effective as circulation loss additives or seepage control agents. And, the step of applying friction to create fine-grained material can produce materials of different sizes to effectively plug pores in permeable formations without side effects. Thus, the particle distribution in the drilling fluid formed from the pellets of the present invention not only ensures uniform mixing of additives, but also enables uniform mixing of different sized additives if desired using particles of various sizes.

Among the inorganic materials used in the present invention, readily available mineral components such as calcium carbonate, mica, diatomaceous earth, Fuller's earth and other silicates, activated charcoal, alumina, alumina gel, graphite, Bitumen and the like. These materials are usually supplied in fiber or ground form. Carbonates can be used alone or in combination with other desired additives. Adding carbonates to inorganic additives can improve acid solubility. At the same time, the density of the pellets can also be increased. Useful materials also include plastics.

A significant increase in density can be observed between the loss of circulation and seepage control materials and high density additives used in the present invention. A typical example includes a cellulosic additive with a density of 10 lbs/cf. After spheroidizing the additive with mica, a density of 17 lbs/cf was obtained. Greater density is defined as a non-insignificant increase in density compared to the raw material used to form the high density additive. Thus, while the addition of a component such as mica increases the density of a mixture of raw materials, compression into a pellet increases the density of the mixture significantly. The increase in density is directly related to the size, shape and material properties of the particles being compressed. For example, an increase in density from 10 lbs/cf to 11 lbs/cf for a given material can be considered a significant increase in density that allows the material to flow from the funnel at a faster rate and reduces dust generation. The materials used in the present invention are preferably low density, highly compressible materials. In addition to the advantages listed above related to mixing speed, this low-density material can be highly compressed, so the resulting product requires less storage space. For example, corn on the cob can be compressed into a pellet that is twice as dense as the cob.

From the foregoing, it will be seen that the present invention is adapted to achieve all of the foregoing objects as well as other advantages which are obvious and inherent in the apparatus and structure of the invention.

It should be understood that certain technical features can be used and used in combination with reference to other features and combinations. This should also be considered and falls within the protection scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope of the invention, it should be understood that all matters herein and previously described, as well as the accompanying drawings, are to be regarded as illustrative and not restrictive. For example, high-density additives can be pesticides, biocides, and other bioactive materials that reduce the tendency to degrade or repel pests. Although one of the features of the present invention is the use of agricultural by-products as loss-of-cycle and seepage control materials thereby reducing the amount of materials that would otherwise be waste, certain agricultural products and other loss-of-cycle and seepage control materials used in the present invention The material is in ground form. Methods of making high density additives from such a loss of circulation and seepage control material include obtaining milled loss of circulation and seepage control material. It is also within the scope of the invention to obtain the material in ground form as opposed to ground material.

Claims (11)

1. from lost-circulation and seepage control material, make the dense additive method that is used for drillng operation for one kind, comprise the steps:

Grind lost-circulation and become smaller particle size with seepage control material;

Heat cycles leakage and seepage control material;

Make this closeization of material thereby exert pressure to lost-circulation and seepage control material, and pass osculum and form coccoid dense additive.

2. method according to claim 1, wherein, described lost-circulation and seepage control material comprise a kind of organic material.

3. a coccoid dense additive that is used for drillng operation comprises a kind of grinding lost-circulation and seepage control material that is squeezed into bead, and the density of described bead is greater than the density of grinding lost-circulation and seepage control material.

4. coccoid dense additive according to claim 3, wherein lost-circulation and seepage control material is an organic matter.

5. coccoid dense additive according to claim 4, wherein lost-circulation and seepage control material is a fibrous material.

6. coccoid dense additive according to claim 3, wherein, lost-circulation and seepage control material is from by groundwood pulp, pine bark, marc, the vegetables slag, yellow pine wood, pine bark, maize cob, peanut shell, the pecan pith, Pericarppium Armeniacae Amarum, the maize cob skin, the winestone precipitation, the cotton burr, the oat shell, the rice shell, seed hulls, sunflower, flax, linseed, cocoa bean, feather, peat moss, jute, flax, mohair yarn, wool, paper, sugarcane, bagasse, sawdust, bamboo, cork, puffed rice, select in the group that tapioca starch and Chinese sorghum are formed.

7. coccoid dense additive according to claim 3, wherein, bead be diameter at 1/8 to 3/4 inch, length is between 1/8 to 1 inch.

8. coccoid dense additive according to claim 3, wherein, the density of bead is bigger 2 to 3 times than the density of grinding lost-circulation and seepage control material.

9. a method of finishing drillng operation circulates in the well that wherein a kind of drilling fluid creeps in the stratum, and this method comprises the following steps:

Grinding is with lost-circulation and seepage control material, to produce particle;

Thereby heated particle produces binding material naturally to liquefaction; And

Thereby the particle of compression heating passes the bead of osculum formation greater than lost-circulation and seepage control density of material.

10. method according to claim 1, wherein, described lost-circulation and seepage control material comprise organic matter.

11. a manufacturing is used for the method for the dense additive of drillng operation, comprises the following steps:

Obtain a milled fibre;

Described milled fibre is compressed into bead, and the density of its bead is greater than the density of milled fibre; And

Bead is joined in the drilling fluid that is used for circulating in well.