DE2420554A1 - PROCESS FOR BITUMEN EXTRACTION - Google Patents

Description

Process for bitumen administration

The present invention relates to a method for obtaining biturns from underground tar sand deposits by means of hydraulic mining, the method in particular on Tar sand deposits can be used, which are not accessible to waste mining due to the great thickness of the cover layer are.

Oil is found in underground formations or reservoirs in which it has accumulated, and the promotion is by drilling of wells in these reservoirs and outflow of the fluid to the surface due to the existing natural pressure or, if only insufficient natural pressure is given by Pumps running. Many petroleum-containing reservoirs contain petroleum which is too viscous to be pumped out of the reservoir under normal conditions. If such reservoirs exist, is

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Funding is only possible through an additional acquisition process., commonly known as secondary or tertiary extraction, where energy is used to move the oil or heat and / or a solvent to lower the petroleum viscosity is added to the reservoir.

The outstanding example of formations containing petroleum, that is too viscous to be conveyed using conventional methods are the so-called tar or bitumen sands. These are found, for example, in the western states of the USA, in western Ganada and Venezuela «. It is known, that these formations have huge reserves of bituminous petroleum, but the petroleum they contain is too viscous, to win it by common techniques.

The current state of the art for the extraction of bitumen from tar sand deposits can generally be considered as stripping mining (strip mining) or classified in si tu separation. The clearing process requires the removal of the top layer mechanical way and the mixture of bitumen and sand, which represents the tar-sand deposit, is then similar Way removed mechanically and conveyed to the surface in a processing plant in order to separate the bitumen and perform sand. Do the in situ separation process make use of the technique of separating the bitumen from the sand in the tar sand deposit itself, so that bitumen turns into something modified form can be transported to the surface, while the sand remains in the Lagex'stätte. The present

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Applied techniques for in situ separation can be considered thermal or emulsification processes. The thermal Processes are in situ incineration (heat flooding) and steam flooding. The emulsification processes also include the Steam application and the further addition of a chemical to promote the emulsification of the highly viscous bitumen, so that it can be transported to the surface where the emulsion is dissolved in bitumen and water. Although many in situ separation processes were proposed, none was both economically and technically successful.

Most in situ procedures involve fluid injection under fairly high pressures. The injection of a high pressure fluid can only be safely performed if the formation overlay is thick enough to cause rupture impede. The mining of tar sand deposits is only economically feasible if the ratio of The thickness of the cover layer to the thickness of the deposit is around 1 or is less. In the case of many deposits, the cover layer is too thick to allow exploitation by clearing mining, and not high enough to hold high pressure fluids.

The foregoing results in the essential, unresolved requirement for a method for extracting bituminous material Material from tar sand deposits, in particular from those deposits which are used for clearing mining or for in situ extraction processes with injection of a fluid under high pressure are not suitable.

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The attached drawing illustrates the above and below ground Plant and equipment for carrying out the hydraulic mining according to the invention in tar sand deposits.

It has been found that bitumen from underground tar sand deposits can be separated by the fact that the tar sand in a hydraulic process with a hot, aqueous Polyphosphate solution, which contains an alkaline substance, such as B. FaOH, is brought into contact. A means for that

is
Method: a rotating injection string which is equipped with nozzle mouthpieces at its lower end so that the fluid can be directed as a jet against the surface of the tar sand deposit. A separate connection to the surface facilitates the movement of the injected fluid containing dispersed bitumen to the surface for further processing thereof. The injection string is designed to rotate while the fluid is being injected through the string and out of the mouthpieces so that a stream of fluid can exhaust the reservoir. Polyphosphate wetting agents are useful in the invention and include Na trimetaphosphate and tetrametaphosphate. The bituminous petroleum is then separated from the polyphosphate solution by reacting it with a hydrocarbon fluid such as diesel oil.

In a tar sand deposit (1) at too great a depth to allow economic clearing mining, and not deep

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enough for thermal conveyance by injection of a high pressure fluid To make this possible, a combined injection-production well was made (2) sunk to the bottom of the same and a casing (3) placed on the formation head. A separate one Injection string (4) runs inside the casing (3) to a point close to the bottom of the deposit. The injection line (4) is equipped with mouthpieces (5) near the bottom of the strand. The equipment on the surface points means for rotating the string when fluid is pumped through the string. This is done by the coupled motor (6) and the sealing devices (7) and (8), which provide a liquid-tight connection between rotating and non-rotating Manufacture parts of the equipment, shown. A pump (9) pumps hot alkaline polyphosphate solution under sufficient conditions Pressure through the injection line to expel and bring it into contact to ensure with tar sand.

A separate flow channel for the return of a solvent-bitumen mixture to the surface is also provided. This may or will be a separate hole the annular space (10) formed between the piping (3) and injection line (4) can be used. On the surface is that Fluid line (11) connected at one end to the annular space (10) and at the other end to a separation tank (12). The Tank (12), which can be equipped with a mixer and a heater, is connected to line (13), which, in turn, with the output of the pump (14), sucks the hydrocarbon treatment fluid from the tank (15),

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tied together. The polyphosphate additive tank (16) is over the pump (9) is connected to the head of the injection line (4).

During operation, alkaline, aqueous polyphosphate solution is pumped in from the tank (16). It is not necessary to start injecting the hot polyphosphate solution with the high pressure that will be needed later, since the solvent jet only has to travel a relatively short distance to hit the reservoir surface. The hot phosphate solution is injected under pressure through the line (4) and the mouthpieces (5) against the surface of the deposit. The bitumen comes into contact with the solution, aided by the high speed of the fluid jet (17), and the bituminized sand is immediately torn from the formation. Some sand, especially very fine-grained sand, can be pumped to the surface.

When bitumen and some sand are removed from the reservoir, a cavity is formed near the mouthpieces. The cavity increases over time. This process is shown by the dashed time lines represented by T .., Tp and T ~. As the cavity grows, it is necessary to increase the injection pressure so that the nozzle jet (17) touches the cavity walls reached at sufficient speed to tear off bituminized sand.

During the procedure, a mixture of bitumen and hot phosphate solution, containing some suspended sand, flows

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Via the connection _{path f,} such as the annular space (10), to the surface. The conveyed mixture flows through the line (11) into the separation tank (12). Hydrocarbon treatment fluid, v / ie for example diesel oil, from the tank (15) is pumped with the pump (14) into the tank (12) in order to effect a separation of bitumen and sand. The sand settles on the bottom of the tank and is removed mechanically through the line (18). Bitumen and hydrocarbon treatment fluid are found in an upper phase and are withdrawn through line (19) for processing. The hot polyphosphate solution forms a third layer, which is fed via the line (20) to the tank (16), from where it can be returned to the line (4).

The fluid injected in the form of a nozzle jet, preferably in the form of a rotating jet, is an aqueous, alkaline solution of a polyphosphate, such as, for example, tetrasodium pyrophosphate, Na, P ₂ O, acid sodium pyrophosphate, and an alkaline agent, such as, for example, caustic soda.

Polyphosphates are inorganic salts whose anions are PO units that are bonded to other tetrahedra via oxygen atoms. The polyphosphates can be in chain form, e.g. B. [P ₂ O ₇ J ⁴ "or (^ ₃ O ₁ J ⁵ "", in ring form ^ P ₃ O ₉ J ³ " or ^ P ₄ O ₂₂ ] ⁴ ", or as tri- and tetrametaphosphates.

Polyphosphates are hydrophilic, surface-active substances in the G-e.gensatz to organic heretic agents, which are called hydrophobic,

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Surfactants can be considered. No oleophilic units are present in the inorganic polyphosphates, so that they are not surfactants in the sense of the alkyl or alkylaryl sulfates, sulfonates or phosphates. The prior art teaches the use of polyphosphates in household detergents and they work as deflocculants in drilling fluids and other suspensions for the purpose of forming soluble complexes.

Any water-soluble salt of pyrophosphoric acid, H ₄ PpO ₇ , can be used for the process of the invention. For example, the Fa, K or Li salts of the acid can be used. The various possible salt series, for example NaJP ₂ O ₇ , Fa ₅ IIP ₂ O ₇ , Na ₃ H ₂ P ₂ O ₇ or NaH ^ P ₂ O _7, can also be used. Polyphosphates such as Naj.P-zO.jQ are also known which can be used. Ring polyphosphates, such as Na ^ (PO ^) ^ or Na ₄ ^ (PO ₅ )., Can also be used. Preferred materials are the water-soluble salts of the ^H 4 ^P 2 ° 7 », in particular acid sodium pyrophosphate and Na — P ₂ O ₇ .

The polyphosphate concentration in the aqueous solution can be very low and range from 0.05 to 2.0%. Although If higher concentrations can be used, this does not result in any particular advantage. Because the material cost is low the economic optimization of the process will require the use of the lowest possible and most effective concentration provide.

Usually a polyphosphate solution alkaline agent is used '40 988 2/0301 ~ " ⁹ ~

admitted. Care must be taken that the cation, des alkaline agent no -insoluble salt with each polyphosphate used. In general, NaOH is the preferred material, although, also KOH, LiOK or NH, OH, can be used.

Sufficient alkaline agent should be added to the solution to keep the Ρττ value above 10, preferably before above 12, set. In general, 0.1 to 5.0 weight percent of oil is sufficient. A common way to get the one you want To maintain PjT- ¥ ert, the input is approximately the same Shares of alkaline agent and polyphosphate.

Heating the aqueous alkaline polyphosphate solution on a temperature which is above the natural formation temperature increases the effectiveness of the hydraulic solvent mining process of the present invention. The solution can surface heated prior to injecting them. The preferred temperature is about 37.8 to 93.3 ° C

An essential point of the process is the fact that the bitumen is not emulsified when it comes into contact with the hot, aqueous, alkaline polyphosphate solution. The bitumen will effectively removed from the sand, but remains in a separate phase that separates a discrete layer from the aqueous solution forms when stirring is stopped. The bitumen which can be pumped to the surface leaves the most of the polyphosphate solution back in the cavity, if

this is desired. * q

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Most of the sand from which the bitumen is removed will settle your bottom of the cavity. This eliminates the need to process large amounts of sand on the surface, something Sand is transported to the surface together with bitumen, but most of the sand remains in the cavity of the underground formation,

As the distance from the injection point to the surface of the cavity increases, the injection pressure should be increased so that the fluid jet can continuously brush the cavity wall. The injection pressure should not increase so much that the top layer would break. As a general rule, the pressure in kg / cm should not exceed the deck thickness in meters. The cavity can possibly become so large that the fluid flow no longer reaches the cavity wall. Additional bitumen can possibly be produced by pumping all of the fluid out of the cavity so that the injected fluid can travel greater distances from the mouthpieces. The end of operation can easily be determined on the surface from the decrease in the speed of bitumen extraction.

The separation of bitumen and aqueous solution occurs quickly when the agitation is stopped. The separation speed and effectiveness is supported by the fact that the mixture with a KOhlenwasserstoff-Trennfiuid, such as Diesel, brings in contact. The tremifluid can be continuous or iii spacing :. at. the surface or in the storage

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equip to be added.

Field trial.

A tar sand deposit to be exploited had a formation thickness of 15.24 m and the cover layer 39 »1 m. Since the ratio of the thickness of the cover layer to the thickness of the deposits was y 1, mining was out of the question for economic reasons. A borehole was sunk in the bottom of the deposit and a casing was placed on top of the deposit. A string of tubing was run into the tubing, the bottom portion of the tubing being equipped with two horizontally arranged nozzle mouthpieces so that liquid pumped through the tubing ran out of the mouthpieces generally in a horizontal direction at a considerable rate. On the surface, the injection string for rotating it was equipped with an electric motor and had sealing devices to create a fluid-tight connection between rotating and non-rotating parts. An aqueous solution of 0.3% sodium acid pyrophosphate and 0.3% NaOH 65.6 ⁰ C was pumped through an installed at the surface pump into the injection strand. Initially, the injection pressure was approximately 3.52 kg / cm "as the jet only had to travel a short distance to impact the tar sand deposit. The mixture of bitumen and phosphate solution was drawn through the annulus that existed between the rotating injection string and the casing The mixture produced was passed into a separation tank and

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Diesel oil added to the mixture to aid quick separation.

As the cavity increased, the solvent flows had to larger ones from the mouthpieces at the end of the injection tube Travel distances before hitting the cavity wall in the reservoir so that the injection pressure increases had to become. The increase in injection pressure is determined by determining the bitumen concentration in the Surface promoted mixture. A decrease in bitumen in the mix indicated that the polyphosphate solution jet was not had been ejected enough from the mouthpieces to reach pristine tar sand. The injection pressure was slowly increased because it is undesirable to close a fracture point between the crushed formation and the earth's surface create, which would lead to an undesirable connection between the top layer and the surface. By increasing the injection pressure for small amounts, e.g. B. 0.35 or 0.7 kg / cm per unit of time, the solvent flow can steadily the outer Touch the cavity walls in the deposit. In general, the injection pressure given in kg / cm is that given in meters should not exceed the specified top layer thickness. The process was continued until there was a significant decrease in the bitumen content in the produced mix and an increase in injection pressure to 8.79 kg / cm did not result in a corresponding increase in the bitumen content of the mixture. this indicated that the maximum area of the polyphosphate solution jet in the cavity had been reached and no further

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Bitumen obtained by means of the method according to the invention could be.

After it was found that the solvent was so far had penetrated into the deposit as possible, the phosphate solution remaining in the cavity was used for reuse in neighboring areas of the deposit obtained by pumping out the fluid.

Lab ο rv e r search e

To determine the feasibility of the method according to the invention and to determine the optimal values of the controllable Laboratory tests were carried out on the parameters.

100 gram samples of a tar sand, which come from the Athabasca area in Alberta, Ganada, were pressed into cylindrical cakes at 422 kg / cm. The pressed samples were placed in an open container filled with various test solutions. A motorized mixing blade was immersed in the solution approximately 3.81 cm from the surface of the tar sand sample and operated. The extent of the tar sands falling apart was observed and recorded after 15 minutes. In all cases, the temperature was 51.7 to 54.4 ⁰ C, After the dissolution of the samples, the mixtures were allowed to settle. Clean sand settled on the bottom and separate layers of bitumen and polyphosphate solution were formed. A small amount of hydrocarbon was dispersed in the aqueous phosphate solution.

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dated. Adding diesel oil loosened the black material, which floated to the surface and could easily be separated. It formed, not an emulsion.

TABEL

Fluid

Sample time after 15 min.

1.) tap water

2.) Water + 0.3 % acidic Ea-Pyropho sphat

3.) Water + 0.3 % NaOH

4.) V / water + 0.3 % NaOH + 0.3 % acid Na pyrophosphate

5.) Water + 0.6 % NaOH + 0.6% acid Na pyrophosphate

6.) Water + 0.3 % acidic Ba pyrophosphate + NH.OH (to adjust the Pq to 10.8) unchanged

50 % decay
% ^{! l}

low decay

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Claims (10)

Claims 1.) Method for bitumen recovery from a mvtertags tar sand deposit _r which has at least one injection and at least one conveying device, characterized in that "that an aqueous solution containing an inorganic polyphosphate and an alkaline agent by an in rotating injection line arranged in the injection device, which at its lower part leaves at least one horizontally arranged Düserimuridstück, is injected. 2 ·) Method according to claim 1, characterized in that the annular space formed between the injection string and the borehole casing is used as a conveying device. 3.) The method according to claim 1 and 2, characterized in that the pressure of the injected through the injection strand Solution stepwise up to a pressure measured in kg / cm, which corresponds to the deposit cover layer thickness measured in meters does not exceed, is increased. 4.) Method according to one of claims 1 to 3, characterized in that the Bitutnenförderrate is continuous and the injection pressure is increased in response to the decrease in the bitumen production rate. -16- 409882/0301 5.) Method according to one of the preceding claims, characterized characterized in that having a temperature of the aqueous solution which is at least as high as the deposit ent temperature is, preferably at about 37.8 to 93.3 ° G, worked vd.rd. 6.) Method according to one of the preceding claims, characterized »that with a polyphosphate concentration of at least 0.1%, preferably 0.1 to 5.0 wt .-? 6, is worked. 7 ■) Method according to one of the preceding claims, characterized characterized that with a concentration of alkaline agent of about 0.1 to about 5.0 wt .-? *! worked will. 8.) The method according to any one of the preceding claims, characterized in that the promoted bitumen-poly phosphate mixture with a hydrocarbon fluid, preferably diesel oil, to separate the bitumen from the mixture is treated. 9 ·) Method according to one of the preceding claims, characterized characterized in that the alkaline agent used is NaOF, LiOH, KOH or NELOH. 10.) Method according to one of the preceding claims, characterized 409882/0301 characterized that as a polyphosphate with a water-soluble salt of pyrophosphoric acid, such as NaH ^ PpO ₇ , NapHpPoO ^ Na ₇ -HPoO ₇ , TTa, P ₉ O ₇ , a K salt of pyrophosphoric acid, a Li salt of pyrophosphoric acid or a water-soluble tripolyphosphate , such as pentasodium tripolyphosphate, is worked. 409882/0301 ' Lee on the side