Патент USA US2112845код для вставки
April 5, 1938. |_. G. HOV-VELL ' 2,112,845 APPARATUS FOR LOCATING HYDROCARBON DEPOSITS IN THE EARTH Filed Dec. 2'7, 1934. . l -— . "'53 Egg ~ / J / /36/// 05M» QM, I 8W‘ 'L 7 ‘1:? njillEQz?myamu? Patented ‘Apr. 5, 1938 2,112,845 __ UNITED ‘STATES PATENT OFFICE 2,112,845 APPARATUS FOR LOCATING HYDROCAR BON DEPOSITS IN THE EARTH Lynn G. Howell, Houston, Tex., assig'nor to Standard Oil Development Company, a corpo ration of Delaware Application December 2'7, 1934, Serial No. 759,373 1 Claim. (o1. 166-1) . This invention-relates to the location of deposits vicinity of the reservoir .1 through the following of hydrocarbon material such as petroleum oil, natural gas or the like beneath the surface of the ground. Deposits of petroleum oil and/or natural gas usually occur in underground strata under considerable pressure. The overlying formations of the ground are permeable to the diffusion of the hydrocarbons from the stratum‘ containing the deposit with a result that the soil gases con 10 tain measurable amounts of ethane and sometimes butane and propane. It has been customary in prospecting for oil by such geophysical methods as the seismic, gravitational, magnetic and elec trical methods to have for an objective the ?nding of underground structures favorable to the ac arrangement of parts: A suction pump 23 is pro vided with an inlet pipe 24 which opens into the upper portion of a container 26 through a suit able sealing means 21. Ethyl alcohol or other cumulation of 011. ~ suitable absorbent. for hydrocarbons well known in the art is disposed in the container 26 to a level 29 below the inlet of the pipe 24. Glass beads 30 or other similar solid particles are dis posedin the body of liquid in the container 26. 10 The conduit l2 opens into the container 25 be low the normal level of liquid in the container. Suction applied by the pump 23 draws the soil gases from the reservoir 1 through the pipe i2 into the body of ethyl alcohol or the like in the 15 container 25. The soil gases bubble through the It is an object of the present invention to ethyl alcohol whereby the hydrocarbons become . dissolved in the solvent and are retained in the locate oil or natural gas directly. Other objects will be apparent from the speci ?cation and from the accompanying drawing in which latter Fig. 1 is a vertical sectional view through the ground showing the apparatus in sectional view; Fig. 2 is a transverse sectional view taken along the line II—]I of Fig. 1; and Fig. 3 is a vertical sectionallview through a modi?ed form of the apparatus in operative posi tion with respect to the ground. Referring particularly to the drawing, refer 30 ence numerals I, I’ designate the surface of the ground containing a bore hole 2,. The hole 2 is preferably drilled to a depth of approximately ll feet beneath the surface of the ground in the territory to be investigated.‘ A tubular member 35 5 is disposed in the hole 2 with its bottom wall 6 disposed in spaced relation to the bottom of the hole 2 to form a reservoir .1, the walls of which constitute the earth stratum 9 in which the hole 2 is disposed. The wall 6 of the tubular 40 member 5 is provided with an opening i I. A con duit l2 extends into the tubular member 5 on the surface of the earth and forms a ?uid tight joint with the opening II. An annular collar I5 is secured in ?uid tight relation to the upper end of the tubular member 5 and is provided with downwardly extending annular ?ange l6 which protrudes into the surface of the ground I, I’ when the tubular member 5 is in position in the hole 2 to form a seal around the tubular member 5 to prevent air from being drawn into the hole 2 from the atmosphere. An additional seal is provided around the hole by means of plaster of Paris or the like, which is poured around the ?anged collar l5 to form‘ a seal I8 for the hole. Soil gases are sucked out of, the ground in the container 26 while hydrocarbon free soil gases are, discharged through the pipe 24. The glass 20 beads reduce the size of the bubbles passing through the solvent thereby giving the hydro carbons a better opportunity to dissolve in the solvent. If desired, a syphon arrangement or any other means for withdrawing soil gases from the reservoir 1 can besubstltuted for the pump 23 and some of the advantages of the invention will be retained. ‘ - In carrying out the pumping operation accord ing to the preferred procedure, a large amount of soil gases is withdrawn from the ground surround ing the reservoir 1- and is passed through the hydrocarbon solvent; for example, approximately 400 gallons of soil gases are extracted from the ground during a period which may constitute four days and four nights of continuous pumping. A partial vacuum is formed in the hole ‘I which pre vents faster pumping. , The solvent containing the absorbed hydro carbons is subjected to analysis for the primary 40 purpose of identifying and determining the per centage of ethane in the soil gases. Soil gases adjacent a stratum containing petroleum oil and/or natural gas contain measurable amounts of methane, ethane and sometimes butane and propane. Ethane is present in the soil gases above oil and/ or natural gas deposits in a concentration of one part in several million parts of soil gas. ‘Also, traces only of ethane or no ethane at all have been found in areas where tube wells have 50 been drilled to salt water and where therefore it is reasonable to conclude there are no oil or natural gas deposits. The end product 01' or: ganic decay is methane. Consequently, methane is found everywhere in varying amounts. It is 55 2 2,112,845 seentherefore that the positive identi?cation of ethane in a gas sample obtained from the soil is an indication of the presence of a deposit of oil‘ known in chemical laboratories. They su?er from the serious disadvantages that rather large samples are required and the sensitivity is low. or natural gas below the point at which the gas It is impossible by these methods to work_ with sample was obtained. an accuracy much greater than 0.1 of 1%. Thus 5 ethane must be present to the extent of one part in about 1,000 parts of gas. Soil gas samples rarely contain such an abundance of ethane. The third method of analysis by means of canal or positive rays permits of the de?nite 10 identi?cation of the different hydrocarbons in the ' The hydrocarbons absorbed in the solvent are therefore analyzed for hydrocarbons heavier than methane, more particularly ethane and possibly butane and propane. In one method of 10 analyzing the hydrocarbons the ethyl alcohol is subjected to elevated temperatures until the gases dissolved in the alcohol have been evapo rated. These gases are then cooled to about -40° C. whereby some of 'the gases are lique?ed 15 and this liquid is drained off. The liquid is mostly alcohol but some of the heavier hydro carbons if present will also liquefy at this tem perature. The remaining gases are then cooled sample and of estimating their relative abun dancies. In this method the gas molecules are shot at a photographic plate by means of an electric accelerating ?eld through crossed elec tric and magnetic ?elds. The molecules suffer a de?ection in both ?elds, the de?ection in the elec tric ?eld being proportional to of! below the boiling point of ethane (whichis 20 -90° C.). The liquid ethane is then drained oil 20 and measured. In making a survey, the bore holes 2 may be and in the magnetic ?eld disposed approximately 500 to 1500 feet apart, although greater and smaller separations mayv 25 be employed in different areas. Reconnaissance surveys using the greater separation of bore holes have been found advisable. Those areas which are found to have soils of high hydrocarbon and especially ethane content are then worked in 30 greater detail with the bore holes closer together. . Referring to Fig. 3, a modi?ed form of the in vention is shown in which I, l’ designate the surface of the ground. A tubular member 35 is provided with an open end adapted to be forced 35 into the ground for a su?lcient distance to form good contact all around the end of the tubular member 35 with the ground. The upper end of the tubular member 35 is closed as indicated at 36 forming a reservoir 31 which opens upon the 40 ground. As shown in its ‘preferred embodiment, the tubular member 35 has the form of a bell jar. Preferably it has a diameter of from three to ?ve feet. A convenient method of sealing it with respect to the ground is to rotate the tubular 45 member until it makes good contact with the ground. Plaster of Paris or other suitable seal~ v ing means designated 39 is then poured around the circumference of the tubular member 35 to form a good seal to prevent the entrance of sur 50 face air into the reservoir 31. Means are pro vided for drawing soil gases from the ground into the reservoir 31 identical in all respects with the - means illustrated in Fig. 1 and like reference numerals are applied to like parts. The means 55 comprises a pump 23 having an inlet pipe 24 which opens into the upper portion of a con tainer 26, partially ?lled with suitable solvent or hydrocarbons such as ethyl alcohol. Glass beads 30 or the like are disposed in the solvent. 60 A pipe l2 protrudes into the reservoir 31 at one end and at its other end opens into the container 25 below the level of the solvent therein. ' It will beunderstood that other methods of analyzing gas samples can be used and some of 65 the advantages of the invention will be retained. For example, the gas samples can be subjected to: 1. Fractional distillation by means of liquid air. 76 QUIDWN .211 111? 25 where e=elementary charge E=electric ?eld strength m=molecular weight H=magnetic ?eld strength 30 v=velocity of molecule Molecules of the same molecular weight are focused on the same spot on the photographic plate. The resolution is very high, being about one part in one thousand parts. This means that 35 particles having weights of 100.0 and 100.1, re spectively, can be separated. In the present case, the molecular weight of methane is 16.04, of ethane 30.06, of propane 44.08 and of butane 58.10. The relative amount of each constituent 40 of the sample is estimated from the intensities of . the different spots or lines on the photographic plate. The emission or absorption spectral analysis can also be used to detect the presence of the hydrocarbons in the soil gases. ' The fifth method is based on the fact that the dielectric constants of these gases are markedly different and that they also have different mag netic susceptibilities. Furthermore, the dielec tric constants increase in the order air, methane, ethane, propane, butane, while the magnetic sus ceptibilities decrease in the same order. It is seen therefore that if a sample of air were placed between the plates of a condenser and inside the coil of an'electric oscillating system tuned to a certain high frequency, say one or several mil lion cycles, the frequency of the system would be higher if methane were substituted for the air, and progressively higher for ethane, propane and 60 butane. The circuit comprising this condenser and coil can be caused to beat against another crystal controlled circuit. Assuming now that the crystal controlled circuit be caused to oscil late at ?ve million cycles and that the ?rst cir 65 cuit be tuned to the same frequency when air has been placed between the condenser plates and inside of the coil, it is easy to see that the accuracy would be as great as one part in ?ve ’ . Combustion. million, since a beat frequency of one cycle per . Positive, or canal, ray analysis. second could be observed easily. . Spectral analysis. the substitution of the soil gas sample for the . High frequency analysis. . Magneto-optic method. If, therefore, air would change the frequency of the circuit by Allison. The ?rst two methods mentioned above are well 15 one cycle, the change could be observed. It is known also that the ratio of methane to ethane 3 2,1 12,845 1 part in one hundred billion parts. Since ethane in natural gas is about eight to one. The appa ratus can therefore be calibrated with samples known to contain certain amounts of methane is‘ present in the soil gases over deposits of oil and/or natural gas in greater concentrations, it and ethane. is seen that the magneto-optic method is amply ' Another highly desirable method is the mag net0—optic due to F. Allison. It is possible to de sensitive for its positive identi?cation. Various-changes may be made within the scope tect one part in one hundred billion by means of this arrangement. The method which is de claim all novelty inherent in the invention as scribed in the literature, for instance in Physi broadly as the prior art permits. 10 cal Review, volume 30, page 66, 1927, volume 31‘, page 313, 1928, and volume 35 page 124, 1930, and elsewhere, is based on the time lag differ ences of the Faraday e?ect behind the magnetic field in liquids as a function of the chemical com 15 pounds dissolved in the liquid. The soil gases of the appended claims in which it is desired to I claim: 10 In gas extraction apparatus, a tubular mem— ber ?lling the bore of a hole in the surface soil of the earth and having a wall extending across its lower end, a tubular casing surrounding the member having a downwardly extending open 15 are passed through alcohol. '.'I'he hydrocarbons are soluble in the alcohol while oxygen and ni end embedded in the earth and a closed end co trogen are insoluble. The alcohol solution con taining the dissolved hydrocarbons is then ana the member in the bore, and a conduit opening through the wall and adapted to be connected to 20 lyzed. Each chemical compound produces a characteristic minimum of light intensity at a certain length of light path. These minima dis appear when the concentration is less than one operating with the tubular member for sealing a source of suction whereby soil gases can be drawn into the conduit. LYNN G. HOWELL.