Патент USA US2408965код для вставки
Oct 8, 1946. w. E. wlNN ET A». 2,408,954 METHOD OF LOGGING WELLS A Filed Aug. 22, 1941 HM/Y TcUR NK \\ ze ii _è . \\‘ El: Nk :l // /0 ì \ F76/ Ä. `~> 2,408,964 Patented Oct. 8, 1_946 UNITED¥ STATES PATENT ortica METHOD oF LoGGrNG WELLS ' William E. Winn, Dallas, Tex., and Patrick F. , Dougherty, Chester, Pa., assìgnors to Sun Oil Company, Philadelphia, Pa., a corporation of New Jersey Application August 22, 1941, Serial No. 407,955v 3 Claims. (Cl. 23-232) „ l The present invention relates to a method of :drilling oil and gas wells and is particularly di rected to a method of detecting the presence of hydrocarbons in the strata traversed by adrlll While a well is being drilled. lt-has long been the practice in drilling to in spect and examine the mud fluid returns from a Well in order to determine the nature of the 2 f of cuttings Ifrom-the drill, such an amount of colloidal material that its viscosity will be sub stantially increased. Conversely when the drill passes throughla formation having a high> salt content the drilling fluid will'become so saline that the clay particles thereinl will be flocculated and the viscosity of the drilling fluid will bede creased materially. ~ Due to these and other causes, among" which may be mentioned the delib strata being traversed by the drill and also the erate variations of the _properties and charact character of the fluid contents, if any, of such 10 teristics of the drilling fluid, by chemicalfor strata. The present invention is directed to an improvement in the method of detecting and de termining the amount ofA hydrocarbons present other treatment, to meet conditions encountered in drilling, thevproperties and characteristics' of the mud fluid issuing from the well, i.' e. at> the in the mud fluid returned from the well and also point> at which it is generally examined, aresub the presence and amount of such hydrocarbons 15 ject to rapid and large variations, and in time the in the strata traversed by the drill, and is par entire'amountvof drilling fluid being circulated ticularly directed to a method of detecting the will be alteredin'character. » „ ` ' presence of low molecular weight hydrocarbons in We have discovered that such variations in the strata traversed by the drill. the properties and characteritics of the drilling In the drilling of oil and gas wells by the ro 20 fluid `will cause serious errors in analysis of the taryvmethod it is customary to circulate a mud 4drilling fluid.`> Thus, a highly viscous mud con laden fluid- down through the drill pipe, out taining a certain amount of hydrocarbons, for in through openings, generally called eyes, in the stance gas, will, in- mostkmethods of analysis, drill where the mud laden fluid exerts cooling and show a different gas content from that of afthin 25 lubricating action on the drill and also picks up mud having the same actual gas content. and suspends cuttings formed Iby the action of lIt is an object of this invention to provide an the drill, the mud with the cuttings suspended improved methodv for examining drillingfluids therein then returning to the surface through the and particularly for detecting and analyzing hy annular space between the drill pipe and the wall drocarbons in vdrilling fluidsobtained from a bore of the bore hole or casing if casing has been set. 30 At the surface the stream of mud fluid is passed s A more detailed object of thev invention is to over a shale shaker, which is merely a vibrating provide a method for analyzing`A and detecting screen, in order to separate the coarser cuttings the'presence of hydrocarbons in a drilling fluid from the drill fluid. The fluid passes through the which will materially decrease the errors in anal 35 shale shaker, flows to a mud pit where it is picked ysis caused by variations in the properties'and upvby the pumps, and is again forced down the characteristics of the drilling fluid. ì A hole. drill pipe. . Since it is the common practice to maintain ` ` ' i Other further objects will be apparent as the description progresses.- " » the drilling fluid at a specific gravity such that -For better understanding of the present inven the hydrostatic head of drilling fluid at the .bot 40 tion, reference should be made to the accompany tom of the hole will be greater than any fluid ing drawing, Fig. 1 of which is a diagrammatic pressure apt to be> encountered in the formations representation vof a well being drilled in accord traversed by the drill there is very little, if any inflow of ñuids from the formations rinto the drilling fluid. Consequently the amounts of gases or other hydrocarbons mixed with the drilling ñuid from the formations traversed by the drill are usually small,. andtheir detection at the sur ance with the ¿present invention, while l5‘ig.12` is , ’a representation of a slight modification of >our face isr frequently accompanied with many diñ‘ì 50 bit 5. lThe mud issues through eyes 6 in the lbit .culties It is wellv known lthat theproperties and char acteristics of the drilling mud are affected by invention; ~ ` i n _ f ~ In the drawing I designates Áa mud pit, from which mud is withdrawn, by pump 2, and forced through line 3,4-"down the drill pipe 4 to the drill and cools or lubricates the bit and picks up the cuttings. _The mud, with cuttings suspended therein, ascends in the annular space between the the nature of the material introduced to the walls of the bore hole 1 Yand the drill pipe 4. The drilling iiuid in the form of cuttings from the 55 lower portion of the drill hole 1 is shown as being formations traversed bythe'drill.v Thus, when uncased while a string of surface casing 8 has the drill is passing through a formation having been set'in the upper portion. ` At the surface the a high content of colloidal material (for example mud from the annular space between the drill a stratum of bentonitic‘ clay) the mud fluid> which pipe and surface casing, 4 and 8 respectively, flows is circulated past thedrill while it is traversing 60 Vthrough line 9 to a shale. shaker Ill, themud pass, such a stratum will'have added to it, in the form 2,408,964 , . 3 I 4 ing through the shale shaker and being returned to the mud pitfI while cuttings are separated out indications as to variations in light hydrocarbon A on the shale shaker and are removed therefrom. We have discovered that by passing gaseous content.v A portion of the mud is withdrawn from the stream of mud fluid issuing from the well prefer-ff ably before the mud fluid realches. the shale shaker, as illustrated in the drawing. This por tion of the mud fluid is withdrawn through .line> .. y ' carbon dioxide through the mud fluid we are able lmore readily to remove the light hydrocarbons therefrom, so that the effect of variations in the properties of the mud fluid, resulting in variations in its ability to retain light hydrocarbons, is mini mized. Since changes in relative amounts of hy exchanger 23, wherein the' mud may Vbe either 10 drocarbons >in the‘mud iluid serve as well as ab heated or cooled to a predetermined temperature. solute amounts to indicate differences in the na I I by pump 26 and passes therethrough-'to aiheat Thence the mud fluid flows to a mixer I2 where it may be chemically treated, as hereinafter more ture of the strata penetrated, the use of carbon dioxide as the stripping agent permits determin ing relative amounts of light hydrocarbons in dicative of the nature of the formations pene trated, such determinations varying more in ac cordance with the hydrocarbon content of the formation and less in accordance with variations in properties of themud than by methods hereto fully explained, by adding chemical or other treating agents thereto through line 24. Suitable means (not shown) are provided in mixer I2 to thoroughly agitate andrmix `the treating agents _added through line `2l rwith the mudfiuid. From the mixer I 2 the mud fluid passes to a stripper I3 wherein light hydrocarbons present in themud fore employed. fluid may be separated therefrom. ~ The mud ‘ ~ Certain other gases, for example, air, steam. methane or ethane, may be employed for strip ping out the hydrocarbons. However, it has been fluid, stripped of light hydrocarbons, is Vdis charged therefrom to a line I4,«either being dis posed of `as waste or returned t0 .the mud pit I. A found that these other gases are much less effec suitable agent for removing hydrocarbons, which 25 tive in removing the hydrocarbons than carbon will hereinafter generally be referred to as a gas, dioxide. Accordingly, if such other gas is used is introduced in the stripper I3 through linev I5 as the stripping medium, a muchlarger propor and bubbled up through the mud fluid vvtherein and is removed therefrom through line I 6. In passing through the mud fluid the gas willistrip tion .of gas is required to minimize variations in the amounts of removed hydrocarbons caused by changes in the properties of the mud than would out hydrocarbon gases present in the mud flow be the case if carbon dioxide were employed and, and possibly also low boiling liquid hydrocarbons. consequently, the time required for treating a given amount of mud fluid is unduly prolonged. It is not known precisely why, carbon ,dioxide is The gas with hydrocarbons stripped from the mud flows through line I6 to a caustic treating tank I7 Where it is bubbled through a solution of caustic soda or other suitable alkali, thence itv ' flows through line I8 to a dehydrator I9 and thence vthrough line 20 to a gas detector or ana lyzer 2I, whence it may be vented to the atmos phere through line 22. As heretofore stated, it is well known in the art ' that asdrilling progresses the character and properties of the mud fiow‘are subject to wide variations due both to the character of material >mixed with the mud 4flowvfrom theformations penetrated by the drill and also due to deliberate ’ variations in the character and property of the mud` fluid by chemical or other treatment. » We have discovered that’ when »a Ygas. is bubbled through the mud fluid being analyzed for the r presence of light hydrocarbons _the variations in the characteristics ofthe mud fluid do notaf‘fect the results obtained as greatly as _when other methods for removing the gaseous or` other light hydrocarbons from the mud flow are employed. " There are three possiblemeans by which the gaseous or other hydrocarbons may be held in the mud fluid: (l) by suspension in the form of minute bubblesv of free gas or oil droplets, l(2) so much more efllcient in removing the hydrocar bons than other gases, but among the possible . reasons may be mentioned the following: (1) the relatively high solubility of carbon dioxide in Water which allows it to dissolve in the water of the mud fluid and displace hydrocarbons dis solved therein; and (2) the high adsorptive pow er of clay or sand particles for carbon dioxide as compared to other gases which results in the dis placement,> by the carbon dioxide, of hydrocar bons ,adsorbed by the solid matter in the mud fluid. Perhaps, also,` the relatively high solubil ity of` carbon dioxide in oil, even as compared to gaseous hydrocarbons such as methane or ethane, may play a part. It should be understood, how ever, that these reasons are proposed only as pos sible. explanations of the effectiveness ,of carbon dioxide and that we do not Wish to be bound by such theories. ` Á , ` Carbon dioxide has another advantage over most other gases that vmay be employed for strip ping out the hydrocarbons in that it may easily be separated from the hydrocarbons, subsequent to their removalfrom the mud fluid,y by absorption „in alkali, thus permitting the hydrocarbonsto be by- absorption in the liquid portion of the,l mud 60 tested separately. Also, if it is desired to analyze fluid, and (3) by adsorption on the surface of the removed hydrocarbons without first separat solid .particles dispersed in the mud fluid.- By ing the stripping agent therefrom, as by the well means of methods knownheretofore, such as >known combustion analysis, carbon dioxide is 'methods employing heat and/or vacuum for driv particularly satisfactory since it will vnot undergo ing out the hydrocarbons, it has been very diffi 6. combustion to liberate heat interfering With the cult to remove substantially all of the gaseous and analysis. lFurther, if it is desired to use`known light liquid hydrocarbons present in the various spectral methods of analysis such as by the mass forms and the amount of such hydrocarbons re spectrograph or infra-red analysis, carbon diox tained by the lmud has been subject to variation ide will not interfere with such analysis so that it depending on the properties of the mud fluid. Thus, when the mud wasv relatively viscous, the contentfof removable hydrocarbons -as deter mined'by these known methods was substantially need not be first removed. Y , , It is therefore preferred‘to use carbon dioxide kas'the gas which is introduced through line I5 into the stripper la. This carbon dioxide with the hydrocarbons stripped from the mud fluid passes methods are‘thus unreliable and give erroneQus , 7 `through line. IB vand may bey analyzed. in any less than when the mud was more-fluid. Such 2,408,964. 5 known or desired manner. As illustrated in the drawing, it may be passed to caustic treating tank I1 wherein it is bubbled through a solution‘of so dium hydroxide or other alkali. The carbon‘di the temperature of the mud fluid being` analyzed substantially uniform. Thus, substantially uni form conditions are maintained on the mud being analyzed throughout the drilling operation or changes in the properties and characteristics >of oxide, by reacting with the alkali in caustic treat the mud can be caused to occur gradually so that ing tank I1, is removed from the separated hy the results of the analysis of the mud vary only drocarbons and hydrocarbons pass through line in accordance with the amountsy of gaseous or I8 to dehydrator I9 where they pass through a other light hydrocarbons in the mud and not in body of calcium chloride or other dehydrating with variations in the aforesaid char agents and thus only hydrocarbons are sent to the 10 accordance acteristics and properties affecting the ability of gas detector or analyzer 2 I, wherein their amount the mud to retain hydrocarbons. In other words and' cliaiiact'er may be determined. It is, of predetermined substantially uniform hydrocar course, to be understood that if some other gas or bon-retentive properties are imparted to the mud vapor is employed in place of carbon dioxide suit prior to the stripping operation in stripper I3, able means for separating the gas from the hy 15 thereby facilitating the determination of a light drocarbons admixed therewith may be provided. hydrocarbon content indicative of the nature of For instance, if air is used as the stripping medi the formation penetrated regardless of variations um, the mixture of air and hydrocarbons` passing during drilling in the properties of the mud which from the stripper I3 through line I6 may be sub its ability to retain light hydrocarbons. jected to a step designed to separate the hydro 20 affect While the present invention has thus far been carbons from the air, for example, to a distilla described in connection with the* detection of tion step. Likewise, if steam is employed as the hydrocarbons in the strata traversed by a drill stripping medium, the mixture of steam and hy during the drillin-g Vof a well, it frequently is de drocarbons issuing from the stripper I3 may be sirable to log the formations traversed bythe passed directly to dehydrator I9 in which the 25 drill after a well has been completed. For in water vapor is removed, the dry hydrocarbon va stance, during the course of drilling the well 1, pors passing out of dehydrator I9 through line 20 certain strata may have been passed through to gas detector 2|. Incase hydrocarbon gas is by the drill bit which showed promise of being used as the stripping medium, the gas removed from the stripper I3 through line I‘S is subjected 30 oil or gas producing formations and it may be desired to obtain additional information con to a type of analysis in which the various indi cerning the strata; or an electric survey may vidual hydrocarbon gases are determined. Thus, be run in the well 1 which indicates that cer if methane is introduced through line I5, the hy tain strata werev passed through by the drill drocarbon gases removed through line I6 will be were not located by other logging means, subjected to the analysis required to separately 35 which and it is, therefore, desired to obtain cuttings determine the amount of methane and the from such formations in order to more fully de amount of ethane and any higher members of the termine their value. Regardless of the reason series, the latter determination identifying hy for which it is desired to obtain additional infor drocarbons present in the mud. If it is desired to mation concerning any particular formation, this determine the amount of methane present in the 40 -information may be obtained in the following mud fluid, ethane may be introduced through line manner. I 5 to gas separator I3 and the ethane and meth The _bit 5 is replaced by an under-reamer 5’ ane removed through line I6, separated and the (Fig.4 2), and the drill pipe Il with the under amount of methane in the mud fluid determined. reamer 5’ secured to the end thereof is lowered However, it is distinctly preferred to use carbon into the well 1 until the cutters 25 on under dioxide since, as stated, this has greateffective reamer 5’ are opposite the formation a: concern ness in removing the light hydrocarbons from the 'Ying which information is desired. Drilling mud mud fluid, and the apparatus for practicingv the is circulated from mud pit I vby pump 2 through illustrated embodiment of the invention has been line 3 down drill pipe 4 and issues from'> openings shown and described particularlyv for the use of . or eyes 6’ in the under-reamer 5’ and *"near the carbon dioxide. . . cutters 25 thereon. The drill pipe is rotated- in In order to still further reduce "the effect of the usual manner so that the cutter 5' will under variations in the properties and characteristics of cut the walls of well 'I in the usual manner. The the mud fluid on the detection of gaseous or other drilling mud circulated down drill pipe 4 returns light hydrocarbons therein, we have provided the 55 to the surface in the annular space between drill treater or mixer I2 in the line II through which -pipe 4 and the walls of well 1 carrying suspended the mud passes. As the mud íiuid passes through the treater I2 suitable and conditioning chemi cals, or preferably solutionsthereof, may be add in it the cuttings from the walls of well 1 at the formation œ formed by the action of the under '5'. The drilling _mud issues from the ed thereto by introducing them through4 valved 60 reamer well through line 9 and a portion thereof is with line 24 and mixing them therewith. We are thus drawn through line II. The treatment of the able to control the viscosity, salinity and other drilling mud' passing ~through line II will 'be the characteristics and properties of the mud fluid "same as that heretofore described, andthe Ymud within a fairly definite or fixed range.. For in is subjected to' analysis to >detect the'presence stance, the visocity of the mud may be controlled vof hydrocarbons Vtherein from the cuttings from by adding aqueous solutions of various alkali formation a: obtained by the -action of under metal phosphates in the well known manner, or at reamer 5’. If desired, thecuttings A‘may be’nsep arated from themud byV usual methods, for in centrated solutions» of suitable salts the salinity may, of course, be readily controlled. vNumerous 70 stance. by the Shale shaker lo, the cuttings washedÍand subjected to detailed analy‘sisï" in speciñc methods of controlling various properties times merely by the addition of water or of con and characteristics of the mud fluids used in drilling are well known and such specific methods do not form a part of the present invention. Also, by means of heat exchanger 23 we can maintain order to obtain additional information concern ing the nature of the formation œ. This method of operation permits the analysis of mud returns from particular portions of the 7 [2,408,964 -bore hole and thus makes it possible to make a more fdetailedand careful study of the more Apromising strata traversed by the bore hole, and also permits a check to be made Von the survey made during drilling in case there are Yany in dications that such survey was not accurate for Some reason, for instance, due to a partial break down of the apparatus, or the like. ‘ At` times it may be desirable to use the latter method of analysis exclusively. In this case an electrical survey may be made of the well and 8 in. or'derto accurately determine the' depth at which the'particular portion o'f the mud ñuid under consideration passed the drill. However, various methodsof determining and making al lowance for this lag in the returns of mud from the drill are well known and, since they form no part of the present invention, they are -not .herein described. What we claim and desire to protect by Let ters Patent is: '1. The method of logging oil and gas wells that are drilled with the aid of a circulating drilling iluid in vorder to determine a light hydrocarbon content of the drilling mud emerging from the Well indicative of the nature of the formation the most promisin-g formations under-roamed and logged in accordance with the present in vention, to thereby obtain the detailed infor mation concerning the nature of the strata trav ersed by the bore hole and their fluid contents. penetrated regardless of variations during drilling This method of operation frequently permits a in the properties of the mud causing variations substantial saving to be made in the cost of in its ability to retain hydrocarbons, which com drilling a well, since the special apparatus nec essary for mud analysis and the trained oper 20 prises diverting a minor portion of the circulat ing 'drillingiluid from the main stream, subject ators and engineers required for its operation, ing 'said minor portion to a treatment which com needbe employed at any particular well for only a limited time and thus a single crew can log a number of'wells being drilled simultaneously prises the addition thereto of materials which will impart uniformv hydrocarbon-retentive prop in contrast to the usual requirement of an ex ert'ies to the minor portion under the same fixed pensive crew for each well during the entire course of drilling. Further savings are made possible since it is unnecessary to conduct the original drilling of the well in any special man n'er in order to facilitate the analysis of mud and the well may be drilled and completed in the most economical and expeditious manner. As thus far described, our invention relates to standard external conditions of stripping, sub jecting the thus treated drilling iluid to the strip detecting and determining the hydrocarbons in the mud fluid. However, it is recognized that ping action of a gas to remove hydrocarbons, separating the mixture of stripping gas and hy drocarbons from the drilling fluid and subjecting said mixture to further treatment including an analysis to determine the amount of removed by drocarbons. f 2. The method of logging oil and gas wellsthat are drilled with the aid of a circulating drilling fluid in orderto determine a light hydrocarbon determining the viscosity and salinity and other ontent of the drilling mud emerging from the properties of the mud as it issues from the well, well indicative of the nature of the formation both by itself and also in conjunction with a penetrated regardless of variations during drill determination of these same properties of the 40 ing in the properties of the mud causing varia same component of the mud as it enters the Well. tions in its ability to retain hydrocarbons which comprises diverting a minor portion of the cir Therefore, it is contemplated that we may either continuously or intermittingly obtain samples culating drilling fluid from the main stream, sub of the mud fluid issuing from the well through jectng said minor portion to a treatment which line 9 and determine the properties and char comprises the addition thereto of materials acteristics of this mud fluid before it is subjected which will _impart _uniform hydrocarbon-reten to any treatment hereinbefore specilied.- Also, tive properties to the minor portion under the much `useful information can be obtained by samples of the mud from line 3 as it enters the well may be continuously collected and subjected to analysis to determine the properties and char acteristics of this mud. Likewise the rate of flow ofthe mud fluid should be noted and re corded Yin order that in conjunction with the same fixed, standard external conditions of strip ping, subjecting the thus treated drilling fluid to the stripping action of carbon dioxide, thereby effecting ther removal, with the carbon dioxide, _from the drilling fluid, of hydrocarbons, and sub jecting the carbon dioxide with the hydrocarbons admixed therewith to further treatment includ depth cf the well the depth at which any com ponent member of the mud fluid passes the bit 55 ing ananalysis to determine the amount of re moved hydrocarbons. 5 may be determined. It is also to be noted that much useful information cani be ascertained by _3. The method of logging oil and gas wells that determining the nature and properties of the cuttings separated from the mud fluid by shale shaker I0. However, we do not herein claim the analysis of such cuttings since »this is a feature of our co-pending application, Serial No. 407,956. It is well known in the art of drilling wells, that in determining the depth at which any material are drilled with the aid of a circulating drilling fluid in order Itordetermine a content of light hy drocarbons inthe drilling mud emerging from the well indicative of the nature of the formation penetrated, which comprises diverting a minor portion` of the circulating drilling fluid from the main stream, subjecting said minor portion of the drilling lluid to the stripping action of carbon Ádioxidathereby effecting the removal, with the carbon dioxide, from the drilling fluid, of hydro from the drill to the surface, and the distance carbons, and subjecting the carbon dioxide with that the drill has advanced during the interval the _hydrocarbons admixed therewith to ,further that a particular portion of the mud fluid was treatment including an analysisto determine the ` travelling to the surface must be subtracted from 70 amount of removed hydrocarbons. from the formations traversed by the drill enters the-mud stream, allowance must be made for the time necessary for the drilling mud to travel the depth at which the drill is operating when this portion of the mud fluid reaches the surface, WILLIAM E. WINN. PATRICK F. DOUGHERT'Y.