Methods and apparatus for detecting the entry of formation gas into a well bore

Claim 7

The method of claim 3 further including the steps of: moving one of said drill string portions relative to the other of said drill string portions to contract said sampling chamber for expelling said mud sample; entrapping a second sample of said drilling mud from said selected depth in said sampling chamber; moving one of said drill string portions relative to the other of said drill string portions to re-expand said sampling chamber for reducing the pressure of said second mud sample to at least said saturation pressure; and measuring the force required to re-expand said sampling chamber for verifying the force measurement obtained from expansion of said first mud sample.

Claim 8

The method of claim 3 wherein said one drill string portion is said upper drill string portion and movement thereof is accomplished by elevating said upper drill string portion.

Claim 9

The method of claim 3 wherein said one drill string portion is said lower drill string portion and movement thereof is accomplished by continuing to excavate said borehole with said drill bit for lowering said lower drill string portion in relation to said upper drill string portion.

Claim 12

The method of claim 7 further including the steps of: moving one of said drill string portions relative to the other of said drill string portions to contract said sampling chamber for expelling said mud sample; entrapping a second sample of said drilling mud from said selected depth in said sampling chamber; remeasuring the force required to support said drill string in said borehole while said drill string portions are again in their said first position; moving one of said drill string portions relative to the other of said drill string portions to re-expand said sampling chamber for reducing the pressure of said second mud sample to at least said saturation pressure; remeasuring the force required to support said drill string in said borehole while said drill string portions are in their said second spaced position; and comparing said force remeasurements for verifying the determination obtained by comparison of said force measurements.

Claim 13

The method of claim 7 wherein said one drill string portion is said upper drill string portion and movement thereof is accomplished by elevating said upper drill string portion.

Claim 14

The method of claim 7 wherEin said one drill string portion is said lower drill string portion and movement thereof is accomplished by continuing to excavate said borehole with said drill bit for lowering said lower drill string portion in relation to said upper drill string portion.

Claim 17

The method of claim 11 wherein said one drill string portion is said upper drill string portion and movement thereof is accomplished by elevating said upper drill string portion.

Claim 18

The method of claim 11 wherein said one drill string portion is said lower drill string portion and movement thereof is accomplished by continuing to excavate said borehole with said drill bit for lowering said lower drill string portion in relation to said upper drill string portion.

Claim 21

The method of claim 14 wherein said sampling chamber is expanded by elevating said drill string to raise said one telescoped member toward said extended position.

Claim 22

The method of claim 14 wherein said sampling chamber is expanded by continuing to excavate said borehole with said drill bit for lowering said one telescoped member toward said extended position.

Claim 25

The method of claim 17 wherein said telescoped members are moved relative to one another by elevating said drill string to raise said one telescoped member toward said extended position.

Claim 26

The method of claim 17 wherein said telescoped members are moved relative to one another by continuing to excavate said borehole with said drill bit for lowering said one telescoped member toward said extended position.

Claim 27

the method of claim 17 wherein the force required to move said one telescoped member for bringing said opposed shoulders together is expressed by the equation: Force (Ph X A)(1 - (Vs X %gas)/((Vs X %gas) + Delta Vs )) where, Ph hydrostatic pressure of said drilling mud in said borehole adjacent to said sampling chamber; A effective pressure area restraining movement of said one telescoped member relative to said other telescoped member; Vs volume of said sampling chamber when said telescoped members are in their said first intermediate position; Delta Vs increase in volume of said sampling chamber resulting from expansion thereof; and %gas percentage, by volume, of formation gas in said mud sample.

Claim 28

Apparatus adapted for determining whether formation gas is present in the drilling mud in a borehold being excavated and comprising: a drill string having a drill bit dependently coupled thereto and including inner and outer telescoped members tandemly connected therein and cooperatively arranged for movement relative to one another between spaced positions; first means cooperatively arranged between said telescoped members and defining an expansible fluid chamber adapted to be expanded from a selected volume to progressively-larger volumes in response to movement of said telescoped members from one of their said spaced positions toward another of their said spaced positions; second means cooperatively arranged between said telescoped members and adapted for sequentially admitting a sample of drilling mud into said fluid chamber as said telescoped members are moved away from their said one position and then entrapping that sample in said fluid chamber as said telescoped members are moved toward their said other position; and third means for obtaining an indication representative of the force required for moving said telescoped members further away from their said one position after a mud sample is entrapped in said fluid chamber.

Claim 29

Apparatus adapted for determining whether formation gas is present in the drilling mud in a borehold being excavated and comprising: a drill string having a drill bit dependently coupled thereto and including inner and outer telescoped members tandemly connected therein and cooperatively arranged for movement relative to one another between spaced positions; first means cooperatively arranged between said telescoped members and defining an expansible fluid chamber adapted to be expanded from a selected volume to progressively-larger volumes in response to movement of said telescoped members from one of their said spaced positions toward another of their said spaced positions; second means cooperatively arranged between said telescoped members and adapted for sequentially admitting a sample of drilling mud into said fluid chamber as said telescoped members are moved away from their said one position and then entrapping that sample in said fluid chamber as said telescoped members are moved toward their said other position; and third means for obtaining an indication representative of the force required for moving said telescoped members further away from their said one position after a mud sample is entrapped in said fluid chamber.

Claim 30

The apparatus of claim 21 wherein said first means include a body associated with one of said telescoped members and having an internal bore with a reduced-diameter portion and an enlarged-diameter portion, and a piston associated with the other of said telescoped members and arranged in said internal bore for defining therein said fluid chamber and movable therein from said reduced-diameter bore portion into said enlarged -diameter bore portion in response to said movement of said telescoped members further away from their said one position.

Claim 31

The apparatus of claim 22 wherein said second means include passage means cooperatively arranged between said fluid chamber and the exterior of said body for admitting drilling mud into said fluid chamber, and valve means cooperatively associated with said passage means and movable between a passage-opening position when said telescoped members are in their said one position and a passage-closing position in response to movement of said telescoped members toward their said other position before said piston is moved out of said reduced-diameter bore portion.

Claim 32

The apparatus of claim 23 wherein said third means include first and second opposed shoulders respectively associated with said inner and outer telescoped members for engagement with a force related to the load on said drill string required to move said telescoped members further away from their said one position.

Claim 33

The apparatus of claim 21 wherein said first means include a body associated with one of said telescoped members and having an internal bore, and a piston associated with the other of said telescoped members and movably arranged in said internal bore for defining therein said fluid chamber.

Claim 34

The apparatus of claim 25 wherein said second means include passage means cooperatively arranged between said fluid chamber and the exterior of said body for admitting drilling mud into said fluid chamber, and valve means cooperatively associated with said passage means and movable between a passage-opening position when said telescoped members are in their said one position and a passage-closing position in response to movement of said telescoped members toward their said other position.

Claim 35

The apparatus of claim 26 wherein said third means include force-responsive means at the surface and adapted for measuring varying loads on said drill string as said telescoped members are moved between their said positions.

Claim 36

The apparatus of claim 21 wherein said first means include sealing means cooperatively mounted on said inner telescoped members and operatively associated with said outer telescoped member for defining said fluid chamber therebetween.

Claim 37

The apparatus of claim 28 wherein said second means include passage means defined between said telescoped members for admitting drilling mud into said fluid chamber, a fluid seal cooperatively arrangeD on one of said telescoped members in said passage means, and a sealing surface cooperatively arranged on the other of said telescoped members in said passage means and adapted for sealing engagement with said fluid seal to close said passage means upon movement of said telescoped members toward their said other position.

Claim 38

The apparatus of claim 29 wherein said third means include force-responsive means at the surface and adapted for measuring varying loads on said drill string as said telescoped members are moved between their said positions.

Claim 39

Apparatus adapted for determining whether formation gas is present in the drilling mud in a borehole being excavated and comprising: a drill string having a drill bit dependently coupled thereto and including inner and outer telescoped members tandemly connected therein and cooperatively arranged for upward and downward movements relative to one another between longitudinally-spaced positions; fluid-sampling means including a body operatively associated with one of said telescoped members and having an internal bore, a piston operatively associated with the other of said telescoped members and movably disposed in said internal bore of said body for defining therebetween an expansible fluid chamber adapted to be expanded from a selected reduced volume when said telescoped members are in a relatively-contracted position to a selected increased volume when said telescoped members are in a relatively-extended position, passage means between said fluid chamber and the exterior of said fluid-sampling means, and valve means cooperatively arranged with said fluid-sampling means and selectively operable in response to relative movements between said body and said piston for admitting drilling mud through said passage means as said fluid chamber is expanded from said reduced volume to a selected intermediate volume and for blocking said passage means as said fluid chamber is expanded from said intermediate volume toward said increased volume for reducing the pressure of a mud sample entrapped in said fluid chamber; and force-responsive means adapted for providing an indication at the surface of the force required for expanding said fluid chamber beyond its said intermediate volume to indicate whether gas is present in a mud sample entrapped in said fluid chamber.

Claim 40

Apparatus adapted for determining whether formation gas is present in the drilling mud in a borehole being excavated and comprising: a drill string having a drill bit dependently coupled thereto and including inner and outer telescoped members tandemly connected therein and cooperatively arranged for upward and downward movements relative to one another between longitudinally-spaced positions; fluid-sampling means including a body operatively associated with one of said telescoped members and having an internal bore, a piston operatively associated with the other of said telescoped members and movably disposed in said internal bore of said body for defining therebetween an expansible fluid chamber adapted to be expanded from a selected reduced volume when said telescoped members are in a relatively-contracted position to a selected increased volume when said telescoped members are in a relatively-extended position, passage means between said fluid chamber and the exterior of said fluid-sampling means, and valve means cooperatively arranged with said fluid-sampling means and selectively operable in response to relative movements between said body and said piston for admitting drilling mud through said passage means as said fluid chamber is expanded from said reduced volume to a selected intermediate volume and for blocking said passage means as said fluid chamber is expanded from said intermediate volume toward said increased volume for reducing the pressure of a mud sample entrapped in said fluid chamber; and force-responsive means adapted for providing an indication at the surface of the force required for expanding said fluid chamber beyond its said intermediate volume to indicate whether gas is present in a mud sample entrapped in said fluid chamber.

Claim 41

The apparatus of claim 31 wherein said body and piston are separate members; and further including means coupling said body to said one telescoped member; and means coupling said piston to said other telescoped member.

Claim 42

The apparatus of claim 31 wherein said body and piston are separate members respectively disposed exterior of said telescoped members; and further including means coupling said body to said one telescoped member; and means coupling said piston to said other telescoped member.

Claim 43

The apparatus of claim 31 wherein said force-responsive means include a weight indicator coupled to said drill string and operatively arranged to provide a first weight measurement of said drill string as said fluid chamber is being expanded from said reduced volume to said intermediate volume and to provide a second weight measurement of said drill string as said fluid chamber is being expanded from said intermediate volume toward said increased volume.

Claim 44

The apparatus of claim 34 further including means at the surface for determining the relative positions of said body and said piston so that the percentage of gas by volume in a mud sample entrapped in said fluid chamber can be determined by the equation: % gas (by volume) ( Delta d/d2)((Wmax - W) X 100% where, Delta d longitudinal displacement of said telescoped members between their position defining said intermediate volume where said first load measurement is obtained and their position where said second load measurement is obtained; d2 maximum longitudinal displacement of said telescoped members betweeN their position defining said intermediate volume and their said relatively-extended position; W the difference between said first and second weight measurements; and Wmax product of the borehole depth, the density of the drilling mud in the borehole, and the cross-sectional area of said piston.

Claim 45

The apparatus of claim 34 further including means at the surface for determining when said fluid chamber is fully expanded so that the percentage of gas by volume in a mud sample entrapped in said fluid chamber can be determined by the equation: % gas (by volume) (d11/d2)(((Ph X A)/(W2 - W1)) - 1) X 100% where, d1 longitudinal displacement of said telescoped members between their said relatively-contracted position and their position defining said intermediate volume; d2 maximum longitudinal displacement of said telescoped members between their position defining said intermediate volume and their said relatively-extended position; Ph hydrostatic pressure of the drilling mud at the borehole depth at which a mud sample is being taken; A cross-sectional area of said piston; W1 weight indication at the time a mud sample is being inducted into said fluid chamber; and W2 weight indication when said telescoped members first reach their said relatively-extended position.

Claim 46

The apparatus of claim 31 wherein said valve means include a valve seat defined in said passage means, a valve member movably disposed in said passage means and cooperatively arranged for movement into and out of seating engagement with said valve seat, and actuating means operative upon relative movements between said body and said piston for moving said valve member into seating engagement with said valve seat as said fluid chamber is expanded beyond said intermediate volume.

Claim 47

The apparatus of claim 31 wherein said valve means include a valve seat defined in said passage means, a valve member movably disposed in said passage means and cooperatively arranged for movement into and out of seating engagement with said valve seat, and actuating means including first means normally biasing said valve member toward seating engagement with said valve seat, an actuating member operatively arranged on said piston for retaining said valve member out of seating engagement with said valve seat until said body and piston are relatively positioned where said fluid chamber is at its said intermediate volume, and second means normally biasing said actuating member against said valve member until said body and piston are relatively positioned where said fluid chamber has a volume equal to or greater than said intermediate volume.

Claim 48

The apparatus of claim 31 wherein said valve means include a fluid seal cooperatively arranged on one of said telescoped members in said passage means and a sealing surface cooperatively arranged on the other of said telescoped members in said passage means and adapted for sealing engagement with said fluid seal to close said passage means upon movement of said telescoped members for expanding said fluid chamber from said intermediate volume toward said increased volume.

Claim 49

Apparatus adapted for determining whether formation gas is present in the drilling mud in a borehole being excavated and comprising: a drill string having a drill bit dependently coupled thereto and including inner and outer telescoped members tandemly connected therein and cooperatively arranged for upward and downward movements relative to one another between longitudinally-spaced positions; fluid-sampling means including means cooperatively arranged between said telescoped members for defining therebetween an expansible fluid chamber adapted to be expanded from a reduced volume when said telescoped members are in a contracted position to an increased volume when said telescoped members are in an intermediate position and adapted to be opened when said telescoped members are in an extended position, passage means between said fluid chamber and the exterior of said fluid-sampling means, and valve means cooperatively arranged on said telescoped members and responsive to relative movements therebetween for admitting drilling mud through said passage means as said fluid chamber is expanded from said reduced volume to a selected intermediate volume and for blocking said passage means as said fluid chamber is expanded from said intermediate volume toward said increased volume for reducing the pressure of a mud sample entrapped in said fluid chamber; and means adapted for providing indications at the surface to determine the differential between the force required to move said telescoped members between their said contracted and intermediate positions and the force required to move said telescoped members between their said intermediate and extended positions to indicate whether gas is present in a mud sample entrapped in said fluid chamber.

Claim 50

Apparatus adapted for determining whether formation gas is present in the drilling mud in a borehole being excavated and comprising: a drill string having a drill bit dependently coupled thereto and including inner and outer telescoped members tandemly connected therein and cooperatively arranged for upward and downward movements relative to one another between longitudinally-spaced positions; fluid-sampling means including means cooperatively arranged between said telescoped members for defining therebetween an expansible fluid chamber adapted to be expanded from a reduced volume when said telescoped members are in a contracted position to an increased volume when said telescoped members are in an intermediate position and adapted to be opened when said telescoped members are in an extended position, passage means between said fluid chamber and the exterior of said fluid-sampling means, and valve means cooperatively arranged on said telescoped members and responsive to relative movements therebetween for admitting drilling mud through said passage means as said fluid chamber is expanded from said reduced volume to a selected intermediate volume and for blocking said passage means as said fluid chamber is expanded from said intermediate volume toward said increased volume for reducing the pressure of a mud sample entrapped in said fluid chamber; and means adapted for providing indications at the surface to determine the differential between the force required to move said telescoped members between their said contracted and intermediate positions and the force required to move said telescoped members between their said intermediate and extended positions to indicate whether gas is present in a mud sample entrapped in said fluid chamber.

Claim 51

The apparatus of claim 40 wherein said means defining a fluid chamber include a longitudinal bore in said outer telescoped member having a reduced-diameter portion and an enlarged-diameter portion, and a piston member arranged on said inner telescoped member and disposed within said longitudinal bore for movement in said reduced-diameter bore portion as said telescoped members are moved from their said contracted position to their said intermediate position and for movement in said enlarged-diameter bore portion as said telescoped members are moved from their said intermediate position to their said extended position.

Claim 52

The apparatus of claim 40 wherein said indication-providing means include first and second opposed shoulders respectively arranged between said telescoped members and adapted for co-engagement with a force representative of the presence or absence of formation gas in a mud sample in said fluid chamber upon movement of said telescoped members to their said extended position.

Claim 53

The apparatus of claim 40 wherein said indication-providing means include a weight indicator coupled to said drill string and operatively arranged to provide a first weight measurement of said drill string as said fluid chamber is being expanded from said reduced volume to said intermediate volume and to provide a second weight measurement of said drill string as said fluid chamber is being expanded from said intermediate volume toward said increased volume.

Claim 54

Apparatus adapted for determining whether formation gas is present in the drilling mud in a borehole being excavated and comprising: a drill string having a drill bit dependently coupled thereto; fluid-sampling means cooperatively arranged in said drill string and including a tubular body tandemly connected to one portion of said drill string and having a longitudinal bore including upper and lower enlarged-diameter bore portions separated at their adjacent ends by a reduced-diameter bore portion, passage means providing fluid communication between the exterior of said body and at least one of said enlarged-diameter bore portions, a tubular mandrel tandemly connected to another portion of said drill string and telescopically arranged in said body for longitudinal movement therein between longitudinally-spaced upper and lower positions, piston means cooperatively arranged on said mandrel for movement between the other end of said one enlarged-diameter bore portion and said adjacent end thereof for inducting a sample of drilling mud therein as said telescoped members are moved from one of said upper and lower positions to a first intermediate position where said piston means enter said reduced-diameter portion and become sealingly engaged therein, and valve means cooperatively arranged between said telescoped members for fluidly sealing said other end of said one enlarged-diameter bore portion as said telescopEd members are moved between said first intermediate position and a second intermediate position where said piston means leave said reduced-diameter bore portion and enter the other of said enlarged-diameter bore portions to expand a sample of drilling mud inducted into said one enlarged-diameter bore portion; and means adapted for providing indications at the surface representative of the force required to move said telescoped members between said first and second intermediate positions to indicate whether gas is present in a sample of drilling mud inducted into said one enlarged-diameter bore portion and released into said other enlarged-diameter bore portion as said telescoped members are moved from said second intermediate position to the other of said upper and lower positions.

Claim 55

Apparatus adapted for determining whether formation gas is present in the drilling mud in a borehole being excavated and comprising: a drill string having a drill bit dependently coupled thereto; fluid-sampling means cooperatively arranged in said drill string and including a tubular body tandemly connected to one portion of said drill string and having a longitudinal bore including upper and lower enlarged-diameter bore portions separated at their adjacent ends by a reduced-diameter bore portion, passage means providing fluid communication between the exterior of said body and at least one of said enlarged-diameter bore portions, a tubular mandrel tandemly connected to another portion of said drill string and telescopically arranged in said body for longitudinal movement therein between longitudinally-spaced upper and lower positions, piston means cooperatively arranged on said mandrel for movement between the other end of said one enlarged-diameter bore portion and said adjacent end thereof for inducting a sample of drilling mud therein as said telescoped members are moved from one of said upper and lower positions to a first intermediate position where said piston means enter said reduced-diameter portion and become sealingly engaged therein, and valve means cooperatively arranged between said telescoped members for fluidly sealing said other end of said one enlarged-diameter bore portion as said telescopEd members are moved between said first intermediate position and a second intermediate position where said piston means leave said reduced-diameter bore portion and enter the other of said enlarged-diameter bore portions to expand a sample of drilling mud inducted into said one enlarged-diameter bore portion; and means adapted for providing indications at the surface representative of the force required to move said telescoped members between said first and second intermediate positions to indicate whether gas is present in a sample of drilling mud inducted into said one enlarged-diameter bore portion and released into said other enlarged-diameter bore portion as said telescoped members are moved from said second intermediate position to the other of said upper and lower positions.

Claim 56

The apparatus of claim 44 wherein said indication-providing means include first and second opposed shoulders respectively arranged on said body and said mandrel and adapted for impacting with a force representative of the presence or absence of formation gas in a sample of drilling mud inducted into said one enlarged-diameter bore portion.

Claim 57

The apparatus of claim 44 wherein said indication-providing means include a weight indicator coupled to said drill string and operatively arranged to provide at least one weight measurement of said drill string as said telescoped members are moved between said first and second intermediate positions.

Claim 58

The apparatus of claim 44 wherein said indication-providing means include a weight indicator coupled to said drill string and operatively arranged to provide a first weight measurement of said drill string as said telescoped members are moved between said first and second intermediate positions and a second weight measurement of said drill string as said telescoped members are moved between said second intermediate position and said other position.

Claim 59

The apparatus of claim 44 wherein said valve means include a valve seat cooperatively arranged in said longitudinal bore in said passage means, and a valve member cooperatively arranged on said mandrel for seating engagement with said valve seat at least as long as said telescoped members are moved between said first and second intermediate positions.

Claim 62

The apparatus of claim 44 wherein said passage means also provide fluid communication between said body exterior and said other enlarged-diameter bore portion.

Claim 63

The apparatus of claim 50 wherein said piston means include an enlarged shoulder on said mandrel, and sealing means on said enlarged shoulder cooperatively arranged to be sealingly engaged only with said reduced-diameter bore portion.

Claim 64

The apparatus of claim 51 wherein said sealing means include a plurality of chevron shaped seals cooperatively arranged to sealingly engage said reduced-diameter bore portion only as said telescoped members are being moved from said first intermediate position to said second intermediate position.