Mud separator monitoring system

• US 6,105,689 A
• Filed: 05/26/1998
• Issued: 08/22/2000
• Est. Priority Date: 05/26/1998
• Status: Expired due to Fees

• Current Assignee: Mcguire Fishing & Rental Tools, Inc.
• Original Assignee: Mcguire Fishing & Rental Tools, Inc.
• Inventors: McGuire, Weldon, Brych, Frank, McGuire, Louis L.
• Primary Examiner(s): Lillis, Eileen Dunn
• Assistant Examiner(s): LEE, JONG SUK
• Application Number:
  US09/085,036
• Time in Patent Office: 819 Days
• Field of Search: 175/48, 175/38, 175/206, 175/207
• US Class Current: 175/48
• CPC Class Codes: E21B 21/067 Separating gases from drilling fluids
• CPC Class Codes: E21B 21/08 Controlling or monitoring pressure or flow of drilling fluid, e.g. automatic filling of boreholes, automatic control of bottom pressure valve arrangements therefor E21B21/10
• CPC Class Codes: E21B 21/14 using liquids and gases, e.g. foams

Abstract

A mud separator monitoring system utilizing electronic transducers positioned in various locations in the mud separator and the lines leading from the mud separator to the mud return pit and gas discharge flare for obtaining data during drilling operations to calculate the volume of gas retained in the drilling fluid, the hydrostatic head of the drilling fluid and gas pressure in the separator on a continuing basis and informing field personnel of conditions in the mud separator indicating potential hazard. The system further monitors continuously the volume of injected gases and hydrocarbon gases circulated during drilling operations for making adjustments to the volume of injected gases required to sustain the drilling operations.

Claims

1. A computerized monitoring system for oil and gas drilling operations including a mud separator to provide indications of conditions in a well bore comprising:

i. a mud pit;

ii. an injection line including a pump for injecting mud into a drill string;

iii. the mud separator having a gas phase and a liquid phase;

iv. a gas transfer line having a laminar flow segment for transporting gas from the mud separator to a flare or other equipment;

v. a mud return line for transferring return mud from the well bore containing a mixture of mud, gas and other hydrocarbons to the mud separator;

vi. a transfer line extending from the bottom of the mud separator to the mud pit;

vii. a mud pressure transducer for measuring the hydrostatic pressure of the mud phase;

viii. a thermal transducer for measuring the temperature of the mud in the mud phase;

ix. a first gas pressure transducer for measuring the gas pressure in the mud separator;

x. a second gas pressure transducer located in the laminar flow segment of the gas transfer line;

xi. a monitor display at the drilling rig to indicate conditions of the mud separator; and

xii. a computer for analyzing data from all the transducers and determining changes in the mud density and activate the monitor display to indicate conditions of the mud separator.

2. The computerized monitoring system of claim 1 wherein a green light on the monitor display is lit when the first gas pressure transducer reading is has less than a cautionary percentage of the mud pressure transducer hydrostatic pressure.

3. The computerized monitoring system of claim 1 wherein a yellow light on the monitor is lit when the first gas pressure transducer reading is between a cautionary and an unsafe percentage of the mud transducer hydrostatic pressure.

4. The computerized monitoring system of claim 1 wherein a red light on the monitor display is lit and an audible alarm sounds when the first gas pressure transducer reading reaches an unsafe percentage of the mud transducer hydrostatic pressure.

5. The computerized monitoring system of claim 1 wherein the volume of formation gases is determined by the computer using an equation A as follows:

##EQU8## The formula assumes specific gravity of gas at 0.6.

6. The computerized monitoring system of claim 5 where specific gravity of the gas is not 0.6, volume of gas, Q, is corrected by using equation B as follows:

##EQU9##

7. The computerized monitoring system of claim 1 wherein the first gas transducer pressure reading is compared to the mud pressure transducer reading indicate on the monitor display conditions in the mud separator.

8. The computerized monitoring system of claim 7 wherein a green light on the monitor display is lit when the first gas pressure transducer pressure reading is less than a cautionary percentage of the mud pressure transducer hydrostatic pressure.

9. The computerized monitoring system of claim 7 wherein a yellow light on the monitor is lit when the first gas pressure transducer pressure reading is between a cautionary and an unsafe percentage of the mud transducer hydrostatic pressure.

10. The computerized monitoring system of claim 7 wherein a red light on the monitor display is lit and an audible alarm sounds when the first gas pressure transducer pressure reading reaches an unsafe percentage of the mud transducer hydrostatic pressure.

11. A computerized monitoring system for oil and gas drilling operations employing a drilling rig to drill a well bore using injection gases and aqueous liquid as circulating drilling fluid through the drill string and returning it to a mud separator to provide data for safe operations comprising:

i. an aqueous liquid pit;

ii. an injection line including a pump for injecting aqueous liquid into the drill string;

iii. gas pressurizing apparatus for injecting gases into the injection line;

iv. a separator having a gas phase and an aqueous liquid phase;

v. a gas transfer line having a laminar flow segment for transporting gas from the separator to a flare or other equipment;

vi. a return line for transferring return fluid from the well bore containing a mixture of injection gas, aqueous liquid, natural gas and formation cuttings to the separator;

vii. a transfer line extending from the bottom of the separator to the aqueous liquid pit;

viii. a first gas pressure transducer located in the gas phase of the separator;

ix. a second gas pressure transducer located in the laminar flow segment of the gas transfer line;

x. an aqueous liquid pressure transducer for measuring the hydrostatic pressure in the separator;

xi. a thermal transducer for measuring the temperature of the aqueous liquid;

xii. a monitor display at the drilling rig to indicate conditions of the separator; and

xiii. a computer for analyzing data from the transducers and determining;

(a) first volume of injected gas, Q₁, flowing to the flare using the following general equation I;

equation I;

##EQU10## (b) and adjusting the first volume of injected gas flowing to the flare using the ratio of the calculated volume of gases over gas volume using the following equation II;

equation II;

##EQU11##

12. The computerized monitoring system of claim 11 wherein the total volume of injected and formation gases, Q₃, flowing to the flare is determined using equation I with the following parameters:

and current temperature transducer and current pressure transducer pressure readings.

13. The computerized monitoring system in claim 12 wherein a volume of hydrocarbon gases, Q_HC, is calculated using equation III:

equation III;

Q_HC =Q₃ -Q₂

where;

Q₂ =corrected initial volume of injected gases, cfm

Q₃ =total volume, including hydrocarbon gases, cfm

Q_HC =volume of hydrocarbon gases, cfm.

14. The computerized monitoring system in claim 13 wherein the actual specific gravity, SpG_F, of the injected gases and the specific gravity of the hydrocarbon gases are calculated using equation IV as follows:

##EQU12## SpG_F =actual specific gravity allocated to injected gases and formation gases.

15. The computerized monitoring system in claim 14 wherein a final total gas, Q_FT, is calculated using the general equation I with the following parameters:

the specific gravity, S, is SpG_F of the injected and formation gases determined by equation IV and the current temperature transducer and current pressure transducer pressure readings.

16. The computerized monitoring system in claim 15 wherein the final total volume of hydrocarbon gases is calculated using equation V:

equation V;

Q_FH =Q_FT -Q₂

where;

Q₂ =corrected initial volume of gases, cfm

Q_FT =final total gas, cfm

Q_FH =final hydrocarbon gases, cfm.

17. A computerized monitoring system for analyzing the conditions of a drilling fluid separator use in conjunction with drilling operations for oil and gas comprising:

i. a drilling fluid pit;

ii. an injection line including a pump for injecting an aqueous liquid drilling fluid into a drill string;

iii. a compressor for injecting gases into the injection line at a predetermined pressure;

iv. a separator having a gas phase and an aqueous liquid phase;

v. a gas transfer line having a laminar flow segment for transporting gas from the separator to a flare or other equipment;

vi. an aqueous liquid return line for transferring return aqueous liquid from the well bore containing a mixture of mud, gas and other hydrocarbons to the drilling fluid separator;

vii. a transfer line extending from the bottom of the drilling fluid separator to the drilling fluid pit;

viii. a drilling fluid pressure transducer for measuring hydrostatic pressure of an aqueous liquid phase;

ix. a thermal transducer for measuring the temperature of the aqueous liquid in the aqueous liquid phase;

x. a first gas pressure transducer for measuring the gas pressure in the drilling fluid separator;

xi. a second gas pressure transducer located in laminar flow segment of the gas transfer line;

xii. a monitor display at the drilling rig of the conditions of the drilling fluid separator; and

xiii. a computer for analyzing data from all the transducers to determine changes in the aqueous liquid density and initiate warning signals.

18. The computerized monitoring system of claim 17 wherein a green light on the monitor display is lit when the first gas pressure transducer reading is less than a cautionary percentage of the aqueous liquid phase hydrostatic pressure.

19. The computerized monitoring system of claim 17 wherein a yellow light on the monitor is lit when the first gas pressure transducer reading is between a cautionary and an unsafe percentage of the aqueous liquid leg hydrostatic pressure.

20. The computerized monitoring system of claim 17 wherein a red light on the monitor display is lit and an audible alarm sounds when the first gas pressure transducer reading reaches an unsafe percentage of the aqueous liquid leg hydrostatic pressure.

21. The computerized monitoring system of claim 17 wherein the volume of formation gases is determined by the computer using an equation selected from equation A and equation I following:

##EQU13## The formula assumes specific gravity of gas at 0.6. ##EQU14##

22. The computerized monitoring system of claim 21 using equation A wherein the volume of formation gases is corrected by equation B as follows: