Monitoring system for drilling operations

• US 6,378,628 B1
• Filed: 06/16/2000
• Issued: 04/30/2002
• Est. Priority Date: 05/26/1998
• Status: Expired due to Fees

• Current Assignee: Frank Brych, Louis L. Mcguire, Weldon Mcguire
• Original Assignee: Frank Brych, Louis L. Mcguire, Weldon Mcguire
• Inventors: McGuire, Weldon, Brych, Frank, McGuire, Louis L.
• Primary Examiner(s): Shackelford, H.
• Assistant Examiner(s): LEE, JONG SUK
• Application Number:
  US09/596,476
• Time in Patent Office: 683 Days
• Field of Search: 175/24, 175/38, 175/48, 175/206, 175/207, 731/520.3, 731/520.4, 731/521.8, 731/521.9, 731/522.1, 731/522.2
• 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 to provide indications of conditions in a well bore comprising:

i. an injection line including a pump for injecting gas into a drill string;

ii. a gas return line having a laminar flow segment for transporting return gas containing a mixture of gas and other hydrocarbons from the drill string to a flare;

iii. a first gas pressure transducer for measuring the gas pressure in the laminar flow segment nearest the drill string;

iv. a thermal transducer for measuring the temperature of the gas adjacent the first gas pressure transducer;

v. a second gas pressure transducer located in the laminar flow segment of the gas return line nearest the flare;

vi. a monitor display at the drilling rig to indicate conditions of the return gas; and

vii. a computer for analyzing data from all the transducers and determining changes in the conditions of the return gas.

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

$\mathrm{equation}<br><br>\text{\hspace{1em}<br><br>}<br><br>A<br><br>\text{;<br><br> <br><br> <br><br> <br><br>}<br><br>Q={42}_a<br><br>\sqrt{\frac{P_1^2-P_f^2}{L}}$

where;

Q=discharge in cubic feet per hour

42=a constant

P₁=initial pressure in lbs. Per square inch, absolute

P₂=final pressure in pounds per square inches, absolute

P_f=P₁−

P₂

L=length of line in miles

a=diameter coefficient

Using specific gravity of gas as 0.6.

3. The computerized monitoring system of claim 2 where specific gravity of the gas is not 0.6, volume of gas, Q, is corrected by using equation B as follows:

$\mathrm{equation}<br><br>\text{\hspace{1em}<br><br>}<br><br>B<br><br>\text{;<br><br> <br><br> <br><br> <br><br>}<br><br>Q_C=Q<br><br>\sqrt{\frac{\mathrm{.06}}{\mathrm{sp}·<br><br>\mathrm{gr}·<br><br>\mathrm{gas}}}$

where;

Q=discharge in CFH

Q_C=corrected volume.

4. A computerized monitoring system for oil and gas drilling operations employing a drilling rig to drill a well bore using injection gases as circulating drilling fluid through a drill string and returning it to a disposal facility to provide data for safe operations comprising:

i. the drill string of the drilling rig;

ii. an injection line for injecting gas into the drill string;

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

iv. a gas transfer line having a laminar flow segment for transporting gas from the well bore containing a mixture of injection gas, natural gas and formation cuttings to the disposal facility;

v. a first gas pressure transducer nearest the well bore located in the laminar flow segment;

vi. a second gas pressure transducer located in the laminar flow segment and spaced apart from the first gas pressure transducer;

vii. a thermal transducer positioned near the first gas pressure transducer for measuring the temperature of the gas;

viii. a monitor display at the drilling rig to indicate conditions of the well bore; and

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

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

equation I;

$Q=\frac{433.45<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{Ta}}{\mathrm{Pa}}\times <br><br>d^{2.667}\times <br><br>{\left(\frac{P_l^2-P_f^2}{\mathrm{LSTZ}}\right)}^{1/2}\times <br><br>\frac{1}{24\times <br><br>60}$

 

where;

Q=calculated volume of gases, cfm

T_a=standard temperature °

R

P_a=standard pressure absolute, psia

d=internal pipe diameter, inches

P₁=initial pressure, psi absolute

P₂=terminal pressure, psi absolute

P_f=P₁−

P₂

L=length of pipeline in miles

S=specific gravity of gas

T=absolute temperature °

R of flowing gases

Z=compressibility of gas factor

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

$Q_2=Q_1\times <br><br>\left(\frac{Q_1}{V_A}\right)$

 

where

Q₁=calculated volume of gases, cfm

Q₂=corrected initial volume of injected gases, cfm

V_A=actual measured volume of injected gases, cfm.

5. The computerized monitoring system of claim 4 wherein the total volume of injected and formation gases, Q₃, flowing to the disposal facility is determined using equation I with the following parameters:

$S=\frac{\begin{array}{c}1/2<br><br>\left(\mathrm{SpG}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{of}<br><br>\text{\hspace{1em}<br><br>}<br><br>N_2+\mathrm{SpG}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{of}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{Air}\right)+\\ \mathrm{SpG}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{of}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{Hydrocarbon}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{gases}\end{array}}{2}$

and current temperature transducer and current pressure transducer pressure readings.

6. The computerized monitoring system in claim 5 wherein a volume of hydrocarbon gases, Q_HC, is calculated using equation III:

7. The computerized monitoring system in claim 6 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:

8. The computerized monitoring system in claim 7 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.

9. The computerized monitoring system in claim 8 wherein the final total volume of hydrocarbon gases is calculated using equation V:

10. The computerized monitoring system of claim 9 wherein the gas injected into the injection line is reduced by the volume of the hydrocarbon gases.