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System, program products, and methods for controlling drilling fluid parameters

  • US 7,908,034 B2
  • Filed: 06/30/2006
  • Issued: 03/15/2011
  • Est. Priority Date: 07/01/2005
  • Status: Expired due to Fees
First Claim
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1. A system for controlling drilling fluid attributes and parameters, the system comprising:

  • a drilling apparatus having at least one casing string cemented within a subterranean wellbore, a combination of the wellbore and the at least one casing string having a plurality of locations of interest located at separate locations;

    a drilling string run within the at least one casing string;

    an annulus formed between an external surface of the drilling string and inner surface of the innermost at least one casing string;

    a drilling fluid inlet;

    a drilling fluid outlet;

    a drilling fluid circulating through the drilling fluid inlet, down through the drilling string, up through the annulus, and out the drilling fluid outlet;

    at least one monitor positioned to monitor drilling fluid parameters of the drilling fluid entering the drilling string;

    at least one monitor positioned to monitor drilling fluid parameters of the drilling fluid exiting the annulus;

    an output port choke in communication with the annulus and the drilling fluid outlet;

    a dynamic density control computer in communication with the choke and including a processor and memory associated with the processor to store operating instructions therein;

    means for measuring expansion and compressibility of drilling fluid conducting drilling assembly components associated with drilling fluid circulation and compressibility of a surrounding earth formation to formulate a description of the physical behavior of the wellbore components;

    means for performing a cased hole pressure test to determine a volume associated with expansion of pressurized drilling fluid carrying components of the drilling assembly during drilling operations;

    means for performing an integrity and fracture pressure test to determine integrity of the cement sealing the at least one casing string to the wellbore and fracture pressure of an associated earth formation to thereby determine a dynamic maximum pressure that can exist at a lower end of the casing string without fracturing the associated earth formation or bonding of the cement; and

    dynamic density control program product stored in the memory of the dynamic density control computer and including instructions that when executed by the processor of the dynamic density control computer, cause the computer to perform the operations of;

    determining separately for each of the plurality of separated locations of interest at least one drilling fluid control variable system limitation of a drilling fluid control variable,measuring a value of an operationally induced drilling fluid parameter at each of a plurality of separate locations when drilling,predicting separately for each of the plurality of separated locations of interest a value of the drilling fluid control variable responsive to each measured drilling fluid parameter value, andcontrolling a drilling fluid parameter responsive to each predicted control variable value and each associated at least one drilling fluid control variable system limitation.

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