DRILLING FLUID FLOW

FIELD OF THE INVENTION

[0001] Aspects relate to detection and surveying technology for underground drilling. More specifically, aspects relate to downhole off-bottom mud pulse telemetry data transmission method accomplished without disablement of drilling fluid flow.

BACKGROUND INFORMATION

[0002] Initiating geotechnical surveys of underground geotechnical features is an important and necessary step in attaining reliable data from beneath the earth's surface. Such surveys are conducted, in large part, during the investigation for hydrocarbons, namely oil and gas. As time progresses, the need for taking such surveys increases as the ability to reach known hydrocarbon reserves decreases. Drilling companies must reach ever deeper and perform many more surveys in order to locate deposits of hydrocarbons.

[0003] Data obtained from the downhole environment must be sent to the uphole environment where the data is generally decoded and evaluated by professionals at the surface. The data may be sent through a wire connected between downhole tools and the surface, known as "wireline" or other methods to speed the transfer of data.

[0004] Today, the primary mode of taking a geotechnical sub-surface survey is to cycle drilling fluid /mud pumps (i.e. turn the pumps off and back on again) to allow a downhole tool to initiate a survey. Such drilling fluid/mud pumps are used to supply a drilling fluid to the drill bit and the drill string in order to flush particles dislodged from the rotary motion of the drill string/drill bit. The drilling fluid also cools the drill bit and associated parts that heat during drilling operations.

[0005] In some wellbores, a significant amount of time may elapse in order to allow the drilling fluid (i.e. "mud") to stabilize within the wellbore. If the mud flow is not stabilized, the result may be poor quality transmission of survey data. In order to mitigate the METHOD AND APPARATUS FOR SURVEYING WITHOUT DISABLEMENT OF

DRILLING FLUID FLOW above situations, a "delayed survey" may be performed, in which the downhole tool is pre-programmed to send the survey data after a time delay, or transmit an "auto survey" where the downhole tool is pre-programmed to send the survey data repeatedly at set intervals. All of these methods result in valuable time and/or data bandwidth wasted.

[0006] There is a need to provide a method and apparatus that will eliminate the wasted time and bandwidth of conventional systems and methods.

[0007] There is also a need to provide an economical method that will allow a driller to continue drilling in an efficient manner and to use available resources to maximize the returns on drilling expenditures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The presented aspects have advantages that will be better understood by referring to the following detailed description of the attached drawings in which:

[0009] FIG. 1 is a side elevation view of a drill rig performing underground drilling and sampling;

[0010] FIG. 2 is a flowchart of a method for surveying, using rotation cessation, without disablement of drilling fluid flow;

[0011] FIG. 3 is a flowchart of a method for surveying, using decrease of weight on bit, without disablement of drilling fluid flow;

[0012] FIG. 4 is a flowchart of a method for surveying, using decrease of fluid pressure, without disablement of drilling fluid flow.

DETAILED DESCRIPTION METHOD AND APPARATUS FOR SURVEYING WITHOUT DISABLEMENT OF

DRILLING FLUID FLOW

[0013] It will be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, this disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not itself dictate a relationship between the various embodiments and/or configurations discussed. Moreover, the subterranean formation of a first feature over or on a second feature in the description may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact.

[0014] In accordance with the present disclosure, a wellsite with associated wellbore and apparatus is described in order to describe a typical, but not limiting, embodiment of the application. To that end, apparatus at the wellsite may be altered, as necessary, due to field considerations encountered.

[0015] An example well site system is schematically depicted in FIG. 1 wherein components described above are incorporated in the larger systems described therein The well site comprises a well. A drill string 105 may extend from a drill rig 101 into a zone of the formation of reservoir 115. The drill string 105 employs a mud pulse telemetry system 100, described later, for transmitting data from downhole to the surface.

[0016] The drill string 105 may also employ any type of telemetry system or any combination of telemetry systems, such as electromagnetic, mud pulse, acoustic and\or wired drill pipe, however in the preferred embodiment, only the mud pulse telemetry system is used. A bottom hole assembly is suspended at the end of the drill string 105. In an embodiment, the bottom hole assembly comprises a plurality of measurement METHOD AND APPARATUS FOR SURVEYING WITHOUT DISABLEMENT OF

DRILLING FLUID FLOW while drilling ("MWD") or logging while drilling ("LWD") downhole tools 125 such as shown by numerals 6a and 6b. For example, one or more of the downhole tools 6a and 6b. may be a formation pressure while drilling tool.

[0017] Logging while drilling tools used at the end of the drill string 105 may include a thick walled housing, commonly referred to as a drill color, and may include one or more of a number of logging devices. The logging while drilling tool may be capable of measuring, processing, and/or storing information therein, as well as communicating with equipment disposed at the surface of the well site.

[0018] Measurement while drilling tools may include one or more of the following measuring tools: a modulator, a weight on bit measuring device, a torque measuring device, a vibration measuring device, a shock measuring device, a stick slip measuring device, a direction measuring device, and inclination measuring device, and\or any other device.

[0019] Measurements made by the bottom hole assembly or other tools and sensors with the drill string 105 may be transmitted to a service computing system 185 for analysis. For example, mud pulses may be used to broadcast formation measurements performed by one or more of the downhole tools 6a and 6b to the service computing system 185.

[0020] The service computing system 185 is configured to host a plurality of models, such as a reservoir model, and to acquire and process data from downhole

components, as well as determine the bottom hole location in the reservoir 115 from measurement while drilling data. Examples of reservoir models and cross well interference testing may be found in the following references:"lnterpreting an RFT- Measured Pulse Test with a Three-Dimensional Simulator" by Lasseter, T., Karakas, M., and Schweitzer, J., SPE 14878, March 1988. "Design, Implementation, and

Interpretation of a Three-Dimensional Well Test in the Cormorant Field, North Sea" by Bunn, G.F., and Yaxley, L.M., SPE 15858, October 1986. "Layer Pulse Testing Using a METHOD AND APPARATUS FOR SURVEYING WITHOUT DISABLEMENT OF

DRILLING FLUID FLOW

Wireline Formation Tester" by Saeedi, J., and Standen, E., SPE 16803, September 1987. "Distributed Pressure Measurements Allow Early Quantification of Reservoir Dynamics in the Jene Field" by Bunn, G.F., Wittman, M.J., Morgan, W.D., and Curnutt, R.C., SPE 17682, March 1991 . "A Field Example of Interference Testing Across a Partially Communicating Fault" by Yaxley, L.M. , and Blaymires, J. M., SPE 19306, 1989. "Interpretation of a Pulse Test in a Layered Reservoir" by Kaneda, R., Saeedi, J., and Ayestaran, L.C., SPE 19306, December 1991 .

[0021] The derrick or similar looking/functioning device may be used to move the drill string 105 within the wellbore that is being drilled through subterranean formations of the reservoir. The drill string 105 may be extended into the subterranean formations with a number of coupled drill pipes (one of which is designated 120) of the drill string 105. The drill pipe comprising the drill string 105 may be structurally similar to ordinary drill pipes, as illustrated for example and United States Patent 6,174,001 , issued to Enderle, entitled "Two-Step, a Low Torque, Wedge Thread for Tubular Connector," issued August 7, 2001 , and includes a cable associated with each drill pipe 120 that serves as a communication channel.

[0022] The bottom hole assembly at the lower end of the drill string 105 may include one, an assembly, or a string of downhole tools. In the illustrated example, the downhole tool string 105 may include well logging tools 125 coupled to a lower end thereof. As used in the present description, the term well logging tool or a string of such tools, may include at least one or more logging while drilling tools ("LWD"), formation evaluation tools, formation sampling tools and other tools capable of measuring a characteristic of the subterranean formations of the reservoir 115 and\or of the wellbore. Such characteristics can include resistivity, temperature, pressure or other

characteristics of interest.

[0023] Several of the components disposed proximate to the drill rig 101 may be used to operate components of the system. These components will be explained with METHOD AND APPARATUS FOR SURVEYING WITHOUT DISABLEMENT OF

DRILLING FLUID FLOW respect to their uses in drilling the well 110 for a better understanding thereof. The drill string 105 may be used to turn and actually urge a drill bit into the bottom the well 110 to increase its length (depth). During drilling of the well 110, a pump 130 lifts drilling fluid (mud) 135 from a tank 140 or pits and discharges the mud 135 under pressure through a standpipe 145 and flexible conduit 150 or hose, through a top drive 155 and into an interior passage inside the drill pipe 105. The mud 135, which can be water or oil-based, exits the drill pipe 105 through courses or nozzles (not shown separately) in the drill bit 116, wherein it cools and lubricates the drill bit 116 and lifts drill cuttings generated by the drill bit 116 to the surface of the earth through an annular

arrangement. The cuttings from the drill bit 116 may then, for example, be screened out and the drilling mud returned to the downhole environment for further removal of cuttings and lubrication of the drill bit 116.

[0024] When the well 110 has been drilled to a selected depth, the well logging tools 125 may be positioned at the lower end of the pipe 105 if not previously installed. The well logging tools 125 may be positioned by pumping the well logging tools 125 down the pipe 105 or otherwise moving the well logging tools 125 down the pipe 105 while the pipe 105 is within the well 110. The well logging tools 125 may then be coupled to an adapter sub 160 at the end of the drill string 105 and may be moved through, for example in the illustrated embodiment, a highly inclined portion 165 of the well 110, which would be inaccessible using armored electrical cable to move the well logging tools 125.

[0025] During well logging operations, the pump 130 may be operated to provide fluid flow to operate one or more turbines in the well logging tools 125 to provide power to operate certain devices in the well logging tools 125. However, when tripping in or out ( for example turning the pumps on and off) of the well 110, it may be in feasible to provide fluid flow. As a result, power may be provided to the well logging tools 125 in other ways. For example, batteries may be used to provide power to the well logging tools 125 in situations where an electrical connection would become challenged due to METHOD AND APPARATUS FOR SURVEYING WITHOUT DISABLEMENT OF

DRILLING FLUID FLOW physical constraints of the wellbore, such as extended reach wells as a non-limiting embodiment. In one embodiment, the batteries may be rechargeable batteries and may be recharged by turbines placed in the drilling fluid/mud during fluid flow. The batteries may be positioned within the housing of one or more of the well logging tools 125.

Other manners of powering the well logging tools 125 may be used including, but not limited to, one-time power used batteries. In non-limiting embodiments, the batteries, as well as electrical control circuitry, are enclosed in a pressure tight compartment to prevent intrusion of materials into the sensitive electrical components.

[0026] As the well logging tools 125 are moved along the well 110 by moving the drill pipe 105, signals may be detected by various devices, of which non- limiting examples may include a resistivity measurement device, a bulk density measurement device, a porosity measurement device, a formation capture cross-section measurement device 170, a gamma ray measurement device 175 and a formation fluid sampling tool 610, 710, 810 which may include a formation pressure measurement device 6a and/or 6b. The signals may be transmitted toward the surface of the earth along the drill string 105.

[0027] An apparatus and system for communicating from the drill pipe 105 to the surface computer 185 or other component configured to receive, analyze, and/or transmit data may include a second adapter sub 190 that may be coupled between an end of the drill string 105 and the top drive 155 that may be used to provide a

communication channel with a receiving unit 195 for signals received from the well logging tools 125. The receiving unit 195 may be coupled to the surface computer 185 to provide a data path therebetween that may be a bidirectional data path.

[0028] Though not shown, the drill string 105 may alternatively be connected to a rotary table, via a Kelly, and may suspend from a traveling block or hook, and additionally a rotary swivel. The rotary swivel may be suspended from the drilling rig 101 through the hook, and the Kelly may be connected to the rotary swivel such that the Kelly may rotate with respect to the rotary swivel. The Kelly may be any mast that has a set of METHOD AND APPARATUS FOR SURVEYING WITHOUT DISABLEMENT OF

DRILLING FLUID FLOW polygonal connections or splines on the outer surface type that mate to a Kelly bushing such that actuation of the rotary table may rotate the Kelly.

[0029] An upper end of the drill string 105 may be connected to the Kelly, such as by threadingly reconnecting the drill string 105 to the Kelly, and the rotary table may rotate the Kelly, thereby rotating the drill string connected thereto.

[0030] Although not shown, the drill string 105 may include one or more stabilizing collars. A stabilizing collar may be disposed within or connected to the drill string 105, in which the stabilizing collar may be used to engage and apply a force against the wall of the well 110. This may enable the stabilizing collar to prevent the drill pipe string 105 from deviating from the desired direction for the well 110. For example, during drilling, the drill string 105 may "wobble" within the well 110, thereby allowing the drill string 105 to deviate from the desired direction of the well 110. This wobble action may also be detrimental to the drill string 105, components disposed therein, and the drill bit 116 connected thereto. A stabilizing collar may be used to minimize, if not overcome altogether, the wobble action of the drill string 105, thereby possibly increasing the efficiency of the drilling performed at the well site and/or increasing the overall life of the components at the wellsite.

[0031] In the illustrated example where an operator wishes initiation of sampling with the drill string 105, a simple implementation of the invention can be triggering of a survey using drill string rotation sensors. Rotation sensors may be included in any of the downhole tools illustrated in FIG. 1 . A suitable connection may be made to control circuitry where a feed of information from rotation sensors is provided to a downhole tool, previously described. A downhole tool can be preprogrammed to transmit survey data (direction and inclination) after a predetermined time interval started once the rotation of the drill string has ceased. The time interval is required in order for the drill string 105 to fully stabilize while a survey is taken. METHOD AND APPARATUS FOR SURVEYING WITHOUT DISABLEMENT OF

DRILLING FLUID FLOW

[0032] As a non-limiting embodiment, a method 200 includes the following steps, as provided in FIG. 2. A portion of a well is drilled 202, for example, a new stand is to be added to the drill string . Next, the drill string is pulled off the bottom while the mud flow pumps maintain mud circulation as well as drill string rotation 204.

[0033] Next, the drill string 105 rotation is stopped 206, while the mud flow circulation is maintained. In other embodiments, described later, other methods for initiation of taking survey data will be discussed. Survey data may then be acquired with the downhole tool after the time period elapses.

[0034] Next, the system is configured to detect the stoppage of the rotation of the drill string 208 through rotation sensors. A predetermined time may then elapse once any of the downhole tools has detected that rotation of the drill string has stopped, as a non- limiting embodiment 210. Survey data, may then be acquired by the system 212 such as a down hole tool. The survey data may be, for example, direction and inclination information of the tool, as a non-limiting embodiment. The data obtained may then be transmitted from the downhole environment to the uphole environment using, for example, mud pulse telemetry 214. Mud pump circulation may not be stopped before the survey data has been received at the uphole environment 216. The mud circulation may then be stopped and a new stand may be added to the drill string 105, if desired 218. Receipt of the transmitted data may occur, for example, at the uphole environment for use by operators in a variety of ways.

[0035] Referring to FIG. 3, another aspect is illustrated, wherein a method 300 is provided for surveying when a weight on bit is used for initiation of surveying and mud pumps are not turned off until after transmission of data from the downhole environment to the uphole environment. In this aspect, at least a portion of a well is drilled 302. The drill string 105 is then pulled off the bottom of the borehole and consequently, the weight on the drill bit is reduced 304. In the illustrated embodiment, a downhole tool METHOD AND APPARATUS FOR SURVEYING WITHOUT DISABLEMENT OF

DRILLING FLUID FLOW recognizes the reduced weight on the drill bit 306. A period of time then passes for the system at step 308. The downhole tool then initiates the step of attaining downhole data from the downhole tool itself beginning the acquisition 310, for example. Data obtained downhole can be a variety of types of data, including temperature, pressure, liquid/vapor ratio as non-limiting embodiments. Data is then transmitted from the downhole environment to the uphole environment 312. In the illustrated embodiment, mud pulse telemetry is used for transmission of the data. In step 314, drilling mud pumps continue to supply drilling fluid/mud to the downhole environment even during the transmission of the mud pulse telemetry signals. Drilling mud circulation is stopped 316 only after the mud pulse telemetry signals are transmitted from the downhole environment. The method may then end at step 318. Receipt of the transmitted data may occur, for example, at the uphole environment for use by operators in a variety of ways.

[0036] Referring to FIG. 4, another aspect is illustrated, wherein a method 400 is provided for surveying when reduction in drilling mud pressure is used for initiation of surveying and mud pumps are not turned off until after transmission of data from a downhole environment to an uphole environment. In this aspect, at least a portion of a well is drilled 402. The drill string 105 is then pulled off the bottom of the borehole and consequently, the weight on the drill bit is reduced 404. Pressure is then reduced to a non-zero value in step 406. In the illustrated embodiment, a downhole tool with a pressure transducer recognizes the reduced pressure of the flowing drilling fluid 408. A period of time then passes for the system at step 410. The downhole tool then initiates the step of attaining downhole data may then begin from either the downhole tool signaling another downhole tool to begin acquisition or the downhole tool itself beginning the acquisition 412. Data is then transmitted from the downhole environment to the uphole environment 414. In the illustrated embodiment, mud pulse telemetry is used for transmission of the data. In step 416, drilling mud pumps continue to supply drilling fluid/mud to the downhole environment even during the transmission of the mud METHOD AND APPARATUS FOR SURVEYING WITHOUT DISABLEMENT OF

DRILLING FLUID FLOW pulse telemetry signals. Drilling mud circulation is stopped 418 only after the mud pulse telemetry signals are transmitted from the downhole environment. The method may then end at step 420. Receipt of the transmitted data may occur, for example, at the uphole environment for use by operators in a variety of ways.

[0037] In the embodiments provided, a survey may be "triggered" by the various method steps provided above. The triggering of the acquisition of data from a downhole source can be performed done by a pre-programmed downhole tool that is placed in the drill string. Various downhole tools may be used in conjunction with aspects presented above. As a non-limiting example a fluid analyzer module having a sensor to sense a phase boundary of fluid beneath the ground surface. Such fluid analyzers may be used to determine a gas to oil ratio "GOR", bubble point pressure and temperature points or curves as necessary. Formation temperature, when determined, may incorporate several temperature profiles along a wellbore extending into the subterranean formations in which testing is to be performed.

[0038] The methods provided have significant advantages over conventional systems. The benefits can include fast data detection and acquisition, followed by a fast initiation of the transmission of these data. This process expedites the drilling of wells.

[0039] An additional benefit includes a stable flow of drilling mud when the data are transmitted by mud pulse telemetry. This improves the reliability of the transmission. Additional benefits allow the operators of the drill rig to minimize degradation on pumps by having to cycle the pumps less frequently than conventional methods. This allows the operator greater flexibility and operating response as repairs will not have to be performed as frequently.

[0040] The methods described herein also allow for high quality of data transmission from the downhole environment to the uphole environment. As conventional systems METHOD AND APPARATUS FOR SURVEYING WITHOUT DISABLEMENT OF

DRILLING FLUID FLOW require the drilling mud/fluid to stabilize before taking readings, the methods described herein allow for alleviation of this issue and immediate data transmission from point to point.

[0041] In a first method described, the method steps include drilling a portion of a well, pulling off of a bottom of the well with a drill string while maintaining a drilling mud circulation and a drill string rotation, stopping the drill string rotation, detecting the stopping of the drill string rotation, waiting a period of time, acquiring survey data after the period of time has elapsed, transmitting the survey data from a downhole

environment to an uphole environment, continuing drilling mud circulation until after the transmitting of the survey data from the downhole environment to the uphole

environment; and stopping drilling mud circulation after the transmitting the survey data from the downhole environment to the uphole environment. In an alternative

configuration, the method may be performed where the period of time is predetermined, as a non-limiting embodiment.

[0042] In an alternative embodiment, the method may be accomplished wherein the detecting the stopping of the drill string rotation is done downhole. In another alternative embodiment, the method may be accomplished wherein the detecting is performed by a downhole tool.

[0043] In another alternative embodiment, the method may be accomplished wherein the transmitting the survey data from the downhole environment to the uphole environment is done by mud pulse telemetry. In a still further method, the method may include the step of receiving the survey data at the uphole environment.

[0044] In another alternative embodiment, a method is provided describing the steps of drilling a portion of a well, pulling off of a bottom of the well with a drill string while maintaining a drilling mud circulation and a drill string rotation, detecting a reduction of a METHOD AND APPARATUS FOR SURVEYING WITHOUT DISABLEMENT OF

DRILLING FLUID FLOW weight on a drill bit, waiting a period of time, acquiring survey data after the period of time has elapsed, transmitting the survey data from a downhole environment to an uphole environment, continuing drilling mud circulation until after the transmitting of the survey data from the downhole environment to the uphole environment, and stopping drilling mud circulation after the transmitting the survey data from the downhole environment to the uphole environment.

[0045] In another alternative embodiment, a method is provided describing the steps of drilling a portion of a well, pulling off of a bottom of the well with a drill string while maintaining a drilling mud circulation and a drill string rotation, reducing a mud pressure circulation to a non-zero value, detecting the reduction of mud pressure;

waiting a period of time, acquiring survey data after the period of time has elapsed; transmitting the survey data from a downhole environment to an uphole environment; continuing drilling mud circulation until after the transmitting of the survey data from the downhole environment to the uphole environment, and stopping drilling mud circulation after the transmitting the survey data from the downhole environment to the uphole environment.

[0046] The abstract provided is to allow the reader to quickly ascertain the nature of the technical disclosure provided. It is submitted with the understanding that the abstract may not be used to interpret or limit the scope and meaning of the claims.

[0047] The foregoing outlines features of several embodiments so that those skilled in the art may understand the aspects of the disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure and that they may make various changes, METHOD AND APPARATUS FOR SURVEYING WITHOUT DISABLEMENT OF

DRILLING FLUID FLOW substitutions and alterations herein without departing from the spirit and scope of the present disclosure.