Saudi Arabian Oil Company

Chao Liu

Younane N Abousleiman

Dung T Phan

Yanhui Han

Katherine Leigh Hull

Shawn Rimassa

Hui-Hai Liu

Murtadha J AlTammar

Vladimir Kazei

Methods and systems are disclosed. The method may include obtaining, using a rock characterization system, a plurality of characteristics for a rock penetrated by a wellbore, and determining, using a model of poroelasticity and the plurality of characteristics, a preferred ultrasonic frequency at which to insonify the rock. The method may further include deploying an ultrasonic stimulation tool in the wellbore, where the ultrasonic stimulation tool comprises at least one ultrasonic transducer, and activating the ultrasonic stimulation tool at the preferred ultrasonic frequency.

Methods and systems to stimulate rock surrounding a wellbore using ultrasound at a preferred frequency

Systems and methods for determining a connected porosity and a non-connected porosity in a fluid-saturated hydrocarbon reservoir are disclosed. The methods include obtaining at least one rock sample from the fluid-saturated hydrocarbon reservoir, determining, using a petrophysical sample analyzer, at least one petrophysical parameter of the rock sample, and measuring at least one of an elastic wave velocity and an elastic wave attenuation for each of a plurality of wave frequencies. The methods further include determining, using a computer processor, the connected porosity and the non-connected porosity of the rock sample using a dual-porosity single-permeability model based, at least in part, on at least one petrophysical parameter and at least one of the elastic wave velocity and the elastic wave attenuation.

Method for determining connected and non-connected porosities

A method of determining rock matrix and fracture permeability to perform a reservoir fluid flow simulation. The method includes: obtaining a petrophysical characterization of a formation sample, measuring a first and second elastic wave velocity of the formation sample at a first and second frequency, calculating an average rock matrix density and an average porosity of the formation sample, determining a set of calculated elastic wave velocities for the first and second frequencies over a range of candidate permeabilities, and determining a rock matrix permeability and a fracture permeability based on the set of calculated elastic wave velocities at the first and second frequency respectively. The method further including performing a reservoir fluid flow simulation based, at least in part, on at least one of the rock matrix permeability and the fracture permeability.

Method for determining rock matrix and fracture permeability by using poroelastodynamics and density averaging schemes

A method for predicting a formation property of a formation, including the steps of: drilling a first well that penetrates the formation, obtaining well properties from the first well, determining a measured formation property from the first well, determining a correlation function that estimates a predicted formation property from the well properties, wherein the correlation function comprises coefficients, calibrating the correlation function by modifying the coefficients until the predicted formation property best matches the measured formation property, drilling a second well that penetrates the formation, obtaining well properties from the second well, determining the formation property from the second well by applying the correlation function with the modified coefficients to the well properties.

Methods for predicting formation properties

A method includes obtaining total stresses and pore pressures of each porous medium of a formation, determining a first and second set of effective stresses for the formation, determining an individual collapse and fracturing mud weight for each porous medium of the formation using a first set of associated failure criteria, wherein the first set of associated failure criteria are based on the first set of effective stresses, determining an overall collapse and fracturing mud weight for the formation using a second set of associated failure criteria, wherein the second set of associated failure criteria is based on the second set of effective stresses, determining a mud weight window for the formation using the individual collapse mud weight, the individual fracturing mud weight, the overall collapse mud weight, and the overall fracturing mud weight, and transmitting a command to a drilling system based on the mud weight window.

Method for the determination of mud weight window in N-porosity N-permeability formations

Systems and methods for predicting a breakdown pressure of a formation and fracturing the formation account for filter cake effects. The systems and methods measure a time-dependent permeability and a time-dependent thickness of a filter cake formed by a first drilling mud. The systems and methods determine a time-dependent permeability model and a time-dependent thickness model of the filter cake. The systems and methods select a breakdown pressure model based on (i) the time-dependent thickness of the filter cake, (ii) the time-dependent permeability of the filter cake, and (iii) the permeability of the formation. The systems and methods use the selected breakdown pressure model to predict the breakdown pressure of the formation and fracture the formation using a drilling fluid having a mud weight associated with the predicted breakdown pressure of the formation.

Fracturing a subsurface formation based on the required breakdown pressure accounting for filter cake

Methods for determining an in-situ pore pressure in a formation rock may include acquiring well log data, calculating a cation-exchange capacity, calculating a mole fraction of fixed charges using the cation-exchange capacity, determining a formation temperature, calculating the in-situ pore pressure, outputting the in-situ pore pressure of the formation rock, and using the in-situ pore pressure in a wellbore stability model to monitor and maintain stability of the formation rock. Corresponding electronic devices may include a computer processor coupled to at least one logging tool, wherein the logging tool is configured to acquire well log data in a formation rock. Non-transitory computer storage mediums may include program instructions, that when executed, may be configured to perform the methods for determining an in-situ pore pressure in a formation rock.

Method of determining in-situ pore pressure in chemically active formations

To estimate natural fracture properties based on production from hydraulically fractured wells, a computer system receives hydrocarbon reservoir production information associated with a naturally fractured hydrocarbon reservoir with entrapped hydrocarbons in which a wellbore has been formed to produce the hydrocarbons. The information includes a wellbore pressure measured over production time. From the wellbore pressure, the computer system determines a time rate of change of the wellbore pressure over the production time. From a plot of a logarithmic time rate of change of the wellbore pressure over logarithmic production time, the computer system identifies multiple plot sections, each representing a respective flow regime of a flow of the hydrocarbons from the reservoir. For each plot section, the computer system determines a corresponding time rate of change of the wellbore pressure intersect value and a reservoir parameter for each corresponding time rate of change of the wellbore pressure intersect value determined for each plot section.

Estimating natural fracture properties based on production from hydraulically fractured wells

Systems and methods for determining shear failure of a rock formation are disclosed. The method includes receiving, by a processor, a plurality of parameters related to physical properties of the rock formation, applying the plurality of parameters to a predetermined failure criterion, and determining shear failure of the rock formation based on the failure criterion. In some embodiments the failure criterion is a modified Hoek-Brown failure criterion that takes into consideration an intermediate principal stress, and the difference between normal stresses and an average confining stress.

Systems and methods for predicting shear failure of a rock formation

A method for measuring a fracture permeability and a matrix permeability of a naturally fractured cylindrical rock sample, includes sealing both flat ends of the cylindrical sample; immersing the naturally fractured cylindrical rock sample in a fluid, and attaching an axial and a radial strain sensor to the curved surface of the sample. Furthermore, the method includes attaching a signal generator to one flat end of sample, and a signal receiver to the other flat end of the sample, and generating a harmonic excitation using the signal generator at a plurality of frequencies and recording the excitation at each of the plurality of frequencies. The method includes calculating an elastic wave propagation attribute at each of the plurality of frequencies, and inverting the elastic wave propagation attribute at each of the plurality of frequencies to determine the fracture permeability and the matrix permeability of the naturally fractured cylindrical rock sample.

Two methods of determining permeabilities of naturally fractured rocks from laboratory measurements

Systems and methods for determining a time-dependent mud weight window are disclosed. The existence of fractures in formation rock along with a type of the formation rock are used to determine the use of a particular solution to determine the mud weight window at a particular time of a wellbore drilling operation.

Systems and methods for determining mud weight window during wellbore drilling

A number of average compressibility values of a fractured rock in a wellbore from a depth of interest is determined, where each of the number of average compressibility values is determined according to a different average scheme. For each of the number of average compressibility values, a set of effective stresses' values based on that average compressibility value. For each determined set of stresses values, a set of mud weight window values is determined based on the set of stresses values. A mud weight for the wellbore is adjusted to be within the determined set of mud weight window.

Determining safe drilling mud weight

The present disclosure describes methods and systems, including computer-implemented methods, computer program products, and computer systems, for determining a mudweight of drilling fluids in a hydrocarbon reservoir. One computer-implemented method includes: receiving pore pressure data of a rock formation in the hydrocarbon reservoir; determining permeability data of fractures of the hydrocarbon reservoir; determining Hoek-Brown failure criterion data; and determining a safe mudweight window based on the pore pressure data of the rock formation, the permeability data of the fractures, and the Hoek-Brown failure criterion data.

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Brookshire, TX, United States of America

Chao Liu