Abstract: In some examples, a system can include a computer-readable medium storing computer-executable instructions and one or more processors communicatively coupled to a computer-readable medium storing computer-executable instructions, which, when executed by the one or more processors cause the one or processors to receive data of a fracking stage, determine a penetration gradient of the fracking stage based on the data, and classify the fracking stage based on the penetration gradient.

Abstract: Carbonates, such as chalk and limestone, are rather soft minerals and may lose at least some mechanical integrity after undergoing stimulation. For instance, carbonate minerals may experience proppant embedment or asperity weakening after fracturing or matrix acidizing. Methods for hardening a carbonate mineral may comprise: introducing an aqueous carrier fluid comprising an ammonium phosphate salt into a subterranean formation comprising a carbonate mineral, and interacting the carbonate mineral with the ammonium phosphate salt to convert at least a portion of the carbonate mineral into a hydroxyapatite mineral. The subterranean formation may exhibit an increased hardness after forming the hydroxyapatite mineral. The ammonium phosphate salt may be diammonium hydrogen phosphate in some examples.

Abstract: Carbonates, such as chalk and limestone, are rather soft minerals and may lose at least some mechanical integrity after undergoing stimulation. For instance, carbonate minerals may experience proppant embedment or asperity weakening after fracturing or matrix acidizing. Methods for hardening a carbonate mineral may comprise: introducing an aqueous carrier fluid comprising an ammonium phosphate salt into a subterranean formation comprising a carbonate mineral, and interacting the carbonate mineral with the ammonium phosphate salt to convert at least a portion of the carbonate mineral into a hydroxyapatite mineral. The subterranean formation may exhibit an increased hardness after forming the hydroxyapatite mineral. The ammonium phosphate salt may be diammonium hydrogen phosphate in some examples.

Abstract: A method for stabilizing a wellbore includes introducing a hardening agent into the wellbore, mixing the hardening agent with a carrier fluid in the wellbore to produce a wellbore stabilizing fluid, and treating a wellbore wall of the wellbore by contacting the wellbore stabilizing fluid to a surface of the wellbore wall for at least 48 hours. A wellbore stabilizing fluid includes a hardening agent and a carrier fluid. The hardening agent is selected from one of 10 to 100 g/L of the calcium hydroxide nanocrystals, 5 to 99.9% by volume of tetraethyl orthosilicate (TEOS), and 10 to 50 g/L of zinc sulfate. A stabilized wellbore includes a wellbore having a wellbore wall treated with a wellbore stabilizing fluid comprising a hardening agent. The Young's modulus of the treated wellbore wall is at least 5% higher than a Young's modulus of a non-treated wellbore wall.

Abstract: In some examples, a system can include a computer-readable medium storing computer-executable instructions and one or more processors communicatively coupled to a computer-readable medium storing computer-executable instructions, which, when executed by the one or more processors cause the one or processors to receive data of a fracking stage, determine a penetration gradient of the fracking stage based on the data, and classify the fracking stage based on the penetration gradient.

Abstract: Methods and systems for quantifying and minimizing wellbore breakouts are disclosed. The methods include obtaining a mechanical earth model (MEM), determining a critical collapse pressure (CCP) using an inclination angle and the MEM, and determining an initial mud weight based on the CCP. The methods also include generating a breakout analysis using the initial mud weight, the MEM and a numerical modeling algorithm, updating the inclination angle of the planned wellbore, updating the CCP based on the updated inclination angle and the MEM, and updating the breakout analysis using the initial mud weight, the updated CCP, the MEM, and the numerical modeling algorithm. The methods further include selecting the updated CCP based, on the updated inclination angle that meets the stopping condition, calculating a final mud weight for the planned wellbore based on the updated CCP, and conditioning a drilling mud to the final mud weight, using a mud system.

Abstract: A method of increasing hydrocarbon recovery from a wellbore penetrating a tight hydrocarbon formation is disclosed. The method involves inserting a hydro-jetting tool into the wellbore; jetting a thermally controlled fluid against the wall of the wellbore to create a cavity in the wall, using the hydro-jetting tool; injecting, using the hydro-jetting tool, a further amount of the thermally controlled fluid into the wellbore such that the pressure in the wellbore increases, wherein the increased pressure creates a fracture from the cavity, wherein injecting the further amount of the thermally controlled fluid cools the tight hydrocarbon formation surrounding the cavity by circulating the thermally controlled fluid within the cavity; withdrawing the hydro-jetting tool from the wellbore; and recovering the thermally controlled fluid and the hydrocarbons escaped from the fracture in the formation.

Abstract: A method for reducing breakdown pressure at a formation includes detecting a tight reservoir formation in a well and providing hydraulic fracturing equipment assembled together as a hydraulic fracturing system at a surface of the well. The hydraulic fracturing system includes a fluid source containing a base fluid and fluidly connected to a blender and a pump and manifold system fluidly connecting an outlet of the blender to a wellhead of the well. The method further includes connecting a cooling system to the hydraulic fracturing system, using the cooling system to cool the base fluid to a cooled base temperature upstream of the pump and manifold system, pumping the cooled base fluid down the well to the tight reservoir formation, and using the cooled base fluid to lower a temperature of the tight reservoir formation and reduce a breakdown pressure of the tight reservoir formation.

Abstract: A method to predict wireline caliper log data from logging-while-drilling data which includes collecting logging-while-drilling logs and caliper logs from a plurality of wells. The caliper log contains at least one channel. The method further includes pre-processing the logging-while-drilling data, selecting a subset of logs within the logging-while-drilling data, and aggregating the channels of the caliper logs forming aggregate logs. The method further includes splitting the pre-processed logging-while-drilling data and aggregate logs into train, validation, and test sets, wherein the validation and test sets may be the same, selecting a machine-learned model and architecture, and training the machine-learned model to form predicted aggregate logs from the logging-while-drilling data using the training set. Additionally, the method consists of using the machine-learned model to predict the aggregate logs using pre-processed logging-while-drilling data.

Abstract: A method of treating a carbonate formation includes introducing a stimulation fluid into the carbonate formation at a pressure greater than a fracture pressure of the formation and creating openings in the carbonate formation via the stimulation fluid. Then, a fluoride salt solution, optionally including a proppant, may be introduced into the carbonate formation such that it at least partially penetrates into the openings. The fluoride salt may then be reacted with a carbonate surface in the carbonate formation to form fluorite on a surface of the formation thereby increasing a hardness of the carbonate formation.

Abstract: A wellbore stimulation operation method includes conveying a downhole assembly into a wellbore. The downhole assembly includes one or more perforating guns and a pressure wave resonator. The perforating guns are axially aligned with a production zone and fired to create a plurality of perforations in the production zone. The pressure wave resonator is axially aligned with the perforations and actuated to emit pressure waves that propagate radially outward and into the production zone. The pressure waves help remove debris from the perforations.

Abstract: A method for stabilizing a wellbore includes introducing a hardening agent into the wellbore, mixing the hardening agent with a carrier fluid in the wellbore to produce a wellbore stabilizing fluid, and treating a wellbore wall of the wellbore by contacting the wellbore stabilizing fluid to a surface of the wellbore wall for at least 48 hours. A wellbore stabilizing fluid includes a hardening agent and a carrier fluid. The hardening agent is selected from one of 10 to 100 g/L of the calcium hydroxide nanocrystals, 5 to 99.9% by volume of tetraethyl orthosilicate (TEOS), and 10 to 50 g/L of zinc sulfate. A stabilized wellbore includes a wellbore having a wellbore wall treated with a wellbore stabilizing fluid comprising a hardening agent. The Young's modulus of the treated wellbore wall is at least 5% higher than a Young's modulus of a non-treated wellbore wall.

Abstract: A method and an apparatus for determining a collapse pressure of a well using a drill stem test tool (DSTT). The method includes isolating a zone of interest in the wellbore, then reducing and recording pressure inside the drill string while recording acoustic emissions from the sensors on the DSTT, then correlating the recordings of the acoustic emissions with the pressure. The method includes using the processed acoustic emissions to determine a candidate sound of interest and a pressure at which the candidate sound of interest is recorded, then comparing the candidate sound of interest with a reference lookup table of known lithology classifications. The method includes determining a collapse pressure of the wellbore using the lithology of the wellbore and the pressure at which the candidate sound of interest is recorded.

Abstract: A method may include determining time-derivative pressure data based on pressure data regarding a pump system that is performing a hydraulic stimulation operation in a geological region. The method may further include determining a moving average value based on the time-derivative pressure data and a predetermined time window. The method may further include determining a flow rate adjustment for the pump system based on the moving average value, an update interval for adjusting flow rates, and a predetermined flow rate rule. A size of the predetermined time window may be different from the update interval. The method may further include using smoothed pressure data to determine time-derivative pressure data. The method may further include determining a flow rate adjustment for the pump system based on the time-derivative pressure data derived from the smoothed pressure data.

Abstract: A method for reducing breakdown pressure at a formation includes detecting a tight reservoir formation in a well and providing hydraulic fracturing equipment assembled together as a hydraulic fracturing system at a surface of the well. The hydraulic fracturing system includes a fluid source containing a base fluid and fluidly connected to a blender and a pump and manifold system fluidly connecting an outlet of the blender to a wellhead of the well. The method further includes connecting a cooling system to the hydraulic fracturing system, using the cooling system to cool the base fluid to a cooled base temperature upstream of the pump and manifold system, pumping the cooled base fluid down the well to the tight reservoir formation, and using the cooled base fluid to lower a temperature of the tight reservoir formation and reduce a breakdown pressure of the tight reservoir formation.

Abstract: This disclosure presents a method and an apparatus for improving production performance of a well using a drill stem test tool (DSTT). The method includes isolating a zone of interest in the wellbore, then reducing and recording pressure inside the drill string while recording acoustic emissions from the sensors on the DSTT, then correlating the recordings of the acoustic emissions with the pressure. The method includes using the processed acoustic emissions to determine a candidate sound of interest and a pressure at which the candidate sound of interest is recorded, then comparing the candidate sound of interest with a reference lookup table of known lithology classifications. The method includes determining a collapse pressure of the wellbore using the lithology of the wellbore and the pressure at which the candidate sound of interest is recorded.

Abstract: A fracturing fluid composition includes an aqueous fluid, a proppant particle, and a date tree fiber. A method of treating a hydrocarbon-bearing formation is also provided. The method includes injecting a fracturing fluid in the hydrocarbon-bearing formation, where the fracturing fluid includes an aqueous fluid, a proppant particle, and a date tree fiber.

Abstract: A system and method for acoustically profiling a wellbore while drilling, and which identifies depths in the wellbore where the wellbore diameter is enlarged or has highly fractured sidewalls. These depths are identified based on monitoring either travel time or signal strength of acoustic signals that propagate axially in the wellbore. Correlating wellbore depth to travel time of a signal traveling downhole inside of a drill string and uphole outside of the drill string yields an average signal velocity in the wellbore. Depths having a lower average signal velocity indicate where the wellbore diameter is enlarged or has highly fractured sidewalls. These depths are also identified by generating separate acoustic signals inside and outside of the drill string, comparing signal strengths of signals reflected from the wellbore bottom, and identifying the depths based on where there is an offset in the strengths of the reflected signals.

Abstract: A method may include determining time-derivative pressure data based on pressure data regarding a pump system that is performing a hydraulic stimulation operation in a geological region. The method may further include determining a moving average value based on the time-derivative pressure data and a predetermined time window. The method may further include determining a flow rate adjustment for the pump system based on the moving average value, an update interval for adjusting flow rates, and a predetermined flow rate rule. A size of the predetermined time window may be different from the update interval. The method may further include using smoothed pressure data to determine time-derivative pressure data. The method may further include determining a flow rate adjustment for the pump system based on the time-derivative pressure data derived from the smoothed pressure data.

Abstract: A system and method for acoustically profiling a wellbore while drilling, and which identifies depths in the wellbore where the wellbore diameter is enlarged or has highly fractured sidewalls. These depths are identified based on monitoring either travel time or signal strength of acoustic signals that propagate axially in the wellbore. Correlating wellbore depth to travel time of a signal traveling downhole inside of a drill string and uphole outside of the drill string yields an average signal velocity in the wellbore. Depths having a lower average signal velocity indicate where the wellbore diameter is enlarged or has highly fractured sidewalls. These depths are also identified by generating separate acoustic signals inside and outside of the drill string, comparing signal strengths of signals reflected from the wellbore bottom, and identifying the depths based on where there is an offset in the strengths of the reflected signals.