Saudi Arabian Oil Company

Kaiming Xia

Yufeng Cui

Tariq Mahmood

Yanhui Han

Weihua Wang

Saidi Ali Hassani

Todd Allen Green

A system for determining a direction for drilling a well is disclosed. The system has a device in a portion of a conveyance mechanism comprising a cylindrical housing with at least one sensor that tracks a position of the portion during a drilling operation, the device being configured to obtain a plurality of drilling parameters, and a control system coupled to the device and configured to perform at least one reservoir simulation, and prepare a plurality of required parameters while drilling. The device uses an optimization box to simulate increasing an angle between a drilling direction and a maximum horizontal stress by calculating a minimum mud pressure required to prevent borehole collapse. The control system generates an engineering curve representative of each angle simulated and a corresponding mud weight or pressure, and the device and the control system identify an optimal direction corresponding to a minimum drilling mud pressure parameter.

System and method for determining a direction for drilling a well

A bottom hole assembly (BHA) includes components to perform a fracturing process for small hole wells created by underbalanced coiled tubing drilling. The BHA can be used to drill a wellbore and to stimulate an underbalanced coiled tubing drilled well. The BHA, coupled to a coiled tubing, can include a drilling bit, a hydrajetting tool up-string from the drilling bit, and a diverter between the drilling bit and the hydrajetting tool. After the BHA drills a wellbore, the BHA can be moved so that the hydrajetting tool is positioned to perform perforation without removing the BHA from the wellbore. The hydrajetting tool can perforate the formation using a regular perforation fluid first, then using a cooling agent to cool the wellbore area covering the coplanar perforation cluster, and last propagate hydraulic fracture by injecting the main pump schedule through the tubing and the annulus at the same time.

Stimulating wells created by underbalanced coiled tubing drilling

Systems and methods for determining optimal perforation orientations for hydraulic fracturing of wells in a subterranean formation are presented. The method comprises identifying in-situ stresses for a portion of a well bore formed and transforming the in-situ stresses between coordinate systems. Pressure coefficients and a breakdown pressure for each trial perforation phase angle at a perforation cluster determined, and a perforation point in the well bore coordinate system is calculated for each trial perforation phase angle of the perforation cluster. The perforation point in the well bore coordinate system is transformed to the translated global coordinate system for each trial perforation phase angle. A target perforation phase angle is selected at a minimum breakdown pressure for the perforation cluster, and a perforation azimuth and perforation dip is calculated for the perforation cluster at the minimum breakdown pressure for the target perforation phase angles.

Method and system to determine optimal perforation orientation for hydraulic fracturing slant wells

A method includes gathering data about the well and the deep and tight sandstone reservoir, evaluating a diagenetic rock typing and a flow index of the reservoir using the data, and determining a first set of perforation locations based on the diagenetic rock typing and the flow index. The method also includes calibrating in-situ stresses based on the data and determining a breakdown pressure envelope and optimal perforation directions using the in-situ stresses, maximum horizontal stress direction, formation mechanical properties, and well trajectory. The method further includes narrowing the first set of perforation locations to a second set of perforation locations based on the breakdown pressure envelope, comparing the breakdown pressure envelope of the second set of perforation locations to a maximum downhole pressure to determine a perforation method, and performing a fracturing operation on the well using the second set of perforation locations, the perforation method, and the optimal perforation directions.

Method to identify perforation locations for fracturing deep and tight sandstone reservoir

Techniques for hydraulic fracturing a subsurface formation can include using a deterministic model to simulate a deviated well comprising a casing and at least one perforation tunnel. The techniques can include determining a different statistical distribution for each of one or more parameters to the deterministic model. The statistical distributions can be determined from the log data along the measured depth within the wellbore. The techniques can include probabilistically solving the deterministic model to determine a mean and a standard deviation of breakdown pressures along the measured depth within the wellbore. The techniques can include processing the mean and the standard deviation of breakdown pressures to determine an upper bound breakdown pressure based on a level of confidence. The techniques can include drilling and completing a deviated well based on the determined upper bound breakdown pressure and injecting hydraulic fluid to cause hydraulic fracturing of the subsurface formation.

Fracturing a subsurface formation based on a probabilistic determination of the required breakdown pressure

A perforation cluster of a longitudinal section of a wellbore is provided. The wellbore is for hydraulic fracturing in a preferred direction of a subsurface surrounding the longitudinal section. The longitudinal section has a longitudinal axis in a longitudinal direction and defining a radial direction about the longitudinal axis. The perforation cluster includes all of the perforations of the wellbore within the longitudinal section. The perforations are separated in the longitudinal and radial directions. Two perforations are adjacent in the longitudinal direction and have a first diameter. They also have respective centers that are aligned in the preferred direction with respect to the longitudinal axis and 180&#xb0; apart in the radial direction, for initiating fractures through hydraulic fracturing in the subsurface. The remaining perforations have a second diameter smaller than the first diameter.

Perforation cluster layout design and its relative orientation in the subsurface for a hydraulic fracturing treatment

Some methods of hydraulic fracturing of a subsurface formation include using a three-dimensional finite element model to simulate a deviated well with a wellbore casing, a cement adjacent to the wellbore casing, and a perforation cluster with at least two perforations. The FEM is applied (or solved) to determine a breakdown pressure of the deviated well based on an amount of tensile damage of the perforation cluster induced by an applied pressure representing injected hydraulic fluid. The FEM accounts for the 3D complex configuration of wellbore and perforation cluster. A deviated well is drilled and completed with a wellbore casing size, tubing size, wellhead, and hydraulic fracturing pump schedule selected at least in part based on the determined breakdown pressure before hydraulic fluid is injected into the deviated well at an injection pressure, which represents the required breakdown pressure to cause hydraulic fracturing of the rock of the subsurface formation.

Fracturing a subsurface formation based on the required breakdown pressure

Techniques for determining a breakdown pressure of a subterranean formation include identifying in-situ stresses for a portion of a wellbore formed into a subterranean formation; transforming the in-situ stresses (and induced stresses) from a global coordinate system to a wellbore coordinate system of a deviated portion of the wellbore that includes at least one perforation tunnel for a hydraulic fracturing treatment; transforming the in-situ stresses from the wellbore coordinate system to a perforation coordinate system through at least one rotation matrix; determining one or more stresses at a wellbore-perforation interface of the perforation tunnel from the in-situ stresses in the perforation coordinate system; calculating one or more hoop stresses at a perforation tunnel wall of the perforation tunnel from the determined stresses on the wellbore-perforation interface; and determining a breakdown pressure for the subterranean formation based on the calculated one or more hoop stresses and an effect of casing-cement-formation interaction.

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Dhahran, Saudi Arabia

Kaiming Xia