Abstract: The present invention is directed to a method for producing gas from a subterranean formation containing a coal seam. The method includes the steps of drilling a substantially vertical well bore into the subterranean formation, which intersects the coal seam and fracturing the coal seam using a hydrajetting tool to produce at least one pair of opposed bi-wing fractures substantially along a plane of maximum stress. One or more horizontal well bores may also be drilled into the coal seam along which the coal seam can be further fractured.

Abstract: Methods, systems, and apparatus for inducing fractures in a subterranean formation and more particularly methods and apparatus to place a first fracture with a first orientation in a formation followed by a second fracture with a second angular orientation in the formation are disclosed. The first and second fractures are initiated at about a fracturing location. The initiation of the first fracture is characterized by a first orientation line. The first fracture temporarily alters a stress field in the subterranean formation. The initiation of the second fracture is characterized by a second orientation line. The first orientation line and the second orientation line have an angular disposition to each other.

Abstract: The present invention provides methods of monitoring the injection of a fluid into a subterranean formation. The present invention also provides a method of fracturing a subterranean formation. All methods feature the use of a wavelet transform of data generated by the subterranean injection process.

Abstract: Fracture design for well completion includes determining a conductivity profile for the given reservoir to be fractured. Materials needed to obtain this conductivity profile are selected based on their ability to meet the conductivity objective and their rank based on economic value. A further step gives the designer a pumping schedule to be performed on the surface after an initial test in the actual well. This can reduce the iterations required to optimize a fracturing treatment and significantly reduce the redesign process at the well site.

Abstract: A process and apparatus for treating a wellbore, comprising subjecting a substantially same portion of the wellbore to vibratory waves produced by a plurality of vibratory wave generators. The vibratory waves may have about the same frequency or a plurality of frequencies, and the frequencies may partially overlap, not overlap, or be modulated across a range. Additionally, the frequencies may be modulated in an oval, hoop, and flexural modes. The vibratory waves may be produced by firing the vibratory wave generators simultaneously or in sequence. Combinations of a vibrating pipe, piston pulser, or valve may be used as vibratory wave generators. In a preferred embodiment, the thickness and change of thickness of a mudcake on the interior surface of a wellbore are measured to evaluate the effectiveness of the wellbore treatment.

Abstract: Fracture design for well completion includes determining a conductivity profile for the given reservoir to be fractured. Materials needed to obtain this conductivity profile are selected based on their ability to meet the conductivity objective and their rank based on economic value. A further step gives the designer a pumping schedule to be performed on the surface after an initial test in the actual well. This can reduce the iterations required to optimize a fracturing treatment and significantly reduce the redesign process at the well site.

Abstract: The present invention discloses a process and apparatus for treating a wellbore, comprising subjecting a substantially same portion of the wellbore to vibratory waves produced by a plurality of vibratory wave generators. The vibratory waves may have about the same frequency or a plurality of frequencies, and the frequencies may partially overlap, not overlap, or be modulated across a range. Additionally, the frequencies may be modulated in an oval, hoop, and flexural modes. The vibratory waves may be produced by firing the vibratory wave generators simultaneously or in sequence. Preferably, the vibratory waves are acoustically streamed in a viscous boundary layer near obstacles, outside a viscous boundary layer near obstacles, or in a free non-uniform sound field. In a preferred embodiment, a vibrating pipe and a piston pulser are used as vibratory wave generators. In another preferred embodiment, a vibrating pipe, piston pulser, and a valve are used as vibratory wave generators.

Abstract: A method for determining fracture parameters of heterogenous or homogeneous formations which takes into account spurt-loss is provided. The invention provides a method of determining fluid-loss coefficient, spurt-loss and closure pressure based on a general minifrac analysis.

Abstract: This invention relates to a procedure to control fracture orientation in underground formations to increase well productivity. The method is performed by hydraulically fracturing the formation and propping and plugging the fractures which result. The formation is then perforated or notched in a direction angularly disposed relative to the anticipated fracture formation and first hydraulic fracture. The presence of the first fracture will force the second fracture to propagate in a direction away from that of the first fracture. A method for simultaneously fracturing the formation in two directions is also provided.

Abstract: In one aspect of the present invention, a method is provided for determining the fracture closure pressure of a fractured formation. The method includes the steps of injecting a fracturing fluid into a subsurface formation to create a fracture, measuring the pressure response of the formation after injection has ceased, and determining the pressure at the onset of constant volume behavior as the fracture closure pressure. In another embodiment of the present invention, the fracture volume, leak-off volume and efficiency are determined by integrating the fracture closure rate over time, and then iterating with a fluid volume equation. Still another embodiment of the present invention determines the fracture volume, leak-off volume and efficiency by extrapolating the apparent system volume back to the moment when injection is stopped.

Abstract: A method of determining fracture parameters for heterogeneous formations is provided based upon pressure decline measurements from minifrac tests. The inventions provide methods for generating type curves for heterogeneous formations, as well as a leak-off exponent that characterizes specific fracturing fluid/formation systems.

Abstract: A method of performing a mini-frac operation wherein the effects of the compressibility of the fracturing fluid and the increase in fracturing fluid temperature are considered. The mini-fracturing operation is performed and the pressure decline is observed at selected intervals over a determined time period. The observed pressure decline values are adjusted to compensate for fluid compressibility and/or for temperature increase. A correlation term is determined which is utilized to determine parameters of the formation and fracture. The parameters of the fracturing operation are then determined in response to the adjusted pressure decline values. The parameters may be adjusted in response to the compensation for temperature and fluid compressibility either by adjusting the observed pressure decline values and comparing them to a known reference, or by establishing new reference values for the well to be correlated with the observed pressure decline to determine a correlation term.

Abstract: A method for modeling a fractured formation to determine a non-uniform fracture conductivity which will yield fracture performance comparable to that obtained from a fracture having uniform conductivity. Additionally, proppant concentrations and proppant schedules may be established to facilitate performing a fracturing operation to distribute sand in the fracture such that the fracture exhibits a non-uniform conductivity. The modeling technique includes the determining of an optimal fracture conductivity at a plurality of locations along the length of the fracture.

Abstract: Determining pressure characteristics of fluid flow from a wellbore provides a method to obtain physical characteristics of a subterranean reservoir. An analytical solution of flow a flow model for an underground dual porosity reservoir is obtained for the transient flow regime of an unsteady flow exhibiting wellbore storage and skin effects. Using either the continuous solution or a set of type curves obtained from that continuous solution, a match is obtained with an experimental data set. The first time derivative of the dimensionless pressure solution to the flow model can also be used to more easily identify the dimensionless time at which the transient period ends. Using classical relationships between known values and information obtained from the type curves, the effective permeability, dimensionless fracture transfer coefficient, the skin factor, the dimensionless wellbore storage coefficient, and the dimensionless storativity ratio can be ascertained for the underground formation.