A wellbore (10) in an earth formation (12) having a casing (14) and a plurality of pay or production zones (32, 34, 36) provided in the formation. A coiled tubing string (18) from a reel (20) is injected by an injector (24) into the wellbore (10) for first perforating casing section (38) at each pay zone (32, 34, 36) in a single pass of the coiled tubing (18) as shown in FIG. 1. Next, the coiled tubing (18) is utilized for hydraulic fracturing each of the pay zones (32, 34, 36) individually from the lowermost pay zone (32) to the uppermost pay zone (36) in a single pass of the coiled tubing (18). Each pay zone (32, 34, 36) is isolated for the hydraulic fracturing. An upper packer (44 or 54) is provided above each of the pay zones for isolation and a lower packer (56) or sand plug (50) is utilized for isolating the lower or outermost end of each pay zone (32, 34, 36). Swab cups (58, 54A, 56A, 54B, 56B) are also utilized for isolation of pay zones.

A system and method for the measurement of the stresses and pressure perturbations surrounding a well, and a system for computing the optimum location for initiating a hydraulic stress fracture. The technique includes using sensors attached to the wellbore casing connected to a data analyzer. The analyzer is capable of analyzing the stresses on the well system. Using an inverse problem framework for an open-hole situation, the far field stresses and well departure angle are determined once the pressure perturbations and stresses are measured on the wellbore casing. The number of wellbore measurements needed for the inverse problem solution also is determined. The technique is also capable of determining the optimal location for inducing a hydraulic fracture, the effect of noisy measurements on the accuracy of the results, and assessing the quality of a bond between a casing and a sealant.

The present invention is directed to a method and apparatus for controlling the flowback of proppants that have been placed inside fractures of a subterranean formation. The apparatus is defined by a plurality of solid balls, which comprise compressed springs that are encapsulated in a mass of fibrous material and an aqueous soluble mixture of a filler material and an adhesive. In the method according to the present invention, the solid balls are mixed in a viscous slurry and injected into the fractures with the proppants. Over time the aqueous soluble mixture dissolves releasing the compressed springs to fill the openings of the fractures. The fibrous network and expanded springs, which remain, act as a filter or screen to restrict the movement of the proppants from flowing back to the surface during production of the well.

The present invention is directed to a method of isolating hydrajet stimulated zones from subsequent well operations. The method includes the step of drilling a wellbore into the subterranean formation of interest. Next, the wellbore may or may not be cased depending upon a number of factors including the nature and structure of the subterranean formation. Next, the casing, if one is installed, and wellbore are perforated using a high pressure fluid being ejected from a hydrajetting tool. A first zone of the subterranean formation is then fractured and stimulated. Next, the first zone is temporarily plugged or partially sealed by installing an isolation fluid into the wellbore adjacent to the one or more fractures and/or in the openings thereof, so that subsequent zones can be fractured and additional well operations can be performed.

A method and apparatus for initiating an azimuth controlled vertical hydraulic fracture in unconsolidated and weakly cemented soils and sediments using active resistivity to monitor and control the fracture initiation and propagation. Separate or overlapping treatment walls and containment barriers can be created by controlling and monitoring the propagation of fractures in the subsurface. A fracture fluid is injected into a well bore to initiate and propagate a vertical azimuth controlled fracture. The fracture fluid is energized to conduct electrical current while the fracture propagates through the ground. A series of electrical resistivity monitors measure the electrical conductivity of the fracture fluid in real time against the background conductivity of the formation. Using a series of incremental influence functions, the azimuth of the vertical fracture can be controlled by regulating the injection of fracture fluid based upon the induced voltage of the earth and the conductivity of the fluid in the fracture.