Using a combination of a perforating gun with an inflatable to complete multiple zones in a single trip

Abstract

A one trip system for perforating and fracking multiple intervals uses a releasable barrier. The barrier can be an inflatable. A pressure booster system is associated with the BHA so that the existing hydrostatic pressure is boosted when the gun or portions thereof are fired. After firing in one interval, the BHA is raised and the barrier is redeployed and the pattern repeats. Instruments allow sensing the conditions in the interval for optimal placement of the gun therein and for monitoring flow, pressure and formation conditions during the fracturing. Circulation between gun firings cleans up the hole. If run in on wireline a water saving tool can be associated with the BHA to rapidly position it where desired. A multitude of perforation charges mounted in the BHA can be selectively fired by selected corresponding detonator based on a predetermined sequence or surface telemetry command.

Claims

1. A well treatment method, comprising: providing a bottom hole assembly comprising a pressure boost device, a perforating gun having at least one explosive charge, and at least one selectively-actuatable borehole barrier for positioning in borehole near a well formation; wherein the pressure boost device is configured to generate a pulse of pressure and boost pressure in the perforating gun upon firing of the perforating gun; and wherein the borehole barrier upon actuation is configured to isolate a first portion of the borehole containing the perforating gun from a second portion of the borehole; isolating the first portion from the second portion of the borehole by actuating the borehole barrier; initiating the penetration of a well formation near the first portion of the borehole by discharging the explosive charge; and directing the pressure generated by the pressure boost device through the location at which the explosive charge was present and into the well formation; delivering treatment fluid to the formation.

2. The method of claim 1, wherein: putting said pressure boost device in fluid communication with the hydrostatic pressure around said gun.

3. The method of claim 1, wherein: providing spaced barriers as said at least one borehole barrier, with said gun between said spaced barriers.

4. The method of claim 3, wherein: putting said pressure boost device in fluid communication with the hydrostatic pressure between said spaced barriers.

5. The method of claim 1, wherein: providing an inlet to said gun for pressurized fluid from a remote location directed through said gun with said pulse.

6. The method of claim 1, wherein: resetting said at least one borehole barrier for repositioning in the borehole for additional firing of said gun at a different location.

7. The method of claim 1, wherein: supporting said gun and barrier are on a wireline for selective operation thereof.

8. The method of claim 1, further comprising: locating existing fractures in the borehole with at least one sensor; transmitting said existing fracture locations to a surface location; locating said gun in said borehole away from said existing fractures for refracturing.

Description

DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic view of a prior art perforating and fracturing method showing the gun run into hole bottom for initial perforation;

(2) FIG. 2 is the view of FIG. 1 with the guns fired;

(3) FIG. 3 is the view of FIG. 2 showing fracturing the first interval after the guns are fired;

(4) FIG. 4 is the view of FIG. 3 with another gun with a plug at its bottom being run in;

(5) FIG. 5 is the view of FIG. 4 showing the second gun being fired;

(6) FIG. 6 is the view of FIG. 5 showing fracturing after the second gun is fired;

(7) FIG. 7 is the view of FIG. 6 with a third gun with a plug below it being run in;

(8) FIG. 8 is the view of FIG. 7 with perforating after setting the plug;

(9) FIG. 9 is the view of FIG. 8 with the guns removed and tracking against the set plug;

(10) FIGS. 10-12 are the view of FIG. 9 showing the sequential milling of the previously set plugs so that the borehole is ready for production;

(11) FIG. 13 is the present invention showing the BHA at hole bottom;

(12) FIG. 14 is the view of FIG. 13 showing the combined pressuring up for perforation the initial time;

(13) FIG. 15 is the view of FIG. 14 showing the plug repositioned above the initial perforation;

(14) FIG. 16 is the view of FIG. 15 showing the plug set and the next interval pressured while perforated;

(15) FIG. 17 is the view of FIG. 16 with the barrier released;

(16) FIG. 18 is the view of FIG. 17 with the barrier repositioned uphole for perforating and fracturing at the same time;

(17) FIG. 19 is the view of FIG. 18 showing the perforating and fracturing of the next interval;

(18) FIG. 20 is the view of FIG. 19 showing the barrier released;

(19) FIG. 21 is the view of FIG. 20 with the barrier repositioned above the previously made fractures;

(20) FIG. 22 is the view of FIG. 21 showing perforating and fracturing the next interval with the barrier set;

(21) FIG. 23 is the view of FIG. 22 with the barrier removed from the borehole with the spent perforating gun; and

(22) FIGS. 24 and 24a are a schematic view of the pressure boost system associated with the gun and the control system for selective firing of portions of the gun as well as the inflatable barrier(s) and its connection to the pressure booster device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(23) FIG. 13 illustrates a borehole 36 with intervals 38, 40, 42 and 44 and a bottom hole assembly 46 that includes a resettable plug 48 and a multi-component gun 50 topped by a formation correlation tool 52 such as a logging tool and/or sensors for flow or pressure to be used during fracturing. Initially, the assembly 46 is run to near interval 38 at hole bottom 54. Plug 48 is not activated for the initial perforation of interval 38. The fracking fluid is spotted at the gun 50 that portion of the gun to be fired at interval 38 is pressurized with a booster system to be later described so that pressure is raised above hydrostatic in the gun 50 before the gun 50 is fired. Better fractures 56 are created from the combination of the pressurization from the booster system as the gun 50 is fired. In FIG. 15 the plug 48 which is preferably an inflatable, is released and moved uphole to just below interval 40. In FIG. 16 the plug 48 is set and the pressure is boosted as the gun 50 is fired to create fractures 56 from the high pressure and high flow rates that ensue when the gun 50 fires. The gun 50 is deflated in FIG. 17 and moved to just below interval 42 in FIG. 18. The gun 50 is inflated in FIG. 19 and again pressure is built up with the booster system and gun 50 is fired to create fractures 58 after which the plug 48 is released in FIG. 20 and repositioned next to interval 44 so the process above can be repeated to create fractures 60 after which the gun 50 and associated plug 48 are removed from the borehole, as shown in FIG. 23.

(24) FIGS. 24 and 24a show schematically the assembly 46 in more detail. The inflatable plug 48 is connected to the discharge line 64 from a pressure booster assembly 66. Assembly 66 can be a pump operated with power from a wireline that delivers assembly 46 or from a cable that extends through coiled tubing that delivers assembly 46. Igniter 68 is used to fire gun 50 resulting in a release of force from the shooting of the gun that is schematically illustrated by arrow 70. At the same time, the boosted hydrostatic pressure as a result of the use of booster 66 delivers a high pressure pulse combined with high flow rates from surface pumping through now opened passages through gun 50 as a result of its being fired as well as direct flow from the borehole into the perforations. This is represented by arrow 72. Arrows 74 schematically represent how the inflatable(s) 48 grows in diameter to seal off against the inside wall 76 of casing 78. Arrow 80 represents a communication/power cable that powers a controller 82 to determine what portions of the gun 50 are to be fired at each location. Items 84 and 86 represent instruments or logging tools that provide real time data at the surface of conditions close to the fracking location including such data as pressure, temperature and flow rate to give some examples. The gun 50 is configured to punch out back plates to allow the pressurized fracking fluid to rush into the perforating tunnels to intensify creation and propagation of fractures in the rock. The pressure booster of FIGS. 24 and 24a optionally in a separate scenario to be chosen not to be used. The fracking pressure would be provided from the surface and the well would be controlled by mud weight and therefore being over balanced to hold back fracked zones' reservoir producing pressures as the well is progressively fracked during the well fracking program.

(25) Those skilled in the art will appreciate that the assembly 46 can be run in on wireline and advanced with a tractor or with an articulated peripheral seal that allows a volume of fluid behind the seal to be pumped to advance the assembly 46 with a minimum of pumped fluid. In between firings of gun 50 when the assembly is delivered on coiled tubing, circulation can take place to clean up the borehole of residual proppant delivered as part of the fracturing operation. Other advantages of the method of the present invention are the one trip nature of the process that accomplishes isolation, perforation and fracturing of multiple intervals in a single trip. The plug is resettable so that no milling is necessary when all the intervals have been treated. The effectiveness of the fracturing is enhanced with pressure buildup into the gun as it is fired so that the high pressure fluid at high volumes can rush through the gun and into the perforations as they are made by the firing of the gun. If delivered on wireline the BHA can be positioned with minimal water consumption by using a peripheral articulated seal and pumping water behind it to reach a desired location. Logging tools with the assembly 46 allow pinpoint location of the gun 50 in a given interval based on real time data. This can be a very advantageous feature in re-fracturing applications. The assembly 46 can be delivered on coiled tubing with an interior cable for signal or power supply functions. The coiled tubing allows better control of the BHA in pushing and pulling maneuvers as compared to small outside diameter wirelines. Seismic sensors can be employed in the assembly 46 for monitoring of the fracking operation.

(26) The BHA contains multitude of charges and corresponding detonators selectively activated from the surface or following a pre-programmed operational sequence, therefore detonating simultaneously or in a prescribed sequence to take advantage of the operational efficiency benefits introduced by this invention. A charge or group of charges can be selectively detonated in the operational sequence at each fracking station isolated by the retractable pressure sealing packer for the combined perforation and fracking operation which can be done in sequence, simultaneously or overlapping in time soon after perforation is developed. Alternatively an upper sealing retractable packer could be deployed on top of the BHA allowing perforating and fracking in any sequence along the well or in different fracking events or BHA trips donwhole during the production life cycle of a fracked well possibly targeting a secondary well or a reservoir re-fracking stimulation. A pressure booster could pressurize the fracking fluid volume between the upper and lower retractable packers deployed with the BHA. This pressure booster could operate under telemetry control which could be wireline, pressure pulse, dropped or pumped down balls triggering a prescribed or pre-programmed operational sequence.

(27) Before the initial fracking of the well select the well zones to be isolated perforated and fracked applying this invention method using either or both cased well and open hole formation evaluation log analysis to determine well zones which are economically attractive with sufficient production potential after being fracked by this invention method. This well zone selection analysis is conducted optionally assisted and jointly interpreted with seismic data obtained either in the surface or borehole. The selected well zones to be fracked could be isolated with the lower upper and or lower retractable packers. The reservoir could be characterized by other deep measurements like borehole seismic and surface seismic, deep transient Electromagnetic (EM) survey (surface and borehole), and during the reservoir production phase after fracking program is completed gravity measurements (Surface and borehole gravity measurements).

(28) During well re-fracking operation targeted to stimulate production and either increase or restore secondary production levels identity and prioritize well fracked zones lacking production with potential for re-fracking of infill-fracking intervals between previously fracked well locations. Selection and prioritization of well zones for re-fracking based on cased hole production logging tool to determine the zones initially fracked which are producing below targeted levels and need to be re-fracked to re-stimulate and increase fracked well production.

(29) The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below: