AU5346900A

AU5346900A - Fiber optic monitoring of sand control equipment via tubing string

Info

Publication number: AU5346900A
Application number: AU53469/00A
Authority: AU
Inventors: Edward J Zisk Jr.
Original assignee: Baker Hughes Inc
Current assignee: Baker Hughes Holdings LLC
Priority date: 1999-08-17
Filing date: 2000-08-17
Publication date: 2001-02-22
Also published as: NO20004120D0; NO20004120L; GB0020233D0; CA2316131A1; GB2354782A

Description

P/00/01i1 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Fiber optic monitoring of sand control equipment via tubing string The following statement is a full description of this invention, including the best method of performing it known to me/us: Freehills Carter Smith BeadleMELC60037O269.9 FIBER OPTIC MONITORING OF SAND CONTROL EQUIPMENT BACKGROUND OF THE INVENTION Field of the Invention The invention relates to the oil production industry. More particularly the •0 invention relates to monitoring and optimizing operation of sand control equipment in production oil wells.

Prior Art Hydrocarbon fluids are produced from underground reservoirs that are generally composed of such hydrocarbons, sand, gravel, clay, silt, bedrock, etc. Upon 10 pumping hydrocarbon fluids from these wells, particulate matter present in the 0 reservoir such as particulates of that material noted may be produced along with the target fluid. This is particularly a problem with respect to oil production.

o To control the production of particulate matter, which damages equipment both in the subsurface environment and at the surface, a sub industry has developed, generally known as "sand control". The sand control sub industry employs many tools in the downhole environment which trap the particulate matter much the way a filter does. Sand control equipment reduces the amount of produced particulate matter, reduces damage to the production equipment and alleviates the job of separating the particulate matter from desired products in the produced fluids. In order for sand 2C control equipment to filter the most solids, the equipment needs to be installed properly and then to continually and over time run efficiently; it must remain optimized. Optimization of sand control equipment has traditionally been a question of engineering before installation such that the equipment will perform as expected.

Since the downhole environment is never a certainty however, it could not heretofore be clearly determined that the equipment set properly. Moreover, monitoring of the condition of sand control equipment over time has been problematic. Thus, the art is in need of a method and apparatus capable of confirming setting of the sand control equipment and monitoring its performance and condition in an ongoing manner.

SUMMARY OF THE INVENTION The present invention comprises a method and apparatus of actively monitoring the installation, integrity, and performance of sand control equipment in a production well. The method and apparatus of the invention enhance the ability of an •oil production crew to control unwanted fines that may occur during production. The 'instrument comprises optical fiber that is integral with, or attached to the inside or outside surfaces of the sand control equipment. The optical fiber, or fibers, with or without integrated sensors, are employed to monitor key parameters during the installation process to precisely locate the equipment in the well, monitor all aspects of the installation/completion process, including but not limited to the addition of aggregate, and then monitoring the integrity and performance of the operational assembly. Typical parameters to be monitored include, but are not limited to chemical species, vibration, acoustic recognition of an event, pressure, temperature, strain, density, and vibration. An embodiment of the instrument is comprises an optical fiber or fibers attached on the circumference of the sand control equipment in a configuration or pattern determined by the measurement point density required.

Additional optical fiber is then attached to the equipment during the installation of the equipment into the well. The optical fiber assembly can comprise bare optical fiber, or fibers, with or without a variety of coatings and buffers, or optical fiber(s) contained in a cable or tubular steel which may or may not be hermetically sealed depending upon desired longevity and performance of the optic fiber. The optical fiber assembly can be protected by installing the fiber in channels in the equipment or by the equipment having protuberances to keep the fiber(s) from rubbing the wall of the well during running. The optical fiber assembly is connected to a fiber optic sensing demodulator either at the surface, the wellhead (surface or subsea) or downhole.

During installation, the exact depth of the sand control equipment can be determined by monitoring the length of the optical fiber from a known point to a discrete optical signature within the fiber, that signature being located in a section of fiber mounted to the downhole equipment. As one of skill in the art is aware, a confident knowledge of location of a downhole tool is both elusive and invaluable.

This feature of the invention is therefore of great benefit to the art.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic elevation view of a wellbore having completion and •sand control equipment installed therein, said sand control equipment having the optical fiber system of the invention integrated therein; .Figure 2 is an enlarged view of a portion of Figure 1 which illustrates optic fibers wrapped around the sand control equipment; Figure 3 is a view of an alternate wrapping pattern of the invention; "Figure 4 is another alternate embodiment of the invention; Figure 5 is yet another alternate embodiment of the invention; Figure 6 is a perspective schematic view showing one arrangement for S protecting the optic fibers employed in the invention; Figure 7 is a perspective view showing an alternative arrangement for protecting the optic fibers employed in the invention; and Figure 8 is a perspective view showing another alternate arrangement for protecting the optic fibers employed in the invention.

DETAILED DESCRIPTION OF THE INVENTION It is important to note that one or more fibers are employable in the inventin which may be arranged in one or more of the configurations discussed hereunder without departing from the scope of the invention.

Referring to Figure 1, one of ordinary skill in the art will recognize the depiction of a wellbore 10 and installed equipment therein. The equipment includes packers 12 and sand control devices 14 which may be of the added aggregate type or the no-added-aggregate type without affecting the function or components of the invention. Optical fibers 16 are also visible in Figure 1. In order to appreciate the pattern of optical fibers in Figure 1 reference is made to Figure 2 wherein the wrapped fiber 16 is more easily appreciated. The density of the wrapped fiber 16 is dependent upon the measurement resolution required and spacial resolution of the fiber optic demodulator used in the invention. The equipment at issue is a fiber optic sensing demodulator 18 (Figure 1) which is illustrated at the well head or the surface but which could be placed in an alternate location downhole, may, for example, require one meter of fiber to resolve a condition. In this case, the wrapping pattern must place one meter of the fiber in each area to be monitored. This may require that the fiber be densely wrapped or may allow a less dense wrap depending upon what is to be monitored. Likewise, a demodulator with higher resolution capacity might need only .25 meters in each location being monitored.

Also visible in Figure 2 is sand control equipment segment 14 joint area where segments of sand control equipment are joined. Preferably in connection with the invention, the fiber 16 may be continuous or optically connected by a connector (not shown) over this joint area 20. Either method is acceptable and is dictated by circumstances rather than by function. One of ordinary skill in the art is equipped to determine which method is best for this particular application.

Referring now to Figure 3, a very dense fiber optic pattern is illustrated which allows for monitoring of small locations on sand control equipment 14. The pattern employs both a zig zag pattern and a longitudinal array of fiber 16. This may be the same fiber or different fibers. The embodiments of Figures 4 and 5 also provide varying density of monitoring, varying cost and complexity. Figure 4 provides a longitudinally back and forth pattern of fiber 16 while Figure 5 merely employs fiber 16 in a conduit 22 at 0 and 180 degrees around the circumference of sand control equipment 14.

Referring to Figures 6-8, it is important to note three alternative embodiments to protect the fiber during monitoring. Specifically referring to Figure 6 first, sand control equipment 14 is provided with a groove 24 spiraling along the outside surface thereof as shown. It should be noted however that the groove could be located parallel to the longitudinal axis of equipment 14 or in another pattern if desired. The groove 24 is preferably of dimensions at least slightly larger than the optical fiber to be used so that said fiber will be completely enveloped within the groove and therefore be protected from impact or abrasion during monitoring. In this embodiment the reduction capability of the demodulator to be employed must be known so that the groove 24 is at an appropriate spacing to render the system effective. In another embodiment, referring to Figure 7, a plurality of raised portions (protuberances) 26 are extending from an outer surface of sand control equipment 14. The arrangement provides additional flexibility since the fiber 16 may be laid around the circumference of the equipment 14 in whatever density it is needed. Many different density levels are possible with the embodiment of Figure 7 while maintaining a protective environment for fiber 16. A third protective environment for fiber 16 is illustrated in Figure 8. In this embodiment the fiber 16 is actually housed within the sand control equipment 14 in a conduit 28. Conduit 28 need only be large enough to house fiber 16 without deforming the same. The conduit may be in any desired configuration including but not limited to straight or spiraled.

In operation, the invention effectively and actively monitors the installation of o ***sand control equipment, its integrity over time and the performance of that equipment.

During installation, an exact depth of the sand control equipment is obtainable using a discrete optical signature in the fiber at the location of the downhole equipment and the length of the fiber optic cable that has entered the wellbore. In order to maintain the integrity of the installation and performance thereof, parameters such as chemical species present, vibration, acoustic recognition, pressure, temperature, strain, and density may be queried by the optical demodulator 18 through fiber 16 directly or through integrated sensors. If done directly, monitoring may take place through monitoring point or distributed measurand along the equipment directly through the fiber itself using for example microbending (pressure) Raman Backscatter and optical time domain reflectometry (temperature). Examples of integrated sensor used include interferometry (all parameters) grating, (all parameters) florescence (mostly chemical species, viscosity and temperature) and photoelasticity (temperature, acceleration, vibration and rotational position). From the various measurements, progress and quality of the sand control process can be monitored. The system also provides a real time check on the sand control equipment and will alert surface personnel to problems before damage is done.

It should be noted that the optical fiber 16 can be outside the sand equipment as shown in figure 6 or inside as shown in Figure 8 or can be in a separate tool (not shown) deliverable to the sand control equipment through the tubing. In any of these embodiments all of the parameters noted can be sensed and immediate knowledge of the conditions downhole are known at the surface. Fiber could be secured to the equipment in such a way to allow the flow field of the sand and carrier fluid to induce mechanical loads, dynamic and/or static, on the fiber. Example: A turbulent flow of "fluid would cause a loosely mounted fiber to vibrate. When the flow stops, static sand °.present, the fiber becomes stationary. Monitoring of the fibers movement/or force applied can be used to determine where sand is present. This is useful to determine progress of alpha and beta waves.

While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present .**invention has been described by way of illustration and not limitation.

It will be understood that the term "comprises" or its grammatical variants as used herein is equivalent to the term "includes" and is not to be taken as excluding the presence of other elements or features.