Field weldable connections

P-0001[0001] This application is a continuation-in-part of U.S. application Ser. No. 09/970,353 filed Oct. 3, 2001.

FIELD OF THE INVENTION

P-0002[0002] The subject matter of the present invention relates to communication lines. More specifically, the subject matter of the present invention relates to an apparatus and method of protecting and sealing spliced communication lines.

BACKGROUND OF THE INVENTION

P-0003[0003] Communication lines are used in a wide range of applications in the oilfield industry. The communication lines transmit monitored data regarding downhole conditions such as temperature and pressure to surface instrumentation. The communication lines can also be used to send information down the well from the surface. Additionally, communication lines may also be used to electrically power downhole equipment. Communication lines may include electrical conduits, optical fibers, and other methods for data or power transmission.

P-0004[0004] In environments such as those encountered in downhole wells, the communication lines are exposed to hostile conditions such as elevated temperatures and pressures. To protect the fragile communication lines from the hostile conditions, the communication lines are generally carried within protective tubing that provides an environmental seal. Problems arise when the seal must be broken during assembly, installation and/or repair of the communication line. For example, in downhole applications, in order for the communication line to be fed through production equipment such as packers, the line must be cut and then spliced with the downstream line. Thus, after splicing, the communication line must once again be sealed from the harsh environment.

P-0005[0005] There exists, therefore, a need for an apparatus and method of splicing communication lines that provides structural integrity and protects the communication line from the surrounding environment.

SUMMARY OF THE INVENTION

P-0006[0006] An embodiment of the present invention provides a downhole connector assembly for sealingly attaching a first and a second segment of a control line. The control line has an outer housing that encapsulates a polymeric secondary housing having a communication line therein. The connector assembly comprises at least one weld coupling welded to the outer housing of the first and second segment of the control line. At least one reflective sleeve replaces at least a portion of the secondary housing such that the reflective sleeve is located between the communication line and the welds of the weld coupling.

BRIEF DESCRIPTION OF THE DRAWINGS

P-0007[0007]FIG. 1 is a sketch of a communication cable.

P-0008[0008]FIG. 2 is a sketch of a section of cable that has been prepared for splicing.

P-0009[0009]FIG. 3 is a sketch of the welded splice assembly.

P-0010[0010]FIG. 4 is a sketch of another embodiment of the welded splice assembly having a pressure housing.

P-0011[0011]FIG. 5 is a sketch of another embodiment of the welded splice assembly having a gel or epoxy material within the pressure housing.

P-0012[0012]FIG. 6 is a sketch of another embodiment of the welded splice assembly having a plurality of weld couplings.

P-0013[0013]FIG. 7 is a sketch of another embodiment of the welded splice assembly having a plurality of weld couplings and a pressure housing.

P-0014[0014]FIG. 8 is a sketch of another embodiment of the welded splice assembly.

P-0015[0015]FIG. 9 is a sketch of another embodiment of the welded splice assembly having a plurality of weld couplings.

P-0016[0016]FIG. 10 is a sketch of another embodiment of the welded splice assembly attached to a tool.

P-0017[0017]FIG. 11 is a sketch of a wellbore completion including a spliced communication line.

P-0018[0018]FIG. 12 provides a sketch of the welded splice assembly used for a hydraulic or fluid conduit.

P-0019[0019]FIG. 13 provides a sketch of another embodiment of the welded splice assembly of the present invention having a reflective shield.

P-0020[0020]FIG. 14 provides a sketch illustrating another embodiment of the welded splice assembly of the present invention.

P-0021[0021]FIG. 15 provides a sketch of yet another embodiment of the welded splice assembly of the present invention.

P-0022[0022]FIG. 16 provides a sketch of still another embodiment of the welded splice assembly of the present invention.

P-0023[0023]FIG. 17 provides a sketch of still another embodiment of the welded splice assembly of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

P-0024[0024] In the following detailed description of the subject matter of the present invention, the apparatus and method of splicing communication lines is principally described with reference to downhole well applications. Such description is intended for illustration purposes only and is not intended to limit the scope of the present invention. In addition to downhole well applications, the present invention can be used with any number of applications such as pipeline monitoring, subsea well monitoring, and data transmission, for example. Furthermore, the communication lines may comprise electrical wiring, which may facilitate transfer of information, power, or both. All such types of communication line splicing are intended to fall within the purview of the present invention. However, for purposes of illustration, the present invention will be principally described as being used in downhole well applications. Further as used herein, the term communication line shall refer to those lines comprising electrical lines or fiber optic lines, as well as lines including combinations thereof or combinations with other types of lines.

P-0025[0025]FIG. 1 provides a sketch of a typical cable <b>1</b> useful in the present invention. The cable <b>1</b> comprises an outer housing <b>5</b>, a secondary housing <b>10</b>, and one or more communication lines <b>15</b>. The outer housing <b>5</b> provides the structural integrity for the cable <b>1</b> and protects the communication lines <b>15</b> from the surrounding environment. Further, the outer housing <b>5</b> provides structural protection for the communication lines <b>15</b> from damage caused by the cable <b>1</b> impacting, or being impacted by, nearby tools and equipment. In one embodiment, the outer housing <b>5</b> is comprised of a metallic material such as steel, or other metallic alloys, for example. The secondary housing <b>10</b> resides within the outer housing <b>5</b> and provides protection for the communication lines <b>15</b> contained within. In one embodiment, shown in FIG. 1, the secondary housing <b>10</b> is made from a polymeric material.

P-0026[0026]FIG. 2 provides a sketch of a segment of cable that has been prepared for splicing. The cable <b>1</b> has been cut so that the communication line <b>15</b> extends longitudinally beyond the outer housing <b>5</b> and the secondary housing <b>10</b>. Afterwards, a portion of the secondary housing <b>10</b> is removed in order to create a void <b>20</b>, which is defined by the outer housing <b>5</b> and the secondary housing <b>10</b>.

P-0027[0027]FIG. 3 provides a sketch illustrating the communication line splice of the present invention. In FIG. 3, the two communication lines being spliced are designated <b>15</b><i>a </i>and <b>15</b><i>b</i>. Once the cables <b>1</b><i>a</i>, <b>1</b><i>b </i>have been prepared for splicing, thermal insulators <b>25</b><i>a</i>, <b>25</b><i>b </i>are inserted into the void <b>20</b> (shown in FIG. 2) so that the insulators <b>25</b><i>a</i>, <b>25</b><i>b </i>lie between the outer housing <b>5</b> and the communication lines <b>15</b><i>a</i>, <b>25</b><i>b</i>. The insulators <b>25</b><i>a</i>, <b>25</b><i>b </i>protect the communication lines <b>15</b><i>a</i>, <b>15</b><i>b </i>from the heat of the welding. Additionally, the insulators <b>25</b><i>a</i>, <b>25</b><i>b </i>prevent the secondary housing from melting and outgassing, which can result in poor weld quality. Prior to splicing, a weld coupling <b>35</b> is slid over one of the cables <b>1</b><i>a</i>, <b>1</b><i>b</i>. The cleaved communication lines <b>15</b><i>a</i>, <b>15</b><i>b </i>are then spliced together by conventional techniques, such that the communication lines <b>15</b><i>a</i>, <b>15</b><i>b </i>are operatively connected at the splice <b>30</b>. The weld coupling <b>35</b> is then slid to cover the ends of both cables <b>1</b><i>a</i>, <b>1</b><i>b</i>, and the weld coupling <b>35</b> is secured in place by welds <b>40</b>. In one embodiment the welds <b>40</b> are formed using an orbital welder. Once welded, the weld coupling <b>35</b> protects the splice <b>30</b> from corrosion, erosion, and physical damage resulting from environmental and operational conditions. Additional protection is provided against hydrocarbon darkening resulting from contact with conductive fluid.

P-0028[0028]FIG. 4 provides a sketch of another embodiment of the weld assembly. In this embodiment, a pressure housing <b>45</b> fits over the weld coupling <b>35</b>. The pressure housing <b>45</b> is slid over the same cable <b>1</b><i>a</i>, <b>1</b><i>b </i>as the weld coupling <b>35</b>, but is slid prior to the sliding of the weld coupling <b>35</b>. After splicing and after the weld coupling <b>35</b> is secured in place, the pressure housing <b>45</b> is attached to the cables <b>1</b><i>a</i>, <b>1</b><i>b </i>such that the weld coupling <b>35</b> is isolated from environmental conditions. For example the housing may be attached by welding, ferrules, or elastomeric seals, among other means. A port <b>50</b>, located in the pressure housing <b>45</b> enables pressure testing of the welded assembly.

P-0029[0029]FIG. 5 provides a sketch of another embodiment of the weld assembly. In this embodiment a gel or epoxy material is pumped through the port into a cavity <b>52</b> defined by the pressure housing <b>45</b>, the cables <b>1</b><i>a</i>, <b>1</b><i>b</i>, and the weld coupling <b>35</b>. This fluid is used for pressure testing. The fluid is pumped into the cavity <b>52</b> at a high pressure, and the welded splice assembly is monitored for signs of failure. After pumping, the port <b>50</b> is plugged to seal in the viscous fluid. When the spliced section of cable is installed downhole, the viscous fluid cures and hardens due to the high downhole temperatures. The cured material thus provides additional protection for the splice <b>30</b> against erosion, corrosion, and other environmental conditions.

P-0030[0030]FIG. 6 provides a sketch of another embodiment of the weld assembly having a plurality of weld couplings <b>35</b><i>a</i>, <b>35</b><i>b</i>. The embodiment shown in FIG. 6 shows two couplings, but any number can be used and remain within the purview of the invention. The first weld coupling <b>35</b><i>a </i>is slid over the first cable <b>1</b><i>a </i>and the second weld coupling <b>35</b><i>b </i>is slid over the second cable <b>1</b><i>b</i>. An additional thermal insulator <b>25</b><i>c </i>is inserted to protect the splice <b>30</b> at the housing junction <b>55</b>. After the cables <b>1</b><i>a</i>, <b>1</b><i>b </i>are spliced, the first weld coupling <b>35</b><i>a </i>is welded to the first cable <b>1</b><i>a </i>and the second weld coupling <b>35</b><i>b </i>is welded to the second cable <b>1</b><i>b</i>. The first weld coupling <b>35</b><i>a </i>is then welded to the second weld coupling <b>35</b><i>b </i>at the housing junction <b>55</b>, thereby enclosing the splice <b>30</b>. In this manner, both welds near the secondary housing <b>10</b> are formed prior to the weld couplings <b>35</b><i>a</i>, <b>35</b><i>b </i>being sealed to the surrounding environment. Thus, any resulting outgassing of the secondary housing <b>10</b> is able to escape to the environment and does not affect the weld quality.

P-0031[0031]FIG. 7 provides a sketch of another embodiment of the weld assembly. In this embodiment, the pressure housing <b>45</b> protects the two weld couplings <b>35</b><i>a</i>, <b>35</b><i>b </i>against erosion and other damaging environmental conditions. The pressure housing <b>45</b>, through its port <b>50</b>, enables testing of the welded connections with a standard fluid for pressure testing, such as hydraulic oil, or by a different viscous fluid, such as a gel or epoxy material.

P-0032[0032]FIG. 8 provides a sketch of another embodiment of the pressure housing <b>45</b>. In this embodiment, the pressure housing <b>45</b> is attached to the cables <b>1</b><i>a</i>, <b>1</b><i>b </i>by means of fittings <b>60</b><i>a</i>, <b>60</b><i>b</i>. The first fitting <b>60</b><i>a </i>and the pressure housing <b>45</b> are slid over the first cable <b>1</b><i>a</i>. The second fitting <b>60</b><i>b </i>is slid over the second cable <b>1</b><i>b</i>. After splicing, the fittings <b>60</b><i>a</i>, <b>60</b><i>b </i>and the pressure housing <b>45</b> are positioned such that the weld coupling <b>35</b> is contained within the pressure housing <b>45</b>. The fittings <b>60</b><i>a</i>, <b>60</b><i>b </i>are then tightened, thereby sealing the welded connections inside the pressure housing <b>45</b>. The fittings <b>60</b><i>a</i>, <b>60</b><i>b </i>in this embodiment seal to the cables <b>1</b><i>a</i>, <b>1</b><i>b </i>through a dual ferrule systems <b>65</b><i>a</i>, <b>65</b><i>b</i>. The fittings <b>60</b><i>a</i>, <b>60</b><i>b </i>seal onto the pressure housing <b>45</b> by means of an elastomeric seals <b>70</b><i>a</i>, <b>70</b><i>b</i>. These sealing mechanisms <b>65</b><i>a</i>, <b>65</b><i>b</i>, <b>70</b><i>a</i>, <b>70</b><i>b </i>are not the only means by which the seals can be made. All mechanisms by which one could sealingly join the pressure housing <b>45</b> and the cables <b>1</b><i>a</i>, <b>1</b><i>b </i>are intended to fall within the purview of the present invention.

P-0033[0033]FIG. 9 provides a sketch of another embodiment of the splice assembly. In this embodiment, the fittings <b>60</b><i>a</i>, <b>60</b><i>b </i>are connected to pressure housing <b>45</b> by means of a sealing pipe threads <b>62</b><i>b</i>, <b>62</b><i>c</i>. A removable port <b>75</b> is used to pressure test the welded splice assembly.

P-0034[0034]FIG. 10 provides a sketch of another embodiment of the splice assembly. In this embodiment, communication line <b>15</b> is spliced to a downhole tool <b>80</b>. The weld coupling <b>35</b> is welded to the outer housing <b>5</b> on one side and a section of the tool <b>80</b> on the opposite side.

P-0035[0035]FIG. 11 provides a sketch of a wellbore completion including a spliced communication line. The cable <b>1</b> is installed downhole to communicate with or power a piece of downhole equipment <b>85</b>. The equipment <b>85</b> may be controlled by a controller located at the surface.

P-0036[0036]FIG. 12 provides a sketch of the welded splice assembly used for a hydraulic or fluid conduit. In FIG. 12, a weld coupling <b>35</b> is secured over the spliced hydraulic or fluid conduits <b>100</b><i>a</i>,<b>100</b><i>b </i>by welds <b>40</b>. Once welded, the resulting spliced hydraulic or fluid line can be pressure tested prior to placement downhole.

P-0037[0037] Another embodiment of the welded splice assembly of the present invention is described with reference to FIG. 13 that provides a partial sketch of a segment of cable <b>1</b> that has been prepared for splicing. In this embodiment, a small reflective sleeve <b>110</b> is inserted into the void <b>20</b> between the communication line <b>15</b> and the outer housing <b>5</b>. The reflective sleeve <b>110</b> can be comprised of material such as aluminum or steel, or can be coated with a reflective material.

P-0038[0038] The reflective sleeve <b>110</b> and the communication line <b>15</b> are centered inside the outer housing <b>5</b> with the use of centralizers <b>112</b>. By using the centralizers <b>112</b>, a substantially uniform air gap <b>114</b> is created that provides insulation around the communication line <b>15</b>. The centralizers <b>112</b> are preferably made of a non-electrically conductive material that does not out-gas when exposed to high temperatures. An appropriate material for use as the centralizers <b>112</b> is PEEK, for example.

P-0039[0039] The communication line <b>15</b> is spliced and the weld coupling <b>35</b> is welded to the outer housing <b>5</b> of the cable <b>1</b> using a welding electrode <b>42</b>, as described with previous embodiments. As discussed above, the weld coupling <b>35</b> protects the splice from corrosion, erosion, and physical damage resulting from environmental and operational conditions.

P-0040[0040] During the welding process, the reflective sleeve <b>110</b> protects the insulation <b>16</b> and conductor <b>17</b> of the communication line <b>15</b> from the heat of the welding. For example, in the case of optical communication lines, the optical fibers are protected. Additionally, at extreme temperatures, the reflective sleeve <b>110</b> protects the insulation <b>16</b> of the communication line <b>15</b> from thermal radiation, which can be the primary means of heat transfer at extreme high temperatures.

P-0041[0041] A pressure housing, as detailed in earlier described embodiments (e.g., FIGS. 4, 5, <b>7</b>, <b>8</b>, and <b>9</b>) can be provided for pressure testing the splice assembly and for isolating the weld coupling from environmental conditions.

P-0042[0042]FIG. 14 provides an illustrative sketch of an embodiment of the welded splice assembly of the present invention that provides a method adapted to protect the welded splice assembly against problems associated with having air trapped within the weld coupling <b>35</b>. As discussed above, after the splice <b>30</b> is made, the weld coupling <b>35</b> is slid over the connection and welded to the outer housing <b>5</b> of the cable <b>1</b>. During the welding of the first end of the weld coupling <b>35</b>, the opposite end of the weld coupling <b>35</b> is open and thus provides a means for equalization of air pressures. However, during the welding of the second end of the weld coupling <b>35</b>, problems associated with trapped air can arise. For example, as the electrode <b>42</b> moves into the last part of the cross-section of the weld coupling <b>35</b> and attempts to trap the air, the expansion of the air caused by the continuous addition of heat can cause a hole to be formed in the weld pool.

P-0043[0043] As shown in FIG. 14, a grinding or honing wheel <b>116</b> is provided to uniformly remove material off of the surface of the outer housing <b>5</b> of the cable <b>1</b>. The resulting cable <b>1</b> has a circular cross-section in which the outer housing <b>5</b> has a substantially uniform outside diameter. Thus, a tighter fit with a smaller inner diameter weld coupling <b>35</b> can be achieved. By having very close contact between the two welded surfaces, the expansion of air through the last part of the weld pool can be prevented.

P-0044[0044]FIG. 15 provides an illustrative sketch of another embodiment of the welded splice assembly of the present invention adapted to protect the welded splice assembly against problems associated with having air trapped within the weld coupling <b>35</b>. In this embodiment, after welding the first end of the weld coupling <b>35</b> to the outer housing <b>5</b> of the first cable la with a fillet weld <b>40</b>, the second end of the weld coupling <b>35</b> is welded to the outer housing <b>5</b><i>b </i>of the second cable <b>1</b><i>b </i>with a butt weld <b>44</b>.

P-0045[0045] At the butt weld <b>44</b>, the two faces of the weld <b>44</b> can have a very tight fit. Provided the weld penetration is not too deep, the molten weld pool can be prevented from contacting the expanding air and causing a defect. The butt weld <b>44</b> can be performed using facing tools that are commonly used for butt welding hydraulic tubing but specially adapted to accommodate and protect the communication line <b>15</b> during the metal removal operation.

P-0046[0046]FIG. 16 provides an illustration of another embodiment of the welded splice assembly of the present invention adapted to protect the welded splice assembly against problems associated with having air trapped within the weld coupling <b>35</b>. In this embodiment, compression fittings such as ferrules <b>118</b> are used on the end of the weld coupling <b>35</b>. The ferrules <b>118</b> can be of the type used to create metal-metal seals on small diameter tubing, for example.

P-0047[0047] The ferrules <b>118</b> are swaged onto the end of the weld coupling <b>35</b>, creating a metal-metal seal between the weld coupling <b>35</b> and the ferrules <b>118</b> and between the ferrules <b>118</b> and the outer housing <b>5</b> of the cable <b>1</b>. The swaging nut <b>120</b> is built split to be removable from the cable <b>1</b> after swaging. Provided the weld electrode is properly positioned, the entrapped air is isolated from the weld pool <b>122</b> by the metal-metal seal, preventing the forming of defects. As before, only the second end of the weld coupling <b>35</b> needs to use the ferrules prior to welding.

P-0048[0048]FIG. 17 provides an illustrative sketch of yet another embodiment of the welded splice assembly of the present invention adapted to protect the welded splice assembly against problems associated with having air trapped within the weld coupling <b>35</b>. In this embodiment, a two-piece weld coupling <b>35</b> is used. The two ends of the two-piece weld coupling <b>35</b> are first welded to the cables <b>1</b><i>a</i>, <b>1</b><i>b </i>with fillet welds <b>40</b>. Because the other end of each half of the two-piece weld coupling <b>35</b> is open, no air entrapment occurs during application of the fillet welds <b>40</b>.

P-0049[0049] The two halves of the weld coupling <b>35</b> are then welded together using a butt weld <b>44</b>. The two faces of the halves of the two-piece weld coupling <b>35</b> have the required finish and geometry to prevent air escape during the welding process. The weld penetration is selected to be less than full to prevent the weld pool <b>122</b> from coming in contact with the expanding air. The wall of the weld coupling <b>35</b> and the resultant penetration are designed so that the resultant assembly has the required collapse strength.

P-0050[0050] It should be noted that the above embodiments described with reference to FIGS. 14 through 17 can be used to advantage with any of the earlier described embodiments of the welded splice assembly. The methods and apparatus used to protect against problems associated with having air trapped within the weld coupling <b>35</b> can be used to advantage in embodiments employing thermal insulators or reflective sleeves.

P-0051[0051] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such are intended to be included within the scope of the following non-limiting claims: