In the pre-Macondo blowout era the offshore industry had an impressive record of safety, especially considering the complexity and magnitude of the work being done in relatively harsh conditions. The failures and spillages of Macondo have indicated that there are a number of safety areas which have not received appropriate progress in large part because history had not experienced a major failure of a BOP stack at that depth of water. This paper addresses several areas of technology which can be implemented to increase safety on new deepwater drilling BOP systems or retrofitted on current BOP systems in the field. These safety areas include better use of accumulator capacity, greater control over BOP stack functions, more redundancy of control, and improved ability to shear wellbore components. The ready availability of these safety upgrades and methods for full BOP Subsea operation and control, high volume ROV operations, and shearing drilling collars represent significant upgrades to Subsea drilling equipment safety systems post Macondo. Depth Compensated Accumulators Depth compensated accumulators represent a major safety improvement post-Macondo, although they were already seeing market acceptance before Macondo. The problem with accumulators on Subsea stacks is that more than 100 accumulator bottles would be needed instead of approximately seven for the depth compensated version1. Additionally, the depth compensated accumulators can be retrofitted on the ocean bottom by using multiple frictionless controls, also a major safety upgrade presented later in this paper. The basic concept as seen in figure 1 is that a dumbbell piston has pressurized nitrogen in the top chamber and working fluid immediately below in a second chamber. The second chamber is divided from the third chamber by a central, stationary bulkhead. The third chamber is pressurized with environmental pressure, typically through an intermediate fluid for corrosion reasons. The fourth lower chamber is basically empty or a vacuum. This means that the pressure in the third chamber is not supported from below, but rather is mechanically added to the pressure in the second chamber. This means that at any depth, the pressure in the second working chamber exceeds environmental pressure by the amount of the nitrogen charge. Increased safety impacts of depth compensating accumulators are:High nitrogen (or helium) pressures associated with conventional accumulators in deepwater situations are not required. As the piston area in chamber 2 is slightly less than the area in chamber 1, the nitrogen pressure never exceeds the working fluid pressure.Complex calculations are eliminated, the accumulators are simply run and operate subsea similarly as they operate on the surface.When the accumulator comes to the surface, dumping the nitrogen in the accumulators is not required.When the accumulator is re-run, the nitrogen does not have to be recharged,There is no danger that only some of the nitrogen banks have been recharged, but not all of them.

A presentation of the analysis, testing, and development of the ability to do extended reach pipeline blockage remediation. Results of scale model testing, full scale testing, technical surveys, and computer analysis of coiled tubing perfonnance as an extended reach transportation means is included. A discussion of an invitation and requirements for DeepStar funding in a pipeline test loop is included. DEFINITIONSDeepStar: An industry wide cooperative effort to develop economically viable, low risk methods to produce hydrocarbons from deepwater tracts in the Gulf of Mexico.

Development of the ability to do extended reach pipeline blockage remediation. Results of full scale testing in a pipeline designed to have the degree of difficulty of a 5 mile subsea pipeline are included. Also, a discussion of the extended reach impact of viscous friction drag on coiled tubing is included. Vendors who have succeeded in passing the DeepStar test requirements are indicated along with possible extensions of this technology to longer distances than 5 miles. Definitions DeepStar: An industry wide cooperative effort to develop economically viable, low risk methods to produce hydrocarbons from deepwater tracts in the Gulf of Mexico. DeepStar 3202: A committee formed to further the technology of pipeline blockage remediation. Differential Pig: a tool in the bore of the pipeline which has a pressure differential across it for the purpose of generating an axial force on an internal work string (coiled tubing) Degree of Difficulty: A term used within the paper to try to compare different styles of pipeline construction on an objective basis. Extended reach: For the purpose of this program, a nominal 5 mile distance into a pipeline Nominal 5 mile pipeline: An idealized pipeline which generally reflects the averaged degree of difficulty of typical Gulf of Mexico pipelines of 5 mile length. Vendor: a company that volunteered to take part in this project by offering "long offset blockage removal tooling" for testing in the simulated 5 mile test loop. Simulated 5 Mile Test Loop: A short test loop fabricated to be as difficult to traverse as a typical 5 mile subsea pipeline. (See fig. 2) Skate: A non-powered wheeled means which is attached to a coiled tubing string to assist in extended reach remediation. Overview Of major concern, to an Oil Operator embarking on a long offset subsea production development, is the possibility of encountering a subsea pipeline blockage, due to wax or hydrates problems. Very often, such blockages are inaccessible to either chemical or mechanical removal and therefore necessitate removal of section of pipeline, or indeed, pipeline abandonment. DeepStar has provided for testing of coiled tubing technologies and extended reach concepts with the objective of extending the reach of coiled tubing blockage removal techniques from approximately 1 mile to 5 miles. Current technology limits the extended reach to the range of 1 to 1½ miles. The primary means to achieve the goals of the DeepStar CTR 3202 program is to build a 900' long 6 5/8" pipeline which can be reasonably said to simulate a 5 mile nominal subsea pipeline in degree of difficulty; and then do comparative testing in that pipeline. When a Vendor can navigate the standardized test pipeline and remove a standardized wax blockage under standardized test conditions, the Vendor will be reported to the oil companies supporting DeepStar as having extended reach remediation capability. Steps in the Program In order to identify and move the state of the art forward in extended reach pipeline blockage remediation, several steps were undertaken in this program.

Summary This paper discusses the theories of repair sealants on ball valves andtesting done on various sealants to determine their basic characteristics. Preliminary penetration, chemical, and flow testing results are presented, along with a discussion of field problems. Introduction The use and application of sealants to ball valves (Fig. 1), both on landand offshore, is critical to their long-term operation and reliability. Inspite of this critical need, little formal testing has been done, documented, and distributed to the industry on this subject. This paper reflects a firststep on behalf of several companies to develop technology to supportstandardized guidelines for the specification and use of these products. Example of a Failed Field Application Fig. 2 shows the seat ring pulled in a 24-in. ANSI 600 ball valve operatedat 500 to 600 psi on dry gas in the Far East. The pipeline was similiar to 500miles long, with 220 miles offshore and 280 miles onshore. Roughly 300 valves(12 through 30 in.) were used in this project. As Fig. 2 shows, the sealantmaterial is so caked and hard that it completely bridged the seat ring (see the Glossary for definitions of terms). It literally supported the seat ring offthe ball in the valve. The leakage past this seat would be so prolific that anobserver would have questioned whether the valve was closed. In this particularcase, the line could not be closed off to allow the insertion of a pig in thepig trap. Fig. 3 shows what the seat ring looked like after it was removed andcleaned. Immediately inside the dark band is a small face groove that allowsdistribution of the sealant around the face of the seat. Small holes aredrilled in the interface groove to intersect a second small outer groove, whichcommunicates with the external sealant injection fittings. The sealant flowsthrough the sealant injection fittings, into the outer groove, through thesmall holes, into the face groove, and around the seat/ball interface. (Thedifficulties of flowing along this path are discussed later.) Fig. 4 shows atest laboratory report on a sample of the sealant material returned to Houston. The material was an asphaltic material that resembled tar. It dissolved inmineral spirits and completely melted at 150 to 175 degrees F. Thus, if theline had high-temperature production, the sealant would just melt anddisappear. We show this example to emphasize that this is not a minor problem. Imagine having to disassemble and repair three hundred 12- to 30-in. ballvalves along a 500-mile pipeline. This would be a disaster, especially in theunderwater portion. Sealant Chock Valves A secondary problem with sealant injection is the occurrence of check-valvefailures within injection fittings. Typical check valves within fittings allowthe sealant to push a ball off the seat. The ball is normally held against theseat by a coil spring. After the sealant passes the ball, it then passesthrough the coils of the spring, through a drilled hole, and into the outergroove of the seat ring, as discussed above. The sealant material occasionallyis so stiff that, instead of going around the ball, it pushes the ball downuntil the spring goes to stack height. Thus, the sealant flow path iscompletely closed off and the flow is stopped. Fig. 5 shows a comparative testbetween Injection Fitting X, which ports the sealant through the spring, and Injection Fitting Y, which ports ports the sealant through the spring, and Injection Fitting Y, which ports the sealant around the spring. The pile ofsealant adjacent to Fitting X was the amount passed before the fitting bridgedover. The pile adjacent to Fitting Y is a complete gun load. There was noindication of any bridging during the test. Fig. 6 shows a second test whereapplication of pressure was continued on Fitting X. The injection fitting wasdestroyed at approximately 10,000 psi. psi. It is important to note here thatthe sealant material was loaded with teflon repair chips. The sealant did nothave the light consistency of cup grease, which is usually injected into ballvalves without problems. Although penetrometer readings were not taken at thatparticular test, it was considerably softer than some of the readings seen oncommercially available sealants after 220 degrees F testing. Preliminary Testing of Commercial Products Preliminary Testing of Commercial Products To determine the basic characteristics of available sealants, sampleswere secured from all but one of the known suppliers. They are referred to as Brands A through E. Penetration Testing. The samples were tested by the procedures specified Penetration Testing. The samples were tested by the procedures specified in ASTM Spec. D 217–60T. The testing basically consisted of preparing astandardized sample and dropping a standardized penetrometer cone (Fig. 7) intothe sample. The depth to which the cone sank into the sample was measured in1/10 mm and recorded. Fig. 8 shows the basic design of the penetrometer cone. The change in the design from a 15 to a 45 degree angle penetrometer cone. Thechange in the design from a 15 to a 45 degree angle from the centerline is at areading of about 150 (0.590 × 254). The readings on the samples ranged from 220to 43. To put these in perspective, standard automotive multipurpose grease(cup grease) is perspective, standard automotive multipurpose grease (cupgrease) is specified to have a reading of 265 to 295. Children's modeling claywas tested to have a reading of 38. Table 1 summarizes the data recorded. Thesequence of testing provided 45 days of heating at 140 degrees F, 1 day at 32degrees F, and 7 provided 45 days of heating at 140 degrees F, 1 day at 32degrees F, and 7 days at 220 degrees F for the same samples. New samples werenot used for the succeeding tests. Samples D and E probably best illustrate thedifferent characteristics of the available sealant material. Sample D startsout relatively thick, but not quite as thick as modeling clay. After 140degrees F testing, Sample D softened. When removed from the oven after 220degrees testing, it was a liquid. In actual service, Sample D likely would haveprovided no sealing capabilities. When it cooled after the 220 degrees Ftesting, Sample D had a penetrometer reading of 24 and was extremely hard for asealant material (considerably harder than modeling clay). When stirredthoroughly, it became almost as soft as it was originally. Sample E wasconsiderably softer, with a penetrometer reading of 185. A reading of 171 afterthe heat testing indicates that it is formulated for stability. The finalreading of 220 after stirring indicates that Sample E becomes somewhat softerwhen stirred, but not significantly. Testing in Mineral Spirits. As the data in Table 2 show, Sealant Acompletely dissolves in relatively mild mineral spirits. It had two of theworst mechanisms: with too much heat, it becomes hard to pump; and with thewrong fluid, it may dissolve and disappear. Flowing Testing. Sealants A and E were determined to represent the extremesof available sealants for flow testing. *Now with Merriworth Services August 1991 P. 277

A discussion of the theories of repair sealants on ball valves and testing which has been done on various sealants to determine the basic characteristics of the sealants. Comparative testing has been done on sealants manufactured by 5 different suppliers for flowing losses to the sealing locations, thermal effects, arctic or freezing effects, and ability to bridge a standard .005" gap. INTRODUCTION The use and application of sealants to ball valves, both on land and offshore is critical to the long term workability and reliability of many of the valves. In spite of this critical need, little formal testing has been done, documented, and distributed to the industry on this subject. This paper reflects an ongoing testing program to develop technology in this area which will support standardized guidelines for the specification and use of these products. This program continues and expands upon testing described in 1990 Offshore Technology Conference Paper no. OTC 6393 and titled "THEORY, HISTORY, AND RESULTS ON SEALANTS FOR SUBSEA SERVICE". DEFINITIONS Bridging: The ability of a sealant material to span across and seal a gap in a sealing interface. Penetration number: Depth in tenths of a millimeter that a standard cone penetrates the sample of grease or sealant under prescribed conditions of weight, time, and temperature. Penetrometer: A device used to measure the penetration of a standard cone in the grease or sealant under standard conditions. Sealant: A grease-like mixture which is intended to bridge over small gaps in sealing interfaces (i.e. between the ball and seat of a ball valve) and cause effective sealing to occur. Sealing interface: Any surface along which one part is sealed against another. Most specifically in this discussion, the contact area between the ball and seat of a ball valve. Unworked: A sample of grease or lubricant which has been subjected to only the minimum handling in transferring it from the sample can to the test apparatus. Working: Subjecting the lubricant or sealant to any form of agitation or shearing action. SEALANT SAMPLES USED FOR TESTING Figure no. 1 gives basic data from each of the sealants/lubricants which were used in this test program. The 8 sealants indicated were purchased from 5 different suppliers, with one supplier providing two samples and one supplier providing three different samples. The chart illustrates that each of the sealants are rated for at least 450 degrees F. service, and are sold both as a lubricant and a sealant. Figure no. 2 shows 7 of the samples used for the majority of the testing on this project. Each sample was placed in a standard sized can which closely approximates the size of a standard ASTM Penetrometer Cup. The car size selected was A 12.5 OZ. can which is available from grocery stores containing a number of brands of Tuna Fish. The can is 4" in diameter and approximately 2 1/4" tall.