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Fifty-two completions made in the Gulf of Mexico between June 1978 and May 1982 have been analyzed to evaluate three commonly used techniques for perforating and cleaning up perforations before gravel packing. Since detailed flowing bottornhole pressure (BHP) information was not available in all cases, a method was developed to evaluate the completion efficiencies by using an inhouse computer program. This program models well performance by simultaneously solving the equations governing fluid flow in the reservoir, the near-wellbore region, the gravel-packed perforation tunnels, and up the production tubing. The results showed that perforating underbalanced with a tubing-conveyed casing gun yielded more efficient completions than the other two techniques.

There is a large unmet need in South Africa for bone marrow transplantation. Umbilical cord blood (UCB) is an important source of stem cells for the treatment of haematological and non-haematological diseases. Access to the two existing private umbilical cord blood stem cell banks (UCB SCBs) in South Africa is limited to individuals that can afford it, which further aggravates the ever increasing divide between families from different socioeconomic classes. The problem is compounded by a severe global shortage of genetically compatible samples, representative of the South African demographics. Establishing a public human UCB SCB in South Africa would provide more South Africans with access to previously unavailable treatment in the form of affordable, genetically compatible stem cells for bone marrow transplantation. A public UCB SCB has many facets to consider, one of which is public preparedness and support for the bank. This was assessed in a social feasibility pilot study which is reported here. In addition to the findings of this social feasibility study, other important considerations for establishing a public human UCB SCB in SA include; (a) testing the samples for HIV and other infectious diseases (required for compliance with international regulatory standards); (b) flow cytometric analysis for enumeration of CD34+ UCB stem cells; (c) mapping of HLA genotypes/alleles; and (d) a study of the economic feasibility of this endeavour.The social feasibility study was conducted to gauge public preparedness and support for a public SCB through patient interviews and questionnaires. The process was dynamic due to its novel nature for interviewers and interviewees alike. Many obstacles were met and dealt with which lead to the compilation of results discussed here in the form of a pilot social feasibility study.In the South African context, we are faced with unique and rich challenges relating to cultural and religious differences that are further augmented by linguistic constraints, 3 educational insufficiencies and logistical and administrative limitations. Complicating factors encountered during the informed consent process included cultural differences, religious practices, traditions and superstitions together with language constraints and an educational disparity.Despite many initial obstacles, preliminary results from the informed consent questionnaire were favourable with regard to the establishment of a public UCB SCB. These initial results prompted the revision of the questionnaire and interview process and the compilation of a more succinct and coherent definitive social feasibility study which will form a separate study and which we hope will ultimately assist in the decision of whether or not to establish a public UCB SCB in South Africa. Nevertheless, results from this pilot study appear to be favourable and highlight particular areas which could influence community support for a public SCB. Educating the general public with regard to the workings and benefits of public stem cell banking is ...

SPE Members Abstract Thirty-two tubing conveyed underbalanced perforating jobs conducted in the Gulf of Mexico perforating jobs conducted in the Gulf of Mexico between May, 1980, and May, 1982, have been carefully reviewed in order to draw correlations between procedural variations and trouble prone jobs. General procedural guidelines designed to avoid past problems were formulated and are presented. The procedures are designed for the presented. The procedures are designed for the generalized case where the perforating guns will be pulled out of the well in order to gravel pack and pulled out of the well in order to gravel pack and not for those run as part of a permanent completion. Careful application of these procedural guidelines has resulted in reducing rig time requirements by an average of 35% on 33 additional tubing conveyed underbalanced perforating jobs conducted subsequent to the establishment of the guidelines contained in this paper. Introduction Perforating underbalanced with a tubing conveyed casing gun can result In high rate completions. As a result, it is rapidly becoming one of the most popular techniques for perforating. Although it is basically a simple procedure, subtle differences in the procedures used can result in reduced safety and increased costs due to the many pitfalls that can be encountered. The procedural pitfalls that can be encountered. The procedural guidelines presented in this paper were developed by careful comparison of the design procedures and the actual sequence of events which occurred for 32 tubing conveyed underbalanced perforating jobs conducted between May, 1980, and May, 1982. RUNNING THE TUBING CONVEYED PERFORATING GUN A typical bottom hole assembly schematic is shown in Figure 1. Selection of the size and type of gun should be made after consideration of a few critical items. The outside diameter of the gun should be as large as possible for performance reasons but small enough to wash over in the event enough sand is pulled into the casing to cause the gun to become stuck. This happened on one occasion and presents a particular problem in 5 in. [12.7 cm] casing where it is difficult to find an effective perforating gun that can be washed over. Both perforating gun that can be washed over. Both ported plug and scalloped hollow carrier guns are ported plug and scalloped hollow carrier guns are available. Obviously, ported plug guns have many more seals that must remain intact and have been avoided for that reason. The scalloped guns have the potential to leak only at the connections between gun sections and have proven very reliable, as not a single gun has leaked. It has been a practice to use the longest gun sections available practice to use the longest gun sections available to minimize the number of connections. This in turn minimizes the number of seals and increases the length of perforations which can be shot because there is approximately a 2 ft [0.6 m] length at each connection that cannot be loaded. Because it takes longer to run a tubing conveyed gun, explosives should be selected to allow for at least several days exposure at the bottom hole temperature. Certain types of problems can be corrected without having to trip the guns but may require the guns to remain on bottom for 48 hours or longer. In one extreme case, a gun remained on bottom for seven days at 300 degrees F [420 K] and was successfully fired. Several different types of firing heads are available including the bar drop systems, pressure activated systems, and electrically fired systems. All of the guns in this data base were fired using the bar drop system. This system has been successful at depths up to 15,600 ft [4750 m], in fluid densities up to 17.6 lbm/gal [2110 kg/m] and in wells with an of inclination of 60 degrees [1.05 rad] from vertical. Of paramount importance with this type of system is the use of clean fluids and careful rig practices. Solids contents of 500 parts per million or less are easily and economically per million or less are easily and economically achievable using modern filtering equipment. Discussions with other operators have confirmed that mud systems are much more likely to create problems because of solids settling on and around the firing head. P. 519