Invert and all oil/synthetic drilling fluids are being used in high-angle wells, which can be excellent candidates for gravelpacking. This practice has led to a need for a complete fluid system to drill and gravel-pack the reservoir. The new system should also be completely compatible with the fluids and provide the highest degree of formation damage protection. The Invert Gravel Pack Fluid (IGPF) system can provide an option for carrier fluid for gravel-packing payzone intervals drilled with invert (oil- or synthetic-based) drilling fluids. The primary advantage is the compatibility of the drilling fluid and the gravel-pack fluid. This compatibility helps maintain the highest degree of lubricity of the wellbore, which can aid in the operation of the gravel-pack assembly while providing the highest degree of formation inhibition. The fluid is free of any solids for density, yet, based on current design, provides an invert system weighing to at least 12.2 ppg. To validate the new system, design work was first conducted in Baroid's Houston Research and Development lab. Additional testing and validation was done at Westport Laboratories and Halliburton's laboratory in Duncan, Oklahoma. Testing consisted of regained permeability, filtercake erodability, and testing on a gravel-pack simulator loop to help determine the effectiveness of the fluid as a gravel carrier. This paper describes the testing protocol and fluid design. It also describes the fluid properties to help prove the effectiveness of the fluid as a carrier fluid and shows a relationship with the properties of conventional brines used as carrier fluids. Current Practice Common practice is to drill down to the top of the zone of interest and displace the drilling-fluid system. The zone of interest is then drilled with a specialized fluid that is designed to help minimize formation damage. These specialized fluids can provide excellent cleanup either by remedial treatments or by placing the well on production. After this interval has been drilled, whether with a water-based system or an invert-based system, it is then typically displaced to a completion brine to begin the completion phase of the well. After displacement, the well is circulated clean and measured to help ensure that solids have been removed to an optimum level. Typical measurement is based on NTU values. After the well has been circulated clean and the fluids have been monitored, preparation is made to run the completion assembly. If the well is to be gravel-packed, properly sized gravel will be pumped and placed in the annular section between the completion assembly and the wellbore. During the sand-control operation, the drilling-fluid filter cakes from these systems can be eroded to a very thin submillimeter thickness without compromising fluid-loss control. The filter cakes can still sustain high differential pressure. This has been verified by large-scale lab testing and actual field results. Depending on the completion type, the gravel carrier fluid is either viscosified or left nonviscosified. After the well is gravel-packed, it can be placed on production. In this application, production permeates through the filter cake, gravel, and gravel-pack assembly into the production tubing. If a remedial cleanup treatment is required to remove the filter cake, the cleanup is normally carried out before placing the well on production. This remedial treatment, however, can be performed after the well has been placed on production. Until recently, horizontal wells drilled with an invert system were still gravel-packed with completion brine. The industry's perception is that displacing from an invert system to a completion brine can adversely impacting well productivity because of one of the following factors:Incompatibility of drilling fluid with completion fluidFormation incompatibilitiesFormation of precipitatesPotential for creating a sludge/emulsion

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. This paper was prepared for the 1970 Evangeline Section Regional Meeting of the Society of Petroleum Engineers of AIME, held in Lafayette, La., Nov. 9–10, 1970. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal, provided agreement to give proper credit is made. provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract A study has been made as to the effect of acidic type effluents for Deep Well disposal, on various cementing compositions as well as their effect on plastic pipe. Data will include laboratory test results on API Class A, C and H Cements, Pozzolan Cement, Resin Cement, Gypsum Cement with Resin Phase and a Resin Slurry using Sulfuric Acid, Nitric Acid, Hydrochloric Acid and Mixed Acids. A section is devoted to well design which includes optimum pipe to hole size ratios, recommendations for down hole equipment such as special packers, the use of plastic and stainless steel pipe and various techniques gained from field experience in cementing Acid Disposal Wells. Introduction It is only within the last decade that the magnitude of the damage wrought to our natural resources, surface as well as sub-surface, has become a major concern to individuals, sportsman groups, conservation, State and Federal Government Agencies. Viewpoints are many and varied as to the availability of sufficient fresh water supplies to take care of both human and industrial needs, however, the consensuses seem to be that supplies are available if they are not wasted through misuse or by pollution from industrial wastes. More stringent laws are in the making by both the State Governments and the Federal Government. Most areas are concerned with the problem of pollution in one form or another, with the more serious situations developing in industrialized and metropolitan areas. In many of these areas, water pollution as pertains to lakes, rivers and streams as well as underground fresh water supplies is a very serious problem. The primary methods used in the disposal of industrial wastes are surface and sub-surface. Many different means have been used in surface disposal operations depending upon the type of waste and the condition of the final waste at the receiving point. Generally the treatment for surface disposal is classified as chemical, physical, or biological; however, any physical, or biological; however, any combination of these three may be used. Where the final product is deposited back to an area for re-use, some of the more expensive methods of surface disposal include land fills, settling tanks, filtration systems, aeration, floatation, oxidation, chlorination, pH adjustment, etc. These are not the most effective methods of waste disposal as considerable damage can result from spillage, overflow from heavy rains, seepage, etc.

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