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N.b. Muecke - One of the best experts on this subject based on the ideXlab platform.
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Heated Mud Systems: A Solution to Squeezing-Salt Problems
SPE Drilling & Completion, 1994Co-Authors: N.b. MueckeAbstract:Summary Squeezing Salts have been a major problem to operating companies worldwide for many years. Most previous solutions to the problem have been aimed at treating the symptoms rather than the cause. Generally, these have been based on running casings capable of withstanding the nonuniform Salt loadings because satisfactory cementations have been virtually impossible to achieve because of large washouts in the Salt layers. The solution is to use standard oilfield equipment to drill a gauge hole through the squeezing Salts, thus providing an optimum cementation environment. Various methods were used to try to resolve the problem; the last was the use of thick-walled casings in conjunction with saturated potassium/magnesium drilling fluids to reduce Salt washout. Unfortunately, washouts still occurred because the Muds could not be saturated at the surface to downhole conditions. Now, the drilling fluid is heated on the surface, enabling the required level of Salt concentration to be achieved. The heating system, comprising a boiler and heat exchanger from a conventional well-test package, has been used on eight wells to date. In each case, a gauge hole was drilled through the squeezing-Salt sections and, subsequently, successful cementations were performed. Introduction Squeezing Salts have been responsible for major drilling problems in many areas of the world for over half a century. They occur primarily in the Zechstein Group of evaporites within the operating company's area of activities. They are responsible for such problems as stuck pipe and casing failure during drilling and casing failure during production, sometimes as long as 12 years after drilling. Since 1960, approximately $170 million (at 1992 drilling costs) has been spent redrilling wells with failed casing strings. An additional squeezing-Salt-related problem is annular pressure, which can occur if quality cementations cannot be achieved. Salt can "flow" into the uncemented annulus compressing the annular fluid. Bleeding off the annular pressure at surface to protect casing shoes results in the continued influx of Salt. Various methods have been used to try to reduce these problems. Mud weights of 1.6 specific gravity have controlled the Salt creep during drilling. However, large washouts in the squeezing-Salt layers resulted in poor cementations and casing failures. The use of oil-based Muds (OBM's) has solved the washout problem in other regions of the world. However, our environmental policy is to avoid use of OBM's whenever possible. Consequently, we developed the saturated potassium/magnesium (K/Mg) Salt Mud. This Mud, in conjunction with thick-walled casing run across the squeezing-Salt zones, reduced both drilling- and casing-related problems. While the number of stuck-pipe problems was reduced, poor cementations across the squeezing-Salt zones continued because of the large washouts still occurring in the squeezing-Salt layers. These occurred because the K/Mg Muds remained undersaturated at surface conditions relative to downhole conditions. In 1991, the company was associated with a project to drill two wells for use in the solution mining of Mg and K Salts. Gauge holes were a prerequisite for the identification of the objective Salts by electric logging. Excellent results were achieved by drilling with a heated Salt Mud that had been saturated at the surface to downhole conditions. The heating requirements for this project were modest because the top of the squeezing Salt occurred at 1500 m, requiring a circulating temperature of 45 C to achieve the necessary saturation level. However, in the company's area of activities, the top of the squeezing Salt generally occurs between 2500 and 3000 m, requiring temperatures in the order of 70 C. Despite the need for higher temperatures, the success of the project prompted wider use of the heated Mud systems on a trial basis. To date, eight wells have been drilled with the system, resulting in the drilling of a virtual gauge hole with successful cementations being achieved in each case. The Zechstein group (Figs. 1 and 2) is an Upper Permian evaporite sequence, 900 m thick, distributed across much of The Netherlands, Great Britain, and the North Sea and extending into Germany and Poland. The Zechstein provides the seal for the pay zones in the majority of gas fields within the company's area of activities. It is composed of four major, essentially identical, stratigraphic sequences: Zechstein 1 through Zechstein 4 (ZEZ1, ZEZ2, ZEZ3, and ZEZ4). Each corresponds to a change in sea level that allowed a major influx of seawater into a large coastal basin. Precipitation of Salts during the evaporation of each of these influxes resulted in the deposition of the Zechstein group. The order of precipitation is primarily as follows: carbonates (calcite and dolomite), sulfates (anhydrite and gypsum), chlorides (halite, "rock Salt"), and finally a mixture of chlorides and sulfates (carnalite, sylvite, kieserite, and bischofite-the squeezing Salts). The differing solubilities of the various Salt types have resulted in a large lateral distribution of the Salts. Each sequence has essentially the same order of precipitates from top to bottom, but, because of regional climatic variations, groundwater effects, and various deformation mechanisms, considerable variation in sequence content can be found throughout the basin. In many regions, several Zechstein members are out of sequence or completely absent, with the troublesome squeezing Salts being deposited primarily toward the center of the basin and only in the ZEZ2, ZEZ3, and ZEZ4 sequences. The most problematic of the Salts, the bischofite, is found only in the ZEZ3 sequence and only in some regions. The basal unit of each sequence is a Salt-clay layer. This layer is unevenly distributed over much of the Zechstein basin and has a maximum thickness of 15 m, but is more commonly 2 to 5 m thick. The Appendix provides greater detail on the Zechstein group and the components of each sequence.
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Heated Muds solve squeezing-Salt problems
1993Co-Authors: N.b. MueckeAbstract:Squeezing Salts have been responsible for major drilling problems in many areas of the world for over half a century. In NAM's area of operations, they occur primarily in the Zechstein group of evaporites. They are responsible for problems such as stuck pipe during drilling and casing failure during both drilling and casing failure during both drilling and production, sometimes as much as 12 years after drilling. Since 1960, some US $170 million (at 1992 drilling costs) have been spent redrilling wells with failed casing strings. In 1991, NAM was associated with a Billiton project to drill 2 wells for the solution mining of magnesium and potassium Salts. Gauge holes were a prerequisite to identify the objective Salts by electric logging. Excellent results were achieved by drilling with a heated Salt Mud that had been saturated on surface to downhole conditions. The heating requirements for the Billiton project were modest, as the top of the squeezing Salt occurred at approximately 1,500 m (4,920 ft), requiring a circulating temperature of 45 C (113 F) to achieve the necessary saturation level. However, in NAM's operations, the top of the squeezing Salt generally occurs between 2.500 m and 3,000 m (8,200 ft andmore » 9,850 ft), requiring temperatures on the order of 70 C (158 F). Despite the need for higher temperatures, the success of the Billiton project prompted NAM to introduce the heating system on a trial basis. To date eight wells have been drilled using the system, resulting in the drilling of a virtual gauge hole with successful cementations being achieved in each case.« less
Andreas Bahr - One of the best experts on this subject based on the ideXlab platform.
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Sulfidic and non-sulfidic indium mineralization of the epithermal Au–Cu–Zn–Pb–Ag deposit San Roque (Provincia Rio Negro, SE Argentina) — with special reference to the “indium window” in zinc sulfide
Ore Geology Reviews, 2013Co-Authors: Harald G. Dill, Mirta M. Garrido, Frank Melcher, Maria C. Gomez, Berthold Weber, Liliana I. Luna, Andreas BahrAbstract:Abstract At San Roque in Patagonia's Rio Negro Province, Argentina, an In–Au–Cu–Zn–Pb–Ag mineralization ( Salt–Mud flats controlled the youngest mineralization with Mn, Li, Ca, Mg, V, Sr, Cu, Ag and In bound to oxides, hydroxides, sulfates and subordinate carbonates. The quartz vein mineralization is made up of oxides, hydroxides prevailing over sulfides and containing W, Fe, Au, As, Pb, In, and Cu. It formed at the passage from the vadose into the phreatic zones under oxidizing to slightly reducing conditions. The level marks the boiling level of the hydrothermal solutions involved in the mineralizing process. The hypogene stockwork mineralization is exclusively made up of sulfides containing Zn, Pb, Cu, In, Ag and Bi in the phreatic zones. It developed under reducing conditions. Indium is present at all levels within the volcanic rocks and has been derived from sphalerite rich in Cd (
Harald G. Dill - One of the best experts on this subject based on the ideXlab platform.
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Sulfidic and non-sulfidic indium mineralization of the epithermal Au–Cu–Zn–Pb–Ag deposit San Roque (Provincia Rio Negro, SE Argentina) — with special reference to the “indium window” in zinc sulfide
Ore Geology Reviews, 2013Co-Authors: Harald G. Dill, Mirta M. Garrido, Frank Melcher, Maria C. Gomez, Berthold Weber, Liliana I. Luna, Andreas BahrAbstract:Abstract At San Roque in Patagonia's Rio Negro Province, Argentina, an In–Au–Cu–Zn–Pb–Ag mineralization ( Salt–Mud flats controlled the youngest mineralization with Mn, Li, Ca, Mg, V, Sr, Cu, Ag and In bound to oxides, hydroxides, sulfates and subordinate carbonates. The quartz vein mineralization is made up of oxides, hydroxides prevailing over sulfides and containing W, Fe, Au, As, Pb, In, and Cu. It formed at the passage from the vadose into the phreatic zones under oxidizing to slightly reducing conditions. The level marks the boiling level of the hydrothermal solutions involved in the mineralizing process. The hypogene stockwork mineralization is exclusively made up of sulfides containing Zn, Pb, Cu, In, Ag and Bi in the phreatic zones. It developed under reducing conditions. Indium is present at all levels within the volcanic rocks and has been derived from sphalerite rich in Cd (
Wu Su-fang - One of the best experts on this subject based on the ideXlab platform.
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Process modification of Salt-Mud treatment in caustic soda evaporation
Chlor-alkali Industry, 2003Co-Authors: Wu Su-fangAbstract:A series of problems such as insufficient centrifuge capacity and unsuitable process piping arrangement have been found through analyzing the abnormal phenomena occuring in the Salt-Mud treatment in the original evaporation system.The measurements have been taken,including replacing the centrifuge,innovating the devices and improving the piping arrangement.Consequently,the output is increased from 85 243 t/a to 95 475 t/a and the steam consumption is reduced from 3.808 t/(t·NaOH) to 3.451 t/(t·NaOH).
Jiang Xingcai - One of the best experts on this subject based on the ideXlab platform.
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Reservoir Fluids Identification Method Based on Time-lapse Logging in Salt Mud Invasion Environment
Well Logging Technology, 2011Co-Authors: Jiang XingcaiAbstract:Because of Salt Mud invasion it is difficult to identify reservoir fluids in the beach area.Based on theoretical research,established is an array induction logging dynamic intrusion response model and developed is a time-lapse logging numerical simulation software.This method can analyze the impact of 18 parameters on the array induction logging responses,such as permeability,porosity,saturation,Mud salinity,formation water salinity,formation and wellbore pressure,etc..Given are the characteristics of the dynamic changes of radial resistivity distribution,Mud invasion depth,log response,water saturation,formation water resistivity,formation water salinity with the Mud soaking time.Provided is quantitative identification reservoir with log data.Through the time-lapse simulation and response analysis of 78 layers of 11 wells in Liaohe region,the quantitative interpretation standard of the reservoir has been determined,the coincidence rate of which is increased by 10%,therefore the difficult problems are solved about low resistivity oil and gas layer identification in the beach area.Log application show the above method is a new approach for reservoir fluid identification.
