774 Subsurface Geologic Methods 



30. How are water-locating surveys made and for what purposes? 



31. Wliat are the steps followed in applying a Hydrafrac treatment to 

 a formation? 



32. What factors should be considered before applying the Hydrafrac 

 treatment to a formation? 



33. In what areas has the Hydrafrac treatment proved successful? 



34. What is meant by well "acidization"? 



35. Define primary, secondary porosity? 



36. What methods are used in locating porous intervals in carbonate 

 sections? 



37. Briefly outline two methods used in acidizing a well. 



38. What is the purpose of shooting a well? Why should precautions be 

 taken in this procedure? 



39. What are the functions of a drilling fluid? 



40. What are the major properties of drilling fluids? 



41. Why is sand in drilling fluids undesirable? 



42. The viscosity of a drilling fluid depends on what factors? 



43. What is the average fluid density of a drilling fluid? WTiat mineral 

 is commonly added to drilling fluid to increase its weight? 



44. What is meant by "wall cake"? What property of a drilling fluid con- 

 trols the development of this cake? 



45. Drilling fluids may be adversely affected by what factors? 



46. Comment on the term "thinners" as applied in chemical treatment 

 of a drilling fluid. 



47. What are the two classes of compounds which are effective in chem- 

 ically treating a drilling fluid? 



48. Does cement unbalance a drilling fluid? Why? 



49. How does temperature effect the properties of drilling fluids? 



50. List live types of drilling fluids and give reasons for their particular 

 uses. 



51. What is meant by "formation testing"? 



52. What is the purpose of a "choke bean" in a formation tester? 



53. What is a "cone packer," "wall packer," "double wall packer"? 



54. What applications does hook-wall packer testing have? 



55. What is the purpose of a high-pressure control head in making a 

 formation test? 



56. Wliat is the most desirable hole diameter for formation testing? 



57. What are the usual steps followed in cementing casing? 



58. From a mechanical view point what points are of vital concern for a 

 good casing cementing job? 



59. What features should a geologist be concerned with during a casing 

 cementing operation? 



60. What materials are added to a cement slurry to prevent loss of cir- 

 culation? 



61. What are two types of wall-cleaning devices and for what purpose 

 are they used? 



