AbstractsEarth & Environmental Science

"The object of this investigation is to determine the stresses about a hole in a thick plate of large dimensions compared with the radius of the hole when the plate is loaded parallel to the axis of the hole under various conditions of restraint, and to apply the results to the case of a deep well. The case of a plate with an initial stress in its plane is also considered...The problem arose from difficulties encountered in the drilling of deep oil wells. After drilling has proceeded to a certain depth, the sides of the bore hole apparently collapse and fill up the hole, resulting not only in wasted time and effort but in the loss of the drill bits. By considering the region around the well as a thick plate of dimensions very large compared to the radius of the bore hole, the conditions will be seen to correspond to one of the cases investigated. Part III of this thesis is devoted to application of the results of the general investigation carried out in parts I and II to the special problem of stresses about a deep well and the causes of the failures described above. All the cases investigated do not apply to deep wells, but it was felt that a complete investigation of the general problem might find application in other fields and would enhance the value of this thesis" – Introduction, p. 1-2.