Simultaneous Drilling: A Radical New Method for Drilling Development Wells

Introduction Recent reports from the Soviet Union indicate that a fair degree of success is being attained with simultaneous drilling in certain fields. Although there is not a great deal of information available about the process, it is possible to determine the basic principles and some of the mechanical details involved. While any radical change in drilling methods is viewed with skepticism, only a critical evaluation can determine if it is justified or if some part of it may be made to serve our purposes. Simultaneous drilling is a method of drilling two directional wells alternately from a single rig and using a single drilling crew. While originally used with turbodrills, it lends itself to adaption so that it may be used with rotary drilling equipment. It is not intended for wildcat drilling, but will find its widest application in development drilling, particularly from offshore platforms. In simultaneous drilling, the two wells are drilled from the same rig, alternating the drilling from one well to the other each time a "round trip" is made. Actually, no round trips are made with this method of drilling the drill stem coming out of one hole being run down the other hole without the necessity of stacking the pipe. Rig Design In order to accomplish this with maximum speed and still retain simplicity in the drilling rig, the following rig is proposed. The floor of the simultaneous drilling rig is somewhat larger than that of the conventional rotary rig in order to accommodate a second rotary table and provide working space around each rotary (see Figs. 1 and 2). A single crown and traveling block assembly is used, which is shifted on a geared track by a series reversible motor between predetermined positions over each rotary as required. Two different mud systems are used with a single set of mud pumps and a manifolding system to give individual control of mud conditions in each well. Fingerboards and other auxiliary equipment are provided so that either rotary may be used for conventional drilling should the need arise. Two sets of terminal equipment are required, and certain other adaptations must be made.