Drill stem test

Abstract: A method for determining a property of formations surrounding an earth borehole being drilled with a drill bit at the end of a drill string, using drilling fluid that flows downward through the drill string, exits through the drill bit, and returns toward the earth's surface in the annulus between the drill string and the periphery of the borehole, including the following steps: obtaining, downhole near the drill bit, a pre-bit sample of the mud in the drill string as it approaches the drill bit; obtaining, downhole near the drill bit, a post-bit sample of the mud in the annulus, entrained with drilled earth formation, after its egression from the drill bit; implementing pre-bit measurements on the pre-bit sample; implementing post-bit measurements on the post-bit sample; and determining a property of the formations from the post-bit measurements and the pre-bit measurements.

Abstract: An electrohydraulic drilling system for drilling holes in material such as rock utilizing a drill stem connected to a flexible cable. The electrical spark or plasma that creates the electrohydraulic pressure wave is powered by an electrical pulse propagated down the cable from a pulse generator to the drill stem. An advance mechanism on a jackleg support is utilized to move the drill into the rock during the drilling process. The drill stem and cable combination enable holes to be drilled in the roof of tunnels where the floor to roof height is less than the depth of the hole to be drilled. The electrohydraulic process provides higher drilling efficiencies than conventional systems.

Abstract: The recovery of petrochemical and geothermal resources requires extensive drilling of wells to increasingly greater depths. Real‐time collection and telemetry of data about the drilling process while it occurs thousands of feet below the surface is an effective way of improving the efficiency of drilling operations. Unfortunately, due to hostile down‐hole environments, telemetry of this data is an extremely difficult problem. Currently, commercial systems transmit data to the surface by producing pressure pulses within the portion of the drilling mud enclosed in the hollow steel drill string. Transmission rates are between 2 and 4 data bits per second. Any system capable of raising data rates without increasing the complexity of the drilling process will have significant economic impact. One alternative system is based upon acoustical carrier waves generated within the drill string itself. If developed, this method would accommodate data rates up to 100 bits per second. Unfortunately, the drill string is a periodic structure of pipe and threaded tool joints, the transmission characteristics are very complex and exhibit a banded and dispersive structure. Over the past 40 years, attempts to field systems based upon this transmission method have resulted in little success. This article examines this acoustical transmission problem in great detail. The basic principles of acoustic wave propagation in the periodic structure of the drill string are examined through theory, laboratory experiment, and field test. The results indicate the existence of frequency bands that are virtually free of attenuation and suitable for data transmission at high bit rates.

Abstract: A method and system of forming a lateral wellbore in a time and trip saving manner using a mill/drill to locate and place a casing window. In one aspect of the invention, a lateral wellbore is drilled with liner which is subsequently left in the lateral wellbore to line the sides thereof. In another aspect, the mill/drill is rotated with a rotary steerable system and in another aspect, the mill/drill is rotated with a downhole motor or a drill stem.