Atlantic Richfield Company

John Howard Striegler

Eddie P Howell

Frank J Schuh

David D Hearn

James A Dech

Medium curvature deviated wellbores having a radius of curvature in the range of 200 feet to 400 feet are drilled with downhole drilling assemblies for drilling the curved wellbore portion and for correcting or holding the horizontal wellbore portion and which are connected to the end of a drillstem made up of elongated elastically bendable drillstem members which may be cyclically compressively stressed during rotation of the drillstem. The elastically bendable drillstem members are characterized by joint forming portions at opposite ends of an elongated tubular body and which are of a diameter which minimizes the tendency for the drillstem to buckle during drilling. Spaced apart stress bearing sleeves are attached to or integrally formed with the tubular body and are of a diameter greater than the body and preferably equal to the diameter of the tool joint portions. The drillstem is made up of the elastically bendable compressive service drillstem members extending through the curved and horizontal portions of the wellbore and heavy walled drill pipe or drill collars are provided in the drillstem in the vertical hole portion to impose compressive loads on the drillstem through the curved portion of the wellbore.

Medium curvature directional drilling method

A method for drilling a drainhole through a subsurface formation without intersecting upper or lower boundaries thereof in which a directionally sensitive measurement while drilling device carried on the drainhole string is used to measure a formation property which indicates proximity to a formation boundary. Upon detection of such proximity, the direction of drainhole drilling is changed to direct the drainhole away from the detected boundary.

Method for drilling drainholes within producing zone

During the analysis of sample oil from an oil bearing formation, drilling fluid oil filtrate invasion into a cored oil bearing subsurface formation is detected in a way that does not require the use of special chemicals or tracers. Significant oil filtrate invasion is detected by determining the relative quantities of the same two hydrocarbon materials in the formation oil, drilling oil, and sample oil. Preferably, each hydrocarbon material is one or more hydrocarbons selected from the group consisting of hydrocarbons with eight carbon atoms through hydrocarbons with thirty-five carbon atoms. The drilling oil may be topped crude oil or formation oil that has had most of the hydrocarbons with one carbon atom through six carbon atoms removed. Fuel oil may have been added to the topped oil.

Detection of drilling oil filtrate invasion in a core

A slim hole drilling method wherein a wellbore of a diameter no greater than about 6 inches is drilled using a drill pipe rotation rate of at least 500 rpm and rotating the drill pipe with at least one electric motor operably connected to the drill pipe. Drilling power units for carrying out the drilling method which employ at least one electric motor in mechanical connection with the drill pipe for rotating the drill pipe and moving with same as it advances toward and away from the wellbore.

Slim hold drilling

A method of recovering bitumen from a subterranean tar sand formation characterized by a plurality of steps. First, a continuous wellbore having a second section thereof contained within the formation and first and third sections thereof extending the second section to the earth's surface is formed. Next, the first and third sections of the wellbore are cased. Thereafter, a heated fluid is circulated through the wellbore contacting the formation to reduce the viscosity of the bitumen contained therein rendering the bitumen mobile. Subsequently, bitumen mobilized by the heated fluid is recovered via the wellbore.

Recovery of bitumen from tar sands

A method of producing bitumen from a subterranean tar sand formation characterized by the following muti-step process. First, a continuous wellbore having a second section thereof contained within the formation and a first and a third section extending said second section to the earth's surface is formed. Next, a perforated liner is inserted into the wellbore extending the entire length thereof and having perforations so positioned thereon to be adjacent the second section of the wellbore. Thereafter, a heated fluid is circulated through the wellbore, contacting the formation via the perforations, thereby reducing the viscosity of the bitumen contained therein rendering it mobile. Subsequently, the mobilized bitumen is recovered via the wellbore.

Production of bitumen from tar sands

A method of producing bitumen from a subterranean tar sand formation by the following multi-step method. First, an injection well is drilled to the formation and extended into the formation. Subsequent thereto, a perforated liner is inserted into the injection well extending the entire length thereof and having the perforations provided in the portion of the injection well in contact with the formation. Next, a plurality of production wells are drilled and completed into the formation positioned above and along the length of the injection well. Thereafter, a heated fluid is circulated through the injection well contacting the formation via the perforations and thereby reducing the viscosity of the bitumen contained therein rendering same mobile. Subsequently, the mobilized bitumen is recovered through the plurality of production wells.

Production of bitumen by steam injection

A method of recovering bitumen from a subterranean tar sand formation by the following multi-step method. First, an injection well is drilled to the formation and cased. Perforations are provided in the portion of the injection well contacting the formation. Next, a plurality of production wells are drilled and completed into the formation positioned above and along the length of the injection well. Thereafter, a heated fluid is circulated through the injection well contacting the formation via the perforations and thereby reducing the viscosity of the bitumen contained therein rendering same mobile. Subsequently, the mobilized bitumen is recovered through the plurality of production wells.

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Richardson, TX, United States of America

John Howard Striegler