Abstract: A distributive transmissometer, comprising a series of light sources that illuminate and map out a volume of space to be sampled to a one-dimensional space, a light detector, the one-dimensional space being mapped to the light detector such that spatial dust density distribution of the volume to be sampled can be determined; and, a lens for focusing light emitted by the light sources toward the light detector.

Abstract: A distributive transmissometer, comprising a series of light sources that illuminate and map out a volume of space to be sampled to a one-dimensional space, a light detector, the one-dimensional space being mapped to the light detector such that spatial dust density distribution of the volume to be sampled can be determined; and, a lens for focusing light emitted by the light sources toward the light detector.

Abstract: A method and apparatus for drilling and completing multiple wellbores from a single drilling rig and from within a single wellhead is provided. In one embodiment, a template is disposed at a predetermined location downhole within a casing. In one aspect, a first casing string is lowered with the template to the predetermined location and disposed within a first wellbore. A second wellbore may be drilled through a bore in the template. A second casing string may then be lowered through the bore into the second wellbore. In another embodiment, at least two wellbores are drilled and completed from a surface casing having a crossover portion.