Asymmetric casing centralizer

A method of facilitating the distribution of cement flow in an annular region defined between a casing and a wall of a horizontal wellbore section through which the casing extends, the method comprising:

• inserting the casing through a tubular body of a casing centralizer, the casing centralizer comprising a plurality of straight vanes and a plurality of spiral vanes, each of the plurality of spiral vanes oriented to spiral the same direction and further comprising first and second circumferential sections;
• inserting the casing and the casing centralizer into the horizontal wellbore section;
• automatically rotating the casing centralizer about, and relative to, the casing during the insertion of the casing and the casing centralizer into the horizontal wellbore section, wherein the casing centralizer is automatically rotated within the horizontal wellbore section at least until at least a portion of the first circumferential section is positioned below at least a portion of the second circumferential section;
• and
• conveying the cement flow into the annular region;
• wherein, during the conveyance of the cement flow into the annular region:
• a first pressure drop is defined across the length of the tubular body at a first circumferential location within the first circumferential section,
• a second pressure drop is defined across the length of the tubular body at a second circumferential location within the second circumferential section, and
• the first pressure drop is less than the second pressure drop to facilitate the distribution of the cement flow in the annular region.

A casing centralizer comprising:

• a tubular body defining an internal passage through which casing is adapted to extend;
• a first vane of a first geometry projecting longitudinally along an exterior of the tubular body;
• a first adjacent vane at a first angular offset from the first vane and defining, along with the first vane, a first passage for fluid flow, the first passage presenting a first fluid flow resistance to the fluid flow;
• a second vane of a second geometry projecting longitudinally along the exterior of the tubular body at a second angular offset from the first vane;
• and
• a second adjacent vane at a third angular offset from the second vane and defining, along with the second vane, a second passage for fluid flow, the second passage presenting a second fluid flow resistance to the fluid flow, the second fluid flow resistance being different than the first fluid flow resistance;
• wherein at least one of the vanes is a straight vane and at least two of the vanes are spiral vanes, and each of the spiral vanes spiral in the same direction.