Abstract: An inertia bar to be installed in a well between a sucker rod string and a subsurface pump. A string of the bars adds weight to the sucker rod string and maintains it under tension throughout a pumping cycle. A sufficient number of the bars are used to place a neutral zone within the inertia bars. The neutral zone is a zone in which there is neither tension nor compression in the bars. The body of each bar has a relatively large diameter, which for example may be the same as the outside diameter of the couplings used to connect the individual sucker rods. The bar has pins at its ends for engaging the couplings, which pins have the same dimension as standard sucker rod pins. The bar can be engaged by a conventional elevator when it is to be removed from a well.

Abstract: A subsurface pumping installation in which solvent or diluent is introduced to the well from the surface and blends with the well fluid to enable it to be pumped more readily. The diluent is introduced through a power tubing which may be either concentric with the casing or concentric with a production tubing within the casing. A mixture of well fluid and diluent is conducted to the surface through an annulus which surrounds the power tubing. The diluent is injected into the well fluid in a blending chamber inside the pump, where it blends effectively without loss into the formation around the pump.

Abstract: A subsurface pumping installation for handling viscous or sand-laden fluids. The installation includes parallel power and production tubing strings, a pump located at the bottom of the power tubing string, and a crossover which affords communication between the pump and the production tubing string. Diluent is conducted to the well through the power tubing string. A portion of the diluent is conducted to the pump barrel below the plunger, where it serves to exclude well fluid from the plunger. Another portion may be conducted through a bypass tube to a mixing chamber below the pump, where it mixes with well fluid.