Well Completion Technology of Radiation Well in Sand and Pebble Formation

Abstract

The invention provides a well completion process of a sandy cobble stratum radial well. The well completion process comprises vertical well construction and horizontal collector pipe construction, wherein the process of the horizontal collector pipe construction comprises the following steps of: putting a first strainer with a drill bit into a preformed hole on the wall of the vertical well, and starting an oil cylinder and a vibrator so that the oil cylinder and the vibrator drive a hydraulic horizontal drill to propel the strainer while impacting and revolving; drilling by a revolving vibroflotation method, and simultaneously starting sand draining and dewatering pumps in the well; stopping drilling till the designed depth, retreating the hydraulic horizontal drill and keeping the strainer and the drill bit in the water containing layer; sealing the gap between the strainer and the preformed hole; after the water and sand in the strainer are cleared way, closing the upper cover plate to seal the strainer; and hoisting the hydraulic horizontal drill in other preformed holes and carrying out operations by the same method until the construction of all horizontal collector pipes is completed. The well completion process provided by the invention is capable of driving the long strainer into the sandy cobble stratum and guaranteeing the water yield of the radial well.

Description

technical field [0001] The invention relates to a well forming process, in particular to a well forming process for radiation wells Background technique [0002] The radiation well is composed of a large-diameter water collection well and several to dozens of horizontal radiant tubes driven into the aquifer with a certain length from any elevation and horizontal direction in the water collection well. The diameter of the water collection well is usually greater than 3.5m, and it is difficult to drill holes in the sand and pebble formation with a particle size greater than 200mm, using the commonly used drilling rigs at home and abroad. Due to the large diameter of the drilling hole, if the rotary drilling rig is used for positive circulation drilling, it is difficult for the momentum of the mud pump to suspend the pebbles and make the pebbles rise with the mud and overflow the hole. Therefore, the commonly used method is reverse circulation drilling, that is, using mud pumps...

AI Technical Summary

Problems solved by technology

The diameter of the water collection well is usually greater than 3.5m, and it is difficult to drill holes in sand and pebble formations with a particle size greater than 200mm, using the commonly used drilling rigs at home and abroad.

Due to the large diameter of the drilling hole, if the rotary drilling rig is used for positive circulation drilling, it is difficult for the momentum of the mud pump to suspend the pebbles and make the pebbles rise with the mud and overflow the hole. Therefore, the commonly used method is reverse circulation drilling, that is, using mud pumps to The sand and pebbles loosened by the drill bit are drawn out from the drill pipe, and the mud recirculates back into the hole. Due to the limitation of the diameter of the drill pipe, larger pebbles cannot be discharged from the drill pipe. These large pebbles must be fished out separately to continue drilling. hole, the drilling process is cumbersome

[0003] In addition, at present, the jacking method is mainly used for the construction of the horizontal pipe of the radiation well in the sandy pebble formation at home and abroad, that is, the jack is used to push the water filter pipe into the aquifer. The length of the water filter pipe is generally not more than 10m, and the shorter water filter pipe directly affects the water output of the radiation well

[0004] Scholars at home and abroad have done a lot of work on the water yield of radiation wells, and have achieved certain results. From the existing data, there are many formulas for calculating the water yield of radiation wells, which can be roughly divided into two categories: one is empirical The second is a semi-theoretical and semi-experiential formula, but these formulas do not take into account the diameter of the filter pipe, the opening ratio, and the impact of the formation sand discharge on the water output during the construction process, and cannot accurately describe the water output of the radiation well. Accurately conduct economic analysis

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