Abstract: Provided is a two-stage reverse-torque bent screw orientation tool. An existing bent screw orientation technology has the technical problems of large friction resistance, difficult control of a borehole track, a low drilling speed and the like, and restricts economic, safe and long-acting development of oil and gas. In order to solve the above problems, the two-stage reverse-torque bent screw orientation tool is invented and composed of a first-stage clutch mechanism and a second-stage clutch mechanism, and the first-stage clutch mechanism and the second-stage clutch mechanism are both composed of a battery, a battery compartment, a pressure sensor, an electromagnetic valve, a body, a plug, a piston, an outer tooth cylinder, an inner tooth cylinder, a transmission cylinder, a connecting cylinder, a bearing, a limiting cylinder, a lower joint, a thrust bearing, a battery compartment, a circuit board, a cover plate and the like.

Abstract: A system and method for in-situ amelioration of saline-alkali soil using microalgae. Sewage and microalgal seeds are pumped into an microalgae growth pond for growing microalgae, and online equipment is used for monitoring the level of nutrients in the pond. When the microalgae reach the stationary phase of their growth, the screen mesh is lifted to separate microalgae from liquid, so that they are conveniently harvested by scraping. The harvested microalgae are returned to the soil as a soil ameliorant.