A lateral force detector for downhole rod pipes in oil wells

During oil production, pipe leakage, and rod breakage are often caused by eccentric wear of rod and tube, thus significantly affecting the productivity of oil fields. At the extrusion, the lateral contact force between the sucker rod and the inner wall of the tubing is the key to understanding eccentric wear prevention. Based on this, we have designed a set of downhole rod tube lateral force testing instruments based on the arbitrary stress synthesis principle, which includes three parts: mechanical, circuit, and software. Among them, the mechanical components are designed based on the actual connection form of the oil pipe joints and are fixed between two sections of downhole oil pipes. The hardware circuit mainly filters, amplifies, converts A/D, stores, and communicates weak bridge voltage signals. The software program is divided into two parts: the design of the measurement device main control program and the data analysis program, which respectively realize data acquisition, storage, communication, and data conversion and analysis processing. Finally, the results obtained both in the lab and in the oil field show that the proposed lateral force detecting method is scientifically sound, and the designed lateral force detector can meet the field requirements in strength, pressure resistance, temperature resistance, and measurement accuracy, and may provide a significant reference for future studies in prevention of the eccentric wear of sucker rod in oil field.