Organic boron system can not only effectively increase viscosity of fracture fluid in fracture, but also reduce frictional resistance in borehole and perforation hole, which has got a good application in Tuha oilfield.

In all drilling operations of horizontal wells, frictional resistance and torque restrict the extention of horizontal displacement, clean and stability of borehole increase the difficulty of directional drilling in Dongfang 1-1 gas field.

With the analysis of hot oil pipeline heat and flow characteristics,the pipeline between heating stations is divided into different parts and different frictional resistance equations based on these parts and numerical solution are used.

Study of unsteady friction models in transient flow for leak detection;

Bridge construction monitoring of design alteration and analysis of friction test;

Influence of unsteady friction on transient pipe flow;

Analysis on friction drag and torque from extended reach wells and the influence on well drilling depth;

By taking 6-8 sidetracking well in Dagang Oilfield for example, the problems, such as well track control, wellbore clean, torque and friction drag encountered in 3D high deviation sidetracking operation and related technical measures are discussed, and requirement of torque, curvature and friction drag in 3D high devi.

The causes of sand plugging during fractur ing oper-ation with low proppant concentration in Anpeng oilfield are that nat ural fractures are highly developed leading to severe lost circulation;that the fracture beginning position has a different direction with that of the maximum main stress and near wellbore friction drag is large;and that the rocks have l arge elastic modulus.