Casing Program of Deep Well with Evaporite Bed in Tuofutai Block

In order to solve the problems of lost circulation and collapsing in the igneous rock and sticking in evaporite formation during drilling long open hole through evaporite bed in Tuofutai Block,optimization of casing program was carried out to ensure the safe and rapid drilling practices.By combining inversion results of Drillworks software with the practical field test data,the three pressure profiles of Tuofutai Block were analyzed.The strength of the igneous rock samples was assessed by using Brazilian test and stress-strain test.To determine the reason why the pressure sealing technology was difficult to improve bearing capacity of igneous rock formation,the fracture distribution of the igneous rock was researched by using imaging logging data and scanning electron microscopy techniques.Based on three positions that had to be sealed and one risk in deep evaporates bed that were determined according to the analysis of the above results,a special casing program for sealing evaporite bed was designed.Field application demonstrated that this new casing program could keep igneous rock and evaporite bed from downhole problems such as lost circulation,collapsing and sticking.