Anti-channeling cementing technology for shallow adjustment wells in Karazhanbas Oilfield

After cementing job in the shallow adjustment wells in matured blocks of Karazhanbas Oilfield, there existed some problems like low acoustic amplitude logging pass rate, severe annulus pressure. Analysis shows that the reason for this is that the guidelines for design of previous cement slurry gradually deviated from the actual conditions of the oilfield. In view of the actual field requirements, the cement slurry formulation was adjusted by removing the fluid loss agent, reducing the use of dispersants, choosing reasonable experimental temperature and optimizing the admixture ratio. The thickening time and initial setting time of the adjusted low temperature early strength cement slurry system were controlled within 2 h and 4 h respectively. If controlled within 8 h, its strength may be over 3 MPa. This adjusted cement slurry system was applied for the eight well times, and the cementing qualification rate was up from 69% to over 90%, which has basically solved the difficulty in cementing of adjustment wells with thin oil layers, thin isolating layers, active aquifer, and has created a favorable condition for efficient development of the Oilfield.