Formation interval determination method of MPD based on risk aversion and casing level optimization

MPD is one of the effective means to solve drilling problems in deep-water and deep-stratum complex formations such as narrow pressure window. To reduce cost, it mostly implemented only window strata. However, at present, there no scientific method determine matching stratum interval under “conventional + MPD” composite mode. Aiming this problem, by introducing methods risk quantitative evaluation taking principle “avoiding reducing cost”, combined with accurate ECD calculation considering multiphase flow, paper puts forward determination MPD, which can section construction much possible optimize casing level on premise ensuring safety. Based artificial bee colony algorithm, intelligent setting depth condition control established, quickly accurately obtain maximum its corresponding optimal parameters open-hole section. The case analysis shows that, compared conventional mode, “upper lower save layer while proposed provide theoretical basis for compound mode efficient design levels control.