Research And Application Of Complicated Structure Well Completion Technology

Complicated wellbore well completion is one of the most rapidly developed and applied technology inthe 21 century worldwide. It has become the main technical approach to increase recovery efficiency andeconomic benefit. Its application field is expanding quickly. In the past, Jidong oilfield has been developingby drilling conventional directional wells. In the beginning of "the tenth five-years-layout", developmentcost of Jidong oilfield is high, but oil production is rather low, about 600,000t annually and 5.9t per well daily,and so is the recovery efficiency, with 18.8% of normalized recovery efficiency. To the shallow naturalwater drive reservoir, recovery percent of reserves is in a low degree by laying conventional directionalwell grid. Some wells' producing pressure differential and liquid-withdrawal intensity are high, from whichedge water and bottom water breakthrough arise, and water content rate rises rapidly. Other shallowreservoirs with unconsolidated cementation are liable to produce sand and block. Therefore, frequentoperation, sand control and block removing are needed, but the result is not good. For some medium-deepand deep reservoirs which are developed by water injection, physical characteristics is bad and formationheterogeneity is high, so operation measures of oil and water wells are difficult to fufill.How to develop fault block reservoir scientifically and efficiently is become a serious subject.Complicated/wellbore wells, especially horizontal wells, with higher flow efficiency and lowerproducing intensity, can recover difficult reservoirs, increase recovery efficiency and single-wellproduction. Fully utilizing the existing watered-out producers, partial wellbore of casing deformed wells forside-track horizontally, existing drilling and production platforms, and oil transferring system, have theadvantage to recover the remaining oil rapidly, economically and efficiently. Powerful support of completiontechnology is needed to apply these complicated wellbore wells.Focusing on these problems, related geology data, developing data and information of state of the artare fully collected as the base of this paper. Each episode of the whole completion process is well studied,while the features of fault-block reservoir are considered. The conducted research is concerning complicatedwellbore well drilling fluid, reservoir protection technology, cementing and perforating completingtechnology, and screen completion technology of loose sand reservoir.To perform the technology research of cementing and perforating completion of complicatedwellbore wells, methodology research is conducted firstly, and three well completion methods areestablished, including horizontal well casing cementing and perforating completion, horizontal well linercementing and perforating completion, and side-track horizontal well liner cementing and perforatingcompletion. Secondly, in the cementing technology research, a series of cementation completiontechnology has been studied and developed, including expanding cement cementation, low-densitycement cementation, deep slant well cementation, fly ash cementation, two-stage cementing cementation,highly-deviated well cementation, etc. At last, complicated wellbore well perforation technology andperforation fluid research have been carried through, formed horizontal well optimized orientingperforation technique and small-diameter-side-track horizontal well orienting perforation technique. Theunconsolidated sand reservoir complicated wellbore well screen pipe completion technology can predict andevaluate formation sand producing, optimize sand-proof pipe and relevant parameters, and match the relatedoperation techniques based on formation evaluation and formation analysis (including grain size analysis).