Study And Application Of Multilateral Well Techniques On The Site Of G104

Multilateral well technique is an important technique which meets present oilfield developing and economic demands. It is an advanced drilling & production technology developed on directional well technique, high deviated well technique and horizontal well technique. G104-5P42, G104-5P56 and G104-5P55 wells are three fishbone-shaped horizontal multilateral wells and located in the G104 block of Huabei Oilfield which belongs to the higher area of north High 104-5 Block, Gaoshangbao Oilfield.Well trajectory control technique is one of the key technologies of this kind of well. Different stratum situation have different problems, in order to control well trajectory and hit the target, site party take following measures: apply several angle-adjustable drilling motor; make rotary table in low speed; let directional drilling technique cooperate with oriented drilling technique. A good control on well trajectory ensures a correct target hitting, rock object assures that the distance between oil-producing intervals and well trajectory keeps in the range of 0.4~1.4m, finally, 100% drilling rate and design requirements are able to be achieved.In order to successfully complete multilateral well, it is necessary to make research on and apply drilling/completion fluid techniques, such as, make the hole clean and control the lubrication and stability of drilling fluid according to the actual condition of the well.In order to safely run intermediate casing and effectively protect casing during the completing operation, it is necessary to use drilling assembly with single and double centralizers to make a wiper trip and make great efforts to clean the borehole. During the trip, constantly adjust the angle of the drilling assembly, thus ensuring its stable position. Adequate preventive measures against complicated situation and accidents ensure a safe drilling operation, therefore, according to operation features of this kind of well, various preparing work in the respect of lost circulation and pipe sticking should be done.