渭北油田高水垂比水平井钻井设计与应用

The Design and Application of Horizontal Well Drilling with High Dep/TVD Ratio in the Weibei Oilfield

为解决渭北油田长3储层埋深浅、水平井水垂比高带来的摩阻大、井眼轨迹控制难等问题，开展了浅层高水垂比水平井钻井设计研究。在分析主要钻井技术难点的基础上，对不同尺寸井眼的摩阻和扭矩进行了数值模拟，将待钻井设计为三开井身结构，三开水平段采用φ215.9 mm钻头钻进；为了确保准确着陆入靶，根据长3储层的地质特征，采用双增井眼剖面；根据各开次钻遇地层的特征和钻井要求，一开井段采用塔式钻具组合，二开和三开井段采用倒装钻具组合，加重钻杆放在井斜角为45°～60°的井段内；根据渭北油田钻遇地层的特点，采用钾铵基聚合物钻井液，水平段控制钻井液滤失量小于5 mL ；为降低钻井成本，充分利用现有钻井设备，选用ZJ30型非顶驱钻机。现场应用表明，利用常规钻井装备，采用上述钻井设计，解决了渭北油田长3储层浅层水平井钻井中存在的问题，实现了长3储层的有效开发。

To solve drilling difficulties in the Chang‐3 Reservoir of the Weibei Oilfield that displayed high friction and difficult well trajectory control caused by shallow burial depth and high ratio of horizontal departure and true vertical depth（Dep/TVD） ,the research on horizontal drilling technology with high ratio of Dep/TVD in shallow reservoir was conducted .Based on an analysis of the primary drilling technology difficulties in the oilfield ,a numerical simulation for friction and torque was made in different hole sizes . Three spudding well sections were adopted ,and φ215.9 mm drill bits were used to drill the last horizontal section .In order to ensure accurate landing and targeting ,a double build hole profile was adopted according to the geological characteristics of the Chang‐3 Reservoir .According to characteristics and drilling require‐ments of the formations drilled in the three sections ,the first section adopted a tapered bottomhole assem‐bly ,the second and the third spudding sections adopted inverted BHA that the heavy weight drill pipe was applied in the hole section with a deviation angle of 45° to 60° ,a potassium ammonium‐based polymer drill‐ing fluid was used and the fluid loss less than 5 mL in the horizontal section .To reduce drilling cost ,the existing drilling rig ZJ30 without a top drive was selected .Field practice shows that ,the conventional drill‐ing equipment and drilling technology mentioned above can be used to solve the drilling difficulties of shal‐low horizontal wells ,so as to achieve the effective the development for the Chang‐3 Reservoir of the Weibei Oilfield .