1、PAGE PAGE 3DDI定向井難度系數1、AHD 沿井眼的位移 AHD or Along Hole Departure is the sum of the displacement between individual survey stations. 沿井眼的位移是各個測量點位移的總和。 It is a measure of true departure in a well essentially stretching a well straight, like a string (azimuth only, not inclination). 它是一口井拉伸為直線的真實位移的測量，就像

2、一條線（僅是方位而不是井斜的變化）。 So a well with no azimuth change will have a surface to TD departure equal to the AHD. 因此一口井如果沒有方位的變化將是一個面達到總井深，其位移等于沿井眼的位移。 A well with turn in it will have a greater AHD compared to the surface to TD departure. 一口彎曲的井所產生的沿井眼位移相對面到TD的位移來說要大些。 This can be derived simply by using P

3、ythagoras to calculate the distance between the survey stations and then summing them. 這可以用勾股定理來計算各點的位移，并匯總。 y = northing, x= easting 2、ERD Ratio 水垂比Extended Reach Drilling ratio: This is the AHD to TVD ratio. Essentially it gives a ratio of the total displacement (AHD) to the vertical depth. It can

4、 be considered as a measure of the Drilling Envelope in ER Horizontal Drilling. 水垂比： 大位移井的水垂比：是沿井眼位移與垂深之比。本質上，它給出了一個總位移與垂深之比。它可以被認為是大位移水平井的一種量度標準。 3、Tortuosity 彎曲度 This is the cumulative dogleg planned into the well or for a drilled well, the total dogleg change (positive addition) even when it is a

5、 drop. 這是對于計劃鉆一口井或已鉆井的總狗腿度，甚至當井眼降斜時總的狗腿度變化（正的增加） 。 Typically, as the length of the wellpath increases, so too will the tortuosity. Actual drilled tortuosity is often higher than the planned well tortuosity, especially in wells with long tangent sections, since the DLS in the tangent is often difficu

6、lt to maintain at zero. 一般來說，當井眼軌跡長度增加，彎曲度也增加。實際鉆的彎曲度通常比計劃的彎曲度要高，特別是長穩斜段，因為在穩斜段的狗腿度很難保持在0度。 From a completions perspective, it is recommended that the overall well tortuosity be maintained below 0.8 degrees/100 ft in order to minimize the risk of the completion assembly hanging up before getting to

7、bottom. 從一個總的觀點來看，接薦的井眼總彎曲度應保持在0.8度/100英尺以下，以減少下入井底前整個管柱遇阻下不到底的風險。 Increasing tortuosity (in this case, localized hole tortuosity) may also lead to downhole drilling tools being subjected to higher shocks and thus increase the potential for failure. 增加的彎曲度（在這種情況下，局部的井眼彎曲度）將同樣導致井下鉆井工具遭受較高的振動，而增加失效的風險

8、。 4、DDI 定向鉆井難度系數 Directional Difficulty Index is high level performance measure used to benchmark drilling performance. It becomes especially useful when used as an evaluation method on complex well geometries. It provides a first pass evaluation of the relative difficulty to be encountered in drilling a directional well. 定向鉆井難度系數： 定向鉆井系數是用于評定鉆井完成情況的高水平方式。當用作復雜幾何井眼的評價方式時就變得特別有用。它提供了在鉆定向井時所遇到的相對難度的評價。 The following guidelines can be used to classify wells based on DDI: 基于DDI，以下列準則可用于定向井的分類： DDI 6 Relatively short, simple wells or simple profiles with low tortuosity DDI6.8，深定向井伴隨高難度的曲折度軌跡。難度大。