High strength-to-weight aluminum alloy drill pipe is a powerful torque and drag reduction tool for horizontal and deviated wells. Aluminum drill pipe (ADP) enables achieving strength-to-weigh ratios equivalent to 160 ksi yield-strength steels and is typically 30-50 percent lighter than similarly sized steel drill pipe (SDP).
高强度-重量比铝合金钻杆是水平井和斜井中能够承受强大扭矩，并减小阻摩的工具。铝钻杆(铝钻杆ADP)能够达到与屈服强度为160 ksi的钢钻杆相当的强度-重量比，而且通常情况下，铝钻杆要比同样大小的轻质钢钻杆(标准钢钻杆SDP)轻30%-50%。
Penn Virginia Corp. tested ADP in complex and highly deviated well profiles on a four-well pad in the Eagle Ford Shale–the first such application of ADP in a horizontal shale play. A “mixed” drill string design was used in three of the four extended-reach wells to drill the curve and laterals sections with ADP, while drilling the vertical sections with standard SDP. The drill string for the other well consisted of only SDP.
佩恩弗吉尼亚公司在Eagle Ford鹰福特页岩区的一个四口井的井场的复杂井剖面的大斜度井钻进中测试了铝钻杆铝钻杆ADP，这是在页岩区块的水平井钻进中首次应用铝钻杆铝钻杆ADP。在四口井中的三口大位移井的曲线和水平井段部分，使用了“混合”钻柱设计进行钻探，而钻进垂直井段时，则使用标准的钢钻杆标准钢钻杆SDP。另一口井钻进使用的钻柱只有钢钻杆标准钢钻杆SDP组成。
All four wells were designed with 7,000-foot lateral sections and utilized steerable mud motors. The wells are spaced 15 feet apart at the surface, and the typical lateral separation was 400-600 feet. The wells drilled with the ADP string had significantly improved rates of penetration and reduced torque compared to the well drilled with the SDP-only string using the same bottom-hole assembly (BHA) and bit.
所有四个井设计中都包含了7000英尺的水平井段，并使用导向泥浆马达。地面的井口间距为15英尺，而水平段间隔是400-600英尺。在使用相同的井下钻具组合(BHA)和钻头的条件下，与只使用标准的钢钻杆标准钢钻杆SDP相比，使用铝钻杆铝钻杆ADP进行钻井，显著提高了钻井速率。
表 钢钻杆和铝钻杆的特征
Given its light weight and strength-to-weight characteristics, ADP is well suited to long deviated or extended-reach wells, where reducing torque and drag loads is critical to drilling performance. The most common alloy used in manufacturing ADP has a maximum yield strength of 58,000 psi. While this is considerably lower than common steel pipe grades, the strength-to-weight ratio of ADP is equivalent to or better than steel pipe because of its lighter material density and greater buoyancy effect. ADP typically has a greater wall thickness than equivalent SDP, and is generally at least 40 percent lighter than equivalent-sized steel pipe.
由于其重量轻、强度-重量比大的特点，铝钻杆ADP非常适合于大斜度井和大位移井，能够减小扭矩和摩擦负载，这对于钻井性能至关重要。用于制造铝钻杆ADP的最常见合金的最大屈服强度是58000psi。虽然这个数值远远低于普通钢管等级，但是铝钻杆ADP的强度-重量比相当于或优于钢管，因为其材料密度更小和浮力效应较大。铝钻杆ADP的壁厚通常要大于同等的标准钢钻杆SDP，通常比相同尺寸的钢钻杆要轻至少40%。
Table 1 compares the mechanical properties of steel and aluminum grades in terms of density, Young’s modulus, yield and tensile strength, and the strength-to-weight ratio for 5-inch SDP and 5 7⁄8-inch ADP. The strength-to-weight ratio represents the ultimate length of a single size drill string that can be suspended without exceeding the yield strength of the material.
上表比较了某等级钢和铝的力学性能，包括了密度、杨氏模量、屈服强度和抗拉强度以及5英寸的标准钢钻杆SDP和5 7⁄8英寸的铝钻杆ADP的强度-重量比。强度-重量比代表了在不超过材料的屈服强度条件下，能够悬挂的单一尺寸钻柱的最终长度。
ADP’s high strength-to-weight ratio decreases torque and drag loads while maintaining resistance to axial, torsional and lateral loads. Since aluminum alloys are more flexible than steel, ADP buckles at a lower given compression than SDP. However, the increased flexibility is balanced by the fact that the lighter weight reduces contact side forces to minimize friction between the drill string and borehole. Minimizing friction decreases hook load and torque at the surface, and importantly, reduces compression while running an ADP string in the hole to potentially extend horizontal reach.
铝钻杆ADP的高强度-重量比减小了扭矩和摩擦负载，同时保持了对轴向阻力、扭转和横向负载承载能力。由于铝合金比钢更柔韧，与标准钢钻杆SDP相比，铝钻杆ADP可以在较低的压缩力下弯曲。然而,柔韧性的增加被更轻的重量造成接触侧向力的减小平衡掉了，接触侧向力能减少钻柱与井眼之间的摩擦。最大限度地减少摩擦降低了大钩载荷和扭矩，并且重要的是削弱了在钻大位移水平段时，铝钻杆ADP在井眼内的受压缩程度。
（来源：金正纵横翻译事业部编译）
