顺南超深水平井分段完井管柱优化设计方法

Optimization Design Method for Multistage Completion String of Shunnan Ultra-Deep Horizontal Well

针对塔中北坡顺南超深水平井的超高压、超高温特性及管柱设计矛盾突出问题,提出了一套用于超深水平井分段完井管柱的优化设计方法。对塔中北坡顺南某超深水平井的井筒压力、温度分布及油套管安全系数进行计算,并对完井管柱的尺寸、完井液密度和封隔器位置等参数进行优选,有针对性地制定了解决管柱设计难题的对策,完成管柱组合优化设计,得到了不同工况下的施工控制参数:在50 MPa平衡套压下,低挤酸液时最大泵压不得超过74 MPa;压裂排量为7 m^3/min时,预测泵压110 MPa;假设日产纯气20×10^4 m^3,预测油压53 MPa,不需平衡套压;关井时预测油压68 MPa,不需平衡套压;开采后期产能衰竭,纯气油压不低于14 MPa。基于优化完井管柱组合,对封隔器进行校核可知,各工况下悬挂封隔器和分段裸眼封隔器性能均满足设计要求。研究结果对类似完井管柱的优化设计有很好的借鉴作用。

To address the problem of ultra-high pressure ultra-high temperature and difficult completion string design in the ultra-deep horizontal wells in Shunnan in the north slope of Tazhong, a set of optimization design methods for ultra-deep horizontal well multistage completion string is proposed. The wellbore pressure, temperature distribution and production casing safety factor of an ultra-deep horizontal well in Shunnan are calculated. The parameters including the completion string size, the completion fluid density and the position of the packer are optimized. The countermeasures for address the design problem of the completion string are formulated in a targeted manner. The design of the completion string is optimized and the operation control parameters under different working conditions are obtained: under the pressure of 50 MPa balanced casing pressure, the maximum pump pressure should not exceed 74 MPa during low acid squeezing. When the fracturing displacement is 7 m 3/min, the predicted pump pressure is 110 MPa. Assuming daily gas production of 20×10 ^4 m ^3, the predicted tubing pressure is 53 MPa, presenting no need to balance the casing pressure. The production capacity is exhausted in the late development stage, and the pure gas tubing pressure should be no less than 14 MPa. Based on the optimized completion string, the packers are stress checked, and the performance of the liner hanger packer and the multistage open-hole packer under all working conditions meets the design requirements. The study could provide references for similar designs.