LD高温高压气井井身结构优化与适用性评价

LD区块储层超高温高压，压力窗口极窄，压力预测误差大，套管层次及下深优化的余地小，井下复杂频繁，优化井身结构降低井下复杂至关重要。考虑已钻超高温高压探井遇到的复杂情况、现有的地质认识，结合国内塔里木油田与川东北地区实钻经验，提出了LD高温高压气井井身结构优化方案，并建立了井身结构适用性评价方法。推荐的井身结构方案在不改变一开井眼尺寸的基础上，通过放大技术套管，预留了备用井眼，为下部薄弱层位预留风险应对空间，具有井下复杂的风险处置能力。对推荐的井身结构方案开展水力性能评价、扭矩极限校核、管柱下入可行性分析，结果显示该井身结构方案具有较优的适用性。为LD区块开发安全作业、降本增效提供了保障，具有较好的应用前景。

Wellbore Structure Optimization and Applicability Evaluation of LD High Temperature and High Pressure Gas Wells

The LD ultra-high temperature and high pressure reservoir has the characteristics of extremely narrow pressure window, large pressure prediction error and little room for casing layers and running depth optimization, which leads to higher risk of downhole complexity. It is very important to optimize the well bore structure and reduce the occurrence of downhole complexity. Considering the complicated situation of drilled ultra-high temperature and high pressure exploration wells and the existing geological conditions, combining the experiences of drlling in Tarim Oilfield, the optimized wellbore structure scheme of LD high temperature and high pressure gas well is recommended and the applicability evaluation process of wellbore structure is formed. On the basis of not changing the size of the first spud hole, the recommended wellbore structure scheme reserves risk response space for the lower weak layer by enlarging the technical casing size, and has the ability to deal with downhole complex risks. The hydraulic performance evaluation,torque limit check and feasibility analysis of pipe string running have been carried out for the recommended wellbore structure scheme and the results show that the wellbore structure scheme has better adaptability, which provides a guarantee for the safe operation, cost reduction and efficiency increase of the development of LD block, and has a good application prospect.