成熟田

油井延寿和改造利用的剩余套管寿命预测

多维维纳过程方法预测套管剩余使用寿命，从而实现安全、经济高效的油井寿命延长和改造，用于二氧化碳注入、碳捕获与封存和地热应用。

油田里，石油工人正在工作。
资料来源：郑在书如/盖蒂图片社。

多年来，提高采油率技术的进步使得许多油田得以延长其在开发运营阶段规划的预期寿命。然而，这些成熟油田中的大多数油井的设计寿命仅限于油田的规划寿命。此外，由于钻探新井需要高额的资本支出，因此，以最小的钻井成本延长现有油井的寿命，从而延长产量，引起了人们的关注。

延长油井寿命 (LE) 不仅可以将油井从生产井重新用于注入井，还可以用于其他新兴技术，例如碳捕获和储存中的二氧化碳 ( CO₂ ) 注入以及地热能生产。

为确保作业安全，井筒完整性应是油井长期封堵和改造决策中的首要考虑因素。套管是确保长期封堵期间油井完整性的关键屏障部件。

本文首先提出了一种多维维纳过程方法，用于预测整串套管的剩余使用寿命（RUL）。该方法考虑了运行条件（OC）的变化，例如井完整性事故和维护措施，因为这些因素最终决定了套管的劣化速率。该方法尤其适用于评估和预测老旧油井的井完整性，因为这类油井的数据和记录通常有限，无法可靠地应用数据驱动模型。

第二部分展示了如何利用剩余使用寿命（RUL）分析，结合不同未来运行条件和用途的套管载荷分析，为油井寿命延长（LE）决策提供依据。案例研究将这些方法应用于一口老旧注入井，并利用套管腐蚀测井数据进行分析。该井曾发生油管泄漏，导致生产套管内部腐蚀。结果表明，该井具有寿命延长的潜力，但前提是必须及时修复，并采用特定的、与温度相关的二氧化碳注入运行条件，且套管坍塌是高风险失效模式。

本摘要摘自挪威科技大学的D. Semwogerere和J. Vatn、巴西石油公司的D. Colombo以及挪威科技大学的S. Sangesland和A. Pavlov撰写的SPE 232799号论文。该论文已通过同行评审，并以开放获取的形式发表在OnePetro平台的SPE Journal上。

原文链接/JPT
Mature fields

Remaining Casing Life Prediction for Well Life Extension and Repurposing

A multidimensional Wiener process approach predicts casing remaining useful life, enabling safe, cost-effective well life extension and repurposing for carbon dioxide injection, CCS, and geothermal applications.

oil field, the oil workers are working
Source: Zheng Zaishuru/Getty Images.

Advances in improved oil recovery methods over the years have allowed many fields to exist beyond their originally planned lifetime, determined at the plan for development and operation stage. The majority of the wells in these mature fields, however, are designed to last only for the planned life of the field. In addition, because drilling new wells requires high capital expenditure, the option of extending the life of existing wells to prolong production at minimal drilling expenditure has garnered interest.

Well life extension (LE) can allow for repurposing wells not only from producers to injectors but for other emerging technologies, such as carbon dioxide (CO2) injection in carbon capture and storage and for geothermal energy production.

For safe operations, well integrity should be the major consideration in well LE and repurposing decisions. Casing is a vital well barrier component in ensuring well integrity during the LE period.

This work first presents a multidimensional Wiener process methodology to predict the remaining useful life (RUL) of the entire casing string, taking into consideration changes in operating conditions (OCs), such as well integrity incidents and maintenance actions, as these ultimately determine the casing degradation rate. The methodology is especially useful for assessing and predicting well integrity of legacy wells, from which data and records are usually limited and data-driven models cannot be applied with confidence.

The second part shows how RUL analysis can be used for well LE decisions considering casing load analysis for different future OCs and purposes. A case study applies these methodologies on a legacy injection well using a casing corrosion log. The well had experienced a tubing leak that led to corrosion inside the production casing. The results show that the well has LE potential but only under timely repair and specific temperature-dependent OCs for CO2 injection with casing collapse as the high-risk failure mode.

This abstract is taken from paper SPE 232799 by D. Semwogerere and J. Vatn, Norwegian University of Science and Technology; D. Colombo, Petrobras; and S. Sangesland and A. Pavlov, Norwegian University of Science and Technology. The paper has been peer reviewed and is available as Open Access in SPE Journal on OnePetro.