钻井/完井液

分散沉降的重晶石：一种提高切割和拔出塞子和废弃作业性能和安全性的方法

进行一项基础研究以确认螯合剂在分散沉淀重晶石中的潜在用途，强调控制这一过程的因素的复杂性，并为未来旨在优化工业应用中的分散方法的研究提供坚实的基础。

223118_图.jpg
用于分散试验的筛分系统。
来源：论文 SPE 223118

沉降重晶石是油井建设和油井控制活动中的一项已知挑战。这种现象在油井废弃活动中的切割和拉动作业中带来了操作和安全挑战。本文介绍了一种缓解这些挑战的新方法，即使用螯合剂（特别是石油工业中常用于溶解重晶石垢的乙二胺四乙酸 (EDTA) 和二乙烯三胺五乙酸 (DTPA)）分散沉降的重晶石颗粒。

进行了实验室测试，以评估这两种螯合剂在不同浓度、重量体积比、pH 值和持续时间下的效果。本次测试使用了从封堵和废弃作业中回收的沉降重晶石样品。

最初，目视检查表明螯合剂在将沉淀的重晶石材料破碎成较小颗粒方面发挥了一定作用。随后，使用一系列筛子评估粒度分布并量化分散度，结果显示颗粒分散度的增加与螯合剂浓度和重量体积比的增加相关。

与溶解水垢的实验相反，沉降重晶石的分散性表现在广泛的 pH 范围内。此外，随着时间的推移，分散性最初有所增加，而加入氯化钾等活化剂对整体分散过程没有明显的影响。

这项研究表明，通过使用油田中常用的传统螯合剂（如 EDTA 和 DTPA）有可能解决重晶石沉降问题。它提出了优化其解决重晶石沉降问题的方法。此外，该研究提出了 EDTA 和 DTPA 系列螯合剂在分散沉降重晶石方面的更广泛适用性，从而提高了螯合剂的使用性能并增强了油田的安全性。

本摘要摘自 H. Yousuf、M. Khalifeh 和 A. Saasen（斯塔万格大学 IEP）、L. Gasparotto（北里约格兰德联邦大学）和 R. Godsoy（Equinor）撰写的论文 SPE 223118。该论文已通过同行评审，可在 OnePetro 上的 SPE 期刊上作为开放获取获取。

原文链接/JPT
Drilling/completion fluids

Dispersing Settled Barite: An Approach To Improve Performance and Safety of Cut and Pull in Plug and Abandonment Operations

A fundamental research study is conducted to confirm the potential usefulness of chelating agents in dispersing settled barite, emphasize the complex nature of the factors that control this process, and provide a solid basis for future studies aimed at optimizing dispersion methods in industrial applications.

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Sieve system used for dispersion test.
Source: Paper SPE 223118

Settled barite is a known challenge in well construction and well control activities. This phenomenon creates operational and safety challenges during cut and pull operations in well abandonment activities. This paper introduces a novel approach to mitigate these challenges by dispersing settled barite particles using chelating agents, specifically ethylenediaminetetraacetic acid (EDTA) and diethylenetriamine pentaacetic acid (DTPA), commonly used in the oil industry to dissolve barite scales.

Laboratory tests were conducted to assess the effect of these two chelating agents across varying concentrations, weight-to-volume ratios, pH levels, and durations. Settled barite samples retrieved from a plug and abandonment operation were used in this test.

Initially, visual inspection suggested some action of chelating agents in fragmenting settled barite materials into smaller particles. Afterward, a sequence of sieves was used to assess the particle-size distribution and quantify the dispersion, revealing an increase in particle dispersion correlating with higher concentrations of chelating agents and weight-to-volume ratios.

Contrary to scale-dissolving experiments, the dispersion of settled barite manifests across a broad pH spectrum. Furthermore, an initial increase in dispersion was observed over time, while the introduction of an activator such as potassium chloride displayed no discernible effect on the overall dispersion process.

This work shows the potential resolution of settled barite issues through the application of conventional chelating agents, such as EDTA and DTPA, commonly used within the oil field. It suggests methodologies for optimizing their performance in addressing barite settlement concerns. In addition, the study proposes the broader applicability of chelators within the EDTA and DTPA family for dispersing settled barite, thereby enhancing performance and augmenting oilfield safety in chelator use.

This abstract is taken from paper SPE 223118 by H. Yousuf, M. Khalifeh, and A. Saasen, IEP, University of Stavanger; L. Gasparotto, Universidade Federal do Rio Grande do Norte; and R. Godøy, Equinor. The paper has been peer reviewed and is available as Open Access in SPE Journal on OnePetro.