Overview

This project was under a relatively tight scheduling window with rig up planned for February 17, 2021. When the FNL-1 debris sample arrived at the Coastal Chemical Co., LLC (CCC) Lab ( Jan 29, 2021) the N-SPEC 105 was already ordered, N-SPEC equipment was being mobilized and field personnel were being allocated for pre-job quarantine requirements.

Large Midstream Company Requires Chemical Cleaning Without Debris Sample

N-SPEC Pipeline Services, a Division of Coastal Chemical, was approached by a large midstream company to help develop a chemical cleaning protocol for a pipeline in British Columbia. The pipeline is 30-inch OD and 44.5 miles of very dry gas service. The client wanted to clean the pipeline in preparation for an EMAT (Electro-Magnetic Acoustic Transducer) tool run. EMAT tools provide very detailed information on pipeline internal conditions but they are sensitive and prone to sensor fouling from debris accumulation. Consequently, the client was keen on cleaning the pipeline as close to bare metal as possible. The client requested a preliminary cleaning proposal from N-SPEC, however the challenge for N-SPEC was there were no internal debris samples available for solids identification and chemical product testing.

Without the benefit of a pipeline sample, the N‑SPEC Project Management team referenced years of successful pipeline cleaning projects to generate a chemical procedure of four cleaning runs utilizing the N‑SPEC 105 pipeline cleaner mixed with diesel.

The procedure called for a 7,000gls of N-SPEC 105 chemical and diesel appropriate for cleaning the entirety of the length of the pipeline over 4 (1,750gls per) chemical cleaning runs. The chemical and diesel was to be injected at the pig launcher site and captured at the pig receiver site. This procedure was approved by the client and the paperwork for importing the products from the US to Canada began.

Based on the sensitivity of the EMAT tool and the need to make certain the pipeline was prepared after the cleaning phase, the client contracted with Pipepipelines2Data to assess the amount and location of the debris in the pipeline. A P2D tool run on the pipeline was performed Jan 20, the pipeline was mapped, the debris was measured and located in the pipeline. The P2D pig run also generated a solids sample from the pig receiver. A P2D technician arranged for the sample to be sent to the CCC Lab in Broussard, LA for analysis.

Figure 1 – Original FNL-1 Sample

Testing Results

PRODUCTRESULT
15% N-SPEC-105 / 85% DieselNon-soluble, Non-dispersible
PowderSolv 401Moderately soluble, Moderately dispersible
PowderSolv 211Moderately soluble, Moderately dispersible
PowderSolv 507Moderately soluble, Highly dispersible
PowderSolv 508Highly soluble, Highly dispersible
PowderSolv 175Moderately soluble, Moderately dispersible
Figure 2 – Fifteen Minutes of soaking with no agitation – samples were then shaken up
Figure 3 – 60 minutes after agitation

Immediately N-SPEC Project Management recognized from the product solvency test that the original cleaning chemical recommendation would not be as effective as necessary to prepare FNL-1 for an EMAT run because the debris in the pipeline had zero affinity for the original cleaning chemical (N-SPEC 105) and its chosen diluent (diesel).

PS-211, PS-507, PS-508, PS-175 were eliminated from consideration because of the nature of the dry gas pipeline and dewpoint control concerns on FNL-1.

N-SPEC PMs agreed that PowderSolv 401 was the correct choice for this project. PowderSolv 401 is a patented, water based, neutral pH Iron Sulfide dissolver that is blended with a surfactant (for pipeline cleaning) and Ethylene Glycol. The PS-401 reaction with Iron compounds in the pipeline is a neutral reaction, that does not create H2S or any other hazardous by-products.

Discussing Solutions

N-SPEC PMs requested a last-minute meeting with representatives from the client and P2D to discuss the lab testing results and the necessary product recommendation pivot from N-SPEC 105 and diesel to PowderSolv 401. This meeting was scheduled for February 3, which was 17 days before the project was set to commence.

The February 3 meeting was held, the client was very receptive to the fit for purpose concept of changing the chemical cleaning procedure and the reasoning and data behind the changes.

During the discussion of changing the chemical, it was also brought up that P2D’s debris mapping showed the overwhelming majority of the debris in the pipeline was over the last seven miles of the run. The client asked would N-SPEC consider injecting the PS-401 just upstream of the beginning of the debris field to maximize the PS-401’s cleaning impact on the worst part of the pipeline?

N-SPEC PMs agreed and adjusted the PS-401 injection point from the inlet of the pipeline at the pig launcher to a valve on a riser approximately 7.5 miles (at KM59) from the end of the run. This change also cut the volume recommended of PS-401 by 2200gls, saving the client a significant amount of money in the process.