Predicting the Amount of Lost Circulation While Drilling Using Artificial Neural Networks: An Example of Southern Iraq Oil Fields

Abstract

Lost circulation is a serious problem that imposes some extra costs to petroleum and gas exploration operations. Substantial technical and economic benefits can be accomplished if the severity and frequency of mud loss are considered during the well planning procedure. This will lead to preventing the occurrence of losses by using treatments/solutions that are applied before entering lost circulation zones. In the present work, new models were developed to predict the amount of lost circulation using artificial neural networks (ANNs). This model was implemented to obtain a deeper understanding of the relations between the losses rate and the controllable drilling variables (i.e., rate of penetration [ROP], flow rate [FR], circulation pressure [CP], weight on bit [WOB], and rotation per minute [RPM]). The losses rate was found to be sensitive to high ROP, FR, and CP, such that increasing these parameters continuously increase the amount of lost circulation. While a slight rise in the losses rate was observed at high WOB and RPM. The proposed ANNs model was used to predict the losses rate for two wells, and comparison plot (actual amount of lost circulation versus predicted) was introduced as a function of depth. An accurate and early prediction of lost circulation has been of great importance to avoid the risks associated with this problem's occurrence.

Nanomaterial-Based Drilling Fluids for Exploitation of Unconventional Reservoirs: A Review

“…Ten wells that were to be completed with liner and perforation in underbalanced drilling operations used HPHT OBDF as drilling fluid at 8 1 2 " section. Similarly, two other open hole and screen wells used carboxylic acids and the acidity of the OH bond (Cs/K-COOH) as drilling fluid.…”

“…This solids-free drilling fluid has many advantages including reduction of the risk of the formation damage. HPHT OBDF invert emulsion was chosen as drilling fluid to at 12 1 4 " sections to encounter washout that occurred in the shale section when drilling with Cs/K-COOH. The HPHT OBDF invert emulsion was chosen as the best option for high angle reservoir sections.…”

“…One of the wells, named 'Well I', was the first well to be drilled and completed (with screens) using the invert emulsion HPHT OBDF with MBS. A 290 m long section with approximately 35 degree inclination of 8 1 2 " was drilled using one bit run, where it was the fastest 8 1 2 " section drilled on Kristin field. Well J was drilled soon after Well I was completed.…”

“…The interval was completed with less than half of the programmed dilution rate using the solid removal equipment. The same drilling fluid system was used for 12 1 4 " section. The temperature at bottom hole was expected to reach 482 K.…”

“…Every drilling activity requires appropriate drilling fluids program, where they are used extensively across the globe. Different types of drilling fluids are available within the market with differing performances designed to fit selective purposes, in addition to varied costs of fluid and environmental impacts [1,2]. The consumption of drilling fluids and additives depends directly on drilling fluid activities that are carried out globally.…”