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Wellbore Hole Cleaning Calculator

IP.com Disclosure Number: IPCOM000240104D
Publication Date: 2015-Jan-02
Document File: 5 page(s) / 810K

Publishing Venue

The IP.com Prior Art Database

Abstract

When drilling oil wells, drill cuttings left in the wellbore produces great risk of damaging the drilling operation. It can jeopardize the well construction process to the extent of having to abandon the well without being able to use it as intended or even not at all. Currently, hole cleaning plots are produced from drilling data collected at the rig site. These plots give an indication whether the wellbore is sufficiently cleaned. There is no systematic, physical monitoring (weight or volume) of the drill cuttings being transported out of the well. This disclosure includes concepts to provide this service.

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When drilling oil wells, drill cuttings left in the wellbore produces great risk of damaging the drilling operation. It can jeopardize the well construction process to the extent of having to abandon the well without being able to use it as intended or even not at all.  Currently, hole cleaning plots are produced from drilling data collected at the rig site. These plots give an indication whether the wellbore is sufficiently cleaned. There is no systematic, physical monitoring (weight or volume) of the drill cuttings being transported out of the well.

Often, pneumatic silos include manual weight cells, but no data collection is performed (Figure 1). With inexpensive modification to the hardware valuable information can be derived.

Figure 1: Fluid circulatory system. Cuttings containers with weight cells (bottom left).

The proposed concept collects data related to the the drill cuttings/waste returned to the surface in order to gain a high-quality overview with respect to the wellbore cuttings load situation. This is accomplished by using input for densities, and volume & weight measurement logs.  A system is made up of drill cuttings tanks (minimum two silos) and a cuttings blower unit (dual parallel units (Figure 2)).

Figure 2: Cuttings handling system. Dual blowers (6) and cuttings containers (8).

The containers have weight cells installed on them. (Currently the cells are completely mechanical with no electronics in them. The container may be refitted with new weight cells that are electronic in design.)  The weight cells are connected to a data logging system. This is the data logging system that is the standard on drilling rigs. The data logger records the weight of the containers as they are filled with drill cuttings. The weight sensor unit is powered by a battery pack. Further, the battery powered weight sensor has sending/receiving capability.

Within the data logging system there are: records of the hole-volume of the drilling well; the total fluid volume, including the surface tank’s fluid volume is recorded.  The logging system calculates the time it takes the drill cuttings to be transported from the drill bit at the bottom of the well to the surface bell nipple.

By using silo weight measurement logs in combination with feeds from the data logs the theoretical volumes of rock cuttings and mud adhered to these cuttings can be calculated and provided continuously in real-time. The following real measurements and inputs will be used for this calculation:

ρc – Density of dry cuttings [kg/m3]

ρm – Density of mud on cuttings (adhesion) [kg/m3]

m" – Total mass of slurry [kg]

V" – Total volume of slurry [m3]

The ρc and ρm are variables that are manually set as constants (Or real-time dynamic values – see secondary targets) in the calculator by the rig site data logging engineer.

m" is the mass measurements of the cuttings/slurry being collected in the HCB tanks. This value comes from the modified electronic weight cell...