This paper documents attempts to automatically unload gas wells in the Western Sedimentary Basin at various depths and producing conditions. The results include production increases of 25 percent, with reduced operating costs. The criteria for application of this technology and a cost/benefit analysis are presented. This work is being incorporated in a large-scale project currently underway in Oklahoma, which will be discussed briefly as an example of integrating automation technology with expert systems to provide field-wide optimization of a major gas field.
In upstream oil and gas production, supervisory control and data acquisition (SCADA) systems assist operators by constant monitoring of entire fields. These systems will even telephone the operator in the middle of the night if a serious problem occurs. The operator certainly wants to be alerted when a problem occurs, but wellhead automation now has the capabilities of proactively averting problems, literally allowing the operator to sleep better at night.
For gas wells, the production of water causes many operational problems up to chronic loss of production. Operators combat water problems by blowing the well down, dropping soap sticks, stopcocking the well, or perhaps rocking the well if the problem is severe. If a well is in a remote area, the operator may not be able to attend the well often enough to avoid problems.
Automation equipment has been adapted to perform some of the routine operations. Wellhead equipment can now be set up to detect the presence of liquids in the wellbore and unload the well automatically. The equipment adjusts to changes in water production, adjusting the unloading times accordingly.
Advantages to automated unloading are numerous. Unloading the well regularly allows the liquids to be sent down the flowline, reducing venting of gas. The average amount of liquid in the well is reduced, increasing production. The operation is performed day or night when the well needs unloading, as opposed to when the operator is available. Wells in remote areas receive the attention they need constantly, without stressing the operator in times of severe weather. Venting to atmosphere is eliminated, reducing environmental problems. In economic terms, often the largest advantage is that the wells can be flowed up the casing, reducing friction pressure in the wellbore and increasing production.