Artificial Lift

Data from fluid level, dynamometer, pressure, and motor power measurements were acquired by a standalone programmable monitoring system that uses internet and cellphone communication with the Cloud for remote monitoring of well performance. The paper presents results from the tests that lasted several weeks, beginning with well pump down, just after new pump installation and continuing during normal production operation.  The performance of the well was monitored in detail and additional measurements were acquired as needed based on the real time performance of the pumping system. 

Corrosion and fatigue are the primary causes of sucker rod failures in artificial lift systems. Harsh well fluid conditions lead to material loss and detrimental pitting which then lead to initiation points for fatigue fractures to occur. Production in aggressive service environments with higher acid gas concentrations associated with increased levels of hydrogen sulfide (H2S) and carbon dioxide (CO2) requires good fatigue life associated with corrosion resistance.

In reciprocating rod lift, the On-Off tool is a device that allows the operator to easily disconnect the rod string from the pump. This is especially advantageous in an oversized tubing pump application or when used in conjunction with an insert pump in the case of the pump becoming stuck. It is important for the end user to understand the cause of some typical On-Off tool failure modes, which will allow for a better understanding of proper tool selection. 

This paper Introduces a successful new chemical technology applied in ESP, SRP and GLV systems. The technology uses a microencapsulation method which creates a solid chemical treatment conformed by a specific chemical formulation designed especially for each case, this solid component is introduced in a Chemical Screen body and then is installed at the end of tubing. The new downhole treatment technology was designed and successfully applied in 25 wells in the Permian Basin to control scale and corrosion, achieving run times of more than 365 days.

Different types of forces NOT accounted for by the wave equation are 1) mechanical friction, 2) piston force acting on the polished rod due to tubing back pressure and 3) true vertical rod weight.  Mechanical friction will be discussed from 1) over-tight stuffing box, 2) down hole sticking due to a severe dogleg in the wellbore profile and 3) friction from paraffin along a section of the rod string.

Comitt Well Solutions’ Excite system is an innovative down hole tool specially designed for pin-point refracturing and re-stimulation applications. The system is fully hydraulic and can accommodate any space-out between its isolation packers. The patented technology treats each cluster in the wellbore in a single trip and allows treatment of both existing and newly added stages.

Rod pumps are not the ideal system of lift when it comes to handling gas. We can only do so much with the configuration downhole especially for wells with open hole completions. Despite the limited options, we are coming to find that we can do better by manipulating parameters at the surface. Historically, we have manipulated back pressure on the tubing in order to control when gas breaks out of solution in the tubing. Now we are finding, on certain well types, that manipulating back pressure on the casing in order to keep gas in solution through the pump is proving to be successful.

There are many challenges associated with sucker rod lift in deviated wellbores that can lead to high failure rates and lost production. Tubing failures are amongst the costliest workovers and are often a result of metal to metal contact between the rod coupling and the tubing. Evaluating tubing on-site using both gamma and electromagnetic inspection allows for proper design optimization before returning to production.

Oasis Petroleum has ~1000 rod pump wells in the Bakken producing from 8000’ - 10,000’. A focused effort has been made over the past few years to reduce the failure rate from ~1.0 failures/well/year to the current rate of .68 failures/well/year. This has been the result of a holistic approach which has encompassed improvements in rod design, surveillance, training, development of Standard Operating Procedures and Best Practices, trialing new technology and POC optimization. This paper will document some of the successes and failures during this journey.

Rod lift design methods remain overwhelmingly unchanged since the mid-20th century. Meanwhile, drilling and completion technology has undergone a dramatic transformation. The innovation gap between the two technologies and low-flow artificial lift has resulted in the need for improved design and workflow methods to more effectively operate an unconventional well throughout its lifecycle. New design and workflow processes have been developed that improve upon today’s common practices through the observation of unconventional well characteristics and root cause analysis of equipment failure.