SOCIETY
OF PETROLEUM ENGINEERS
Mid-Continent Section, Tulsa, Oklahoma
Abstracts courtesy of Ken Saveth, ksaveth@juno.com
Progressing Cavity Pumps in Open Hole - Jim Tupman: Kudu Industries, Inc.
Some of the subjects to be discussed in this presentation are:
Inherent Risks & Challenges
Field History
Trial Candidates - Torque Predictions
Downhole Equipment Description
Pre-Installation Preparations
Proper Installation & Running Procedure
Actual Performance
INHERENT RISKS & CHALLENGES
The first thing to consider is if there is there really a reason to take the risk. The integrity of the wellbore (i.e. is the formation hard rock, is there scale concerns, is it an unconsolidated sand, etc.) is also critical. Being an open hole completion, is the open hole section in gauge? This is to see whether the selected PCP will fit in the well. In an open hole completion, the repercussions for tubing backoff are high so this also needs to be considered as one of the possible risks.
FIELD HISTORY & TRIAL CANDIDATES
To get an idea as to the history of the field utilized in this study, a few parameters were looked at. The EMSU field is operated by Chevron USA. The formation is the Grayburg with a pay zone from 3700’ - 4000’ with the field was discovered/developed in the 1920’s - 1940’s. A majority of the completions are open hole. Currently, the field is waterflooded which was initiated in the late 1980’s
So far, the response is localized. With increasing volumes & rising fluid levels, the current beam units (640’s & 912’s) are overloaded. For these reasons, PC pumps were a logical lifting method.
Two candidates were selected. The first candidate well was the EMSU #399. This well had the following specifications:
5 1/2" Casing, 4 3/4" OH
Required production of 800 BPD
Pump Setting Depth of 3967’
KUDU 200 TP1200 with a torque of 439 lbf.ft.
The second candidate well was the EMSU #216 which had the following specifications:
7" casing, 6 1/28" OH
Required production of 1400 BPD
Pump Setting Depth of 3951’
KUDU 400 TP1350 with a torque of 913 lbf.ft.
Other downhole equipment included a Halliburton R-4 OH Packer (anchor),a perforated sub, centralizer/stabilizer, production tubing with Cam Lock connections, & an anti-torque anchor.
In actual performance, the EMSU #399 was tested from June through August 1996. In August, the unit went down due to a polished rod coupling failure. Upon pulling out of the hole, the R-4 Packer was not set. As for the bottom hole pump, there was no damage. Mechanically, this test was a success however; economically it was a failure. The test in the EMSU #216 was initiated on October 10, 1996 & is still continuing.
PRE-INSTALLATION PREPARATIONS
There are a few preparations that need to be done prior to installing a PCP system in an open hole completion. The most important is the proper selection of the candidate well. If need be, a fluid sample needs to be taken in order to test the reservoir fluids with the available PCP elastomers. The complete well conditions is critical in selecting the proper pump size. Without it, an accurate selection cannot be made. A record of the caliper log is also important in order to know what the I.D. of the OH area is. The centralizers/stabilizers need to be machined to the proper size & the proper tubing Cam-Lock requirements need to be set. Any torque or tension anchors need to be of quality construction & properly installed. Be sure to verify proper tubing & sucker rod make-up. Whenever possible, install amperage chart recorders to provide diagnostic capability. If rod guides are to be used, be sure to use adequate quality & quantity of guides to minimize rod/tubing wear. When actually running the pump, ensure proper rotor space-out for actual operating conditions as well as proper drive head installation.
Running progressing cavity pumps in OH completions has & can be done successfully providing all the proper preparations have been made & adequate care has been taken to ensure good information is obtained.
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