A Ten-Year Review of Corrosion Mitigation in the Hastings Field
Authors: Gaither O.D. 
Published: December 2007

In the early 1950's the problem of corrosion in oil wells producing water became extremely critical in the Hastings field. Wells producing with high water percentages and subsequently high water rates were capable of completely destroying a new string of tubing within 18 months. A study was initiated in early 1952 to determine the cause and possible methods of corrosion mitigation. The study revealed that a definite correlation existed between tubing holes and expensive casing-hole repairs. The comparative effectiveness between chemical inhibitors and coated tubing was determined from test installations during the evaluation period from 1952 to 1954.An economic analysis of the mitigation methods as compared with no mitigation and tubing replacement lead to the conclusion that installation of plastic-coated tubing was the most desirable and economical method of handling the problem. This case history reviews the factors, influencing the decision to install coated tubing and summarizes the results of the program after 10 years' producing history. Prices, cost figures and chemical volume requirements presented in this paper are those historically available from 1954 field records. Similarly the paper does not compare the more recent inhibition procedures or improved chemicals and reduced chemical prices, since these choices were not available when the decision to install coated tubing was made. Any economic analysis for current evaluations should consider inhibitor squeeze techniques and solid inhibitors, as well as reduced chemical costs due to improved chemicals and technology.

Introduction

Each year American industry spends millions of dollars in the fight against Corrosion. The oil industry is one of the major participants in the battle, and the fight is extremely widespread. Fronts range from protecting offshore installations to onshore installations involving problems of protecting pipe lines and well casings from earth currents to the relatively simple problem of providing suitable coatings for the prevention of atmospheric corrosion. The oil industry is unique in one respect, in that a great portion of its investment is in wells which have little if any salvage value or utility, except for their primary purpose of producing oil and gas. Quite obviously, the multi-million dollar investment in wells must be protected, or replacement wells will be required in long-life fields. The high cost of replacement wells definitely justifies the considerable effort and expense necessary for well corrosion mitigation. Early in 1950, Pan American Petroleum (then Stanolind Oil and Gas Co.) was confronted with well corrosion in the prolific Hastings field. Pan American's investment was in 477 wells, and the average well life was conservatively estimated to be in excess of 50 years. The costs for replacement wells at that time far exceeded the original well costs in the discovery and development period from 1935 to 1937. Wells producing with high water-oil ratios were severely corrosive, and in some instances were capable of destroying a string of new tubing within 18 to 24 months. Holes in the casing were often found opposite holes in the tubing, which compounded the problem and spurred efforts to find a successful mitigation program. This paper presents the problem, solutions and the relative economics of the mitigation program at Hastings, and reviews the application after 10 years of operating history.

Location and General Field Description

The Hastings field is located midway between the towns of Pearland and Alvin, Tex., and about 8 miles south of the city limits of Houston. U. S. Highway 35 bisects the field, appropriately named Hastings East and Hastings West. The field is classified as a faulted anticlinal structure probably under deep-seated domal influence. The production is 30 to 31 API gravity sweet oil from the Frio section of Oligocene age. Average well depth is 6,000 ft and temperatures and pressures are normal. The field is under hydraulic control, and large volumes of approximately 100,000-ppm NaC1 salt water are produced from flank wells.

JPT

P. 1045ˆ